Transcript Vegetable Production Course

Vegetable Production
Introduction:
International rate of increase in the population is about 2% →2× each 3035 years which is now about 7 Billion. This means that:
Demand for food is increasing continuously while cultivated area or
involvement of the area (old and new) is not proper with the increase in
demand. Soil of very good properties is suitable for all sectors, so land
involved in agriculture is of very low characteristics →which will
increase the cost of cultivation. Total area is about 10% of the total.
Rich countries can either produce or import even if with high cost,
while poor or developing countries are suffering from Hunger situations
and malnutrition (in Asia, Africa, and Latin America).
Ref.: Table 1 and 2
The ratio of differences between rich and poor countries is about
20 years in life expectancies ‫ متوسط العمر‬.
This is because of variation in Energy requirement/person and
availability of fruits, vegetables (tubers, and or fruit nuts) which are
important sources of high nutritional requirements (minerals,
vitamins, proteins, starches, fats, and sugar), plus their importance
for crude fibers → commercial sector → which is not possible by
poor import or cultivate.
One of the main reasons for hunger is the unbalance situation
between number of people/km² area, and the arable land used for
production. For example, Asia had reached saturation per km² →
which means low food supply and low new land to be added,
because of increasing in the number of people.
Ref.: Table 1.1 and 1.2
Table1: Worldwide Production of Vegetables in 1993 in descending order.
Vegetable
Remarks
Production (1000MT)
Category 1:
Roots and tubers
Potato
Sweet potato
603,195
Staple Food
‫غذاء اساسي‬
Cassava
Yams
288,183
123,750
153,628
‫نوع بطاطا حلوة‬
28,126
Carrot
13,977
Artichoke
1,137
Category 2:
Vegetables, including melons
465,457
Tomato
70,623
Cabbage
40,414
Onions (dry)
29,961
Watermelons
Cucumber and gherkins
27,063
‫خيار ومخلل‬
18,326
Cantaloupes, and other melons
12,976
Green peppers
10,630
Eggplant
8,682
Pumpkin, squash, gourds
‫قرع‬
8,019
Garlic
7,624
Cauliflower
6,754
Green peas
4,602
Green beans
3,087
Table 2: Major Vegetable Producing Countries*.
Country
Production (1000MT)
China
125,509
India
60,010
United States
32,660
Turkey
18,468
Italy
13,035
CIS**
10,450
Spain
9,945
Egypt
7,474
Mexico
5,651
Nigeria
5,495
Total worldwide
465,457
* Vegetables (except roots and tubers) including carrot and melons.
** Commonwealth Independent States
Vegetable: A horticultural food crop, most grown as annuals
and few as perennials. Most are herbaceous, edible part is
either roots, stems, leaves, immature floral part, immature
seeds and immature or mature fruits, where the edible part
is highly rich with water which means the storage period is
relatively short even under proper conditions, and can be
eaten either raw or cooked.
Table 1.1. Some comparisons of developed and developing regions of the world.
Developed
Developing
Population
¼ of total
¾ of total
Population growth
1.5% per year
2-3% per year
Population in agriculture
13% (2-48%)
60% (17-93%)
Arable land per person
0.56ha(1.4 acre)
0.21ha(0.5acre)
Total/person/day
3370 cal
2280 cal
From plant sources
70%
90%
Total/person/day
99 g
58 g
From animal sources
56%
21%
Food energy:
Protein:
Source: FAO data (1979).
low food supply in developing countries could be also related to the use
of well fertilized land for export, activities. In addition to what mentioned
before.
Table 1.2. Food producing capacity of some countries in relation to
population density and arable land in 1979
Population density
(people/ km²)
Arable land a
(ha/person)
Australia
2
2.97
Canada
3
1.87
Argentina b
10
0.94
United States
24
0.86
U.S.S.R.
12
0.86
Congo b
5
0.44
Mexico b
35
0.32
India b
228
0.24
Italy
194
0.17
United Kingdom
233
0.12
Philippines b
166
0.11
China b
102
0.10
Egypt b
41
0.07
Netherlands
413
0.06
Japan
312
0.04
Country
Source: FAO data (1979).
a
Arable land:
(a) If greater than 0.8 ha/person, food supply usually
adequate; export of surplus.
(b) If in range of 0.4-0.8 ha/person, country is 80% to
completely self-sufficient. (c) If less than 0.4 ha/person,
diet high in food of plant origin; import of food for
adequate diet.
b
Developing nations.
Importance of Vegetable
The intake of proper nutrients is necessary for well being.
Proper food means different kinds of food with proper balance and
optimal amounts.
The required amount of nutrients can vary with sex, age, size of the body,
activity and environmental conditions.
The term under nourished means lack or inadequate caloric intake.
The term malnourished means lack of minimum daily intake of proper
food that including essential amino acids, vitamins, minerals and others.
Both malnourished and undernourished can lead to diseases as
marasmus disease, also it can increase susceptibility to infections and
diseases, stunting of child’s growth even physical or mental →so it leads
to reduction in intelligence level.
Importance of food components:
Ref.: Table 3
1) Water: for dissolving minerals, maintain the osmotic balance in
cells and drive out the metabolic waste. Daily intake is 1100ml from
food and 1100ml from drinks and 250ml from metabolic water =
2450ml.
Daily output of water is 1350ml as wastes and 1100ml as
evaporation, and losses from skin and lungs, so the total daily
output is 2450ml.
- Metabolic water can be derived from carbohydrates (CHO),
proteins, and fats, where:
1g of starch→ 0.6g of H2O
1g of protein→ 0.41g of H2O can be obtained from vegetables
1g of fats→1.07g of H2O
2) Energy: all foods released energy as they are broken in the body. Man
needs about 2400-2500 kcal/day, where:
1g of CHO→4kcal as metabolic energy
1g of Fats→9kcal as metabolic energy
1g of Protein→4kcal as metabolic
energy
Can be obtained from
vegetables
3) Carbohydrates (CHO): main CHO compounds in plants
are starch, sugar (sucrose, glucose, fructose), for
example, sun flower and onion are rich in fructose.
4) Lipids: fats and oils: adequate diets should have
almost 15% of total calories derived from lipids. Fats of
vegetables are generally oils while those of animal are
solids. Vegetable fats are of less cholesterol in the blood.
Also blood pressure and heart diseases are related to
excess intake of fats (animal fats).
5) Proteins and amino acids: for building of body and enzymes
formation which carry out the body functions.
The 8 essential amino acids are not synthesized by body cells,
so they are taken from food (plant and animal).
-Protein quality: present of amino acids in proper proportion so as
to be utilized effectively essential ‫ألن غياب واحد يمنع تكوين األخر‬
- Net protein utilization: % of amino acids ingested as protein and
retained in the body as protein. Vegetables show 50-70% ‫متوسطه‬
-Protein efficiency ratio: weight gained/unit of protein fed which is
for vegetables =2.0
Protein malnutrition can cause kwashiorkor = nutritional disorder
cause brain damage for ages from 6months-6years old.
Ref.: =Tables 4.2+4.3
6) Vitamins: they are potent organic substances, need for normal
body function.
Ref.: Table 4
a. Fat-soluble vitamins: that can be stored by body.
 Vitamin A: which is essential for vision in dim light and it’s
deficiency cause abnormal dry skin. Highly found in green
plants.
 Vitamin E: which acts as antioxidant, it’s deficiency affects
on the reproductive mechanism, but it's low in vegetables.
 Vitamin K: which is important in coagulation of blood,
found in fresh dark vegetables as spinach.
Daily intakes of vegetables is greater than animals
b. Water-soluble vitamin: can’t be stored by body in a significant
amount, so we need continuous food sources.
Vitamin B1 (Thiamine): prevents Beriberi ‫ضعف‬, cofactor in CHO
metabolism. It’s deficiency prevents normal metabolism of pyruvic
acid that come from CHO metabolism → brain and nerve which
depends on CHO = as a source of energy will be affected
negatively. Vegetables are good sources of B1.
Vitamin B2 (Riboflavin): it is a part of enzyme system to convert
the food to chemical energy. Leafy vegetables are good sources
even rich.
Vitamin C (Ascorbic acid): prevents scurvy ‫اسسعبرطو‬
‫توور الثةو = معر‬
‫ونو ا الو‬, it’s deficiency can cause anemia, poor wound healing and
connective tissue formation. Green vegetables are high in vitamin C as
pepper while tomato juice contain from 15-20mg (good), but potato has
low vitamin C content, which by using sufficient amount → can be good
source.
Vitamin B6 (Pyridoxine): has a role in nervous tissue metabolism
and in anemia. Vegetables are high in this vitamin.
Folic acid (Tetra hydrfolic acid): important in nucleic acid and
protein syntheses of the cell. Spanish, broccoli, cabbage and
lettuce are good sources.
7) Minerals (Table 5): They are required to support human biochemical
processes by serving structural and functional roles, they are divided into
two categories:
a. Macro-elements units: including:
Na, K, and Cl: important in maintaining osmotic balance of body fluid.
Ca, Mg, and P: important in blood and skeletal system, P also involved in
many enzymatic reactions.
S: important in protein building throughout it’s role in enzyme system.
Fe: important in hemoglobin formation of the red blood cells.
b. Microelements units: including:
I: for thyroid activity.
Cu: for tyrosin activity, it’s lack block Fe metabolism
and cause anemia.
Zn: involved in at least 8 enzymes systems.
Co: in vitamin B12 activity (anemia prevention).
Mn: cofactor in many enzyme reactions.
F: important to prevent dental decay.
All these can be obtained from vegetables.
Table 3: Proximate Composition (per 100g edible portion) of some
important vegetables.
Common Name
Energy
(kcal)
Moisture (g)
Protein (g)
Fat
(g)
CHO
(g)
Bitter ground
25
92.4
1.6
0.2
4.2
Brinjal (eggplant)
24
92.7
1.4
0.3
4.0
Cabbage
24
92.4
1.3
0.2
5.4
Capsicum
22
93.4
1.2
0.2
4.0
Carrot
42
82.2
1.1
0.2
9.7
Cassava
157
59.4
0.7
0.2
38.1
Cauliflower
27
91.0
2.7
0.2
5.2
Celery
17
94.1
0.9
0.1
3.9
Cucumber
18
96.3
0.4
0.1
5.2
French bean
32
90.1
1.9
0.2
7.1
Garlic
30
62.0
6.3
0.1
29.8
Lettuce
14
95.1
1.2
0.2
2.5
Muskmelon
17
95.2
0.3
0.2
3.5
Okra
35
89.6
1.9
0.2
6.4
Onion
50
86.8
1.2
0.1
11.1
Peas
84
78.0
6.3
0.4
14.4
Potato
97
74.7
1.6
0.1
22.6
Spinach
26
90.7
3.2
0.3
4.3
Sweet Potato
114
59.4
0.7
0.2
38.1
Tomato
22
93.5
1.1
0.2
4.7
Watermelon
26
92.6
0.5
0.2
6.4
Yam
102
74.0
1.5
0.2
24.0
Source: Refs. 5-7.
Table 4: Vitamin Content (per 100g edible portion) of some important vegetables
Common Name
Vitamin A
(IU)
B1
Thiamine
(mg)
B2
Riboflavin
(mg)
B3
Niacin
(mg)
Vitamin C
(mg)
Bitter ground
416
0.07
0.09
0.5
88
Brinjal
(Eggplant)
244
0.04
0.11
0.9
12
Cabbage
130
0.05
0.35
0.3
47
Capsicum
900
0.06
0.06
0.5
128
Carrot
11000
0.06
0.05
0.6
3
Cassava
0
0.05
0.10
0.3
25
Cauliflower
60
0.11
0.10
0.7
78
Celery
240
0.03
0.03
0.3
9
Cucumber
0
0.03
0
0.2
7
French bean
600
0.08
0.11
0.5
19
Garlic
Trace
0.06
0.23
0.4
13
Lettuce
900
0.06
0.06
0.3
8
Muskmelon
558
0.11
0.08
0.3
26
Okra
172
0.07
0.10
0.6
13
Onion
Trace
0.08
0.01
0.4
11
Peas
640
0.35
0.14
2.9
27
Potato
24
0.10
0.01
1.2
17
Spinach
8100
0.10
0.20
0.6
51
Sweet Potato
8800
0.10
0.06
0.6
21
Tomato
900
0.06
0.04
0.7
23
Watermelon
590
0.03
0.03
0.2
7
Yam
0
0.1
0.01
0.8
15
IU: Vitamin A is formed of Isoprene units each has 5 carbon atoms.
Table 4.2: Minimum requirements of essential amino acids: national
research council (g/day)
Amino acid
Young male adult
Young female
adult
Infant of 15lb wt.
Leucineª
1.10
0.62
1.05
Isoleucineª
0.70
0.45
0.83
Lvsineª
0.80
0.50
0.72
Threonineª
0.50
0.31
0.61
Tryptophaneª
0.25
0.16
0.15
Valineª
0.80
0.65
0.74
Methionineª
1.10
0.29
0.32
Cysteine
Phenylalanineª
Tryosine
0.22
1.10
0.22
0.63
0.90
Histidine
0.24
ª Essential amino acids.
Table 4.3: Essential amino acid composition of some vegetables in comparison
to hen’s egg and the limiting amino acid determining protein score.
(% of FAO hen’s egg)
Name
Trypto
pha
n
Th
reo
nin
e
Isol
euc
ine
L
e
u
ci
n
e
Methioni
L
ne
y
plus
s
cystin
i
e
n
e
Phenylan Valin
ine
e
plus
tryosi
ne
Collards
‫ملفوف‬
88
58
47 ª
64
81
49 ª
71
68
Kale ‫لفت‬
68
70
51
74
49
34 ª
0
64
Spinach
102
87
70
87
96
67 ª
74
75
Potatoes
67
77
66
57
83
40 ª
62
73
Sweet
potato
es
109
92
73
65
74
63 ª
101
102
Common
beans
58
85
86
98
116
37 ª
94
83
Broadbea
58
64
95
99
88
21 ª
69
68
Lima
beans
59
93
88
94
104
57 ª
85
86
Mung
beans
46
61
84
103
107
31 ª
64
81
Peas
67
76
85
94
115
46 ª
91
77
Lima
81
beans
(green
)
88
93
92
98
40 ª
86
89
Peas
52
(green
)
72
69
71
74
34 ª
63
56
6.4
5.5
(g/100g protein)
FAO hen’s egg b 1.6
5.1
6.6
8.8
10.0
Source: Kelley (1972)
ª Limiting amino acids.
b
based on average figures.
7.3
Table 5: Mineral Content (per 100g edible portion) of Some Important
Vegetables.
Common Name
Calcium
(mg)
Phosphorus
(mg)
Iron
(mg)
Bitter ground
20
70
1.8
Brinjal (Eggplant)
18
47
0.9
Cabbage
49
29
0.4
Capsicum
9
22
0.7
Carrot
37
36
0.7
Cassava
50
40
0.9
Cauliflower
25
56
1.1
Celery
39
28
0.3
Cucumber
10
25
1.5
French bean
56
44
0.8
Garlic
30
310
1.3
Lettuce
35
26
2.0
Muskmelon
32
14
1.4
Okra
66
56
1.5
Onion
47
50
0.7
Peas
26
116
1.9
Potato
10
40
0.7
Spinach
93
51
3.1
Sweet Potato
32
47
0.7
Tomato
13
27
0.5
Watermelon
7
10
0.5
Yam
12
35
0.8
Factors affecting amounts of nutrients in vegetables:
1) Genetic make up of plant: under same growing conditions →
you can see wide range of nutrient content in the same
population. So selection and breeding program can be used to
improve nutritional content of various vegetable spp.
2) Environmental conditions:
a. Seasonal factors: temp., moisture, and light, but excess or
shortage of any factor negatively affects on nutrient content.
b. Atmospheric conditions and composition of toxicants and
pollutants, also affects negatively on nutrient content.
c. Soil factors: chemical and physical properties of soil, and soil
moisture content.
d.
Cultural practices: fertilization,
competition and maturity aspect.
pests,
diseases,
weeds,
•3) Losses during and after harvesting:
•A . Harvest: volume of losses varies depending on spp. it self and
its ability to resist braising and brake of cells. Mechanical induces
more damage than hand harvest also transport could cause
damage.
•B .Holding and storage prior to processing: time and temp. can
affect nutrient value. Content of Vitamin C is an index for proper
storage condition since it is very labile.
•C .Washing prior to processing: if you use recycled water which
gets warmer and if you use detergents → some soluble
substances can be leached and contamination with trace metals
can occur while pesticides residues can be removed (non
systemic pesticide).
•D .Peeling and chopping: removal of peel even mechanical or by
using soda → nutrients concentrated in skin can be removed
especially Vitamin C because by oxidation which follows peeling
or chopping or from tomato since concentrated under skin.
E .Blanching: exposing vegetables to steam or hot water to
inactivate enzymes which may deteriorate the product. By this
technique, water soluble vitamins and minerals can be exposed to
losses.
F .Processing: done by:
1) freezing; 2) dehydration; 3) canning; or 4) pickling. Thermal
processing can induce major loss.
G . Packaging and storage: depends on container to be used,
storage temp., and duration of storage temp., and duration of
storage. Low or no O2 by N2 replacing conditions, vacuum, low
temp. and darkness to keep low temp., and no chlorophyll
pigments, are best for nutrient retention. So, as temp. and/or
storage time increase quality will decrease.
Vegetables can be grouped as a source of nutrients
into:
1) High CHO as: white potato, sweet potato, sugar beet, sweet
corn, dry beans, and cassava.
2) High in oils: legume seeds, and mature vegetables seeds.
3) High in proteins and amino acids: beans, peas, most leafy
vegetables (cruciferous vegetables= Brassica spp.), and sweet
corn.
4) High in Vitamin A: carrot, sweet potato, cucurbits, pepper, green
leafy vegetables, green beans, and peas.
5) High in Vitamin C: crucifers, peppers, tomato, melon, most leafy
vegetables, immature seeds of beans, and white potato.
6) Rich in minerals: most leafy vegetables especially crucifers and
root crops.
So by under standing nutrient content of vegetables, it is possible
to depend on plants when you take crops rich in protein in
sufficient amounts.
So, what are the suggestions to improve vegetables situation?
A) Increase of food supply :by
1) Increase production: it is now about 2% per year to face the
population growth, 20% from new areas involved and 80% due to
Technology. As: new CVs, good cultural practices, fertilization,
irrigation, plant population and regulators. This means better
sustainability.
2) Development of new food forms from other resources using byproducts, wastes and residues, (hydroponic) .
3)Increase the efficiency of nutrient production By eliminating animals from
food chain
a- plant →animal (excluded) →man
Efficiency of land production will increase if we produce directly for human
consumption, and concentrating on those that substitute low
consumption from animals (valuable food = fats + protein of animals).
Ref.: Figure 1.1.
b- Selection of crops that produce highest quantity of nutrients as for
example efficiency of producing the 8 essential amino acids to improve
the nutritional status.
Ref.: Figure 1.2
4)Multiple cropping: greater than cropping cultivation in one year
a- sequential cropping: growing of two or more crops in a
sequence/year, could be done by soil less cultivation.
b- Inter cropping: growing of two or more crops simultaneously on
the same land-either mixed or in alternative rows or strips.
c- Ratoon cropping (to save all the time): cultivation of regrowth
parts of the same crop after harvest (suckers and adventitious
shoots).
d- Relay cropping: the simultaneous growth between two or more
crops, occurs in part of the growing period of each crop,
normally the 2nd crop is seeded or transplanted when the first
crop reaches the productive stage, as cucumber then tomato.
B) Improving the world vegetables: National
1) Improving efficiency, distribution, and conservation (in the same
country) by cooperatives and institutions. Since single farmers
can not if prices at producing sites are low, and costs of
transport to areas that they need are high, so they can not
control diseases, rodents, … during handling to decrease
losses.
2) Reducing losses and wastes during all production stages by: 1)
Protect against diseases, insects, using immune cultivars; 2)
Stop erosion and water wastes.
3) Taking care of subsistence crops as much as the valuable
exportable crops to achieve stability.
4) Improving the use of wasted organic parts of vegetables.
C) Improving international trade of vegetables,
since the nature of vegetables is highly perishable → trade
activity is very low.
-The concentration should be directed towards processing,
dehydration, freezing of products for longer distances, and
improving means of transport either by air or seas, and using
refrigerators for national transport of long distances.
- Also demand for vegetables increase during winter which can
be by producing in tropical and subtropical regions, and forcing
the vegetables. This needs programming, grading, and
improving the quality of production. (Intrinsic and phenological
characters).
Figure 1: Possible routes from production to consumption of
vegetable.
(from Ref. 5.)
Production
Storage
Processing
Storage
Processing
Storage
Processing
Storage
Home Preparation
Consumption
Fig. 1.1.:Time required to raise foods.
Months to raise concentrated feed
Months to reach earliest maturity
30
25
20
15
10
5
co
w
Di
ar
y
Be
ef
La
m
b
Sw
in
e
po
ta
to
Ch
i ck
en
Sw
ee
t
To
m
at
o
G
ra
in
s
Ri
ce
Ch
Ra
in
di
es
sh
e
ca
bb
ag
e
So
yb
ea
n
0
Fig. 1.2.: Efficiency of crops and animals in producing the essential
amino acids on an area basis
Average pounds per acre - essential amino acids
Average pounds per acre - essential amino acids
20
15
10
5
Lamb
Beef
Pork
Cheese
Eggs
Almonds
Cor,
Walnuts
Spinach
Beans,
Rye flour
Cabbage
Peanuts
White
Carrots
Corn
Beans,
Soy
0
Vegetables are among those that produce the highest quantity of amino
acids which also occurred in short period of time
In Jordan, major production areas of vegetables are:
1) Dry lands: were annual precipitation rate is 300mm or more, mainly in
Irbid, Amman, Maa’daba, and Balka. That share with about 4.5 million
J.D. of the total income, and represents about 1.6% of the total
cultivated area. The production is changeable in relation to rainfall
quantity.
Main crops are deep rooted ones as: tomato, okra, sweet melon, and snake
cucumber. It is characterizing with low production because of: 1- Low
plant density; 2- Rare treatments; 3- Low yielded cultivars are used.
Since expected profit is low.
2) Irrigated up lands: Beside lands irrigated by springs or by ground water,
even protective and open field, both share with about 155 million J.D. of
the total income, and represents about 53.8% of the total cultivated
area. Mainly in Mafraq, Zarqa, Maa’daba, and Baqa.
Main crops are: tomato, eggplant, cucumber, cauliflower, sweet melon, and
squash. Average yield is relatively low except when area is covered with
plastic houses, because of low experience to fertilization, irrigation and
pest or diseases management.
3) Jordan Valley Area: From north to south, the vegetables are
planted from August to February, there are two planting times; in
August and in Spring.
In the southern regions spring planting time is of high risks because
of many factors:
1) Water: it is a limiting factor;
2) Annual precipitation is decreasing from year to year;
3) High labor cost which represents about 50% of the total input
cost;
4) Mechanization is not effectively used;
5) Land is divided to 30 donum areas between owners which means
low technology implementation.
Main crops during fall season are: tomato, potato, onion, squash,
eggplant, and others as pepper, beans, and cucumber showing
about 100,000 donum of cultivated area.
Main crops during Spring are: Jews mallow, tomato, potato, musk
melon, eggplant, onion, okra and water melon showing about 45,000
donum of cultivated area.
Factors influencing vegetables growth:
1- Climatic factors : Interaction of temp. x moisture x wind x solar
radiation = atmospheric condition per period of time and
summation of these atmospheric conditions, which determine the
climatic conditions for many years, also,
2- Also, Soil conditions that depends on climatic factors, is another
factor.
For both climatic and soil factors appear the adaptation of plant
spp. and ability to grow.
1) Climatic factors:
A. Temperature.
B. Moisture or precipitation rate
C. Light
D. Wind
E. CO2 concentration
A. Temp.: limits growth and distribution of plants, it is a result of solar
energy that equals 2g cal/cm²/minute. Temp. distribution: equatorial zone
is the hottest, while polar zones are the coldest with difference in solar
energy received leading to seasons formation/year (summer, Autumn,
Winter, and Spring).
- There is a 45ْC variation between winter and summer, while in equatorial is
just 3ْC.
- Variation over continents is higher than that over oceans and seas because
of larger heat capacity of water than soil.
- Day temp is higher than night temp. where maximum temp. is in
the after noon and minimum temp. is at sunrise.
-As the altitude increase, temp. will decrease in about 6ْC/1000
meter elevation.
Temp. in the southern side of the mountain is higher than that in
the northern side during day.
All these are important factors in selection of adapted spp. Since
for each spp. there is minimum, maximum, and optimum temp.) →
temp. as cardinal.
•Van Hoff's law (Q10 law): Every 10ْC rise→2x dry matter
production in range of 5 ْC to 35ْC.
No. of frost-free days: average period between the last killing frost
in spring and the first killing frost in the fall.
Heat units: degree-days.
Large diurnal range is favorable for net photosynthesis → growth
and production. As night temp. increase it affects negatively on
production.
Vernalization: exposing of seedlings or seeds to low temp periods
(according to spp.) , it will induces or increases flowering.
Devernalization: reversal of Vernalization, when plant exposed to
high temp. (30ْC or more) after low temp.
Fig. 1.3.: Different growth stages.
Growth %
Temp. °C
90
80
70
60
50
40
30
20
10
0
Apr.
Jul.
Oct.
Jan.
Apr.
Jul.
Phase 1: vegetative growth; phase 2: vernalization; phase 3: floral initiation;
phase 4: seed stalk development;
phase 5: flowering and fertilization;
phase 6: seed maturity.
If seeds are exposed to Vernalization, moistened seeds under low
temp degrees will hinder radicle growth) → 1ْْْC-6ْC from 15-60
days.
Most vegetables are injured at temp slightly below freezing.
Freezing and chilling injury:
Tropical and subtropical plants killed or damaged at temp. degrees
below 10ْC as cucumber, tomato, and potato, especially for long
period of time, this is called chilling injury. But if plants subjected
to low temp degrees for a short period of time, then increase in
temp degrees, the plants will not affect by low temp. before. So
time-temp relationship is very important, also the growth stages
from an thesis to shortly before flowering is the most sensitive
period to cold.
Hardening:
Exposing plants to cold temp gradually but not suddenly as like
cabbage. Also hardening can be done by exposing plants to water
stress which can be more applicable.
High temp. injury:
Increasing the temp. and increasing the percentage of relative
humidity affects on leaf temp., it may reach 8 ْC higher than air
temp., and if temp rises it results in protoplasm destruction in
range of 45 ْC-50ْC. Also ↑ temp. during green fruits stage of
tomato → sun-born and scalded of fruit as ripe. Also gradual
exposure to raise in temp. with increasing hrs leads to acclimation
of exposed plants.]
Dormancy:
Little or no growth at unfavorable environmental conditions, as
decrease or increase in temp degrees, or lack or excess of
moisture. Sometimes photoperiod is involved in dormancy all these
+ seed coat dormancy known as external dormancy, while if seed
remain in rest period even with favorable conditions this is called
internal or physiological dormancy which related to the changed in
inhibitors and/or promoters rate that affected by temp variations.
Storage temp. affects also in dormancy were as storage temp
increase → duration of dormancy will decrease.
B. Moisture or precipitation rate: Tables 6.1 and 6.2
It is affected by geographical characters and it is important as
much as temp. in determining the distribution of species.
Relative Humidity (RH) = (quantity of water present in air divided
on the quantity of water at saturation) multiplied by 100% at same
temp. and pressure.
Dew point:
Temp. of air at which the water vapor reaches saturation point, then as
temperature drops down this lead to condensation and formation of dew.
Dew + RH% can protect plants from severe transpiration and increase
pollens viability but could be a cause of diseases and insect spreading.
Amount of rain varies from area to another depending on far or close to
equatorial, coasts, mountains, or valleys, also the distribution, If quantity
fall in a longer period (up to late spring), there is no need for irrigation, but
if all quantity during winter, we need irrigation in summer. Arid regions of
less than 250mm/year, semiarid regions of 250-500mm/year, sub-humid of
regions 500-100mm/year, humid regions of 1000-1500mm/year, and in wet
regions of more than 1500mm/year as precipitation.
Also dew is very important in arid regions, for example, in Palestine drops
of dew equal to 25mm/year which is very important in summer, and that
can be directly absorbed by leaves and release energy as condensate (540
cal/g of condensate water). But dew increase the infection by diseases as
spores of late blight. The plant divided into 3v groups according to water
requirement; They are hydrophytes, mesophytes and xerophytes. Water is
very important for metabolic processes and its a medium for transport of
minerals between cells + transpiration.
Table 6.1.: Water requirements of some vegetables a.
Vegetables Category
cm
in.
Shallow rooted
Cabbage
30
12
Lettuce
45
18
Onion
40-60
15-24
Spinach
25
10
Sweet corn
45
18
Bean
30-45
12-18
Beet
45
18
Carrot
40
15
Cucumber
45
18
Summer squash
45
18
Pea
45
18
Pepper
45
18
Medium rooted
Deep rooted
Artichoke
30
12
Asparagus
50
20
Melon
60
24
Tomato
60
24
Water melon
45-60
18-25
Sweet potato
45
18
Winter squash
45
18
Source: Doneen and MacGillvary (1943).
a
Water required to raise crop to maturity.
Table 6.2.: critical moisture sensitive stage of some vegetables
crops a.
Crop
Moisture sensitive stages
Broccoli
From flower bud development through harvest
Cabbage
From head formation to harvest
Cauliflower
Sufficient soil moisture at all stages
Radish
During period of root enlargement
Turnip
From root enlargement to harvest
Lettuce
At heading stage to harvest: low soil moisture can cause tip burn
Onion
During period of bulb formation
Peas
At flowering through pod enlargement to harvest
Potato white
From tuber initiation through tuber enlargement
Snap beans
During flowering and pod elongation
Soybean
During plant growth and flowering
Sweet corn
During period of silking and ear development
Source: Some data from Change (1968)
a
For most vegetable crops little or no moisture stress
during entire growth period generally gives high yields and
good quality. Flooding is to be avoided.
C. Light:
Important for photosynthesis, energy, inducing change in
plant life cycle as photo period. It varies from mountains
(1.75g cal/cm²) to sea levels (1.5g cal/cm²) at noon.
Also dust, clouds, smoke, and gases will decrease energy
quantity received by earth.
At 4.3 Lux (0.4 foot candle) → photosynthesis is negligible,
while at 1080 Lux (100 foot candle) it is called the
compensation point for many plant spp.
Compensation point: light intensity at which photosynthesis rate
equal or exactly matches respiration rate, or the point at which
photosynthesis and respiration are in balance.
Light quality: photosynthesis is highly at lights of wave lengths
480nm (blue) and 680nm (red).
Ref.: Tables 6.3 and 6.4 = Response to quality and photo period
Duration of light:
Photoperiodism:
is the flowering response of plants to relative changing length of
night or day as the season progresses . Those flower when
photoperiod is lower than the critical maximum day length required
for flowering, then the plant called short day plant, while those
flower when photoperiod is greater than the minimum day length
required for flowering, then the plant called long day plant.
For short day plant: duration of dark period is the critical condition.
Phytochrome is a pigment that absorbs light in red and far-red
regions, it is necessary for photoperiodism response.
Neutral day plants: not affected by day length.
Leaf area index (LAI):
Total leaf area (blades) / unit area of land. It is important to
evaluate efficiency of photosynthesis, and production of
dry matter, it is varying from 2-6, but in some cases it may
reach up to 9 or 12, even vertical crops have high LAI. The
optimum is not the maximum: since the lower leaves show
photosynthesis rate less than the compensation point → it
depends on other → so decrease dry matter production.
Also optimum is deeply related to solar radiation intensity.
Fig.: Relationship of leaf area index and solar radiation of clover.
Environmental factors influencing growth
Growth g/m2 - day
25
20
15
10
5
0
1
2
3
4
5
6
7
Leaf area index
From: Black (1963).
8
9
10
11
Table 6.3: Response to wave length:,
Wave length (nm)
Remarks
Response
Stem elongation
1000-720 far-red
Inhibition of germination of certain seeds
1000-720
Stimulation bulbing of onion
1000-720
Suppress bulbing in onion
690-650 red
Red pigment (lycopene) synthesis
690-650
Stimulate flowering of long day plants
690-650
Inhibit flowering of short day plants
690-650
Promote germination of certain seeds
690-650
Grand rapids (lettuce)
Promote red color formation (anthocyanins)
690-650
Red cabbage color
Photosynthesis
700-400
Chlorophyll formation
650-400
Phototropism
500-350
Grand rapids (lettuce)
Tomato fruits-43 Lux
Table 6.4: Response to photoperiod:
Growth response
Vegetable name
Flowering response:
Long-day vegetables
Spinach, radish, Chinese cabbage,
Short-day vegetables
Soybean, chayote, roselle, sweet potato,
chrysanthemum, winged bean,
amaranth
Day-neutral vegetables
Tomatoes, early peas, squashes, beans,
peppers, eggplant, most cucurbits
Growth response other than flowering:
Long days for bulbing
Onion
Short days for tuber initiation
White potato, Jerusalem artichoke,
yam
Short days for root enlargement
Cassava, sweet potato
D. Wind:
Differences in temp and in pressure creates air motions from high
to low pressure areas, its speed depends on differences in
pressure. Wind can induce many effects as increasing
transportation rate, dust formation, ventilation,decreasing temp,
broken and damage of leaves and branches of plants.
The use of wind breaks is very important.
E. CO2 concentration:
That can be affected by wind speed where if high speed then it will
keep normal concentration which is important for dens canopy.
Also protective structures need CO2 enrichment.
2) Soil factors:
A. Soil texture
B. Soil structure
C. Soil pH
D. Soil temperature
E. Soil moisture
Soil is important for anchorages plants, and its a
source of water and nutrient minerals. Soil
components are altered by cultivation, fertilizers,
irrigation, drainage, and cropping systems. Main
components are derived from parent rocks that
subsequently interact with climate and soil organisms,
leading to formation of soil particles with various ratios
and organic matter.
A. Soil texture:
Is a soil property used to describe the relative proportion of
different sizes of mineral particles in a soil. Particles are grouped
according to their size into clay, silt, and sand. Soil texture
classification is based on the fractions of soil separates present in
a soil. The soil texture triangle is a diagram often used to figure
out soil textures.
Sand particles (2 – 0.02mmӨ), silt particles (0.02 – 0.002mmӨ), and
clay particles (<0.002mmӨ). Sandy soils have very low water
holding capacity and low nutrient content level. Clay soil (poor
aeration): very high water holding capacity and high nutrient
content level.
Sandy loams: is most easily manageable soil that can provide a
well balance of air (aeration) to soil moisture content.
B. Soil structure:
Aggregation of soil granules, good aggregation means →
adequate exchange of gases (CO2, O2) and water.
Compact soil means → bad soil management, little air
space and poor water penetration, root fail to develop in a
well nature.
C. Soil Minerals:
Macro: N, P, K, Ca, Mg, S, (C, H, O from CO2 and H2O).
Micro: Fe, Cu, Mn, Zn, B, Co, Mo and Cl.
Excessive mineral cause → toxicity, while insufficient
cause → even poor or abnormal growth.
Optimal growth and reproductive process can be realized
by proper nutrient balance.
D. Soil pH:
Most plants grow within a range of 5.8 to 7.5 or little bit more (as it has
been classified before). High rainfall means → acidic soil, while low
rainfall means → high CO3 content in soil, so it means → alkaline soil.
According to PH level some minerals as Fe, Mn become of low
availability at alkaline soil conditions, and same will be available at acidic
soils in excessive amounts.
E. Soil temperature:
Depends on air temp, normally it is lower than air temp in spring and
summer, and it is higher than air temp in fall and winter. It is important for
seed germination, root growth and development of under ground storage
organs. (if soil temp is more than 30ْC → poor formation of potato
tubers).
F. Soil moisture:
Water in the soil includes: water vapor, free water (percolated),
capillary water (field capacity), hygroscopic, and crystalline (bonded
with chemicals). Plant roots can absorb: water vapor, free water, and
capillary water. If soil is dry → some hygroscopic can volatilize → water
vapor but the amount is too small to be used by plants.
As most of capillary water depleted → soil converted from field
capacity to permanent wilting point (plant can not extract the remaining
water that is at 15 atmosphere).
So, states = saturation → percolation of free water → capillary → permanent
wilting point. Those are important for plant.
Sandy soil: hold very low amount of water, but most available.
Clay soil: hold very high amount of water, but 20% - 40% as
hygroscopic (on particle size). Saturation for longer period of time, and
poor draining which cause root suffocation and wilting even at
availability of free water.
Growth and photosynthesis rate are largely reduced before plant
reaching to P. wilting point.
Controlling of growing conditions during off season
Tropic and subtropics can be grown all over the year. In temperate
climates, summer crops cant be grown from late fall to winter due
to cold temp, so off season techniques can enable the production
during off season .
The techniques are: glass or plastic houses, tunnels, beds, plastic
mulches, plastic coverings of the surface.
First: Controlling of temperature
Second: Controlling of light
Controlling of temperature: by the following items:
Utilizing topographical features: were southern slopes of hilly land
receives more radiation quantity during day than level or northern surfaces
which means that southern slopes are warmer than northern slopes. So,
southern slopes used during cool weather conditions while northern sides
used during hot weather conditions. Also slope parts of the hills are
warmer than the valley below especially at frost conditions and since cold
air remains below.
Shape of plant beds: beds of sloping side towards south receive higher
quantity of radiation than leveled sides since the rows of plants have
east-west direction, and since the angle of light incident to south slope
will be almost perpendicular most time of the day.
Ref.: Transp. A
•Soil temp: affected by two factors 1) Soil color: light colored soils are
cooler than dark colored soils; 2) Soil texture: coarse soils warm up
faster than fine textured soils, also high organic mater soils needs longer
time to warm up than mineral soils.
Soil moisture: moist soils warm up slower than dry soils since water has
higher heating capacity than soil (dry = air). Conversely, moist soils cooloff slower than dry soils as a result of evaporation → cooling of soil and
this complicate the relationships. (Summer or warm conditions in relation
to winter time).
Mulches: if the soil is well-pulverized, which means higher air between
soil particles, here air acts as insulated layer, so porous soil conducts
less heat than compact soil.
Straw mulch, organic matter…, show higher insulating effect in
hot days. Soils under those kinds of mulches can be as much as
17ْC lower than those without mulches, and will keep soil warmer
than air atmosphere around during cold days, so they need higher
heat efficiency up to warm by atmospheric heating system in
protective structures.
Plastic mulch: clear type warms soil more than black plastic,
both prevent losses of moisture, but black mulches has
advantages of controlling weeds development by preventing
sunlight from reaching the soil surface.
Asphalt mulch: as polyethylene type, its effective, clear type
warming soils. It is good as anticrusting agent.
Aluminum mulch: thin layer of aluminum with biodegradable
backing, they are also effective in repelling aphids → control of
viral diseases caused by aphids.
Ref.: Transp. A
Table 7.1: Effect of asphalt and plastic mulches on soil temperature.
Average temperatures 11 AM to 3 PM a
Depth
cm
in.
No mulched
Asphalt
Clear poly
Black poly
0
0
27.2 (81)
31.1 (88)
31.1 (88)
27.8 (82)
2.0
¾
25.0 (77)
28.3 (82)
28.9 (84)
26.7 (80)
3.8
1½
23.3 (74)
25.0 (77)
24.4 (76)
20.0 (75)
7.5
3
19.4 (67)
21.7 (71)
21.1 (70)
20.0 (69)
15.0
6
15.0 (59)
16.7 (62)
16.1 (61)
15.6 (50)
30.0
12
13.0 (56)
14.4 (58)
13.9 (57)
13.9 (57)
Moisture after 24 days b
0-10
0-4
5.2%
9.9%
7.9%
9.3%
Source: Takatori et al. (1964).
: Air temperature 23.3ْC (74 ْF); 30 cm (12 in.) width
mulch.
a
b:
Initial moisture 19.8%.
Fig. 7.2: Soil temperature in ْC at 12 mm (½ in.) depth; beds running
east-west
Am: ante meridiem, Latin for "before noon".
Pm: post meridiem, Latin for "after noon".
35
30
Air
25
Flat portion
20
South portion
15
10
12
:0 8
0a
m
4
12
:0 8
0p
m
4
12
:0 8
0a
m
4
4
12
:0 8
0p
m
5
12
:0
0a
m
Soil temperature in C
40
Frost protection:
oCan be avoided by: fogging and water sprinkling since water has high
heat capacity (l cal/g) and as water cools → it releases heat, so application
as fogging or mist is important to be continuously as air temp is below
freezing point taking in consideration that ice if formed will damage plant
parts by its weight, and each gm of water as freezes will release 80 cal of
heat preventing sharp drop of temp in the surrounding atmosphere to the
plants.
oAlso use of water in irrigated furrows in the night expected to show frost.
oHeaters and smudge pots: to induce layer of smoke over your crop, its
most efficient when the smoke layer is 9-15cm above ground surface, so
heating of air between soil and the layer will be common.
oFans, wind machines and air crafts: efficient in case of temp inversion in
calm areas where air temp is warmer with height, while the air in touch
with soil is colder. By machine mixing of air → gaining in soil temp up to
3ْC, if soil temp before mixing is -3 ْC to -6 C mixing will not be effective.
Plant protective structures:
1. Bushes or paper barriers: in north side to prevent north cold winds
and helps in trapping sun heat during the day.
2. Hot cap: a miniature green houses to protect one or more number
of plants per structure, made from paper or plastic.
3. Plastic tunnels: that covered with plastic sheets. They are like
miniature plastic houses.
4. Cloches: wire frames or wood frames with glass cover. Its strong
against wind.
5. Cold frames: made of wood or concrete with plastic or glass
covers on the tops which will increase air temp inside the frame.
During night it is possible to cover the glass or plastic cover with
cloth or straw, this will decrease heat losses since straw is of low
heat conduction.
6. Hot beds: as cold frames but heated either by: decomposed
manures, flushing of hot air, hot water or steam through pipes or
by electric heat cables.
7.Lath and screen horses: to decrease light intensity and decrease heat
of sunshine, and protecting from insects, (screen) can show higher
air temp than the outside since air circulation is reduced.
8.Green house, plastic or glass houses: big enough for movement or
working, can be heated, cooled, shaded, ventilated and protected
from direct sunshine by use of baskets or shade boards that used for
seedlings, or shaded ornamental plants, or seedlings at
transplanting time.
*Hardening
of transplants:
By exposing them into cooler conditions than in the nursery, but
better than permanent field conditions and / or by water stress → to
with stand unfavorable conditions. As an example, hardened
cabbage can grow without damage up to -6ْC, while non hardened
can be injured at -2ْC.
Controlling of light:
Light intensity: full sunlight intensity is 54,000Lux,
compensation point is at 1100 to 3200Lux (no growth but
maintaining). So if light intensity is low → artificial light is
repaired to reach to normal level needs for most plants to mature
(8600 – 11000Lux) light intensity X CO2 concentration X temp.
Photoperiod: elongated by light, reduced by dark cloth to
induce flowering or delaying it. Longer days → earlier maturity.
Application of growth regulators as: PCPA (P-chlorophenoxy
acetic acid) NAA (B-naphthalin acetic acid) to set tomato fruits
under cool conditions. PCPA + GA → non puffy fruit (firm).
Ethephon → hasten ripening.
Use of pollinators, vibrators and blowing winds to increase fruit
setting.
Use of gypsum (hydrated calcium sulfate) in seed beds as a
fertilizer to avoid crusting of upper soil and facilitate green color.
Fig. interactive effect of light intensity x temperature x CO2 concentration
on photosynthesis rate.
0.03% CO² 20 or 30°C
0.13% CO² 20°C
0.13% CO² 30°C
Photosynthesis rate
(ml CO2/cm2.hr)
300
200
100
0
0
1500
Light intensity
3000
Growing degree day
Growing degree day calculation (GDD)
GDD are calculated by taking the average of the daily maximum
and minimum temperatures compared to a base temperature, T
base !(usually 10 CC) .As an equation:
GDD=T max-T min - T base.
2
GDD`s are typically measured from the winter low. Any
temperature below T base is set to T base before calculating the
average. Likewise, the maximum temperature is usually capped at
30 cc , because most plants and insects do not grow any faster
above that temperature. However, some warm temperate and
tropical plants do have significant requirements for days above
30°C to mature fruit or seeds.
*For example, a day with a high of.23 °C and a low of 12°C
would contribute 7.5 GDDs.
GDD`s= 23 +12 _ 10 =7.5
2
A day with a high of 13°C and a low of 10 o~ would
contribute 1.5 GDDs.
GDD `s=13+10
_10 =1.5
2
*So( M.M.Tempreture_ T base)* number of days / month =
GDDs/ month
*If tomato needs 1500 DDs of maturity and has =10 ْ
C While temperature of january,febreuary,March,
April , May, June ,are: 13 , 15 ,17, 20 ,23 ,25
Then when mature if planted at 15 Jan..
Jan=16*3 =48
Feb.=28*5 =140
April=30*10 = 300
625
So 1500-1108 =392
392 = 26 of June
15
May=31*13=403
1108
Mar = 31*7 =217
VEGETABLE CLASSIFICATIONS
IMPORTANCE OF CLASSIFICATION
Some orderly method of grouping different vegetables is essential to
catalog or systemize, to some extent, the voluminous information
gathered by man since the dawn of agriculture. Such classification can
present this material orderly and eliminate repetition of many of the
principles related to culture and storage of the harvested crop.
Vegetables used throughout the world number in the several hundreds. In
the United States alone there are over a hundred, including the minor
crops. Therefore, some system of classification is essential.
BASIS FOR CLASSIFICATION
Methods that can be used for classification depend on its usefulness.
Some of the methods or types used:
1) Botanical classification is based according to flower type and structure,
and also on genetics and evolution. The groupings of plants are into
families, genera, species, and varieties. This classification, based on the
botanical relationship, is the most exact system.
2) Optimum growing temperatures, e.g., cool and warm season crops;
temperate or tropical crops.
3) Relative resistance of plants to frost or low temperature.
4) Part of plant used for food, e.g., foliage, stem, roots, flowers, or fruits.
5) Number of seasons a plant may live, e.g., annual, biennial, perennial.
6) Storage temperature and storage life.
7) Optimum soil conditions, e.g., soil acidity, and salt tolerance.
8) Water requirements to harvestable stage.
TYPES OF CLASSIFICATION OF VEGETABLES
Botanical Classification
All plants belong to one community (plant kingdom or community).
Division:
a. Algae and fungi (Thallophyta)
b. Mosses and liverworts (Bryophyta)
c. Ferns (Pteridophyta)
d. Seed plants (Spermatophyta)
Classes of seed plants (Spermatophyta):
a. Cone-bearing (Gymnosperm)
b. Flowering (Angiosperm)
Subclass of flowering plants (Angiosperm):
a. Monocotyledon (Monocotyledonae)
b. Dicotyledon (Dicotyledonae)
Order:
Family:
Genus:
Species:
Variety (botanical), and Group:
Cultivar (horticultural variety):
Strain (horticultura1):
Example: Botanical classification of the summer squash cultivar, 'gray
zucchini' Division: Spermatophyta
Class: Angiospermae
Subclass: Dicotyledonae
Order: Cucurbitales
Family: Cucurbitaceae
Genus: Cucurbita
Species: pepo L.1
Variety: Melopepo, Alef. 1
Cultivar: Zucchini
Strain: Gray
Definitions Used in Vegetable Classification:
Group (Botanical Variety-Old Terminology). A population within a species of
a cultivated crop which is distinct from the rest of the species forms in one or
more
1 L. is for C. Linnaeus, the person first suggesting the name; Ale£. for F. G. C. Alefeld.
VEGETABLE CLASSIFICATIONS
clearly defined characteristics; dwarf growth habit, enlarged taproot, etc.
Group designation is used for horticultural convenience and has no
botanical recognition.
Cultivar: (Horticultural Variety). A cultivar denotes an assemblage of cultivated
individuals which are distinguished by any character (morphological,
physiological, cytological, chemical, etc.) significant for the purpose of agriculture
or horticulture and which retain their distinguishing features when reproduced
(either sexually or asexually). When naturally occurring populations are also
represented by cultivars, the botanical variety name is retained. The cultivar
names are set off in single quotation marks ('zucchini').
Strain: A strain includes those plants of a given cultivar which possess the general
varietal characteristics but differ in some minor characteristics or qualities. A
cultivar with disease resistance incorporated, or early maturation, may be
considered a strain within the cultivar. Selections within a cultivar for differences
in climatic adaption may be considered a strain. The international code for
nomenclature does not recognize the term strain. Any selection that shows
sufficient differences from the parent is regarded as a distinct cultivar.
Table A.l lists the botanical classifications of many of the more common vegetables of
the world.
Strain: A strain includes those plants of a given cultivar which possess the
general varietal characteristics but differ in some minor characteristics or
qualities. A cultivar with disease resistance incorporated, or early
maturation, may be considered a strain within the cultivar. Selections within
a cultivar for differences in climatic adaption may be considered a strain.
The international code for nomenclature does not recognize the term strain.
Any selection that shows sufficient differences from the parent is regarded
as a distinct cultivar.
Table A.l lists the botanical classifications of many of the more common
vegetables of the world.
Usefulness of Botanical Classification
For biologists to (a) establish relationships and origin, and (b) serve as
positive identification, regardless of language.
For horticulturists because (a) climatic requirements of a particular family
or genus are usually similar, (b) use of crop for economic purposes is similar,
and (c) disease and insect controls are quite often similar for related genera.
CLASSIFICATION ACCORDING TO SEASON GROWN
(after J. H. MacGillivray)2
1. Cool Season Crops-Adapted to mean monthly temperatures of 16°18°C (60°-65°F). artichoke, asparagus, Brussels sprouts, broccoli,
cabbage, carrot, cauliflower, celery, chard, endive, garlic, kale, lettuce,
mustard, onion, parsnip, pea, radish, spinach, turnip, white potato.
From J.B. MacGillivray. 1953. Vegetable Production, Used with permission
of McGraw-Hill Book Co., New York.
2. Warm Season Crops-Adapted to mean monthly temperatures of 18°30°C (65°-86°F). Intolerant of frost. Cucumber, eggplant, lima beans,
muskmelon, okra, pepper, snap bean, squash and pumpkin, sweet corn,
sweet potato, tomato, watermelon.
This classification is based on temperature zone conditions and even then
must be used with some caution. In tropical zones where temperatures
are quite uniform, group differences are much less clear.
CLASSIFICATION OF VEGETABLES BASED ON USE,
BOTANY,
OR A COMBINATION OF BOTH
1. Potherbs or greens:
Spinach, New Zealand spinach, chard, dandelion, kale, mustard, collards,
water convolvulus.
2. Salad crops:
Celery, lettuce, endive, chicory, watercress.
3. Cole crops: (all are members of Brassica oleracea except Chinese
cabbage)
Cabbage, cauliflower, sprouting broccoli, Brussels sprouts, kohlrabi,
Chinese cabbage.
4. Root crops: (refers to crops which have a fleshy taproot)
Beet, carrot, parsnip, salsify, turnip, rutabaga, radish, celeriac.
5. Bulb crops: (all species of Allium)
Onion, leek, welsh onion, garlic, shallot, chive.
6. Pulses:
Peas, beans (including dry-seeded or agronomic forms).
7. Cucurbits: (all members of the Cucurbitaceae)
Cucumber, muskmelon, watermelon, pumpkin, squash,
several Oriental crops.
8. Solanaceous fruits: (members of the Solanaceae)
Tomato, pepper, eggplant, husk tomato
9. white (Irish) potato
10. sweet potato
11. sweet corn
CLASSIFICATION BY EDIBLE PART
1. Root
a. Enlarged taproot:
beet, carrot, radish, salsify, rutabaga, turnip, parsnip, celeriac.
b. Enlarged lateral root:
sweet potato, winged bean, cassava, arracacha.
2. Stem
a. Above ground, not starchy:
asparagus, celtuce, kohlrabi.
b. Below ground, starchy:
white -or Irish potato, yam, Jerusalem artichoke, taro.
3. Leaf
a. onion group, leaf bases eaten (except chive)
onion, garlic, leek, chive, shallot.
b. Broad-leaved plants:
1. salad use: lettuce, Chinese cabbage, cabbage, celery (petiole only),
chicory, endive.
2. cooked: (may include tender stems in some): spinach, edible amaranth,
chard, New Zealand spinach, Jew's mallow, dandelion, rhubarb (petiole
only), kale, chicory, Chinese cabbage, mustard, cardoon (petiole only).
4. Immature flower bud:
Cauliflower, broccoli, broccoli raab, artichoke.
5. Fruit
a. immature:
Pea, snap bean, lima bean, broad bean, chayote, summer squash,
cucumber, zucca melon, okra, sweet corn, eggplant.
b. mature:
i. gourd family (cucurbits): pumpkin and winter squash, muskmelon,
Chinese wax gourd, watermelon.
ii. potato family: tomato, pepper, pepino, husk tomato.
CLASSIFICATION OF VEGETABLES ACCORDING TO
SALT TOLERANCE3 (RICHARDS, 1954)
Listed from high tolerance (top) to low tolerance (bottom)
7700 ppm (EC x 103 = 12)
1. High salt tolerance:
garden beets, kale, asparagus, spinach.
6400 ppm (EC x 103= 10)
2. Medium salt tolerance:
Tomato, broccoli, cabbage, peppers, cauliflower, lettuce, sweet corn, white
potato, carrot, onion, peas, squash, cucumber, cantaloupe.
2600 ppm (EC x 103=4)
3. Low salt tolerance:
Radish, green beans.
1900 ppm (EC x 103=3)
CLASSIFICATION OF VEGET4BLES ACCORDING TO
TOLERANCE TO SOIL ACIDITY
1. Slightly tolerant (pH 6.8 to 6.0): asparagus, celery, beet,
spinach, broccoli, Chinese cabbage, cabbage, leek,
cauliflower, lettuce, muskmelon, New Zealand spinach, okra,
onion, spinach.
2. Moderately tolerant (pH 6.8 to 5.5): bean, horseradish,
Brussels sprouts, kohlrabi, carrot, parsley, cucumber, pea,
eggplant, pepper, garlic, pumpkin, radish, squash, tomato,
turnip.
3. Very tolerant (pH 6.8 to 5.0): chicory, rhubarb, endive,
sweet potato, potato, watermelon,
3 Salt concentration based on saturation extracts of soils; EC=electrical
conductivity.
CLASSIFICATION BY ROOT DEPTH INTO SOIL
1. Shallow < 80 cm (3 ft):
Cabbage, potato, lettuce, spinach, onion, sweet corn.
1. Medium 80-160 cm (3-6 ft):
Beans, eggplant, beets, summer squash, carrot, peas,
cucumber.
1. Deep > 160 cm (6 ft):
Artichoke, asparagus, melon, sweet potato, tomato, winter
squash and pumpkin.
CLASSIFICATION BY HABITAT
1. Hydrophyte (aquatic):
Taro, water chestnut, watercress, lotus, water convolvulus.
2. Mesophyte:
most vegetables grown on soil and requiring moderate
amounts of water.
3. Xerophyte:
cactus, some desert cucurbits (buffalo gourd).
Soil and soil preparation:
Soil is storage of mineral nutrients and water, it is the home of
roots, its chemical and physical properties are very important for
production.
- Chemical soil properties: can be changed by adding fertilizers,
organic matter, leaching, and good aeration.
- Physical soil properties: can be changed by drainage, tillage,
organic matter, and lime addition.
Kinds of soil:
1) Mineral soil
2) Organic soil (muck or peat)
Based on soil texture which is used to describe the relative proportion of
different grain sizes of mineral particles in a soil (relative particle size), so
coarseness of soil can be classified into the following groups shown in the
table below:
No.
Name of soil separate
Diameter limits
(mm)
1.
Very coarse sand
1.00–2.00
2.
Coarse sand
0.50–1.00
3.
Medium sand
0.25–0.50
4.
Fine sand
0.10–0.25
5.
Very fine sand
0.05–0.10
6.
Silt
0.002–0.05
7.
Clay
less than 0.002
According to the table:
Water Holding Capacity increase as we go from 1-7.
Nutrients level increase as we go from 1-7.
Organic matter also increases as we go from 1-7.
Soil preparation is more difficult from 1-7.
Mineral soils:
They are separated into three groups: sand, silt, and clay. Those
mineral soil classes preferred by vegetables are: sandy, sandy
loams, silty loams, clay loams, in addition to muck or peat soil as
organic matter soil.
The preferred soil by vegetables could be determined by:
Species growth: its root system; is it legumes or normal
Earliness: sandy soils are the most of them ready to be plowed
after rainfall.
Growing structures.
Water availability: irrigated or rain irrigated.
Length of growing season of crop: sandy soils are not good for
long growing season crops, while heavy soils are better
-Silty loam or loamy soil: in which crops can continue there growing
season in hot summer, its also increases production.
oMuck soils: that contains less than 50% of its components as organic
matter, while peat soils contain more than 50% of its components as
organic matter.
oBoth muck and peat soils composed of plant materials in various stages
of decomposition, and they are characterized by:
1) High organic matter level.
2) Brown–black color (according to the degree of decomposition).
3) High water holding capacity: which may reach up to several times than
it's weight, but the unavailable water is also increase.
4) High N content (about 1.5% – 2.5% of dry weight).
5) Low content of other minerals especially K.
oMuck soils are excellent for celery, lettuce, onion, carrots, beet, spinach,
and cabbage; that can with stand frost conditions and they are relatively
of short growing season which could be determined mainly by frost
dominance.
oAlso muck soil is of poor conduction to heat because of low heat
movement from lower surface to upper surface (inverse to clay loam).
Frostiness depends on:
1. Moisture content: it makes heat movement upward more easily.
2. Compactness: and its effect on heat movement.
3. Start of decomposition: presence of higher amount of minerals
will decrease the probability of frost conditions.
4. Mineral content especially as fertilizers: it affects against frost.
-
Decomposed matter from deciduous and shrub trees is better
than those from confers since confers decompose slowly
because of the presence of resins.
-
Drainage and tillage (make good soil aeration), which is favored
for growth of many organisms, which means better
decomposition. Also addition of lime can improve the media for
good organisms growth (low acidity).
-
Availability of water in medium soil is higher because of
medium particles size.
Soil preparation methods:
1) Drainage
2) Plowing
3) Disking
4) Harrowing
5) Rolling
Good prepared soil means = smooth soil, free of clods and fine soil
surface, so you can plant even a small seed in a uniform depth, which
means uniformity in germination → high uniform stand.
1) Drainage:
Is the natural or artificial removal of surface and sub-surface water from
an area, many agricultural soils need drainage to improve production
or to manage water supplies.
Its important for:
1. Early preparation of soil (better sandy soil), to reach field capacity
faster.
2. Better soil aeration that is important to plant growth (better root
respiration), and for microorganisms.
3. Improve nutrient availability to plant.
4. Allows soil to warm earlier in spring.
The efficiency of Drainage:
1) Rain full intensity;
2) Soil type;
3) Permeability of underlying material layers.
(50ft-0.5mile is the distance between tile or open ditch).
Drainage is more important in muck soils than in mineral type soils to
increase the activity of microorganisms which required for
decomposition.
It is done by:
a) Ditches: in the first few years of cultivation.
b) Tiles: better because no obstacles to cultivation
practices, save land of ditches, save labors of cleaning
ditches and weed cutting.
Normally they are established at depth of 3-5 ft. (rain
fall intensity, and soil type, are protected from being
destroyed by machines, tiles port to canals or ditches.
2) Plowing:
Is a tool used in farming for initial cultivation of soil in preparation for
planting.
The primary purpose of plowing is to turn over the upper layer of the soil,
bringing fresh nutrients to the surface, while burying weeds and the
remains of previous crops, allowing them to break down, and it allows
better root penetration. It also aerates the soil, and allows it to hold
moisture better.
Plowing depth:
6-8-10 inches, is sufficient in most soils.
Deeper plowing depths means poor surface soil.
Plowing time depends on:
1) Time to plant crop;
2) soil type
3) environmental conditions (rain fall and temp).
*Some advises:
-Shorten time before the planting date.
-Longer time as possible if there is soil improving crop (high
vegetative growth of this crop), which needs maximum organic
matter enrichment.
-If there is no irrigation, its perfect for plowing completely the soil.
-Don’t plow when too wet (causes the formation of clods), or when
too dry (it will destroy soil structure), proper time is when its at field
capacity.
-After certain irrigation or rain fall times, plowing can eliminate
weeds.
-Don’t use heavy machines, deep plowing done gradually to avoid
formation of plow panes.
Main advantages of plowing:
a. Kill weeds
b. Create fine seed bed
c. Mix plant residues
d. Reduce erosion by plowing against slope and collecting water
in unbroken furrows
e. Improving physical and chemical status by good aeration
f. Increase the rate of organic matter decomposition when turned
under
3) Disking:
It refers to the farm implement used, so a "disk" is a type of plow that
uses a round toothed blade to cut the surface of the soil, it does not
break the soil up as deep as other types of plows and leaves a quantity
of plant litter on the surface of the field.
4) Harrowing:
Soil broken up, the purpose is generally to to break up clods and lumps
of soil and to provide a finer finish, a good tilth or soil structure that is
suitable for seeding and planting operations. Such coarser harrowing
may also be used to remove weeds and to cover seed after sowing.
Tools for harrowing are commonly called harrows.
Disking and harrowing done soon after plowing, has the object to level,
smooth either the surface by spike tooth or to pulverize clods and sod
parts turned under by spring tooth harrow that bring them up, then with
harrow smooth surface.
Spike harrow
Spring harrow
5) Rolling:
Heavy clay soils drains slowly, meaning it stays saturated longer
after rain or irrigation. Then, when the sun finally comes out and
the soil dries, it forms a hard, cracked surface, so the remaining
clods and sod after all preparation methods above, could be
crushed by rolling, rotivation, dragging: that means smooth soil
surface, which increases the efficiency of fumigation.
Manures and soil improving crops:
Manure: is organic matter used as organic fertilizer in agriculture.
Manures contribute to the fertility of the soil by adding organic matter
and nutrients, such as nitrogen that is trapped by bacteria in the soil.
Intensive cropping system: to plant two crops per year.
Depletion of the organic matter in higher manner than what plant
residues turned back.
Added organic matter could be decomposed by microorganisms → CO2.
Microorganisms evolve 1gm of good soil organic matter (about
2,000,000 microorganism).
Soil of low organic matter decomposition contains about 100,000
microorganism.
Rate of organic matter decomposition depends on: 1) Moisture of soil
(not too much wet or too much dry); 2) soil type; 3) temp linear relation
ship to certain limits; 4) crop type: as cabbage which causes loss of soil
organic matter more than in case of sweet corn.
Advantages of organic matter addition:
1. Increasing carbon exchange capacity by increasing nutrient
content and colloidal function.
2. Increasing water holding capacity especially in sandy and
light soil, and increasing drainage in clayey soils.
3. Improves soil structure.
4. Increasing soil aggregation by cementing soil particles
which will increase soil permeability to water, and soil
aeration.
5. Increasing the nutrient status of soil.
6. Organic matter releases CO2 by decomposition.
7. Organic manures provide food for soil organisms like
earthworms which are responsible for improving soil quality.
8. Crop rotation is not practiced in vegetable cropping, so the
choices are addition of organic matter or using soil
improving crops.
9. Decreasing soil erosion and leaching by wind.
Manures: important to increase organic matter content than nutrient
enrichment in the soil because the last could be realized by chemicals.
Fresh manure has disadvantage:
At the beginning of it's addition, microorganisms in it compete
with plants on minerals especially nitrate (appears as yellow
symptoms on the plant), but later on when these microorganisms
died (decomposed), it will be a good source of nitrogen for plant.
So it's better to add fermented manure or to do fermenting before
planting.
N manure is slowly available, about 5% annually (decreasing
percentage), there is a problem of leached NO3.
Good for long season crops and successive cycles.
Manure has greater efficiency in case of sandy soils, but at the
linear stage of vegetables growth there should be some addition of
chemicals to substitute manure shortage → intensive cultivation.
Also microorganisms release gibbrellin which has a positive effect
on growth of plant → but it may cause lodging.
Advantages and disadvantages of applying non decomposed manure:
Advantages
Disadvantages
Low loss of important ions by leaching
+ gradual decomposition
Burning effect on plant by rapid
decomposition of urine especially in open
porous soil and increase of ammonia
2.
Desirable organisms are found in
fermented manure
Suffering at early stage by microorganisms
competition on NO3
3.
Non decomposed part improve heavy
soil and affects on aggregation
Interfere with water movement after being
plowed under
4.
Change of some insoluble compounds
to soluble through contact with
decomposed manure (as a function of
heat)
Presence of viable weed seeds and microspores
of disease, which is better to be partially
decomposed
No.
1.
5.
Weed and pathogen killing
Advantages of applying full decomposed manure:
1. Have more available mineral elements and in high concentration.
2. High balanced combination of NPK since k can be obtained from
stalk of weeds and vegetables.
3. No burning effect.
4. Major part of weed seeds presented in manure but not in soil, are
killed by decomposition.
5. Not interfere with soil preparation since decomposed out.
6. There is no N starvation due to microorganisms competition.
Time to apply; depends on:
1. Kind of manure: that from cows applied in advance of planting, it
takes time to be decomposed.
2. Stage of decomposition.
3. Kind of crop (long season → needs amount to be added earlier, while
in short season crop it will be decomposed) advised on crops of high
profit.
4. Rotation system of manure: it's good to apply manure to vegetable
crops or to crops preceding vegetables.
Rate and method of application: depends on:
1) Economic situations
2) Kind of crop
3) Fertility of soil
4) Manure type
From 10-15 Ton / Acre is good supplemented by chemicals.
Hen manure added with lower rate than others because of high N
content.
Methods of application: Broad cast if abundant, or in beds or mixed in
furrows if in limited amounts.
Soil improving crops:
Used to improve organic matter conditions of soil so as to be good for
succeeding crops.
They are divided into:
1. Green manure crops: just planted with soil improvement scope and
turned under while green, cultivated in the same season of crop in
rotation.
2. Cover crops: to improve and protect the soil from both wind and
water erosion, grown in winter time so not to interfere with growth
period of vegetable crop.
•
Root distribution in soil profile gives better enrichment and
distribution of organic matter, and better improvement of soil
structure because it decreases leaching by increasing absorption to
that will be used by soil when turned under.
•
Legumes improve N status of soil.
Selection of soil improving crop depends on:
1. Adaptation of crop to climatic conditions and soil characters.
2. Quantity of vegetative matter released (export).
3. Root characters of improving crop.
4. How much easy to incorporate organic matter often in soil.
5. Time in the year to be planted (soil improving crop)
6. Easy to eradicate the improving crop (remained).
Soil improving crops requires cultivation techniques as
normal crops.
Intensive vegetables cultivation requires high quantity of
organic matter so two soil improving crops could be mixed (in
the presence of coincidence growth between them).
As: Rye (in any soil, resist cold) alone or with Sudan grass,
sunflower, rape, and mustard.
Also legumes could be used (as a source of organic matter,
and conserves Nut, and increases N content).
In summer: clover mixed with alfalfa, cowpea also is good.
Time to turn under the soil improving crop, depends on:
1. Time to plant succeeding crop: if early crop, turned in
early spring, but if late crop, prolonged period to
increase organic matter.
2. Kind of soil improving crop.
3. Growth season of improving crop.
4. Soil characteristics.
5. Climatic condition during growth of soil improving
crop.
•It is desirable to apply N (40-100 pounds/acre) as Ca–N
compound, Ammonium nitrate, and urea, at turning under time
in order to titrate the C/N towards N so as to increase food and
also energy for microorganisms, which is important in the
decomposition of plant material and when microorganisms die
→ N consumed will be available for vegetable crops.
In case of shortage of water: it's better to decrease the •
period of soil improving crops to: keep certain level of
moisture for next crop (vegetable crop), and for rapid
decomposition of plant material from succulent tissues
of soil improving crops than dry material if remain until
maturity which also will be enhanced by temp and water
content of soil.
Commercial Fertilizers
The term used for all material (other than animal manure) applied
to soil to furnish new materials to plant.
Maybe single chemical or compound as (potassium nitrate or
could be a mixture of N P K) or organic materials as bones,
cotton seeds …
They are very important for plant vegetable crop because of:
1. Their high availability to face high demand of vegetable
especially at linear growth stage and intensive cultivate.
2. Provide well balance of different elements.
3. Cheaper, easier, faster to resolve deficiency problem than
manure (especially with presence of irrigation system).
Elements required by plant can be subdivided into:
A. Macro elements: that needed in large quantities for plant growth and
development. It includes: C, H, O (all supplied by the environment),
N, P, K, Ca, Mg, and S.
B. Micro elements: essential to plant as those macro but needed in
small quantities. It includes: Fe, B, Mn, Cu, Zn, Mo, Cl, Co, Na, Si,
and V (vanadium).
It is important to fertilize the soil with adequate amounts taking in
consideration the following points:
1. Slow availability of these elements because of slow change
from complex forms and the mobility of elements, simple forms
could be leached.
2. Shallow root systems.
3. Purity of chemicals: this required diversification in chemicals to
apply and use systems that enable high frequency.
4. Intensive cultivation that needs more fertilizers with which
symptoms of deficiency appear clearly but it should be taken in
consideration the pollution it may cause to water, soil, and the
accumulation in fruits.
So commercial fertilizers: formed from one or more of those elements
needed for plant development
Commercial fertilizers include:
A. Complete fertilizer: contains N, P, K and some oligo elements. For
example a commercial fertilizer contains N P K in the ratio of 10:5:10:
this means that in each 100kg there is 10kg of pure N, while for P and K
they could be expressed as P2O5 and K2O.
Also fertilizer formula is important; it detects the source of each element,
as for example N from urea, P from phosphoric acid, and K from
potassium oxide. Why to know the formula? it helps in determining the
solubility of fertilizers because soluble fertilizers should not be added
in pre planting stage as they dissolved and lose by leaching or with
drainage, or evaporated as gas as there efficiency decreased because
of environmental conditions.
What do fertilizer ratio means? the ratio as 2:1:2 of N:P:K helps to
determine what fertilizer ratio to buy, which serve more for every
certain crop and even for each stage of growth.
B. Fertilizers of one element as those of N, P.
C. Fertilizers of two elements or more as ammonium sulphate
potassium sulphate.
D. Foliage fertilizers: contains minor elements, they are sprayed
on leaves to be more efficient to correct the deficiency
symptoms since they are absorbed by faster by leaves.
Foliages are important to avoid mixing of elements that leads
to precipitation of some other elements (this decreases the
availability of some elements), as Fe with Ca or P →
precipitate Fe.
Also could be applied with certain pesticides → decreases
cost.
Fertilizer management related to:
1) Crop characteristics:
Depth of root: shallow roots needs surface and frequent application,
while for deep roots apply fertilizers in furrow or by drilling machines.
Growth rate: linear stage requires more than othere stages.
Type of crop: foliage crops needs high N ratio, while fruity veg. crops
are normal.
2) Soil characteristics:
pH: alkaline soil solution decreases availability of certain elements as
fixing of P as triphosphate (complex), but its not absorbed by roots, also
Fe, Mn, and B, (but Fe and Mn highly available with acidic conditions
and may become in toxic levels.
-Acidic soil may influence to certain level the assimilation of Ca, Mg,
Mo which preferred sub alkaline soil.
-In general macro elements are highly disponible for plant within
neutral pH range.
Salinity: amount of salts dissolved in soil solution, which affects the
osmotic potential and cause toxicity, plasmolysis and death of plant.
-If salinity is high = fertilization in ration manner with more
frequents and ready irrigation system to wash.
Moisture level: with moistured soil → plant will be more efficient in
utilizing fertilizers, but after certain level availability will be decreased
as a result of high leached amount. (NO3 -, NO2 -, Ca ++, Na +, Mg ++).
Soil fertility status determined by:
1.History of fields records.
2.Symptoms on plant.
3.Soil test.
4.Plant analysis.
5.Rhythm at absorption.
Irrigation
Irrigation (water intake) is an artificial application of water to the
soil. It is usually used to assist in growing crops in dry areas and
during periods of inadequate rainfall. Additionally, irrigation also
has a few other uses in crop production, which include protecting
plants against frost, suppressing weed growing in grain fields,
and helping in preventing soil consolidation.
In contrast, agriculture that relies only on direct rainfall is referred
to as rain-fed farming.
Irrigation is often studied together with drainage, which is the
natural or artificial removal of surface and sub-surface water from
a given area.
a. Infiltration: down ward flow of water through soil small pores.
b. Percolation: down ward flow of water into soil through large
pores and through cracks
c. Capillary: up ward flow or out of soil.
Factors affecting water intake:
A- Some factors increase it, as:
1. Soil cracking: resulted from dryness of heavy soil (clay) → and
this will increase water flow, it can be avoided or decreased by;
continue movement; and spreading manure at the surface.
2. Tillage: more efficient in medium to heavy soil.
3. Organic matter: adding it to soil improves soil texture
especially light soils (it will aggregate and this will increase its
water holding capacity), but if heavy soil it will improve its pore
space and so water penetrates more.
4. Crop rotation: it increase the organic matter content in the soil
since crops used one after one → decay of their remaining
roots and increase organic matter content → and increases
pores as in (3) → because of aggregation.
5. Topography: level soil will increase the chance of flowing water
down ward and this will increase water intake.
B- Some factors decrease it, as:
1. Surface sealing: formation of thin compact layer on soil surface which prevent
or decrease water intake.
2. Soil compaction: formation of compacted layers in cases of:
a. Plow pan: resulted from plowing the soil to the same depth year after year
and below this depth no water intake, so plow pan reduces water
infiltration and percolation.
b. Hard pan: resulted from moving heavy equipment over the soil as lories
and tractors, they creates on lower depth hard pan or could be formed
from very heavy clay layers if found, so it decreases water intake.
c. Salts in soil: especially Na-salts or Mg-salts, which causes soil sealing
which appears as oil spots where water react and combine with Na or Mgsalts causing sealing or blocking of water movement as layer.
d. Sediment in irrigated water: if you irrigate with water that has high
percentage of silt, then after time and by the accumulation of silt the water
penetration and intake will be reduced as pores percentage will be
decreased.
e. Topography: adding water on soil with slope → this will increase the run
off and water intake will be reduced; it can be improved by making
terraces and grading of soil.
When to irrigate:
A) Plant signs that appear on plant, they are:
1. Wilting: includes:
a. Midday wilting: at midday where transpiration is very high
and greater than absorption rate → lose of water from
plants tissues is high, which leads to wilting, but afternoon
plant will recover and targor pressure of cells returns full.
(Plant function is related to targor pressure).
b. Temporary wilting point: if the plant shows wilting at the
early morning → you should irrigate directly because the
plant need more time to recover and return normal.
c. P wilting point: most sever type that may cause damage of
plant with which plant will not recover.
- So irrigation should be done before this stage and not later than
temporary wilting point stage, normally at 50% of field capacity.
2.Color of plastids: light green color means normal plant, but
black green means the plant needs irrigation.
3.Temp.: you come at the midday, just feel the leaves if they are
cool, it means the plant doesn't need irrigation, but if the plant
is hot, so it needs irrigation.
4.Growth rate: plants of well supply of water show steady growth
rate and noticed development, while at water stress → growth
rate will be slow or not noticed. This point is very efficient in
linear growth stage of vegetable crops.
5.Stage of development: for each spp. there is critical point in it's
life cycle at which if the spp. exposed to stress will decrease
their yield as: potato and melon: critical period is from blossom
to harvest
Sweet corn: from tussling – silking (male formation flower-appearance
of style on female flowers).
Onion: during bulb formation and development where 50% or more of
the bulb growth is in the last 20-30 days.
Lettuce: just during heading where 50% of it's growth done in 50 days,
while other 50% are accomplished in one week, so it is critical time (this
week) to irrigate in frequent manner.
Cauliflower: at the time of curd formation. ‫تكون الحامل الزهري‬
Cabbage: during heading, and as head starts to develop.
Tomato: has deep root system, so it needs water from transplanting till
to be established in the soil in frequent way, then with wider interval so
as to encourage root penetration not to remain on the soil surface. At
fruit set → abundant irrigation is required.
Cucumber: shallow rooted crop (60% of root found in upper 30 cm), so
it can't tolerate water stress at any time especially at the beginning
(establishment) and during fruit set.
B)
Soil signs:
1. The availability of moisture in the soil, its measured by:
You can determine it by Auger , take a sample, then feel the sample by
hand:
a. If soil is course (light soil) when catched: stick together but
not forming one ball, it means that it needs irrigation.
b. If soil is medium: when catched, particles crumble from each
other, it means that it needs irrigation.
c. If soil is of fine texture: when catched, particles forming a ball
together but will not form a ribbon, it should be irrigated.
2. Soil moisture tension: measured by Tensiometer, where irrigation
based on soil moisture tension.
So we can summarize the factors that indicate the amount of
irrigation water as follows:
Factor
1) Weather
2) Plant
3) Soil
Less irrigation rate
More irrigation rate
Cool
Hot
Humid
Dry
Still
Windy
Deep rooted
Shallow rooted system
Healthy roots
Damaged root system
In complete crop coverage
Complete crop coverage
Deep soil
Superficial soil
Fine texture
Course textured soil
Low salt content
High salt content
Types of irrigation
1. Flood irrigation: either uncontrolled or controlled flood, this method
used for leaching of excess salts, soil needs before starting the flood a
kind of flattened and start from the upper point of the field.
Disadvantages:
a. Can cause soil erosion especially sloping areas at high flow rate.
b. Consumes large amount of water because by this type every inch² of soil
is flooded with water.
furrow
2. Furrow irrigation: is one of the surface irrigation methods
which classified by the slope, the size and shape of the field,
the end conditions, and how water flows into and over the
field. Furrows provide the irrigator more opportunity to
manage irrigations toward higher efficiencies as field
conditions change for each irrigation throughout a season.
Furrow irrigation avoids flooding the entire field surface by
channelling the flow along the primary direction of the field
using 'furrows,' or 'corrugations'. Water infiltrates through the
wetted perimeter and spreads vertically and horizontally to
refill the soil reservoir
a. Can be straight furrows.
b. Can be zigzag furrows.
c. Not costed but consumes a lot of water.
3. Sprinkler irrigation: called head irrigation because water is ported to
head then by pressure will also be pumped as natural rainfall. No
need to level the land, the design of this system should based on the
equation (water discharged = water intake). If water discharged >
water intake → leads to erosion, this method is more efficient in
increasing seed germination than furrow and better to overcome
frost problem.
Sprinkler system
Drip system
4. Drip irrigation: (save labor cost as well as sprinkler), water is
applied just to the plant, it is highly efficient system and face
the evapotranspiration requirement and control incidence of
weeds diffusion than sprinkler, and control the amount of
water (important at areas of limited water sources as Jordan).
Disadvantages:
a. Superficial accumulation of salts that needs soil washing
from one season to another.
b. High cost since it requires pumps, pool, main line, sub main,
drip lines, drippers, filters. Dripper could be: normal as key
clipp, eye clip…
 Biwall: small pores make in both or one side of tube.
 Via flow: perforated tube where water pass through as if
through natural pores of cloth.
5. Basin method.
Schedule shows some irrigation equipments:
Tensiometer
Onion
Family:
Alliaceae (Amaryllidaceae, Liliaceae)
Genus:
Allium
Species
cepa
Origin:
Cultivated for over 5000 years, the onion is one of the oldest and
most used vegetables in the world. Originated in Iran and West
Pakistan. Cultivated by the Egyptians, Greeks and Romans.
Brought to North America by the Spaniards.
Long considered of medicinal value.
Botany:
The onion is a vegetable composed of successive concentric
layers of leaves. These fleshy and juicy layers of skin are
wrapped in a last layer of paper-thin peel that changes colour
when the onion is dried. There are many different varieties of
onions with colours ranging from white to brown, to red, to
purple. Onion is herbaceous crop, biennial if produced from
seeds, but it can be grown annually if propagated leafy or by
bulbs production. It has shallow root system up to 30cm deep in
the soil, having a number of adventitious roots (1.5mm) from disc
stem, that continue to develop during early growth then with
maturity of bulb → roots will die.Leaf is produced from apical
meristem pushing the older leaf sheath bases to the out side
having hollow blade. Bulb resulted from swelling of leaf bases
while inflorescence appears after vernalization in the 2nd year
forming an umbel shape on terminal point of scape including 502000 flowers. Cross pollination by insects, seed of low viable
duration at room temp (2-4 years), but at low temp and low RH
conditions we can increase the viable period for several years .
Culture:
Climatic requirements: onion is a cool season crop. 13-24ºC,
tolerant to frost, low temp is needed during early stages of
growth before bulbing to avoid halting, good bulbing germination
at 25ºC and growth rate start to decrease at temp degrees higher
than 27ºC. Vernalization is important for flowering. Photoperiod is
important for bulbing, but now new cultivars of various
photoperiod requirements are presented.
Fertilizers:
150-200, 100-150, 150-200 of N, P, K respectively are needed,
avoiding Ammonium ions NH4+ application close to plants since
Ammonia NH3 can induce toxicity to plants .
Moisture:
Since it has shallow fibrous adventitious root system → roots
concentrated in upper 30-50cm, so 380-760mm of water is required
according to location to ensure development, establishing of new formed
roots. So addition is in frequent manner especially at critical stages.
Propagation:
Propagated by seeds (sexual) or by bulb lets, then planted either
seedlings or bulb lets in beds with 35-45cm between rows x 71-10 →
reaching to about 2.2-3.4kg/ha as seeding rate for bulb production while
for green bunching → seeding rate X6 of the previous. In general, wide
rows work very well for onions.
Bulb lets (onion sets):
Produced in fall 1-3cm, and then planted in late winter-early spring of the
following year → to give green or mature onion. Sets are produced by
seeding in good seed bed of light loam soil, 70-110 g/m² (2-4cm²/seed) X
6-12mm depth. If planting density increased then bulb lets size will be
smaller.
Transplants:
If you have 10cm x 35cm → 275,000 transplant that has 3-4 leaves after 812 weeks in nursery and less than 6-7mm in diameter at plant base, so as
to over winter conditions of less than 15ºC at transplanting time.
Bulbing:
An important aspect of onion development is the length of day (photoperiod).
Photoperiod, along with temperature, controls when the onions form bulbs. Longday onion varieties will quit forming tops and begin to form bulbs when the day
length reaches 14-16 hrs, while short-day onions will start making bulbs much
earlier in the year when there are only 10-12 hrs of daylight. Intermediate onions
requires from 13-14 hrs, and very long day onions requires more than 16 hrs → for
induction of bulbing not for flowering
Short day onions: that initiate bulbing at shorter day, than others that means =
bulbing occurs when the photoperiod is longer than the minimum period for CV to
do bulbing which incase of short day 10-12 hrs.
Also temp can affect bulbing: high temp speeds up the bulbing process to certain
limit where at 40ºC of tropics → retards the bulbing. Interaction of photoperiod with
temp: short day x high temp → No bulbing but continue to form leaves.
Short day onions: that initiate bulbing at shorter day, than others that
means = bulbing occurs when the photoperiod is longer than the minimum
period for CV to do bulbing which incase of short day 10-12 hrs.
Also temp can affect bulbing: high temp speeds up the bulbing process
to certain limit where at 40ºC of tropics → retards the bulbing. Interaction
of photoperiod with temp: short day x high temp → No bulbing but
continue to form leaves.
Also: Ethephon (2-Cl-ethylphosphoric acid) spraying on leaves at 1.2g/L
induces bulbing of any onion class and enlargement of bulbs at short day,
can be realized by repeated sprayings.
Harvest:
Bulb onions grown from transplants (seedlings) or sets will need about
3 months to reach maturity. Many onions are ready to pull up and
harvest by late summer, roughly late July or early August. It will be
necessary to gather onions from the soil by hand, they are harvested
with leaves and then leaves are cut.
When their tops have fallen over, onions are fully mature, they are
ready for harvesting. Onions harvests after falling down of leaves (water
stress) then stored in conditions around 0ºC (not much lower).
Curing: to prevent entering of rot organisms through the tops (cut) by
allowing drying in files or to be exposed for current wind for 10-12 days.
If piles → better to be protected from direct sun to avoid scalding
allowing in the same time air circulation. Also forcing heated air at 46ºC47ºC can be pumped through piles for 12-24 hrs
Storage:
The most important factors for proper onion storage are good air
circulation, relative dryness and cool temperatures with low humidity. In
order to properly store onions, they must be well ripened and cured.
Those that are immature, soft, or “thick necked” should never be placed in
storage but used as soon as possible since they are still Juvenile (less
bulb diameter). So, as bulb diameter increased, it becomes more sensitive
to cold storage conditions.
Storage: at 0ºC-7ºC or at 25ºC-35ºC → no sprouting in both cases up to 6
months, while at 15ºC-21ºC poor storing condition even at 40% RH or less
and 3ºC → 1 year storage period.
Rest and Dormancy:
That occurred directly after maturity of bulbs which varies from CV to
other in period where bulbs will not sprout even under optimal
condition of temp and moisture this rest after certain period start to
disappear gradually. Also during dormancy if bulbs expose to
suboptimal → No sprouting then when removed → Root emerges
before leaves if you remove roots → delay.
Sprout prevention in storage:
By using Maleic Hydrazide (MH – 30) that sprayed on crop before
harvest when tops are still green or at least the plant should have = phs
active leaves using 2.2 to 3.4 kg/ha. Also Y radiation can inhibit
sprouting.
Nutritive value: high in energy, of medium nutritive value among
vegetables containing CHO as sucrose glucose, fructose, green onion
tops have high provide a content.
Pest and diseases:
1. Red spider mite at dry climates → will be serious.
2. Trips: as sucking insects from onion tops.
3. Leaf miner that feeding under epidermis → ↓ yield.
4. Cut worms: that can cut off young plants from base.
5. Nematodes and wire worms as soil born pest that attach the
roots.
6. Onion maggots ( ‫ )يرق‬that infest sets and bulbs.
7. Downy mildew: very serious at humid climates.
8. Neck rot by Botrytis ellii attacks bulbs or stalk of onion grown
for producing seeds.
9. Soft rot: by Bacteria → water socked areas → soft watery
tissues.
10. Leaf molds, Black mold, fusarium hasel rot, smut.
11.Viral disease that causes chlorotic → hollow streaking, stunt and
distorted flattening of leaves, mainly by aphids.
Potato
Family:Solanaceae
Genus:Solanum
Species:tuberosum
Solanum tuberosum originated in high lands of Andes (Peru,
Columbia, Ecuador, Bolivia) of South America.
Origin and History:
In 1537 it was introduced to Europe by Spanish Explorers. In less
than 100 years it became a staple crop.
A plant disease known as late blight, spread rapidly through the
poorer communities of western Ireland, resulting in the crop failures
that led to the Great Irish Famine, where millions died of starvation
and other millions migrated to U.S.A, because they are mainly
depending on potato
Botany:
A stem tuber forms from thickened rhizomes or stolons. Potatos are stem
tubers, which are the development of enlarged stolons thickened into a
storage organ. Potato is annual crop which means that the tuber is
produced in one growing season and used to perennialize the plant and as
a means of propagation. Also, its herbaceous, dicotyledonous crop that
reproduced asexually. CM2 No. is 48 of the commercial potato (2n = 48) →
Tetraploid since the diploid is (2n = 24 as in wild potato).
Transp. 2
Stolon: a slender horizontal stem of a plant that grows near the
surface of the ground; it can sprouts buds that can become new
plants; potato tubers grow at the end of stolons.
Is not true one but it is Rhizomes.
Potato Culture:
It is a cool season crop; optimal temp for increasing yield is
16-18˚C. Freezing damage crop and above 20˚C tuberization will
be decreased up to 29˚C, where tuberization inhibited.
For every 1˚F above optimum temp → yield will be decreased
by 4%.
Optimum soil temp is 22˚C, lower or higher temp → retards the
emergence of sprouts, which varies from cultivar to other.
High soil temp seems to increase knobbiness (>29˚c), poor
shape and many tubers in the same stolon
Tuber initiation:
Affected by:
1) Photoperiod: short days will induce tuberization.
2) Temp: if days are long so night temp should be less than 20˚C
where optimal night temp is 12˚C for tuberization and the
sensitive part for tuberization is tops but with no stolon.
3) Low nitrogen level → shift to tuber.
4) High light intensity → enhance tuberization.
So, as potato planted in early spring (tops establishing), and as
weather warm and days are longer → storage begins in tubers.
(Anatomy pf potato tuber)
Growing season of potatoes should be 90-120 frost free
days, where as growing season decrease in northern
latitudes, long days compensate this condition to enhance
tuberization, (20˚C x 85 RH% for about 4 days), and using
presprouted tubers shortens the growing period about 10
days besides removal of apical bud after emergence.
Soil, Water, and Fertilizers
Sandy loam, loam, Silt loam or peat soils give high quality
potatos.
So loose textured, well drained soil of pH of 5-6.5 is the best soil
since high soil moisture leads to formation of large lenticels and
heavy soils give no tubers.
Also soil should be of 60-100 cm depth since roots can reach
below this depth.
A total of 500-750 mm of water is required during the growing
season.
N, P, K: 140-220 kg, 90-100 kg, and 110-220 kg/ha. respectively
according to fertility level of soil which should be distributed
intervals (N) avoiding leaching and excess of N → delay or no
tuberization.
Spacing:
Seed tubers that having 40-60 g/tuber are placed at 5-10 cm
depth x 25-30 cm x 75-90 cm between rows. If seed tuber are big,
then cut into pieces having at least one eye (bud) allowing
heading (suberization) of cuts by keeping them at 18-21˚C, 8590% RH for 2-3 days after being treated.
Normally 2.5 million tons of tubers are needed/ha.
Production of certified tubers:
Start with producing virus-free tubers by tissue culture then
testing eye for bacterial ring rot → Elite I select → Elite II
selection, Elite III → fonnlation tubers → certified that used for →
commercial side process.
Producing commercial cultivars:
By growing the certified tubers in cool region where infected
plants show symptoms on their tops → rouged of plants and
tubers.
Harvesting and storage:
Yellowing of vines means maturity of tubers.
If you want to harvest earlier → vines should be beaten down few days
before harvest → skin formation on tubers.
Careful handling to minimize bruising and formation of black spot.
Under mulch there is no green color.
Curing:
For 4-5 days at 16-21ºC and high RH to heal and suberize cuts which
normally done by storing foundations.
Storage:
Best storage conditions are at 4-10 ºC x 90% RH in dark well ventilated
space to avoid sprout development, disease infection, moisture loss by
low temp, and avoid chlorophyll green color development and solanin
(toxin), (for better taste formation) → death but low temp. Starch converts
to sugar → ↓↓ storage durability which can be overcome by storing them
one week before consumption in 18-21ºC → then sugar converts into →
starch.
Sprout inhibitors:
By spraying plants 2-3 week before harvest with maleichydrazide at 10006000 ppm or by 0.5% solution of chloro IPC (isopropyl-Ntetrachlorocarbamate) and nonyl, or by Arayl alcohol (0.05-0.12 mg/L) in
atmosphere of storage rooms.
These treatments will be effective after the rest period (internal dormancy)
which lasts from 4-15 weeks.
Nutritive value:
Rich in CHO (energy components)
Rich in minerals and vitamins, (good in vitamin C content).
Low in proteins and proti amin A (Isoprene units).
Pests and diseases:
Colorado potato beetle, aphids, leafhopper, wire worm, tuber worm, spider
mites and thrips, early blight, late blight, bacterial ring root, rhyzoctonia,
verticillium, fuzarium and 10 viruses caused by aphids and insects.
Sweet corn
Family:Gramineae
Genus:Zea
Species:mays
(Transp. 3)
Its classified into the following sub-species:
1) Sweet corn sacchorata: the sweetish endosperm and
starch accumulation increase with maturity.
2) Pod corn tunicata: enclosed of kernel in a pod as well as
the ear enclosed in a pod or husk.
3) Flour or soft corn amylacea: soft or flour endosperm.
4) Hard corn or flint corn indurata: field corn that has
starchy endosperm, large kernels of round tops, they
are called roasting ears when harvested at immature
stage which used as vegetables.
5)Dent corn indentata: of corneous, soft, and white starch
endosperm producing a dent character at mature stage.
6)Pop corn everta: small kernels and small ears with major
portion of endosperm.
7)Waxy corn ceratina: that is entirely formed of amylopection
while other subspecies are formed of amylose and
amylopection.
a. Amylopection: is a starchy aqueous solution that set to
shift gel at room temp.
b. Amylase: is a starchy aqueous solution that not gel at
room temp.
Origin:
There are several theories about the specific origin but
it says that sweet corn originated in South America,
Mexico and Central America.
Botany:
Annual herbaceous monocotylodonous plants bearing
by seeds (sexual) → it is monoecious plants with
separate male and female flowers, bearing the tassel
as terminal inflorescence and ears as lateral
inflorescence at the axis of leaves. Shallow rooted
crop. Warm season, frost-sensitive crop. Harvested
organ: immature fruit (typically harvested 18 to 21
days after pollinating).
Culture:
Warm season crop, that needs 70-110 frost-free days, having
21-27ºC optimum soil temp for germination and not less than
13ºC, the optimum temp for growth is 21ºC-30ºC showing at
range of 16-35ºC.
Flowering:
Influenced by:
Photoperiod: short photoperiod promotes flowering, while
long photoperiod takes longer time for flowering. So tropical
cultivars don’t flower in temperate regions until day length
decrease to 12-14 hr day, where remain in vegetative growth
until decreasing and may reach 6m height before flowering.
8 hr day + low temp (below 22ºC) also delay flower.
Transp. 3
Soil, Nutrition and moisture:
Sandy loam-clay loam or in peat and muck soil, 6-7 is the optimum pH but
the range can be extended to 5-8 since it is moderately tolerant to salt and
alkaline.
Needs 100-115 kg, 45-112 kg, and 60 kg of N P and K respectively are
required/ha.
Higher doses of N are more applicable for light soil and for early spring
planting. Also 27.4 million ton/ha of barn yard (‫ )مخلفعا البوعوب‬or 9-11 million
ton/ha of poultry manure are recommended.
Supplemental watering is needed to reach to 300-660 mm/season that
mainly done by sprinkles. At tasseling and silking water stress could be of
great negative effect on plant development that causes stalk rot, low plant
height, low ear development and so the yield. So irrigation when 40% of the
available soil water is depleted and not after that. Growth: normally hybrid
seeds produce more vigorous and higher yield.
Treatments against pests are recommended 2.5-4 cm depth x
90 cm between rows x 20-30 cm between plants.
Thinning can be done when plants reach up to 10-15cm
height.
Pollination by insects or gravity → poor fill kernels resulted of
poor pollination where temp is more than 36ºC with hot dry
wind or at water stress → = or nonviable pollens. 19 days after
pollination → ears ready as vegetable then 30 days to mature.
N stress during maturity → shriveling of kernels while excess
→ lodging.
Table 15.1. Effect of photoperiod on 'major belle' a puerto rican cultivar
Photoperiod
No. leaves
visible at
initiation
Days to tassel
emergence
No. leaves at
tasseling
(hr)
Days to
tassel
initiation
10
26
9.5
66
19.8
13
27
9.7
66
19.2
16
50
17.0
87
25.2
a
Source: Arnold (1969)
a :24 ºC (75 ºF) at 32,000 lux (3000 fc).
Table 15.2. Photoperiod and temperature effect on corn (harrow 691 hybrid)
yield.a
Total plant
dry wt
(g/plant)
Grain yield
(g/plant)
Average
number of
kernel
Wt/kernel
(g/dry wt)
174
57
379
0.192
250
55
399
0.171
20ºC/10 hr
day
220
114
427
0.281
20ºC/10 hr
day +
10 hr low
light
478
194
607
0.338
LSD 5%
27
-
91
0.022
Treatment
30ºC/10 hr
day
30ºC/10 hr
day +
10 hr low
light
a
: Data from Hunter et al. (1977).
Table 15.3. Effect of cool and warm temperatures on development golden cross
batman sweet corn
Temperature
Treatment period
Planting to fourth
leaf stage
Warm
Cool
Warm
Cool
Fourth leaf to ninth
leaf stage
warm
warm
Cool
Cool
Average number of leaves
Main stalk
17.5
17.5
14.3
14.9
Below first ear
12.6
12.3
9.8
9.6
Above first ear
4.9
5.2
4.5
5.3
Showing at tassel
initiation
9.3
9.5
6.5
6.3
Source: Arnold (1969).
a Warm: 35ºC days/26.7ºC nights (95º/80ºF); cool: 21ºC days/12.8ºC nights (70º/55ºF); day
length: 14 hr at 32,000 lux (3000 fc)
Stages in growth of Corn
Mature seeds
100
Sweet corn
harvest
Kernel
80
Silking
% of total
Growth
60
Cob
Tasseling
40
Stalk
20
Leaves
0
25
50
75
85
Days after Emergence
100
0
115
Harvest and storage:
At 16ºC (storing conditions) corn remain in a marketable
conditions for 5 days while at 29ºC→ 1-2 days that is incase of
milky harvesting or fresh which can be eaten freshly or freezed
or canned.
Harvesting done by machines, at the early morning during cool
temp condition of the day then immersed in ice water to keep
temp lower than 10ºC then transfer into cooler to be stored at
nearly 0ºC and high RH, so as to decrease the rate of sugar
transferred into starch → ↓ sweetness.
Under vacuum cooled → ears will be wetted down before
packing in ice condition to keep satisfactory quality for 1 week
while at 10ºC → 2 days.
Development of CVs that has gene sugery 1 which prevents
starch building from sucrose and that has gene brittle 1 which
inhibits breaking down of sucrose into fructose. Both 2 genes
allow sweet corn to remain sweet for several days without
refrigeration and extend the time for harvest.
Pest and diseases:
Corn ear → insecticide worm, smut that can be controlled
by resisting cultiovars and crop rotation, ear mold or pink
rot which needs increase irrigation and high temp, sugar
cane mosaic virus, and by insects.
Nutritive value:
High in energy, inprovitamin A, low in essential amino acid
lysine, but new cultivars have developed showing high
lysine content through out the gene (Opaque 2.) which
also increases tryptophan proportion.
Lettuce
Family:Compositae or Asteraceae
Genus :Lactuca
Species :sativa
Origin:
East Mediterranean sea (Asia minor, Iran, Turkistan area).
Cultivated type is probably derived from wild lettuce: Lactuca
serriola.
Botany:
Annual herbaceous plant, its most often grown as leafy vegetable,
with milky juice. There are six commonly recognized Cultivar
Groups of lettuce which are ordered here by head formation and
leaf structure; there are hundreds of cultivars of lettuce selected for
leaf shape and colour, as well as extended field and shelf life, within
each of these Cultivar Groups:
Cultivar Groups subdividing into:
1. Crisphead, also called Iceberg
2. Butterhead forms loose heads. Its leaves have a buttery
texture.
3. Romaine, also called Cos.
4. Looseleaf has tender, delicate, and mildly flavored leaves.
5. Stem lettuce "stem-use” types (called celtuce).
-
(Having as basic chromosomes number of 8-9 (as n)).
Culture:
Cool season crop forming heads at 10-20ºC as mean
temp, but at 21-27ºC lettuce bolting.
It is required cool nights for good quality avoiding
bitterness that related to high temp building of starch.
High moisture and low temp means good head
formation, while low moisture and high temp leads to
disorders formation as tip burn where tips of inner
leaves in head show necrosis.
Well drained fertile soil of pH 6 is most desirable for
growing lettuce, fair tolerance to salts needing about
50-100-150 kg of N from various Article.
Seeds are sown ½–1cm depth x 35cm between rows
x 20-30cm between plants (thinning done when plants
reaching this density).
Possibility of low space for leafy crops mainly transplanting.
Also, seed can utilize about 8kg of P, 130kg of K, and 22 of
Ca/ha depending on nutritional status of soil which can be
incorporated during soil preparation except N that can be
divided into 2-3 parts; one at preparation, 2nd after thinning,
and the last one month before harvesting (50% of crop is
realized at last 2 weeks).
Moisture is highly needed along growth cycle, but in
frequent manner since lettuce has shallow root system.
It is rich in Vitamin A, C and good in minerals as Ca and P.
Harvest and storage:
Needs 60-80 days as cycle during summer to fall, and 90-145 days
during winter and spring, it is highly perishable crop since it has very
high water content. So, it should be precooled to about 1ºC x 95-97% of
RH, either incase of storing or transport → remain for 10-14 days in
good conditions while fast deterioration occur with ↑ temp.
Pests and diseases:
1. Aphids: transmit other diseases, cut worm, army worm, cabbage
loopier, corn ear worm, leaf Hooper, spider mite.
2. Mosaic (seed born disease).
3. Spotted wilt.
4. D.M., P.M., Sclerotina, Anthracnose, bottom rot.
5. Tip burn is a physiological condition that causes lettuce to "die back"
at the edges of the leaves (also rib discoloration). It results from a
change in the moisture relationship between the soil and the plant. Clip
off any brown leaf tissue and use the remainder of the leaf. Frequent
light watering helps to prevent tip burn. Some varieties are resistant to
this condition.
Growth expressed as leaf area per plant for spring, summer ,and fall lettuce.
12
11
10
Fall
9
Mean leaf
area per
plant1000 CM
2
8
7
Summer
6
5
4
3
Early Spring
2
1
70
63
56
49
42
35
28
21
14
Days before First Harvest
7
0
Cabbage and Cauliflower
Family:Brassicaceae (also called Cruciferae)
Genus:Brasica
Species:Oleracea
Cultivar group: Capitata, Botrytis
Called Cruciferous vegetables, they are one of the
dominant food crops worldwide.
The family contains well-known species such as
Brassica oleracea.
Brassica oleracea var. Capitata
Brassica oleracea var. Botrytis
cabbage
cauliflower
Origin:
Native to the Mediterranean region, where it is common along the
seacoast. Originated from wild type Brassica oleracea var.
sylvestris that presented along the Mediterranean Sea coast and
along the Atlantic coast where cabbage from Western Europe,
and cauliflower from Mediterranean sea coast.
Cabbage was used for medical purposes as diarrhea and
headache and as a remedy for poisonous mushrooms.
Botany:
They are biennial herbaceous crop (but if leafy crop it becomes
annual), propagated sexually by seeds, pollinated by insects
forming Silique fruits in which seeds are found.
They are cool season crops forming qualified crop as growth in
low temp.
Cabbage: show best growth at 15-20ºC, over 25ºC
growth is arrested having 0ºC as minimum, but
cabbage with hardening can survive up to -10ºC (for
short period of time).
Young plants of less than 6mm in stem growth can
tolerate colder and hotter temp than older plants.
After juvenile stage, the plant flowers when temp less
than 10ºC for 5-6 weeks, while if temp is lower, the
plant will flower in shorter period of time.
So it is not photoperiod sensitive, but vernalization
effect.
Cauliflower: early type (snow ball) can form curd at 17ºC as optimum,
when having 14-20ºC → is good range for increasing quality curd, while
from 20-25ºC → poor quality curd, so selection provides cultivars that
can show good curds at temp higher than 20ºC which is good for tropical
conditions.
Early type doesn't need cold temp for curd.
Late type (winter): it requires cold period before heading, so it should be
sown not too late, and its better to use intermediate types that form
heads below 10ºC.
Early types show not true flowers when curd but undifferentiated shoot
apices while winter or late one (which need cold temp treatment) show
true floral primordial.
The East Indian cauliflower is tolerate to high temp and to high RH%
since it is resulted from various selections → adaptation to local climate
and for earliness in addition to crossing of local x snow ball resulting in
Indian cauliflower as Early Potato, Early Market and Early Benares which
can produce good curds above 20ºC having 30ºC as maximum → (large
curds) and having 23ºC as minimum. This doesn't need low temp as
snow ball or winter to make seeds (16ºC is low enough to give seeds).
Types of defects in cauliflower curd:
1. Blindness: injury by low temp, slightly above 0ºC when plants
are at 7-leaf stage, or by freezing injury during early curd stages
→ x curd.
2. Button: as a result of transplanting quite large transplants
which directly go into the generative of flowers phase
producing smaller than normal heads. Also poor environmental
conditions which arrest vegetative growth → buttoning.
3. Ricey: disorder of head (like boiled rice) as a result of
development of small white flower buds which related to high
temp (20-25ºC) during curd and more by rapid growth and heavy
N side-dressing.
4. Leaves in curd: as exposing to warm temp after curing →
reversion to vegetative growth.
5. Green curds: excessive exposure to sunlight → chlorophyll.
6. Head shape: low temp (below 14ºC) promotes flat heads, while
high temp (over than 20ºC) promotes formation of conical
shaped heads.
Propagation:
Either by direct seeding or transplanting, this is more practiced in
cold climate and for hybrid seeds.
Hardening of seedling before transplanting is important by being
exposed gradually into low temp for about 10 days or by water
stress or by both together. Then transplanted at 90 x 90 cm apart
incase of large heeded cabbage or at 45 x 90 cm incase of small
heads, watering of soil during or directly after transplanting is
important.
Soil:
Cole crops grow well in all soil types, but do best in rich sandy
loam, loam or silt loam which should be slightly acidic to slightly
alkaline (pH of 6.0-8.0), but if too acidic → lime attition.
Fertilization:
They need about 110 kg, 22-110 kg, 70-220 kg of N, P and K
respectively.
Quantity to be added depends on richness of soil.
Nitrogen shortage leads to low yield, delays maturity, low quality, and
low firmness.
Phosphorus shortage causes "whiptale" of cauliflower.
Harvest and storage:
Reach the maturity of full head size, which is related to cultivars and
can be detected by experience of farmer.
Crop should be stored at 0ºC x 95-98 % RH where cabbage can remain
up to 6 months while cauliflower up to 1 month.
Nutritive value: rich in vitamin C, provitamin A, good level of protein.
Main pests are aphids, warms, botrytis, P.M.
Vegetables legumes
Family: Leguminosae
Legume: botanically is a plant in the family Leguminosae.
Annual or pereninal dicotyledon.
At immature stage → vegetables eating pods and/or seed.
List of vegetable legumes in pages 253, 254, 255.
They are mostly of alternate, compound pinnate leaves showing
butter fly flower.
Pollinated either by self or cross pollination with mainly Bees
for cross.
They are Hypogeal (cotyledon as in pea → remain under soil
surface) or Epigeal (over soil surface) as beans.
Nitrogen Fixation:
Legume plants are notable for their ability to fix atmospheric nitrogen,
due to a symbiotic relationship with certain bacteria known as rhizobia
found in root nodules of these plants, through out nitrogenase enzyme
that presented in bacteria and activated by Fe and Mo.
When plant dies, N levels in the soil will be increased.
Peas
Pisum Sativum
Origin and Botany:
Originated in the eastern Mediterranean region, and in the near east.
Annual herbaceous plant, with a life cycle of one year. It is a cool season
crop grown in many parts of the world; planting can take place from
winter through to early summer depending on location.
Peas have showing alternate leaves.
Peas have both low-growing and vining cultivars. The vining cultivars
grow thin tendrils from leaves that coil around (climb) any available
support
Terminal tip is tendril → called indeterminate, or could be of bushy or
dwarf growth habit → called determinate, showing flower at the axil of
leaves which usually self pollinated.
Showing Blooms at 9-10 leaves in early cultivars and at 15-16 leaves in
late cultivars, having 2-10 seeds /pod.
Seeds can be smooth or wrinkled.
Culture:
Cool season crop, grown in wide range of soil type from light
sandy loams to heavy clays with presence of draining conditions
since pea can not tolerate water soaking status, having pH range
of 5.5-6.5 as optimum.
In Temperate regions peas planted in spring to avoid sever wind
or in late fall where frost effect is still tolerable.
In Tropics and Subtropics peas planted in high elevation which
remains cool. They are sown at 2-4 cm depth x 5cm between
plants x 38cm between rows using 70-110 kg/ha of seeds
showing on increase in germination rate up to 18ºC then it will
decrease.
If the field has not been used for cropping of peas in the resent
years then → seeds should be inoculated with Rhizobium
bacteria before being planted.
Staking is needed for climbing types, if dying → yield is lower.
N, P added at rates of 90 kg/ha, and about 100 kg/ha
respectively, they are mended as preplanting since its later in N
fixation will be used.
If soil status is of low K, then a balanced fertilizer of 4-12-4 NPK
will be used.
Peas grow best at mean temp of 13ºC-18ºC → mature in 57-75
days according to cultivar.
Noticing that before bloom crop can with stand some frost
while at flowering and pod production become susceptible to
frost.
Harvest and storage:
At full pods stage, not hard or starchy seeds, under cool
conditions, it can remain for longer period than at warmer
condition where starch accumulates rapidly, (quality lasts for few
days), while with cool conditions it can last for longer period.
Either by hand, or machine and separations by flotation →
various species gravity, then after harvest → should be cooled
quickly at 0ºC to decrease the conversion of sugar into starch
and to decrease respiration rate.
So, seeds can be stored for 3 weeks at 0ºC, or for 2 weeks at 5ºC
especially in controlled atmosphere (5-7% CO2).
Pests and diseases:
The pea leaf weevil is an insect that damages peas and other
legumes, (damage plant and pods).
Aphids, leaf miner, wire worn, nematodes.
Bacterial blights: caused by water socked lesions, P.M., D.M.
Yellow leaves, pea mosaic as viral diseases → stunting and
mottling of leaves.
Crop rotation can help in controlling diseases.
Common Bean
Phaseolus Vulgaris
Origin and Botany
Originated in Central America (from Mexico to Pero).
warm season crop (in tropics).
Its is an herbaceous annual plant with alternate trifoliate leaves.
Indeterminate and bushy or dwarf, grown up to fleshy pods
(immature seeds).
Indeterminate reaches to 2-3 m height, while determinate
reaches from 20-60 cm, where after 4-8 leaves terminating with
inflorescence showing self pollination (self fertilized).
Forming 4-12 seeds/pod of 0.7 – 1.5 cm in length /seed,
weighting 0.2 – 0.6g/seed.
Culture:
Warm season crop (that makes germination faster), it
germinates at 30ºC as optimum, and stops at 10ºC of soil temp.
At 35ºC germination % is decreased, and if air temp less than or
equal 10ºC, it can injure seedlings.
They are planted at 5-10 cm apart x 60-90 between rows x 2-4
cm depth using 22-55 kg/ha, which should be treated with
fungicide (pesticides) before being seeded. Handling of seed is
important since cracked seed coat or cotyledon → have low
germination %.
Light airy of good drainage soil is the best for growing and for
bacterial activity of N-fixation.
Inoculation with Rhizobium bacteria is important if the field was
not cultivated with been in the recent years.
Preplanting fertilization of 65-110 kg of N/ha, 100kg/ha of P,
70kg/ha of K can be dressed beside row of plants. Also well
decomposed manure be used.
In temperate regions, it is planted in spring after frost danger
finished.
In hot humid tropics diseases will develop rapidly, so plant it in
medium rainfall areas.
Indeterminate beans need support to climb.
Moisture stress will decrease yield drastically at flowering and
pod formation.
Increase temp at flowering → makes abortion; hot dry winds
destroy the delicate flowers.
Some cultivars have been developed to tolerate high temp as
California Red that set pods at 38ºC at anthesis stage
Harvest and storage:
Need 45-80 days to harvest pods according to cultivar, dwarfing
cultivars needs less time.
The harvest of pods is when plant have grow to 3/4 of their
maximum length (full size), and when seeds are succulent.
Storage: at 5ºC can remain up to 25 days, below this range (02.5ºC) induces chilling injury within 10-12 days.
Above 5ºC the storage life decreased as temp increased, where
at 25ºC pods will be at fair condition after 4-5 days.
Pests and diseases:
1. Anthracnose of common bean: causing circular sunken spots
with black edges and pinkish center → free seeds.
2. Common bacterial blight: Red spots on stem and pods → may
cause plant defoliation in sever cases.
3. Bean common mosaic virus: Curley top and mosaic viruses →
induces stunt, deformed, and curling of leaves. It is transmitted
by aphids forming necrotic mosaic patterns on leaves.
4. Aphids, Mites, Thrips, White fly, and nematodes.
5. P.M. that can be controlled by sulfur dust Rust in cool region →
resistant cultivars are used.
Nutritional value:
Good source of cholesterol-lowering fiber
It provides virtually fat free high quality protein
Red lima Bean which is almost like common Beans.
Tomato
Family:Solanaceae
Genus:Solanum
Species:Lycopersicum
Synonyms: Lycopersicon esculentum
Origin:
Native to South America, Mexico and Central America.
Botany:
Tomato plants are vines, typically growing above the ground if
supported.
Tomato plant vines are typically pubescent, meaning covered with fine
short hairs. These hairs facilitate the vining process, turning into roots
wherever the plant is in contact with the ground and moisture, especially
if there is some issue with the vine's contact to its original root. It is
Tomato plants are dicots, herbaceous, annual shrubby plant in temperate
zones, or could be perennial of short life in tropics.
Can be determinate (bushy compact growth), and indeterminate.
Climate:
Adapted to wide range of climatic and soil conditions → so it shows
wide distribution all over the world either protected or in open field of
tropics.
Temp means should be over 16ºC, but if temp drops below 12ºC tomato
gets chilling injury especially if it remains for long period below this
degree.
The optimum range is 21-24ºC, but the minimum soil temp for seed
germination is 10ºC, while 30ºC is optimum and 35ºC is maximum.
Also, if light intensity is more than 1000 foot candle → it will affect
negatively on growth and flowering, but if light intensity falls down →
then supplemented light is needed to increase the photoperiod.
Flowering and fruit set:
If temp degree is more than 38ºC for 5-10 days → this will cause
poor fruit set since the pollens and eggs will be destroyed.
After anthesis (flowering), if temp is more than 38ºC for 1-3
days → this will also cause poor fruit set since embryo
destroyed.
If minimum night temp is more than 25-27ºC for few days → this
will cause poor fruit set before and during anthesis except
incase of tropical cultivars that can tolerate this level.
At 10ºC or below → abortion.
Using of IAA and gibberellins can increase fruit set avoiding
puffy fruits by Gibb presence.
Fruit Ripening:
Tomatoes are often picked unripe (and thus colored green) and
ripened in storage with ethylene. Unripe tomatoes are firm. As they
ripen they soften until reaching the ripe state where they are red or
orange in color and slightly soft to the touch.
Ethylene is a hydrocarbon gas produced by many fruits that acts as
the molecular cue to begin the ripening process.
Tomatoes ripened in this way (ripened in storage with ethylene) tend
to keep longer but have poorer flavor and a mealier, starchier texture
than tomatoes ripened on the plant. They may be recognized by their
color, which is more pink or orange than the other ripe tomatoes' deep
red, depending on variety.
Optimum ripening temp is from 18-24ºC, but less than 13ºC poor
ripening and slow, and below 10ºC chilling injury and → no fruit
ripenes.
32ºc green mature fruit will not formed red color since lycopen (one of
the most powerful natural antioxidant) is inhibited → yellowish color of
ripen fruit in storage.
Also more than 40ºC as mean temp → fruit remains green since
chlorophyll degrading mechanism is inactivated.
Culture:
1. Soil: Sandy loam to clay loam of high organic matter content,
pH range is from 5.5-7.0, plant can't with stand flood for long
period, so well-drained soil is important.
-
Planting in high beds avoiding using infested soil with
nematodes or bacterial wilt, using also resistant cultivars
to fusarium wilt strain and verticillium wilt in infested soil.
-
Incase of poor soil, 112, 22 kg N, P, K /ha are used,
incorporating about 11, 17 of N, P below seeds (during
land preparation) and the rest as plants reach up to 15-20
cm.
-
Also manure is recommended and N is important to
increase yield either direct seeding or transplanting at 3040 cm apart x 1.0-1.25 m between rows for indeterminate
and 50-60 x 1.25-1.5 for bushy plants.
2.Moisture: over watering is detrimental, when plants are small →
frequent watering produce low quality fruits, so frequent watering
becomes less as plant gets older (because of more efficient root
system).
-
Roots can reach 120-150 cm deep in the soil or more unless it will
be blocked by hard pan or reach layer or water table.
-
At cool conditions, the ETP from tomato field reach to 0.3 cm/day
while at hot conditions → it reaches 1 cm/day, as ETP.
-
B.E. Rot is physiological disorder related to un uniformity in water
availability and to Ca deficiency.
Harvest and storage:
-
Tomato requires about 60-90 days to start the harvesting of fruits
(depending on the cultivar, climate condition = temp and
photoperiod).
-
For fresh market, it is harvested at fall green mature stage then
ripened during transportation or in storage, which should occur at
temp degrees more than 10ºC since below that temp chilling injury
happens, as temp is more than 10ºC the rate of ripening will be
faster.
-
Light is also important for development of red pigment lycopene.
Table: Maturity stages of tomato ripening are:
Stage
Days from
mature green
at 20ºC
Description
Immature
green
-
Still ↑ in size, angular in shape, dull
green, immature seeds that not
germinate.
Mature green
-
Bright green to whitish green, rounded
waxy skin, seed embedded in gel,
they are mature and can germinate
→ only and not before this stage →
can ripen.
Breaker
2
Pink color at blossom while the placenta
is pinkish.
Turning
4
Pink covering 10 – 30% of fruit starting
from blossom.
Pink
6
Up to 30 – 60% is of pink – red color.
Light red
8
Up to 60 – 90% is of pink – red color.
Red
10
At least 90% of fruit of red color.
Storage:
Mature green should be stored at 13-18ºC x 85-90% of RH where no chilling
injury and fruits will ripen at temp degrees more than 18ºC.
Rapid ripening up to 30ºC, but more than that temp, red pigment not
formed, fruit color is orange to yellow.
Pests and diseases:
1. One common tomato disease is tobacco mosaic virus, and for this
reason smoking or use of tobacco products are discouraged around
tomatoes. The signs are blotchy yellow and green spots on plant
leaves.
2. Various forms of mildew and blight are also common tomato afflictions
as verticillium and fusarium wilt which causes yellowing of leaves and
reddish brown color of vascular stem system.
3. Nematode that makes knot, like swellings of roots → but resistant
cultivars are available.
4. Phytophthora as soil born diseases due to wet soil.
5. Bugs, worms, and mites.
6. Thrips that cause spotted wilt vines.
7. Tomato Yellow Leaf Curling Virus (TYLCV).
Nutritive value:
1. Tomato fruits produce the most powerful lycopene,
carotene, anthocyanin, and other antioxidants.
2. Ripened tomatoes are good source of vitamin A
(provitamin), and when ripened on vines, it’s a good
source of vitamin C, while if its red off → it has low vitamin
A and vitamin C content.
As weeds parasites: orobanche:
Eggplant
Family:Solanaceae
Genus:Solanum
Species:melongena
Solanum melongena
Origin:
Native to India.
Botany:
The stem is often spiny
The fruit contains numerous small, soft seeds, which are edible, but are
bitter (even if mature or low water levels) because they contain (an
insignificant amount of) nicotinoid alkaloids, unsurprising as it is a close
relative of tobacco.
It is a delicate perennial often cultivated as an annual.
It grows 60-120 cm height, bearing oval shaped or elongated oval fruits
showing indeterminate growth.
Most fruits are purple to blackish purple skin color with white flesh.
Yellow skin is the indication of fruit maturity.
Climate:
Warm season crop, so it needs continuous warm season during
growth up to fruit maturity, having 22-30ºC as optimum, 17ºC as
minimum → so night also should be of warm weather where
pollen deformity increase at 15-16ºC, so it should transplanted
during warm spring especially in northern hemisphere.
Long fruit cultivars are more tolerant to high temp.
Flowering starts after 6th to 14th leaves formation (early to late
according to cultivar) noticing that eggplant is insensitive to day
length for flowering.
Culture:
Good light intensity is required.
Preferring soil of pH from 5.5-7.2, avoiding flooding of water since it
causes root rot.
Light sandy soil if planted in early spring (get ready and warm earlier),
or it can be planted in loam soil for late production.
If rain fall is high, it is planted in raised beds and at water shortage →
but this gives poor fruit color and bitter fruit taste.
Optimum soil temp for seed germination is 30ºC having the range of 2035ºC.
Seedlings are transplanted at 2-3 true-leaf stage.
Also, it can be propagated by layering of stem → adventitious shoots
from immersed nodes, then rooting branches will be detached as new
seedlings.
IAA and NAA growth regulators (plant hormones) can be used for
cuttings propagules.
Requires 150 kg/ha of N, P, and K.
Harvest and storage:
Needs from 75-90 days from transplanting to harvest of first fruits that
can continue at favorable conditions up to 2-3 month (according to
cultivar, climatic conditions …).
Also can be rejuvenated by pruning back of unproductive diseased free
plants then provide nutrients and water in proper manner.
Harvesting done at full size fresh fruits (before seed maturity which
becomes yellow in color).
Storage:
At 10-15ºC x 85-90% RH → remain 10 days with good quality, while below
10ºC chilling injury occurs then after removing from such storage
conditions, pitting and decay occurs after several days at room temp.
Pests and diseases:
Many pests and diseases which afflict other solanaceous
vegetables, such as tomato, pepper , and potato, are also
troublesome to eggplants. For this reason, it should not be
planted in areas previously occupied by its close relatives.
Four years should separate successive crops of eggplants
1. In tropical regions: eggplant Lace lug, aphids, mite leaf hoppers,
flea beetles, fruit borer, nematodes.
2. In temperate regions: flea beetles, potato beetles, aphids, spider
mites, nematodes.
3. Black wilt, Anthracnose, verticillium (fungal disease), mosaic
virus, fruit rot.
Pepper
Family:Solanaceae
Genus:Capsicum
This Genus Capsicum
includes many species, as:
1- Capsicum annuum: Sweet pepper
2- Capsicum frutescens:
Chili pepper
Origin:
Native to Mexico, Central America, and Northern South America
(Andes mountains).
.
Botany:
Annual in temperate regions, and perennial in tropical regions.
Self-pollinated crop (on Bell-like Pod-like berry fruits, (pungent or non
pungent) cultivars.
Needs slightly high temp than tomato for growing since it is more
sensitive to cool and to wet weather.
Hot cultivars are more tolerant to high temp than sweet cultivars.
Below mean of 16ºC → no fruit set as well as over 32ºC.
Maximum temp for fruit set of bell pepper occurs between 16-21ºC.
Culture:
1. Warm season crop, so it needs warm climate and it has long growing
season showing tolerability to extreme hot weather than tomato or
eggplant.
2. Favoring light, fertile, well-drained soil.
3. Can be transplanted or seeded directly, but after frost period
showing optimum germinating temp of 30ºC and 35ºC as maximum.
4.They are planted at 40-60 cm x 75-90 cm between rows.
5.It needs: 170-220 kg/ha of N, and 22 kg/ha of P, while K is not
added unless its availability in soil is low.
Harvest and storage:
Needs 60-90 days from transplanting to fruit harvest (immature) at full
size and still green incase of bell pepper.
Also hot pepper is harvested for fresh consumption while still green, but
for processing it is harvested when ripe (red color).
The best storage temp is 7ºC-10ºC where green pepper can remain 10-15
days below this range → chilling injury causing cell to die and fruit
decay.
Pests and diseases of pepper:
1. Flea beetle, Cut worms, aphids, vegetable weevils, grace
hoppers, wire worms, corn seed maggots, leaf miner, and
caterpillars where these mainly damage plant and/or fruit.
2. Tobacco mosaic virus, tobacco etch virus, potato Y virus and
cucumber mosaic virus, curly to P virus that causes curl up
ward and yellowing of old leaves, spotted wilt which causes
die back of growing plants.
3. Nematodes: gall formations on the roots.
4. Phytophthora root rot: rotting of roots under high temp and
high soil moisture, so good management of water application
is important.
5. Seedling damp-off by Rhizoctonia solani.
6. Pythium and Phytophthora which attack seeds and seedlings
before being emerged throughout the soil.
Nutritive value:
1. They are rich in pro vitamin A, vitamin C at mature stage.
2. Capsecin is the active component of chili peppers, it is
responsible for pungent flavor, it concentrates in septa and
placenta tissues of fruit and in seeds of hot pepper.
Cucurbits
Generally:
Plants of the family Cucurbitaceae are called cucurbits.
Most are climbing (twining, tendril-bearing plants) or prostrate
(as gourd).
They are dicotyledonous, tropical or subtropical (few of
temperate origin).
Most of the plants in this family are annual vines, some are
perennials (Cucurbita ficifolia) = figleaf or buffalo gourd = ‫)يبطين‬.
All are frost sensitive.
Mainly for fruit consumption.
Flowers are unisexual, with male and female flowers on different
plants (dioecious) or on the same plant (monoecious).
Sex expressions are:
-Hermaphrodite: has functional ♀ and ♂ flower parts (perfect
flower).
-Monoecious: plants has both ♂ and ♀ flowers.
-Gynomonoccious: plants have some hermaphrodite and some ♀
flowers.
-Andromonoccious: plants have some hermaphrodite and some
♂ flowers.
-Trimonoccious: plants have hermaphrodite and ♂ and ♀ flowers.
-Gynoecious: plants all flowers as ♀ flowers.
-Anaroecious: plants all flowers as ♂ flowers.
Dioecious: have ♂ flowers in plants and ♀ on others
Most cucurbits showing extensive root system, trailing stems
with branches arised from nodes, simple leaf of 3-5 lobes
showing also tendrils that born from leaf axil (except in bush or
dwarf squash cultivars).
Fruit is an inferior berry or pepo.
Considered as warm season crop, day-neutral crop, as
photoperiod (12 hr days).
Cucumber
Family:Cucurbitaceae
Genus:Cucumis
Species:sativus
Cucumis sativus
Origin:
Cucumbers originated in India, since Cucumis hardwickii is the wild type
of cucumber that found in Himalaya.
Botany:
The cucumber is a creeping vine that roots in the ground and grows up
trellises or other supporting frames, wrapping around ribbing with thin,
spiraling tendrils. The plant has large leaves that form a canopy over
the fruit.
It is annual herbaceous cultivated for immature fruits, prostrated reach
up to 1-3 m, 3-5 lobed simple leaves and angled stems.
It is monoecious, where under long days and high temp, it gives high
number of ♂ flowers than ♀ flowers, but under short days it gives high
number of ♀ flowers than ♂, although it is day neutral.
The main vector of pollination is bees while the parthenocarpic fruit
cultivars don’t need pollination.
Gynoecious lines are used to produce F1 hybrid seeds using of
ethephon (spray) → only ♀ flowers are produced show white or black
spins or fruits, white is the marketable character since it retains the
green color for long period, while black spin fruits are used for picking
since better color retention will be occurred as fruits kept in brine.
Culture:
Warm season crop showing best growth at 18-30ºC, and suffer from
chilling injury below 10ºC.
It needs well drain fertile loam soil of pH range from 6.5-7.5.
Transplanting of seedlings: if naked, it is difficult (but with growing
media, it becomes good), or by direct seeding, (hard to transplanting
since the rate of vegetative growth is higher than root formation for
new transplantings).
Germinating at 25-35ºC as optimum temp needs about 3 days.
Spacing is from 30-45 cm in rows x 1.2 m apart or in beds of 90-120 cm
width.
It needs 70, 110 and 70 kg/ha of NPK, where N can be divided in two
halves, first halve during soil preparation, and the remainder is applied
either frequently (with irrigation water) or as a side-dressing after
plants are thinned at 3-4 true-leaf stage.
Adequate soil moisture is needed for good yields (since fruit has 95%
water) especially in tropical (dry regions), when temp increase during
plant development in the growing season where the minimum of 400
mm of water should be provided to ensure good yield production.
Harvest and storage:
For fresh market: fruits are harvested before reaching fully elongated
and mature seeds (when seeds are still succulent).
For picking: fruits can remain on plant for longer period.
A period of 55-70days is needed from planting to first harvest
according to climatic conditions, cultivar …
Storage:
If storage temp lower than 10ºC → chilling injury suffering and
shriveling of fruits can occur, so the optimum storage condition is 12ºC13ºC x 95% RH, while at 15ºC fruits yellowing and faster degradation are
occured.
If fruits are kept in plastic packages, then fruits need longer duration
since plastic bags retards moisture loss.
Pests and diseases:
Cucumber beetle, squash bug, melon aphids, Nematodes,
fusarium wilt, Anthracnos, D.M., P.M., curly top mosaic virus,
squash mosaic virus, Botrytis, Sclerotia.
Nutritive value:
1. High water content, about 96%, so it is a good source of minerals
and also vitamin C.
2. Bitterness is related to cucurbitacins that concentrated in the upper
part of fruit (near connection to stem) and also influenced by
growing conditions as water stress.
Muskmelon
Family:Cucurbitaceae
Genus:Cucumis
Species:melo
Cantaloupe: Cucumis melo
Honeydew: Cucumis melo
Origin:
Tropical and subtropical west Africa as primary origin, while Iran,
southern Russia, India and east China is the secondary one.
Botany:
It is monoecious or andromonoecious, annual plant, showing long
trailing vines (prostrated) but shallow lobed (more rounded) leaves.
Varieties of Cucumis melo includes:
1.The Cantalupensis group includes the European "cantaloupe" with
skin that is rough and warty, not netted.
2.The Inodorus group includes "honeydew melon", "casaba melon"
or "winter melon". These have smooth rinds and do not have a
musky odor. Honeydew has a smooth, white rind and sweet green
flesh. When eaten, the texture is similar to a reticulated cantaloupe,
but the flavor more subtle and sweeter. Classified sometimes as
Cucumis melo inodorus. ‫شمام أصفر شتوي‬
3.The Flexuosus group, also known as "snake melon". ‫المتطاول‬
4.The Reticulatus Group includes the "netted melon", "American"
cantaloupe". Other common names are the "Persian melon." ‫المشبك‬
‫)(اإليراني‬
5.The Conomon group is the "Oriental pickling melon". ‫سمع‬
6.The Chito group is the "garden melon." Also known as "mango melon". ‫منجا‬
7.The Dudaim group is the "vine pomegranate". ‫رمان‬
These vary in fruit size, shape, smooth or sutured or netted skin,
white to green to yellowish green to yellow to yellowish brown to
orange with yellow or green back grounds, that at maturity
accumulate sugar in fructose, glucose and sucrose forms which
upon ripening becomes fleshy soft and release aromatic
essences.
Culture:
Warm season crop that needs 85-120 days from planting to harvest.
Having 18ºC-24ºC optimum temp for growth favoring arid conditions
(avoid fungal diseases).
Needs deep well-drained fertile soil 7-5 light alkaline pH since it is
sensitive to acidic conditions.
Light sandy soil or sandy loam soil gives early yield, while good yield
obtained from heavier soils but not clay or peat soil.
Its recommended to add 65-135 kg/ha, 28-66 kg/ha of N and P, and
some K if its availability is low, half of the quantity is placed beside
seeds, and the rest is side-dressed shortly after thinning (at 4-6 trueleaf stage).
They are planted 1.5-4 cm depth x 30-60 cm apart x 180-210 cm
between rows or in beds.
Adequate moisture of soil is required up to last week before fruit begin
to ripen.
At 30cm spacing: 1-2 fruits/plant at the same time, if more than 2 →
then small fruits and of low s.s.
Harvest and storage:
In cantaloupe: the formation of abscission zone between fruit and
peduncle, the change in the color of the area touching soil into
yellow, and slight aroma to be smelled from blossom end.
In Honeydew: change in color to yellowish white, waxy feel, and
slight aroma from blossom end, but there is No abscission zone
as in Persian melons.
Both cantaloupe and honeydew are harvested for shipment
before ripe eating stage, and then at room temp, it controls its
ripening in few days, while honeydew needs ethylene treatment →
as its soft from blossom end, and contains aromatic compounds.
So, cantaloupe and honeydew are recording 8-14% and 10-16% of
total sugar content respectively.
Storage:
1) In the case of cantaloupe that doesn’t need Ethylene:
a. It needs directly hydro cooling in ice water to decrease
respiration rate, so low sugar loss, then transfer it to 10ºC
storage place.
b. Hard ripe fruits should be stored at 4-5ºC to fasten ripening
for 4-10 days, then at 15-16ºC from 1-2 days x 95% RH.
2) In the case of honeydew, the following treatment:
a. Unripe mature melons: with white back ground, and some
light green color showing fine hairs → no aroma and hard
blossom end → so it can be treated with 200ppm ethylene
gas at temp degrees > 20ºC.
b. Initiated ripening: white back ground and slight wax surface,
blossom end is slightly springy and had a slight aroma →
ethylene gas treatment at 200ppm is not essential but could
be beneficial.
c.Ripe fruit: creamy white color back color and waxy surface,
total blossom end is springy with good aroma → no
ethylene treatment.
d.Slightly over ripe: creamy white to pale yellow back ground
color, and quite waxy surface, strong aroma but the flesh is
soft → the quality is lower than (ripe fruit above) but still
edible.
d.Over ripe: entire yellow surface, soft and strong fermented
odor, soft flesh, springy and mealy → not edible.
So, honeydew doesn’t need precooling, but after ethylene
treatment of unripe in (a),stay it at 16ºC from 2-2½ day, then at 710ºC, from 3-4 days, while in (b) and (c), they can be stored at 710ºC from 2-3 weeks in 85-90% RH, but below 5ºC chilling injury
occurs.
Pests and diseases:
1) Aphids, green peach aphid, cucumber beetle, leaf-hopper, leaf miner,
red mite nematodes, wire worms, and seed maggot of corn.
2) Pythium, Rhizoctonia attack seedlings, fusarium, phytophthora,
alternarica which caused blights, P.M, D.M.
3) Bacterial wilt that transmitted by cucumber beetle.
4) Viral diseases: cucurbits mosaic viruses transmitted by aphids or
seeds.
Nutritive value:
1) Rich in β-carotene: against lung cancer.
2) Cantaloupe melons are a good source of potassium, Vitamin A, and
folate.
3) Useful laxative
Water melon
Family:Cucurbitaceae
Genus:Citrullus
Species:lanatus
Citrullus lanatus or Citrullus vulgaris
Origin:
Originated in southern Africa, where it is found growing wild, now found
native in north and west Africa.
Botany:
Monoecions, annual, large pinnate lobed leaves, give sweet juice,
oblong or ellipsoidal or spherical fruit reach to or more than 12kg/ fruit,
flesh may be of white, yellow, pink to red color at mature stage.
This flowering plant produces a special type of fruit known as a berry,
which has a thick rind (exocarp) and fleshy center (mesocarp and
endocarp).
Seeds may be white, greenish, yellow, brown, red or black containing
high quantity of CHO, fats, and protein.
Culture:
Warm season crop, needs long growing season (4 months of
frost free weather).
Temp degrees over 21ºC are good for growth.
Good draining, sandy loam, to loam soils, is preferred, then
heavier soils can be used, but with avoiding continuous use of
the same land except if cultivars are resistant to fusarium wilt.
So, crop rotation once every 4-6 years is good.
If you have Nematodes with Fusarium → rotation done each 10
years.
Its recommended to add 70-110 kg/ha, 30-55 kg/ha of N and P
respectively, and some K if its availability is low following the
same process as muskmelon.
Planting density: 1-2 m in rows x 2.5-3 m apart over a beds after
thinning which should be done carefully.
Optimum soil temp for fastest germination is 25-35ºC, where at
20ºC it needs 12 days, and at 15ºC → poor growth.
Minimum of 380 mm of water are needed in light soils (since
this plant has deep roots), while in heavy soils, crop quality may
be less.
Since F.C. condition maintain for longer time, ♂ flowers are
formed firstly then ♀ flowers, which will be pollinated by bees,
so hives of bees are necessary.
Low quality fruits are related to poor pollination.
Pruning to 2 or 3 fruits/plant is necessary for larger size fruits
and high sugar content.
Harvest and storage:
Needs 75-130 days according to, cultivar and growing conditions as
temp.
Fruits normally harvested when the flesh is sweet but not over ripe.
Ripeness is related to the following criteria:
1)The touched part to the soil changes into light yellow color.
2)Thumping where immature fruits give a high pitched sound and
mature fruits give low pitched sound.
3)The tendril that directly opposite to fruit peduncle becomes brown
and dry.
4)Also samples from time to time to taste since most fruits of a
comparable size have same stage of ripeness.
5)Also refractive index of the juice that measure the percent of
soluble solids which should be at least 10.5% at the center of fruit
which supposed to give high percent, then the next highest percent
is in the blossom end, then in the upper side, while the bottom
(ground spot) and stem have the lowest.
Storage:
Warm conditions that needs 13ºC-16ºC storing temp for 2 weeks to
avoid chilling injury.
If needed to be stored for longer period, then 7-10ºC is needed.
Below 10ºC → flesh color fades.
Also 80-85% RH is sufficient since water loss through waxy rind is
very low.
Pests and diseases:
1)Aphids, cucumber beetle that attack leaves, stems and very young
fruits, spider mites.
2)Nematodes.
3)Fusarium wilt, root rot by Pythium and Phytophthora spp.
4)Viral diseases: Potyviruses that transmitted by leaf hoppers → cause
curly and yellowing of old leaves and stunting growth and dark green
color of new leaves. Watermelon mosaic virus transmitted by aphids →
cause molting of leaves and stunt growth, with no fruits.
Nutritive value: Good source of water and energy in dry conditions
especially if sources of water are contaminated, and it’s a good source
of fibers (for digestion).