Coping with water scarcity Crop and Environmental Sciences Division International Rice Research...

Coping with water scarcity

Crop and Environmental Sciences DivisionCrop and Environmental Sciences DivisionInternational Rice Research InstituteInternational Rice Research Institute

Los BaLos Bañños, Philippinesos, Philippines

Reduce seepage, percolation, evaporation

1 Land preparation

2 Crop establishment

3 Crop growth period

Reducing nonproductive outflows

1. Land preparation (get basics right)1. Land preparation (get basics right)

• Field channels for irrigation and drainage• Land leveling• Crack plowing• Soil compaction• Good puddling• Good bund establishment

Plot-to-plot irrigation:difficult to control waterdepth and terminaldrainage

=> construct field canals

Effect of uneven fields:• Submerged spots• Drought spots• Weed growth• Uneven nutrient distribution

Wet land levelling

Modern technology:Laser-guided leveling

Cracks before land preparation

Rapid “bypass flow”

Shallow tillage to plough cracks

Control Shallow Tillage

Wa

ter

use

(m

m)

0

50

100

150

200

250

300

350

400

PercolationOther component

Water use in land preparation, Bulacan, 1993

Thorough puddling

One hole is plug out of bathtub!

Construct good bunds; plaster well. Check during season!

Rat hole in bund

Bund lining

0200

400600800

1000120014001600

18002000

DS2001 DS2002

Lining of bunds: 450 mm less water used

Water input, including land preparation (mm)

IRRI farm DS 2001-2002

Irrigation Rainfall

Innovative farmer in Mekong Delta, Vietnam

2. Crop establishment2. Crop establishment

• Short land preparation phase• Communal seed beds• Efficient use of rainfall (cropping calendar)• Crop establishment:

• Direct wet seeding• Direct dry seeding• Zero till

Lump into community seed beds

WTP > WWSLand preparation

Soaking Sowing Transplanting

Main fieldSeedbed

Main field

SowingSoaking

Transplanting

Wet seeding

Effect of direct seeding

Direct wet seeding

Direct wet seeding: drum seeder

Direct dry seeding

Zero till in direct dry seeding

Amount of water applied to the field to produce 1 kg of rice (MUDA, Malaysia)

Am

ount

of w

ater

(kg

)

Transplanting Direct Seeding1000

1500

2000

2500

3000

3500

4000

Effect of direct seeding

3. Crop growth period3. Crop growth period

• Good bund maintenance (e.g., rat holes)• Reduced evaporation• Reduced percolation and seepage through

decrease pressure head• Reduced ponded water depth• Saturated soil culture• Raised beds• Alternate wetting and drying (separate)

• Aerobic rice (separate)

Keep ponded water depth at 5-10 cm or lower(reduced pressure head => less SP)

Saturated soil culture: just keep soil at saturation (many small irrigation gifts)

Keep 5-cm flooded around flowering!

Water management during crop growth

14 28 42 56 70 840

vegetative reproductive ripeningGrowth Stage

Days after transplanting

1-2 cm 2-5 cm4-7 cm

1

dryingperiod7 days

1-2 cm 2-5 cmsaturated2

saturated1-2 cm3

saturated1-2 cm saturated

5

1-2 cm

10 days

8

1-2 cm5 cm 8 days

saturated

7 cm

7

saturated1-2 cm 2-5 cm 2-5 cm

4-7 cm

6

1-2 cm 5 cm8 days

7 cm

4

Y Win WPIR

5.0 2,197 0.23

4.9 1,059 0.46

4.6 914 0.50

4.0 880 0.46

5.2 1,693 0.31

5.2 2,187 0.24

4.5 874 0.52

4.0 870 0.46

Guimba, Philippines, 1988

Yield

(t ha-1)

Water (mm)

WPIR

(g grain kg-1 water)

Transplanted

Flooded 7.4 694 1.06

SSC 6.7 373 1.81

Wet seeded

Flooded 7.6 631 1.20

SSC 7.3 324 2.27

Saturated soil culture (SSC)

Munoz, Philippines, 1991

Yield

(t ha-1)

Water (mm)

WPIR

(g grain kg-1 water)

1996

Flooded 4.3 1,417 0.31

SSC 4.2 1,330 0.32

1997

Flooded 4.7 1,920 0.25

SSC 4.5 1,269 0.36

SSC in dry-seeded rice

San Jose City, Philippines, 1991

30 cm

37 cm 15 cm

250 cm

Raised beds; alternate irrigation (furrows); Ghaziabad,Uttar Pradesh, India; Rice-Wheat Consortium site

Raised bed cultivation in India

Rice on raised beds to keep soil saturated

Meerut and Ghaziabad (Delhi), India

Direct Seeded Transplanted

Rice on raised beds; Punjab, India

Yield

(t ha-1)

Water (mm)

WPIR

(g grain kg-1 water)

2001

Flooded 5.5 1,609 0.34

Beds FC 3.2 1,030 0.35

Flat FC 3.2 928 0.31

2002

Flooded 5.4 1,578 0.34

Beds FC 3.7 992 0.38

Flat FC 3.7 1,032 0.36

Raised and flat beds at Field Capacity

Delhi, India

Extreme measures: reduce E by plastic film

Experimentation in riceSome farmer adoption

China: thousands of haIn North China PlainIn upland crops(maize, cotton, melon,.)

Rice farmers adopting plastic film in Shiyan, China(6000 ha)

• Higher soil T => earlier establishment• Less E• Less weeds• Higher yields

Applying film: make sure there is no air between film and soil

Pierce holes for transplanting seedling

New machine development: can cover the film and pierce holes at the same time, operated by only one person

Irrigate through furrows: keep soil below saturation

Clear film from land after harvest. Waste disposal?