Fertigation for Vegetable and Fruit Crops

Ram A Jat, Suhas P Wani and Team

Horticulture at a glance in

Karnataka (2008-09)

o Geographical area of Karnataka: 19.0 m ha o Cultivated area : 12.18 m ha (63.99%) o Irrigated area: 3.13 m ha (25.69%) o Area under horticultural crops: 1.8 m ha (14.76%) o Karnataka ranks 5th in area after MH,KL,AP and WB and

8th in production after WB,UP,TN,MH,AP,BR and GJ of horticulture crops at India level.

o Karnataka accounts for 8.08% of area and 5.58% of total production of horticulture crops at all India level .

Source: DES, GOK

Area, production, yield and economic value of horticultural crops in Karnataka during 2008-09

Crops Area

ふ000’Haぶ Production

(Lakh t)

Yield (M t/ha) Value (Billion

Rs)

Fruits 317.59 55.34 17.43 59.66

Vegetables 421.13 67.57 16.05 41.52

Spices 242.94 6.49 2.67 15.85

Plantation crops 787.31 4.76 0.61 58.07

Commercial flowers 27.02 1.97 7.33 4.83

Medicinal plants 1.98 0.03 1.60 0.10

Aromatic plants 1.68 0.18 11.03 0.21

Grand total 1799.68 136.37 7.58 18.02

Source: DOH, KN

Productivity (t/ha) of horticultural

crops in KN, India and world (2008-09)

Crops Karnataka India Highest in India World Highest in

world

Fruits` 16.7 11.2 TN (25.8) 10.42 USA (24.3)

Banana 24.91 37.0 MH (62.0) 19.20 Indonesia (54.3)

Grape 18.82 23.5 TN (29.8) 9.14 India (23.5)

Mango 11.44 6.0 UP (12.8) 7.05 Brazil (16.8)

Papaya 73.46 37.0 TN (182.2) 24.84 Indonesia (72.7)

Pineapple 62.05 16.0 KN (61.7) 22.58 Indonesia (61.2)

Vegetables 16.05 16.2 TN (30.4) 17.28 Spain (34.8)

Brinjal 23.81 17.3 KN (24.3) 16.93 Japan (34.4)

Cabbage 19.81 22.2 Orissa (27.8) 22.37 Korea (67.3)

Cauliflower 18.02 18.7 WB (25.4) 17.23 Italy (22.3)

Okra 8.38 10.5 AP (15.0) 6.58 Egypt (15.7)

Onion 16.04 16.3 GUJ (24.5) 19.20 USA (53.9)

Potato 5.65 18.8 GUJ (25.4) 17.22 France (45.6)

Tomato 32.69 18.6 KN (29.5) 24.83 USA (77.4)

Source: DOH, KN Source: NHB, FAO

Strategies to improve productivity as

suggested by NHM

Research & extension: inputs/ farming systems/ technologies

Promotional as well as Commercial production for selected crops on cluster basis – project-based approach

Micro irrigation for improved water use efficiency

Strengthening delivery mechanism for seeds / planting material /

nutrients/pesticides Establishment of TC units/plant health clinics

Hi-tech farming/precision farming

Status of drip/sprinkler irrigation in states

(area in ha)

State Drip Sprinkler Total

Haryana 3915 5,03481 5,07396

Rajasthan 8891 4,51708 4,60599

Maharashtra 2,18442 1,14102 3,32544

Karnataka 1,07688 1,40000 2,47688

Tamilnadu 96689 1,3566 1,10254

Andhra Pradesh 85236 21490 1,06726

Madhya Pradesh 6194 100000 1,06194

Orissa 2036 20220 22256

Uttar Pradesh 4559 10000 14559

Punjab 4262 10000 14262

Kerala 10265 1208 11473

Sikkim 30 10030 10060

Others 30000 50000 80000

Total 578207 1445805 20,24011

Source: NHM

Potential for drip/sprinkler irrigation in

states (area in m ha)

State Drip Sprinkler Total

Uttar Pradesh 3.35 10.53 13.88

Maharashtra 4.11 3.30 7.41

Madhya Pradesh 1.19 5.98 7.17

Rajasthan 1.86 4.01 5.87

Punjab 0.65 3.57 4.22

Haryana 1.03 2.75 3.78

Karnataka 2.02 1.47 3.49

Bihar 0.84 2.44 3.28

Andhra Pradesh 2.16 0.99 3.15

Gujarat 2.04 0.89 2.93

West Bengal 1.12 0.99 2.11

Kerala 1.69 0.25 1.94

Tamil Nadu 1.37 0.21 1.58

Orissa 0.84 0.42 1.26

Others 1.89 1.67 3.56

Total 27.00 42.51 69.51

Source: NHM

“Application of plant nutrients by dissolving them in irrigation water particularly with the drip system is termed as fertigation”

Benefits of fertigation:

Higher water and nutrient use efficiency

Resource saving; labour, time

Higher productivity and product quality

Reduced environmental pollution

Effective weed management

Reduced soil compaction

Gives flexibility in farm operations

Effective use of undulating soils

Manipulating plant growth and

development

Nutrients which can be fertigated

N and K are most commonly fertigated

Micronutrients can be supplied more effectively through fertigation

Ca, Mg and S should be applied through their conventional sources like gypsum and dolomite directly into soil.

P fertigation improves its use efficiency; should be applied alone and water should be acidified to prevent clogging.

Selection and compatibility of fertilizers

In selecting fertilizers four main

factors should be considered:

1. Plant type and stage of growth

e.g. tomato is very sensitive to high NH4

concentration. Plants are more sensitive

to form of N at fruiting stage

2. Soil conditions

3. Water quality

4. Fertilizer characteristics and price

Contd.

Selection and compatibility of fertilizers Contd.

Liquid fertilizers are best for fertigation as they readily dissolve in irrigation water

But lack of easy availability and high cost restrict their use

Fertigation using granular fertilizers pose several problems like differences in their solubility in water, compatibility among different fertilizers and problem of filtration of undissolved fertilizers.

Compatibility chart of different water

soluble fertilizers

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 LC C C C

NCPAH, GOI

Fertilizer Evaluation for Suitability to

Fertigation

Property NH4NO3 (NH4)2SO4 K2SO4 KCl KNO3 H3PO4 MAP

Solubility High Medium low Medium Medium High Medium

Precipitation low High High low low low High

Compatibility Good Poor Poor Medium Medium Medium Good

corrosion Medium Poor Poor Poor Good Poor Medium

NCPAH, GOI

Fertilizer Management under

Fertigation

About 1/4th of RDF should be applied as pre-plant as it ensures nutrient supply to plants during early stage when irrigation may not be required.

In coarse- textured soils it is essential to supply only a part of RDF through fertigation with low rate but high frequency and, rest as pre-plant to reduce leaching losses.

Fertilizers can be injected daily, on alternate days or weekly depending on irrigation frequency, soil type, daily nutrient requirement of the crop etc.

The effectiveness of fertigated nutrients can be enhanced when injected at the end of irrigation run, with only 30-40 minute period of clear water to flush the nutrients from the system.

Contd.

Fertilizer Management under Fertigation Contd.

When saline irrigation water is used it is necessary to reduce pH of irrigation to about 5.5.

Balance between NH4/NO3 supply. High NH4 leads to – Decrease in soil solution pH

– Decrease in uptake of other cations

– NH4 may be toxic to plant roots

NO3 uptake enhances P and Fe uptake but increase soil solution pH to undesirable levels

Optimum NO3 :NH4 should be 80:20

Rates of uptake of N, P and K during different

physiological growth stages of tomato and lettuce.

Vegetative period:

High demand for NPK

Fruit ripening:

High demand for N and K,

reduced demand for P

Silver, 2010

Nutrient requirement of open field tomato according to its physiological stages

Physiological stage Days Ratio Kg/ha/day

N P2O5 K2O N P2O5 K2O

Planting - Flowering 25 1 1 1 1.6 1.6 1.6

Flowering - Fruit Set 20 1 0.5 1.5 2.1 1.0 3.1

Fruit Set- Fruit Ripening 25 1 0.3 2 2.8 0.6 5.6

Fruit Ripening-Harvest 35 1 0.3 2 3.6 0.6 7.2

Total 105 280 90 500

Fertigation program

Physiological stage Fertilizers Kg/ha/day **

Planting - Flowering 20-20-20 8

Flowering - Fruit Set 14-7-21 15

Fruit Set- Fruit Ripening 14-3-28 20

Fruit Ripening-Harvest 14-3-28 26

** Plants are irrigated every 3-5 days in heavy soils, and every 2-3 days in light soils. To calculate the fertilizer dose

at each irrigation, multiply the daily amount of fertilizer by the days interval between irrigation cycles. ( Source:

Imas, 1999)

Water Management

As the water soluble nutrients move with the

wetting front precise management of the

irrigation water quantity is essential to avoid

nutrient leaching beyond the crop root zone.

Even with fertigation, over-irrigation can result

in severe nutrient deficiencies and reduced

crop yields.

Soluble nutrients moving with water front And Leaching of Soluble Nutrients out of Root Zone due to Over Irrigation

For precise water management tensiometers installed in different parts of the field

is useful technique.

Root zone

A. Soluble nutrients moving with

water front

B. over-irrigation leading to nutrient leaching

Filtration is prerequisite for fertigation to avoid clogging of the drip lines and emitters and to maintain the uniformity of water and fertilizer application

The type of filtration system will depend on the source and quality of the water

In fertigation system a second filtration system after fertilizer container is necessary to remove particulate matter or precipitates

Deep well water may contain soluble divalent iron, which on contact with phosphate may produce gel-like precipitate that can block the trucklers and filters

Filtration system

Constraints and their Solutions for Successful

Adoption of Fertigation

o High initial cost:

Cost can be brought down by cost cutting measures like use of micro tubes, paired row system etc.

o Clogging of lines:

Due to chemical precipitation: For HCO3 precipitation use of acid fertilizers and acids like H3PO4, HNO3, and HCl and, check the comp ability and solubility of solid fertilizers before use.

Due to microorganisms: Use of acids/chlorine, flush the system after fertigation

Contd.

Constraints and their Solutions for Successful Adoption of Fertigation Contd.

o Salt injury: Severe problem with saline

irrigation water and in arid climate

When saline irrigation water is used for irrigation apply extra water for leaching of salts beyond crop root zone.

Fertigation with NO3 as it competes with Cl ions.

Use of plastic mulch/ sub-surface irrigation to reduce evaporation

Contd.

o Nutrient deficiency:

In heavy soils due to low water infiltration denitrification may occur at high soil temperature Low concentration of N and regulation of water supply.

Hydrolysis of urea may lead to NH3 toxicity or NH3 volatilization Acidification of irrigation water

o Oxygen deficiency:

Continuous water supply may lead to exclusion of oxygen from saturation zone Deliver optimum amount of water

Constraints and their Solutions for Successful Adoption of Fertigation Contd.

Conclusion

Fertigation provides a variety of benefits to the users

like high crop productivity and quality, resource use

efficiency, environmental safety, flexibility in field

operations, effective weed management, and

successful crop cultivation on fields with undulating

topography.

For getting desired results due consideration on

aspects like fertilizer and water management,

filtration system etc. is essential.

Initially famers may face problems in successfully

operating the fertigation system but may overcome

such constraints over a period of time with

experience.