coping with water scarcity crop and environmental sciences division international rice research...
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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?