Transcript Quality is - International Plant Nutrition Institute

K EFFECTS ON YIELD QUALITY
Adolf Krauss
International Potash Institute
Basel, Switzerland
… K effects on yield quality
Contents
Why quality?
 Where is the link between K and quality?
 What can we prove?
 Conclusion

… K effects on yield quality
Why quality?
… Why quality?
… because urbanisation is advancing
Regional urbanisation
100
90
share of urbanites
80
70
60
Brazil
EU-15
India
50
40
30
20
10
0
1940
1960
1980
2000
2020
2040
… Why quality?
… because urbanisation is advancing, that is more urbanites and less rural
people - also in Brazil
Demographic development of Brazil as compared to
EU-15
350
300
M inhabitants
250
Brazil urban
Brazil rural
EU-15 urban
EU-15 rural
200
150
100
50
0
1940
1960
1980
2000
2020
2040
… Why quality?
… the society is also rapidly ageing like in the OECD countries
Ageing society in OECD countries
1400
1200
million inhabitants
1000
800
600
400
200
0
1960 1970 1980 1990 2000 2010 2020 2030 2040 2050
> 65 yr
15-64 yr
<15 yr
… Why quality?
… with income and ageing the food habit changes
… why quality?
… less cereals and more fruits and vegetables ...
Change in the diet in Brazil compared to EU-15
300
supply kg/cap/year
250
200
Brazil cereals
Brazil fruits&veg
EU-15 cereals
EU-15 fruits&veg
150
100
50
0
1950
1960
1970
1980
1990
2000
2010
… why quality
… less cereals and more fruits and vegetables ...
Per capita food supply 2000 in selected countries
(FAO, 2004)
300
kg cereals; fruits&vegetables
250
200
cereals
fruits&veg
150
100
50
0
EU-15
Brazil
India
… why quality?
… and more vegetable oil with raising income ...
Relationship between per capita GDP and
consumption of vegetable oil
(FAO/CIA 2004)
30
y = 0.5406x + 6.3747
R2 = 0.8866
kg/cap veg oil
25
20
15
10
5
0
0
10
20
GDP '000 USD per capita
30
40
… why quality?
… and customers look first for quality when selecting food
Relative importance of product attributes in
product choice
after TRAILL, 1999
quality
26%
9 others
25%
guarantee
9%
price
17%
freshness
9%
reputation
14%
… K effects on yield quality
Why quality?
What is quality?
… what is quality?
Quality is
…an intrinsic property of food by which it
meets predefined standard requirements.
Determinants of food quality can be grouped
into several properties. Food quality therefore
refers to the value, which is subjectively or
objectively attached to food with respect to
quality properties…
(Alabaka, 1999)
… What is quality?
Nutritional properties
Hygienic
properties
Functional properties
FOOD QUALITY
Environmental compatibility
Organo-leptic
properties
Safe food
… K effects on yield quality
Why quality?
What is quality?
Where is the link between K and quality?
… Where is the link between K and quality?
… for example, in N metabolism …
CO2
PEP
NH3
K+
K+Malate-
protein
SHOOT
K+NO3
PHLOEM
XYLEM
K+Malate-
KNO3
Malate
Pyruvate
HCO3
K+
K+
NO3
NO3
ROOT
Model for the circulation of potassium in relation to nitrate and
malate transport (after MARSCHNER, 1995)
… Where is the link between K and quality?
… for example, in sugar transport
… Where is the link between K and quality?
… for example, in sugar transport
Effect of K status of cane on sugar transport
(exposure 4 hrs)
(after HARTT, 1969)
14
percent C transport from fed leaf
120
100
80
stalk
adjacent leaf
fed leaf blade
60
40
20
0
deficient K
adequate K
… Where is the link between K and quality?
… unless excessive Cl- affects sucrose storage in cane stalks
Leaves
Exchange processes of Cland sucrose in sugarcane
(KRAUSS, 1992)
Sucrose
Synthesis
Cl- and K+
Retrans Stalk
location storage
Cl-+K+
cells
Cl-+K+
Cl-+K+
Sucrose
Exchange
processes
Cl-+K+
Sucrose
Cl-+K+
Xylem
Transport
Cl- and K+
Sucrose
Cl-+K+
Roots
… Where is the link between K and quality?
… unless excessive Cl- affects sucrose storage in cane stalks
Leaves
Exchange processes of Cland sucrose in sugarcane
Sucrose
Synthesis
Cl- and K+
(KRAUSS, 1992)
Retrans Stalk
location storage
Cl-+K+
Relationship between Cl and sucrose in cane stalks
cells
40
Cl-+K+
35
Cl-+K+
sucrose % in DM
30
2
Sucrose
y = 71.015x - 171.67x + 110.17
R2 = 0.8278
25
Exchange
processes
20
Cl-+K+
Sucrose
15
10
Cl-+K+
5
0
0.5
0.7
0.9
1.1
Cl % in DM
1.3
1.5
Xylem
Transport
Cl- and K+
Sucrose
Cl-+K+
Roots
… Where is the link between K and quality?
… for example, in water utilization
K1
K2
K3
Wilting of sugar beets as affected by K supply
… Where is the link between K and quality?
… K regulates stomata aperture
Potassium and stomata aperture
(from MARSCHNER, 1995)
450
6
4
250
K content (10
3
200
150
2
100
1
50
0
0
open stomata
closed stomata
l)
guard cell
volume
-12
300
5
volume (10
350
K
-14
mol/stomata)
400
… Where is the link between K and quality?
… K is the insurance for quality formation even under climatic ...
Photosynthesis
(µmol CO2 m-2 s-1)
50
Low K
40
Adequate K
30
20
10
0
LOW
MILD
SEVERE
Drought Stress
From CAKMAK, 2003
… Where is the link between K and quality?
… or biotic stress
Unbalanced
high N
sugar
balanced
N
Krebs
cycle
sugar
Krebs
cycle
soluble
org N
compounds
secondary
compounds
soluble
org N
compounds
secondary
compounds
organic N
Phenols
Quinones
organic N
Phenols
Quinones
Synthesis of pathogen repellents in plants as affected by the level of N supply
(after GRAHAM, 1983)
… K effects on yield quality
Why quality?
What is quality?
Where is the link between K and quality?
What can we prove?
… What can we prove?
… adequate K improves the nutritive value
- for instance in wheat - higher protein content and better appearance
Yield and quality of wheat in India as affected
by K
5.4
grain yield
protein content
11.6
5
11.4
t/ha
4.8
11.2
4.6
11
4.4
% protein
5.2
11.8
10.8
4.2
4
10.6
3.8
10.4
-K
+K
-K
+K
… What can we prove?
… adequate K improves the nutritive value
- with higher oil content, more people can get their daily need
from the same field
Yield and quality of oilseed rape in China as
affected by K
2.9
2.85
38.6
seed yield
oil content
38.4
38.2
+K
38
37.8
2.75
37.6
2.7
37.4
37.2
2.65
37
2.6
36.8
-K
+K
% oil
t/ha
2.8
-K
… What can we prove?
… adequate K affects the functional property
- with higher sugar content, less cane is required for the same sugar output
and thus, less energy for transport and extraction
Relationship between soil K absorption ratio (K in % of
CEC) and stalk size and sucrose content of cane in
Egypt
2
20
1.8
19.5
1.6
19
1.2
1
18.5
0.8
Poly. (sucrose %)
Poly. (stalk kg)
0.6
18
0.4
17.5
0.2
0
17
1.5
2
2.5
% K on CEC
3
3.5
sucrose %
kg/stalk
1.4
… What can we prove?
… adequate K affects the functional property
… the same applies to potato and starch production
Tuber yield and quality of potatoes in Poland
40
17.4
38
17.2
tuber yield
17
starch content
34
16.8
32
16.6
30
16.4
28
16.2
26
16
24
15.8
22
15.6
20
15.4
NP
NPK
NPK+Mg
% starch
tuber t/ha
36
… What can we prove?
… K is involved with organo-leptic properties
… amino acids are important components for tea quality ...
Impact of balanced fertilization with K and Mg on
quality of tea (China)
30
amino acids mg/g made tea
29
28
-Mg
+Mg
27
26
25
24
NP
NPK1
NPK2
… What can we prove?
… K is involved with organo-leptic properties
… and potato crisps keep a bright colour when the tubers are fed with
adequate K because it lowers the content of reducing sugars
Color index of potato chips as affected by K
supply
8
color index (10=excellent)
7.5
-K
7
6.5
6
5.5
5
4.5
4
0
217
108
kg/ha K2O
315
+K
… What can we prove?
… K controls hygienic properties
… mouldy fruits, cracked tomatoes from K deficient plants are
disliked by consumers ...
… What can we prove?
… K controls hygienic properties
… also black spots in potato tubers can be controlled by adequate K ...
Relationship between K supply and
incidences of black spots in potato tubers
(Germany)
7
25
20
NP control
5
4
15
3
10
2
tubers with black spot
K-content of tubers
1
5
0
0
0
100
200
kg/ha K2O
300
K mg/kg
black spot incidences
6
NP + KMgS
… What can we prove?
… K enhances the content of functional compounds
… Vitamin C and antioxidant contents are improved by adequate K ...
Balanced fertilization increased yield and
improved quality of cabbage in Russia
86
270
265
Effect of K on isoflavones in soybean seeds
Heads t/ha
80
260
78
255
76
250
74
245
72
70
240
68
235
-K
+K
O=C
HO-C
Vit C
HO-C
O
H-C
HO-CH
CH2OH
(BRUULSEMA*, 2002)
2100
total isoflavones ppm (expressed as aglycones)
82
head yield
Vit-C content
Vit C mg/kg
84
275
2050
2000
1950
1900
1850
1800
1750
1700
1650
-K
+K
… What can we prove?
… K keeps plants healthy and hence the food
-K
+K
CONTROL
-K
+K
POTASSIUM
… What can we prove?
… K improves the appearance and shelf-life of many crops
… What can we prove?
… K improves the appearance and shelf-life of many crops
Tuber yield and storage loss of potato tubers
(Bansal & Shahid Umar, 1998)
33
6
31
5
Economy of potato tubers in India
(Bansal & Shahid, 1998)
4
25
3
23
21
2
19
1
17
15
0
0
100
kg/ha K 2O
yield
30
storage
loss (4
weeks)
25
VCR for K2 O
27
storage loss %
tuber yield t/ha
29
20
100 kg/ha K
150 kg/ha K
15
150
10
5
VCR harvest
VCR 2 weeks later VCR 4 weeks later
… What can we prove?
… K use meets the environmental requirements
… because at balanced fertilization, N use efficiency is improved
Residual NO3 in the subsoil (kg/ha) as
affected by fertilization in China
Impact of Farmer's practice, FP and Site
specific nutrient management, SSNM on
recovery efficiency of N fertilizers, REN, of rice
in SE Asia
140
5.8
120
5.7
100
38
rice yield
REN
36
5.6
80
34
5.5
grain yield
60
40
32
5.4
30
5.3
28
5.2
20
26
5.1
0
farmers practice
=excessive N
unbalanced
high N
balanced NPK
24
5
22
4.9
4.8
20
FP
(111-18-17 kg/ha N-P-K)
SSNM
(120-22-66 kg/ha N-P-K)
REN %
160
… What can we prove?
… growth limitation of the shoot e.g. at K deficiency signals to the roots to
refrain from further N uptake, so, the plant cannot be forced to absorb N above
its needs …
Low demand
high demand
shoot
shoot
Growth
Growth
Xylem
Phloem
Xylem
Phloem
Growth
Growth
root
Nitrogen
root
Nitrogen
after ENGELS & MARSCHNER, 1995
… K effects on yield quality
In conclusion:
• legislative measures
• trade barriers
• gaps in knowledge
• agric. practice
• quality auditing
• confidence of
consumers
Producer
• globalisation
• trade liberalisation
• competition
• selective and critical
consumers
• ...
Consumer
• healthy food
• cheap food
• plenty food
• protection of the
environment
• safeguarding natural
resources
• ...
… K effects on yield quality
… Thank you