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

12/16/2011

2

Crop nutrients requirementCrop nutrients requirement

Depend on:

yields

Method of growing

variety

cropSpecific needs

greenhouse – open field

Method of fertilization and different

fertilizers !!!

Type, quantity, concentration.

Basal

Top dressing

Fertigation

Foliar spray

How to split between ?

12/16/2011

3

Irrigation

+

=

Nutrients

Fertigation

Why? Soluble fertilizers

FERTIGATION

12/16/2011

4

Advantages of Fertigation

Integration of fertilizers with irrigation water.�

Uniformity of fertilizer distribution in active rootvolume.

�

Same amount of nutrients for every irrigated plant.�

Ability to adjust concentration and composition ofnutrients in active root volume according to plantconsumption requirement, respectively to phonologicalstages.

�

Repartition between base dressing and fertigation

Base dressingBase dressing(before season)

fertigationfertigation(during season)

??% N,

% P2O5

% K2O

12/16/2011

5

Repartition between base dressing and fertigation

depend on rainfall level and the ratio

. (irrigation/irrigation+rainfall) during season

Irr

Irr + Rain

in soil leveland nutrient soil typedepend on

analysisMainly 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

12/16/2011

6

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

12/16/2011

7

Repartition between base/top dressing and fertigation

Mainly for P, Kdepend on nutrient mobility in soil

N03, urea

PP 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 %

12/16/2011

8

Soluble fertilizers

UREA

46%46%

A.N 34%

A.S 21%

MAP 12-61-0

MKP 0-52-34

KCL 0-0-60

KNO3

13-0-46

K2SO4

0-0-50

N ---- P ----K

Nitric acidPhosph. acid KOH

Soluble fertilizers

Calcium nitrateMagnesium nitrate

Magnesium sulfate

16% Mg

Amonium

sulfate 21% N

K2SO4

0-0-50Ca---Mg---S

Calcium-

Magnesium

nitrate

Kiserite 24%

Epsom salts

Amon.

Thiosulfate

Calcium chloride

15.5-0-26

35%

11-0-16

12/16/2011

9

Fertilizer N content (%) Solubility (g/liter)

Ammonium sulphate 21 750

Urea 46 1100

Ammonium nitrate 34 1920

Calcium nitrate 15.5 1290

Nitrogenous Fertilizers

Fertilizer K content( % )

Solubility (g/liter)

Potassium sulphate 50 110

Potassium chloride 60 340

Potassium nitrate 44 133

Solubility of Potassic Fertilizers

12/16/2011

10

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

12/16/2011

11

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

12/16/2011

12

90, 120, 160 litres

Fertilizer Tank

The plant: 4 main phases

sowingharvest

Kc

Crop

Coefficient1.2

1.1

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

1

2

3

4

Quant. 4 10 15 13 kg/ha/day

12/16/2011

13

Proportional method:

(quantity/water unity)

mg/l or ppm

g/liter

kg/m3

1 g/l or kg/m3 of “13-0-46”

give 130 ppm N 460 ppm K2O

0.5 g/l or kg/m3 of “13-0-46”

give 65 ppm N 230 ppm K2O

12/16/2011

14

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

( )

),,,(

1

tzrCNUz

Cq

r

Cq

r

Cq

r

CD

z

CD

zz

CD

r

CD

rz

CD

r

CD

rt

C

zrr

rzzzrzrrrzrr

−

∂

∂++

∂

∂

−

∂

∂+

∂

∂

∂

∂+

∂

∂+

∂

∂+

∂

∂+

∂

∂

∂

∂=

∂

∂θθθθθθ

θ

Convection-dispersion equation (CDE) for solute transport

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 0.014Sandy 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

12/16/2011

16

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 alongwith 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

12/16/2011

17

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