Transcript TIME AND STAGE OF HARVEST AND HARVESTING TECHNIQUES

TIME AND STAGE
OF HARVEST
AND
HARVESTING
TECHNIQUES
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Abstract
• Time and stage of harvest of crop play greater role in
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attaining good crop produce.
Premature or delayed harvest adversely affects
quality and quantity of produce.
Factors considered for time of harvest are economic
part aimed, products utility and post harvest storage.
All the crops are having certain criteria(physiological
maturity and harvest maturity symptoms)for
harvesting the produce.
All over the globe, different method viz., manual and
mechanical methods are practiced depending upon
the purpose, time and labour availability.
Learning objectives
• To learn the criteria for harvesting and maturity
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symptoms of various crops
To study the harvesting time, stage, methods and
machineries available for harvesting.Next Previous End
Introduction
• Time of crop harvest is one of the most important strategy
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influences yield, quality and storage of crop.
Premature or delayed harvest often adversely affects quality of
the produce.
Pre-mature or immature harvest is desirable for certain
products that are preferred juicy and succulent. Produce may
become more fibrous and tough or hard if harvested at full
maturity, as in the case of pulse crops for vegetable purpose
and millets for consumption as fried grain.
If the crops such as cereals, pulses and oilseeds are left in the
field for too long after maturity, the crop will be predisposed to
pests and germination is inevitable due to vagaries of weather.
There are different stages for various crops, which demarked
as maturity stages, harvesting in those stages gives high
income and good quality produce.
Farmers are following traditional techniques for harvesting the
crops produce, but advancement of science and technology
gave way for new innovation and equipments and machineries
for harvesting the produces.
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Main Body
I. TIME OF HARVESTING
II. STAGE OF HARVEST
III. METHOD OF HARVESTING
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Time Of Harvesting
• Reaping what has been sown is literally known as
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harvesting.
Yields are expected to be high in crops .
In order to realize the expected yield, the crop must be
harvested when the economic product is at its optimal
quantity and quality.
Generally, crops are harvested when they are said to be
mature.
Ideal time to harvest depends on a number of factors,
including the economic part, utilization of the product
and post harvest storage.
Economic part
• The economic product could be the grain, root, leaf,
stem or other parts for different crops.
• Translocation of the stored food from parts of economic
importance to other parts will reduce the yield of desired
products.
• Crops are to be harvested when the desired product is at
its maximum quality and quantity. (Cont)..
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Utilization
• Economic product may be same, but, it may be
desirable to harvest in fresh or dry.
• Maize may be harvested fresh or dry, depending on the
intended use.
• Similarly pigeon pea, cowpea, peas etc.
• The purpose of growing the crop determines when it is
best to harvest it in order to have the highest quality
and quality of the desired product.
Post harvest storage
• Harvested produce often requires some form of storage
at the site of production, before disposal.
• The produce may deteriorate in such storage if
harvested at improper moisture content.
• There must be supplementary drying facilities for drying
the produce to safe moisture content for storage.
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Maturity
• Crops can be harvested at
physiological maturity or at
harvest maturity or storage
maturity depends on situation
or need of produce
Physiological maturity
• Crop is considered to be at
physiological maturity when the
translocation of photosynthates
is stopped to economic part.
• It refers to a developmental
stage after which no further
increase in drymatter in the
economic part.
• In cereals, moisture content of
grains is very high during
milking stage and it gradually
deceases due to accumulation
of photosynthates. Next
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• A steep fall of moisture content from 40% to 20% is
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an indication of attaining physiological maturity.
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At this stage, translocation of carbohydrates is
stopped due to formation of abscission layer
between rachis and grain.
At this stage, plant reaches maximum dry weight,
increasing production inputs doesn’t produce any
gains in yield.
The grains at this stage are of hard dough
consistency.
If grain is harvested prior to its physiological
maturity, it would have low drymatter, poor quality
and will shrivel upon drying.
Various crops have different indicators of maturity .
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Physiological maturity symptoms
of some field crops
Rice
Golden yellow colour of the grain and senescence of lower
leaves
Wheat
Complete loss of green colour from the glumes before
physiological maturity. Centre spikes are used as indicator
grains.
Barley
Loss of green colour from the glumes or peduncle
Maize
Black layer in the placental region of corn kernels
Sorghum
Black layer formation in the placental region of grain
Pearl millet
Appearance of bleached peduncle in some varieties
Redgram
Green pods turning brown, about 25 days after flowering
Soybean
Loss of green colour from leaves
Groundnut
Development of black colour in the inner shell of the pod
Pulses
Turning of green pods to brown colour
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Harvest Maturity
• Harvest maturity for a crop is when
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the product of interest is at best
quality and maximum yield.
Determining maturity, the highest
yield of the produce may be the best
indicator followed by the farmers.
In certain grains, harvesting is done
around 25% moisture,
But, in most cases, harvesting grain
crops is at 15 to 18% moisture.
When the crops are grown for
forage, the best time for harvest is
when the crop has attained
Harvest maturity of sorghum
maximum vegetative yield, coupled
with high quality.
It is best to cut cereal crops at earheads emerging stage for fodder.
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(Cont)
• Harvest maturity generally occurs 7-10 days after
physiological maturity.
• The important process during this period is loss
of moisture from the plants and grains.
• The general symptoms of harvest maturity are
yellowing of leaves, drying of grains or pods.
• Crop is harvested at physiological maturity when
there is need to vacate the field for sowing
another crop.
• Under all other situations, it is advisable to
follow harvest maturity.
Storage maturity
• When there is no scope or chance for post
harvest drying, the crop is to be harvested at a
stage where it can be directly stored.
• For grains, <14% moisture content is advocated.
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Harvest maturity symptoms of
some important crops
Rice
Hard and yellow coloured grains, golden yellowing of leaves
Wheat
Yellowing of spikelets
Sorghum
Yellow coloured ears with hard grains
Pearl millet & Compact ears, upon pressing, hard seeds come out
Foxtail millet
Finger millet
Brown coloured ears with hard grains
Pulses
Brown coloured pods with hard seeds inside pods
Groundnut
Pods turn dark and dark coloured patches inside the shell. Kernels red or
pink. On pressing the kernels, oil is observed on fingers.
Sugarcane
Leaves turn yellow, sucrose content is >10% and brix reading >18%
Tobacco
Leaves slightly yellow in color, specks appear on the leaves
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STAGE OF HARVEST
• Determination of harvesting date is easier for
determinate crops and difficult for indeterminate
crops.
• At a given time, the indeterminate plants contain
flowers, immature and mature pods or fruits.
• If the harvesting is delayed for the sake of immature
pods, mature pods may shatter.
• If harvested earlier, yield is less due to several
immature pods.
This problem can be over come by
 Harvesting pods or ears when 75 %of them are
mature, or
 Periodical harvesting or picking of pods,
 Inducing uniform maturity by spraying paraquat or
sodium salt.
(Cont)…
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Criteria for harvesting of crops
Rice
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32 days after flowering
Less than 4-9% green grains
Milky grains - less than 1%
Moisture content of grains - less than
20%
80% of panicles are straw coloured
and grains in lower portion of panicle
is in hard dough stage.
40 days after flowering
Grain moisture content - less than 28%
Pearl millet
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28 to 35 days after flowering
Maize
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Sorghum
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Blackgram and greengram
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Less than 22 to 25% moisture in grain
Husk colour turns pale brown
25 to 30 days after tassellilng
About 15% moisture in grain
Grains in hard dough stage
The ratio of brix of top and bottom part
of cane must be nearly one
Brix - 18 to 20%
Sucrose - >10%
35-40 days after flowering
80-85% of pods turn brown
Pods turn brown or black
Cotton
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Bolls fully opened
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Wheat
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Sugarcane
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Redgram
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• For deciding harvesting date of fodder crops, some more
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additional aspects are to be considered.
They are: toxins present in the crop, nutritive value, purpose
of harvest (whether for stall feeding or for storage) and single
or multi-cut.
When toxins are present, they are generally high in early
stage. Ex. Durrin, a toxic principle present in sorghum is high
up to 30 days after sowing.
The nutritive value of fodder crop (especially protein content),
decreases and fibre content increases with the advancement
age of the crop.
For stall feeding, crops are harvested when protein content is
high and also when the fodder is succulent with more leaves
at young stage.
Harvesting is delayed by a few more days to get more
drymatter if the purpose is hay making.
Crops with ratooning ability are harvested at periodical
intervals, while, others are harvested as a single cut.
At the time of first cutting, atleast two active leaves have to be
left for quick regeneration.
(Cont)…
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Grazing
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Grazing by the animals in pasture is another
method of harvesting of forage crop.
Three important methods of grazing are,
 Continuous Grazing
 Rotational Grazing
 Rational Grazing.
Continuous Grazing
• Continuous grazing is allowing the livestock on the
pasture lands throughout the growing season
without any restriction.
• This system of grazing requires less labour and
animal performance is good.
• Uneven grazing is the only disadvantage in this
system.
• The livestock tend to return to the new growth that
is succulent and palatable and don’t feed on more
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Rotational Grazing
• Rotational grazing system is one in which the field
is divided into several sub-units and animals are
allowed to graze in sub-units one after another.
• The carrying capacity is 10 to 25%. This also like
continuous grazing, but cost on labour and
fencing are more.
Rational Grazing
• Rational grazing, also known as strip grazing,
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represents the most intensive grazing system.
The idea is to provide a day’s ration for the herd
and then to a fresh supply of forage the next day.
This system may provide 15 to 40% yield
increase over the rotational system, but more
labour is required in this system.
Soilage which is cutting grass and stall feeding
is not a grazing system, but it is an alternative to
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grazing.
METHOD OF HARVESTING
• Different methods of harvesting are followed in different
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countries, largely depending on timely labour availability
and costs associated with harvesting.
Manual harvesting is still the major method of harvest in
developing countries while mechanized harvesting
dominates in developed countries.
Manual Harvesting
• Manual harvesting is most common in under•
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developed and developing countries.
Even in developed countries, certain crops are
harvested manually for highest quality and premium
price (delicate vegetables and fruits).
Certain crops are handpicked without using any tools.
The sickle, spade and digging rods (crowbars) are the
major traditional tools for harvesting and digging.
In manual harvesting, sickle is the most important tool.
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Manual Harvesting
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The other tool used for
harvesting is knife especially
for harvesting of plants with
woody stems.
• The output is low and the
effort required for operation
is high.
• In inderminate crop, harvesting
is done at intervals as the
economic product comes to
maturity at different periods.
• Pods or fruits are picked at
periodical intervals.
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Harvestin greengram,
blackgram cotton etc., is known
as picking and is done at 15 days
interval.
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Mechanized harvesting
• Developing countries
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like India, five types
of reapers are used.
They are, tractor side
mounted, tractor front
mounted, power tiller
operated, self
propelled walking and
self propelled riding
types have been
developed for
harvesting wheat,
rice, soybean, finger
millet and mustard.
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Combine Harvesting
• Combine harvesting of
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rice, wheat and soybean
has been accepted by
farmers in regions with
labour shortage during
harvesting period.
These are more suitable
for custom hire service.
Animal and tractor
drawn potato and
groundnut diggers and
digger shakers have
been developed and
commercialized.
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Thrasing Equipment
• Traditionally, this is practiced
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by bullock trampling, which
is arduous and time
consuming.
Later, animal drawn thresher
was used.
These have been gradually
replaced by power threshers.
Multi-crop threshers are ideal
for threshing major cereals,
oilseeds and pulses.
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(Cont)…
• Threshers have been fabricated for
separating groundnut pods from the
plants.
• Maize shellers and groundnut
decorticators of different sizes have
been developed and commercialized.
• Good designs of cleaners, graders,
driers, decorticators, storage
structures, rice mills, dhal mills, oil
mills and other processing equipment
are commercially available for
primary processing, value addition
and recycling wastes.
• These equipments help in minimizing
losses and maintaining the quality of
the produce.
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Summary
•Time of crop harvest is most important to get
quality produce.
•Ideal time to harvest depends on economic part,
utilization of the product and post harvest storage of
produce.
•Crops can be harvested at physiological maturity or
at harvest maturity or storage maturity depends on
need of produce.
•Harvest maturity for a crop is when the product is at
best quality and maximum yield.
•When there is no scope or chance for post harvest
drying, the crop is to be harvested at a stage where
it can be directly stored is called storage maturity.
(Cont)…
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Problem in harvesting
• When harvesting coincides with heavy rain or
cyclones, there will be a problem in harvesting the
matured crops.
• The crop may be submerged and the seeds may
start germinating on the plant itself.
• These problems are common in monsoon season
crops especially rice in south India and can be
overcome by growing dormant varieties.
• Most of the rice varieties have few days of
dormancy. The other way of saving the crop is by
spraying 500 litres / ha of 25% salt solution which
hastens maturity by 8 days.
• When the economic product is underground,
harvesting is difficult if the soil dries due to lack
of rain.
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• Different methods of harvesting are followed in
different countries, largely depending on timely
labour availability and costs associated with
harvesting.
• Manual harvesting is most common in underdeveloped and developing countries.
• Developing countries like India, tractor side
mounted, tractor front mounted, power tiller
operated, self propelled walking and self
propelled riding types are used.
• Combine harvesting of rice, wheat and soybean
has been accepted by farmers in regions with
labour shortage during harvesting period.
• Multi-crop threshers are ideal for threshing
major cereals, oilseeds and pulses.
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Assessment
• At physiological maturity, transport
ofphotosynthates are stopped to reproductive
parts (True/False).
• Black layer formation in the placental region is the
physiological maturity symptom of sorghum
(True/False).
• Harvest maturity generally occurs one month after
physiological maturity (True/False).
• Durrin, a toxic principle present in sorghum is high
in early stage of crop (30 days after sowing)
(True/False).
• Manual harvesting is still the major method of
harvest in developing countries while mechanized
harvesting dominates in developed countries
(True/False).
• Combine harvesting of rice, wheat and soybean
has been accepted by farmers (True/False).
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References
• Dayanand, T.B. and A. Hosein, 1987. Black
layer and grain maturity in grain sorghum.
Crop Science, 9: 473-476.
• Hanuff, J.W. and R.D. Wych. 1982. Visual
indication of physiological maturity of hard
red spring wheat. Crop Science, 22:584-588.
• Reddy, S.R. 2008. Principles of crop
production. Kalyani Publisher, Ludhiana.
• Yellamanda Reddy, T. and Sankara Reddi,
G.H. 1995. Principles of Agronomy. Kalyani
Publisher, Ludhiana.
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