Efficient Water Management Strategies for Higher

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Improving water use efficiency through micro irrigation (Drip/Sprinkler system) ... Ring Pit. Trench and Mound. Saucer. 5 times. 4 times can be made mechanically.
Efficient Water Management Strategies for Higher Water Productivity Anurag Saxena Central Arid Zone Research Institute, Jodhpur, Rajasthan E-mail: [email protected]; [email protected]

Environmental constraints of arid zone • • • • • • • • • • • •

Low and Erratic Rainfall < 400 mm (cv. 40- 80%) High Temperature (45- 48oC) Intense Radiation (15.12 to 26.50 MJ m-2 day-1) High Wind Velocity (20- 40 km hr-1) High Evapotranspiration (1800- 2200 mm yr-1) Deep and generally saline groundwater Presence of excessive fluoride nitrate- unsafe drinking water Over-mining of fresh groundwater Poor drainage network Sandy Soils with low WHC Overgrazing due to high Biotic Pressure due Frequent Drought (47%)

SPATIAL VARIATION OF RAINFALL • • •

Mean Annual rainfall - 1170 mm Maximum mean rainfall - 11000 mm (Cherrapunji) Minimum mean rainfall - 100 mm (Western Rajasthan)

Rajasthan India

Scenario/ Problem • Scarce water in arid regions • Fall in groundwater 0.5 – 1.0 m annually • Over exploitation of water led to 70 – 80% area under dark zone

Rapidly depleting ground Water- A major concern Safe Critical Nagaur

Nagaur

Rainfall in the west and east Rajasthan Meteorological sub-division

Monthly rainfall (mm) June

July

August

Sept

West Rajasthan

24

175

95

55

East Rajasthan

48

273

210

250

Total 237 blocks, Over exploited –140 (Dark zones), Rest critical

Water use Drinking Agriculture Industry Power generation • • • •

Water loss 04% 80% 10% 06%

Soil moisture Percolation Run-off ET

Groundwater main source of water Depleting at an alarming rate Need to produce more with less water Improving crop WP is must

10% Useful 9% 19% 40% Loss 81% 41%

The Problem • Demand of other sectors increasing • Share for in 2050 will be less by 15-20% • However, 1% of water productivity gain in agriculture means 10% increase of availability for other uses Water Consumption (Virtual Water)



We drink 2~3 litres/day (15-20 Glasses)



We eat 1500 – 10000 litres/day

Virtual water content of products Commodity 1 kg grain

Water (Litres) 1 – 2,000

1 kg cheese

5000

1 kg beef

16000

1 cup coffee

140

1 kg wheat bread

1600

1 kg rice

2500

1 Hamburger

2400

100 g Chocolate

2400

1 kg sugar

1500

1 kg tomato

180

Dryland-adapted system 200

150 mm

Runoff harvesting – additional 35% of annual rainfall

Type of water  Green water: volume of rainwater evaporated or incorporated into product  Blue water: High value (competition with other uses), don’t use in agriculture, water

has relative low value  Grey water footprint: volume of polluted water  In agriculture optimally use green water

Focus on:  Rainfed Agriculture  Water Harvesting  Supplementary Irrigation

Technological Options/ Strategies • Increasing water availability

• Improved agronomic practices (Tillage, weeding, mulching etc. ) • Crop planning based on longest growing period: Choosing efficient farming systems • In-situ rainwater harvesting and management •

Deficit /Extensive irrigation

• Improving water use efficiency through micro irrigation (Drip/Sprinkler system)

Crop production depends on • • • • • • •

Rainfall & its distribution Crop & varieties Sowing Planting pattern & population Weeding & inter-culture Water management Fertiliser management

398 Better Husbandry

Hybrid, fertiliser & water harvesting

2433

Better Husbandry

1301

1544

Better – poor Tech Gap 2447

Hybrid fertiliser & water harvesting

2845

Integration of Management Practices & water harvesting improves pearl millet yield

Weeding influences WUE (Kg ha-1 mm-1 ) & yield (Kg ha-1 ) of Pearl millet Treatment

Good rainfall ( 548 mm)

Low rainfall (252mm)

Yield

WUE

Yield

WUE

Un-weeded

1672

3.1

1053

4.2

Weeded

1868

3.4

1521

6.0

Mulching improves Yield and WUE of Pearl millet Type of Mulch

Water Use (ET) mm

Yield (kg ha-1)

WUE (kg ha-1 mm-1)

Polyethelene

279

2900

10.4

Bajra husk

269

2300

8.5

No. Mulch

291

1740

6.0

Planting Arrangement improves water use and yield of pearl millet Planting Arrangement

Good rainfall (548 mm)

Low rainfall (252mm)

Yield

WUE

Yield

WUE

50X50 cm(RR)

2914

5.3

2235

8.9

25X75X15 cm (DR)

2732

5.0

2724

10.8

Yield : kg ha-1

WUE: kg ha-1 mm-1

Performance of intercropping systems under two rainfall situations Planting system

Rainfall 409 mm Paired row Alternate row Rainfall 152 mm Paired row Alternate row

Base crop plant population (000 x Plants ha-1)

Yield (Kg ha-1)

Grain

Stover

166 100 166 100

3098 2880 2989 2947

6505 5760 6336 5890

166 100 166 100

475 590 381 506

192 1334 872 1138

1:2

2:2 1: 2

2: 1

2: 2

Rainwater conservation practices A) In-situ Rainwater: Conservation water is stored in soil profile itself B) Ex-situ Rainwater: Conservation Water is stored in a reservoir on pond for recycling 

Inter plot/ row water harvesting



Pit and trench method for vegetable and fruit crops



Bench terrace water harvesting

Micro Catchment Farming

In-situ water harvesting system Pearl millet yield was almost doubled

Circular catchment for water harvesting

Plastic gave 95% Run off

Micro Catchments for horticulture crops Ring Pit

Saucer

Trench and Mound can be made mechanically and economically viable

5 times

4 times

Productivity enhancement and economic benefit  Water harvesting prevent runoff losses by 30-50 % and maintain higher soil moisture regime  Enhanced soil moisture storage by 42% in the upper 75 cm layer alone after mild shower of 27.5 mm  Facilitate better crop production due to better development of root system  Improved water use efficiency by 4-7 times

Runoff Water Conservation

Sowing on specially created furrows

Pearl millet crop

Comparison of conservation of run off water in pearl millet fields

Laser Land Leveling: A water-wise technology Laser Leveler- productivity gain & water saving Yield (kg ha-1) Crop

• • • • •

Increases irrigated area ~ 2% Improves crop stand and yields Increases water productivity Increases nutrient use efficiency Improves farm profitability

Water saving over without laser leveled field (%)

Laser leveled field

Without laser leveling

Potato

11000

8250

25

Onion

10000

8000

20

Check - basin

Land quality degraded by irrigating low quality water

Management of limited irrigation water In arid region water is limited and land is vast, hence water management should aim to maximize production per unit of water rather per unit of land • Water Harvesting is capturing and storing rainfall to irrigate plants or to supply people and animals • Water harvesting will help in reducing dependence on ground water

Techniques in water saving  Rainwater conservation  Extensive irrigation  Deficit irrigation

Runoff efficiency of different sealants Sealant Plastic Pond sediments Compacted earth catchment Flat Surface

Runoff efficiency ( %)

Pearl millet Yield (kg ha-1 )

95.7 88.9 65.9

883.5 557.5 532.5

-

383.5

Pond sediment to improve water retention

Water Use, yield and WUE of Pearl millet by water harvesting System Conventional In- situ Water Harvesting

Yield : kg ha-1

Good rainfall Water use Yield WUE 440 2320 5.3 630

2425

WUE: kg ha-1 mm-1

Low rainfall Water use Yield 143 400

3.9

Water use: mm

212

1240

WUE 2.9 5.9

In-situ water harvesting: Efficient use of limited rainfall & N-fertiliser in pearl millet System

Added Water (mm)

N- levels (kg ha-1) 0

40

Rainfed

0

210

400

In –situ water harvesting

69

660

840

Seasonal rainfall 143mm

Deficit irrigation • Avoid irrigation at less critical stages of crop growth and apply less water at the end so as to eliminate water stored at harvest Extensive irrigation • Apply a small quantity of water over a large area rather than large quantity over a small area

Extensive irrigation maximise production for given water supply

Crop

Water use (mm)

Wheat

840

Mustard

250

Pearl millet

250

Area (ha) 1 3 1 1.5 1 4

Yield (kg ha-1) 5500 9100 1100 2000 4.2 10.3

WUE kg ha-1 mm-1 6.5 10.8 4.4 8.0 16.8 21.0

Increased Area under S-IRR Enhances Pearl millet Production Low Rainfall (143 mm) S-IRR Area Yield

Medium Rainfall (266 mm) S-IRR Area Yield

Good Rainfall (331 mm) S-IRR Area Yield

341 209 117 0

292 145 73 0

190 76 38 0

1.0 1.6 2.9 1.0

3540 4528 5829 1080

1 2 4 1

S-IRR in mm ha-1, Area in ha, Yield in Kg ha-1

3620 5380 7560 1400

1.0 2.5 5.0 1.0

3660 7225 12950 2280

Effect of furrow irrigation on yield and water use Crop

Maize Saving of water (%) Yield (q/ha) Water Use Efficiency (kg ha mm-1)

Irrigation in Irrigation in alternate each furrow furrows 41.3 25.8

30.0 40.6 36.7

Pressurized irrigation systems

Improved conveyance and application efficiencies on coarse & shallow soils Low discharges used Reduced labour requirements Suited to all range of topographies & field dimensions and Easy to operate High irrigation efficiency: Uniform distribution Accurate and easy measurement of water applied Application of fertilizer through irrigation system Mobility, enabling the exploitation of one unit for irrigating other plots

Effects on micro-climate protection against frost Weed growth is minimized since only desired portion is wetted

Comparison of water movement in different irrigation systems

Sprinkler

Drip irrigation

Alternate furrow sub surface drip irrigation

 Uniformity of application tests: Irrigation water collected in containers laid out in the plot. The size of the containers and their layout depend on the type of the sprinkler.  Coefficient of Uniformity of Application (Cu)

Cu (%) = 100 1 − Cu (%) = 100 1 −

𝑥𝑖 −𝑥 𝑥.𝑛 𝑆𝑢𝑚 𝑜𝑓 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛𝑠 𝑆𝑢𝑚 𝑜𝑓 𝑟𝑒𝑎𝑑𝑖𝑛𝑔

Cu (%) = Coefficient of uniformity of application Σ = Total xi = Individual reading – catch can 𝑥 = Mean readings – catch can N = Number of containers (readings) Minimum Cu (%) requirement for sprinkler and drip irrigation in field crops 84 and 90%.

Single sprinkler Sprinkler system operating at too low pressure

too high pressure

Normal pressure

Overlapped sprinklers

Uniform Application: Overlap  50% of sprinkler wetted diameter

Non-uniform Application: Overlap urea > KNO3) • Soil & Water Salinity : (Avoid Na and Cl salts use NO3 salts) • Ca content of water : (Avoid Sulphates) Amount of water required for irrigation Amount of irrigation water =A * B * C * d * E * F • A: Evaporation from open pan (mm/day) • B: Crop factor

• C: Area (m2) • D: Percent area to be wetted • E: Treatment • F: Pan factor

(Litres per day)

Operation time Operation time (Hrs) = Volume of water to be applied per tree/ Total dripper discharge Rate of fertigation • Rate & concentration is calculated to avoid over fertilization • Fertilization schedule of drip irrigated crops is site specific • Primarily depends on concentration of soluble fertilizer & desired quantity of nutrients to be applied during irrigation

Rate of fertigation Qc = Fr * A/C *tr * Ta Qc = Rate of injection of soluble fertilizer solution in to the system (l/h) Fr = Fertilizer rate per application (kg/ha) A = Area to be irrigated/fertilized in Ta Ta = Irrigation application or set time C = Concentration of actual nutrients in the soluble fertilizer (kg/I) Tr = Ratio between fertilizer time and irrigation application time

Micronutrient fertigation  

Micro nutrient fertigation should be separate from macro nutrients If micronutrients are added to high acidic solution of NPK there will be interaction of Fe with P, Zn and both element will not be available to the plant

Effect of planting configurations on crop yields Yield (metric t ha-1) of

Plant arrangement Cabbage

Tomato

Turnip

Cauliflower

Rectangular

35.5

68.4

19.5

20.0

Square

33.2

73.1

20.3

23.8

Hexagonal

16.9

55.1

11.8

13.2

Equilateral

33.0

78.4

22.9

26.0

Drip Improves yield (t ha-1) & WUE (Kg ha-1 mm-1) of Vegetables Crop

Furrow

Sprinkler

Drip

Yield

WUE

Yield

WUE

Yield

WUE

Ridge Gourd

11

1.3

10

1.2

12

1.7

Long gourd

38

4.6

39

4.6

56

8.1

Round gourd

30

3.7

34

4.2

41

5.4

Water melon

67

8.3

75

9.3

82

11.0

Check-basin vs. Drip in Chilli

Yield (t ha-1)

WUE (kg ha-1 mm-1)

Check-basin + 180 kg N

1.93

2.05

Drip + 180 kg N

2.94

5.17

Drip + 135 kg N

2.79

4.90

Drip + 90 kg N

2.06

3.64

Drip + 0 kg N

1.14

2.03

Method

Effect of Water and N on Yield and WUE of chilli Treatment

Yield (t ha-1)

WUE (kg ha-1 mm-1)

Water on Area Basis + N kg ha-1 Total + 180

3.03

4.52

Canopy + 180

2.94

5.17

Wetted +180

1.50

4.54

Check basin

1.93

2.05

High yield potential with drip irrigation (t ha-1)

Method

Tomato

Cabbage

Cauliflower

Drip

78

36

26

Conventional

50

30

20

Drip Provides Gainful use of saline water Method Conventional

Salinity (d Sm-1)

Potato (t ha-1 )

Tomato (t ha-1)

Sweet

20

50

3

26

-

10

-

44

Drip

Drip economises water in potato

Method

Water Use (mm)

Yield (t ha-1)

Furrow

366

20.2

Drip

183

20.5

Drip economizes fertiliser in tomato

Fertilisers (kg ha-1)

Method

Yield (t ha-1 )

Broadcast

N 224

P 88

K 168

72

Fertigation

56

22

42

60

Drip irrigation Vs. conventional irrigation

Crop

Water requirement (L day-1 plant-1)

% increase in

Drip

Conventional

Yield

Water saving

Grape

25-45

90-100

23

48

Pomegranate

20-40

60-130

61

45

Lemon

10-20

25-65

40

40

Papaya

5-8

18-26

75

68

Banana

8-12

30-40

52

45

Tomato

1-2

4-6

50

39

Chillies

1-2

3-6

44

62

Gourds

1-2

3-6

39

53

Saving in fertiliser & water

Vegetable

Fertiliser saving (%)

Water saving (%)

Bulb crops

30 – 40

30 – 35

Cole crops

40 – 50

40 – 45

Solanaceous crops

40 – 50

45 – 50

Cucurbits

60 – 70

60 – 70

Okra

40 – 45

40 - 45

Top problems with drip

o

o o o

o o o o o

System not matched to available flow rates Insufficient pressure & Inadequate filtration Improperly sized main lines & manifolds No or insufficient no. of pressure gauges No flushing manifold Improper or inadequate chemical injection program for clogging control Insufficient water supply for the crop Insect and salt clogging occur regularly Unrealistic expectations

Drip system maintenance • • • •

flushing of filters frequently flushing of laterals and sub-mains running the system at required pressure acid treatment against the salt deposits

• chlorine treatment against the algae

Drip Irrigation Systems - Crops FRUIT CROPS : Almond, Apple, Arecanut, Indian Gooseberry, Ber, Banana, Cashew, Custard Apple, Cherry, Fig, Guava, Grape, Litchi, Lemon, Sweet Lime, Mango, Orange, Papaya, Pomegranate, Pear, Peach, Strawberry, Jack Fruit, Water & Melon VEGETABLE CROPS : Brinjal, Cucumber, Lettuce, Pepper, Potato, Pea, Tomato FIELD & OTHER CROPS: Corn, Cotton, Sugarcane, Tobacco, Betel vine

OIL SEEDS : Groundnut, Sunflower, Jojoba, Castor FORAGE CROPS : Lucerne, Pastures, Turfs, Fodder PLANTATION CROPS : Cardamom, Coffee, Tea, Rubber, Spices, Oil Palm, Coconut

ORNAMENTALS : Rose, Gerbera, Carnation, Gladioli, Poinsettias, Chrysanthemum FOREST TREES : Eucalyptus, Casuarinas, Teak, Acacia, Bamboo, Neem, Dalbergia

Drip Irrigation: Saves 40-45% water

Low cost drip irrigation systems

Conventional drip irrigation systems

Irrigation methods Surface irrigation

Piped system

Furrow

Water flows through furrows over the field

Border strip

Water flows over strip of land

basin

Water is hold in a small basin until irrigator decides

Sprinkler

Spraying water over the soil surface

Drip

Emitting water to top soil at low flow rates

Sub-surface

Control of groundwater

Water Savings - Comparison • Conveyance efficiency

:

Open field channels

70%

Piped distribution

80 - 85%

• Field application efficiency: Surface methods (Irrigation Efficiency) Sprinkler Micro-Irrigation

50 70% 80 - 90%

• Overall efficiency

35% 57% 70%

: Surface methods Sprinkler Micro Irrigation

Polyhouses/ Shade houses • Cultivation under controlled environment for massive yields from small area and faster crop rotations.

• Useful in raising off-season, high value vegetables, floriculture and grafting, nursery raising activities.

• Available in different types with cladding by PE film, Poly carbonate, Poly shade nets

Polyhouse Technology

• Protection from wind current, scorching sunlight & extreme cold conditions • Maximum production from minimum space, labour & minimum use of water • Diseases and pests can be controlled easily

• Protection from birds, animals and human activities • Best quality production of crops throughout the year

Protected cultivation

Thanks