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Water solubel fertilizers
1. 12/16/2011
1
Water soluble Fertilizers:
Opportunities and Challenges
T.B.S. Rajput
Water Technology Center,
Indian Agricultural Research Institute,
New Delhi - 110012
FAI Annual Seminar Dec 8, 2011 presentation
Soil analysis
Crop Nutrients requirements1
2
Choice of fertilizers
3
Method of application4
How much nutrients to apply
Timing and quantity to apply
5
6
Fertigation components
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Crop nutrients requirementCrop nutrients requirement
Depend on:
yields
Method of growing
variety
crop
Specific needs
greenhouse – open field
Method of fertilization and different
fertilizers !!!
Type, quantity, concentration.
Basal
Top dressing
Fertigation
Foliar spray
How to split between ?
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Advantages of Fertigation
Integration of fertilizers with irrigation water.
Uniformity of fertilizer distribution in active root
volume.
Same amount of nutrients for every irrigated plant.
Ability to adjust concentration and composition of
nutrients in active root volume according to plant
consumption requirement, respectively to phonological
stages.
Repartition between base dressing and fertigation
Base dressingBase dressing
(before season)
fertigationfertigation
(during season)
??% N,
% P2O5
% K2O
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Repartition between base dressing and fertigation
depend on rainfall level and the ratio
. (irrigation/irrigation+rainfall) during season
Irr
Irr + Rain
in soilleveland nutrientsoil typedepend on
analysis
Mainly for P, K
depend on method of irrigation and nutrient
mobility in soil
Repartition between base/top dressing and fertigation
depend on rainfall level and the ratio
. (irrigation/irrigation+rainfall)
1 0.7 0.5 0.3 0.2 0Ratio:
Irr
Irr + Rain
No rain No irrigation
fertigation
Base and top
dressing
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Repartition between base/top dressing and fertigation
depend on soil type and nutrient level in soil analysis
Mainly for P, K
% clay
Sandy soil Heavy Clay soil
fertigation
Base and top
dressing
0 % 20% >40%
medium soil
Repartition between base/top dressing and fertigation
Mainly for P, K
drip
fertigation
Base and top
dressing
Micro-jet
depend on method of irrigation and nutrient mobility
in soil
sprinklers Flooding
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Repartition between base/top dressing and fertigation
Mainly for P, Kdepend on nutrient mobility in soil
N03, urea
P P P
K ,NH4
K ,NH4
K ,NH4
N03, urea
N03, urea
Sandy soil medium soil clay soil
Different methods and equipments in irrigation
Flooding
Micro-jet
drippers
N P2O5 K2O CaO MgO
30 60 40 80 80
70 40 60 20 20
Base dressing %
Fertigation%
Base dressing %
N P2O5 K2O CaO MgO
30 100 100 100 100
70Top %
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Solubility of Micronutrient Fertilizers
Fertilizer Content
(%)
Solubility
(g/liter)
Solubor 20 B 220
Copper sulphate 25 Cu 320
Iron sulphate 20 Fe 160
Magnesium sulphate 10 710
Ammonium molybdate 54 430
Zinc sulphate 36 965
Manganese sulphate 27 1050
Fertilizers Urea Ammonium
Nitrate
Ammonium
Sulphate
Calcium
Nitrate
Mono
Ammonium
Phosphate
Mono
Potassium
Phosphate
Potassium
Nitrate
Urea C C C C C C
Ammonium
Nitrate
C C C C C C
Ammonium
Sulphate
C C LC C C LC
Calcium
Nitrate
C C LC NC NC C
Mono
Ammonium
Phosphate
C C C NC C C
Mono
Potassium
Phosphate
C C C NC C C
Potassium
Nitrate
C C L C C C
Compatibility chart among different fertilizers
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Fertigation 2 methods:
Quantitative:
Kg/ha/day or week or month or growth phase
Proportional :
Kg/ m3 (or g/l) concentration in water
Quantitative Proportional
Fertilizer is applied in one
pulse during a part of the
irrigation time.
The fertilizer concentration in
the irrigation water is kept
constant throughout the
irrigation time.
Fertigation Concepts
Irrigation
Fertigation solution
gradient
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Preparation of Stock Solution
•Assume 20 kg of N is to be fertigated through urea
•Amount of Urea required = 20/0.46 = 43.5 kg
•Solubility of Urea (summer) is 1100 g/liter
•Amount of water required for dissolution = 43.5/1.1= 40 liters
•About 50 liter capacity container be taken and filled with 40
liters of water and then dissolve the 20 kg urea by mixing it
slowly.
•Siphon the clear solution for injecting through the fertigation
applicator
Fertilizer and fertigation strategy
influenced the solutes distribution
Solutes dynamics
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Convection-dispersion equation (CDE) for solute transport
15. 12/16/2011
15
Soil
type
Fertigation % N leached of total N added
DRIP Surface
tape
Subsurface
tape
SL B 22.5 23.11 6.64
M 33.15 23.12 8.65
E 13.41 22.68 6.58
M50 28.51 22.69 7.90
C 32.0 23.32 8.43
Av. 25.94 22.98 7.64
L B 9.20 13.20 0.19
M 7.20 12.28 0.194
E 2.78 11.38 0.139
M50 6.68 12.13 0.184
C 6.99 12.38 0.192
Av. 6.57 12.235 0.180
C B 1.964 3.596 0.015284
M 0.4542 8.140 0.015739
E 0.7813 13.849 0.007894
M50 0.9107 10.449 0.014177
C 0.8215 6.582 0.015451
Av. 0.986 8.523 0.014
Sandy loam (SL), Loam (L), Silty clay (C)
B- Fertigation for a total duration of
2 h, starting 1 h after the beginning
of the irrigation cycle
M- Fertigation for a total duration of
2 h, in the middle of an irrigation
cycle
E-Fertigation for a duration of 2 h,
starting 3 h before irrigation cutoff
M50- alternating irrigation, starting
the first and last 25% of each
irrigation with fresh water, and
fertigation during the remaining
50% in the middle of the irrigation
cycle;
C- continuous fertigation, with 1-h
fresh water irrigation before and
after fertigation
Percentage of N leached as a fraction of the total N added
Crop
Stages of crop
Transplant to 6 leaf,
(kg/ha)
6 leaf to fruit set,
(kg/ha)
Fruit set to fruit
development, kg/ha
Fruit set to ripening,
(kg/ha)
N P2O5 K2O N P2O5 K2O N P2O5 K2O N P2O5 K2O
Potato 44 32 16 26 26 58 130 87 196 - - -
Tomato 55 98 58 35 17 35 30 15 45 30 15 172
Capsicum 55 122 58 35 17 35 30 15 45 30 15 172
Onion 60 107 60 32 33 32 31 15 171 32 32 32
Red cabbage 32 32 32 35 18 35 33 15 173 - - -
Carrot 55 120 120 30 15 171 30 15 171 - -
Lettuce 55 122 122 35 18 35 - - - - -
Cucumber 55 121 121 35 17 35 35 17 35 - -
Water melon 110 10 10 25 25 25 30 15 75 - -
Melon 15 15 5 30 15 45 35 18 80 35 17 55
Suggestive schedule of fertigation for vegetable crops
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Constraints in Fertigation
•There is lack of research and developmental
information in respect of its rate of application, amount
applied and frequency adopted.
•The fertigation material is either not available in desired
form or available at higher price, than the conventional
fertilizer.
•Once the fertigation practice is being followed along
with Micro irrigation system causes higher clogging.
The farmers must be trained to adopt fertigation along
with other chemigation technique.
Year Drip
Irrigation
(ha)
*Nitrogen (N)
requirement,
matric tons
*Potassium (K)
requirement,
matric tons
*Phosphorous (P)
requirement,
matric tons
Up to 2009-10 1897280 227673.6 151782.4 151782.4
Source: Progress reports from state governments
*N = 120 kg/ ha, P =80 kg/ha and K = 80 kg/ha
Area Covered under Drip/Sprinkler
irrigation under CSS on Micro Irrigation
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Conclusions
The Government of India (GOI) plans to cover 27 Mha under
drip and sprinkler systems
Presently the specialties WSF are not affordable by the
farmers. If P requirement can be met, N& K can be taken care
of through urea and KCl.
Efforts should be directed for developing proper fertigation
technology with the presently available conventional fertilizers
till specially fertilizers becomes affordable.
Integrated fertigation technology with organic/bio liquid
fertilizer and WSF need be generated.
Thanks
