Rice Agriculture - The case of water scarcity. BAM B.A.M. Bouman. Crop, Soil and Water Sciences Division International Rice Research Institute

Transcription

1 Sustainability and Security in Rice Agriculture - The case of water scarcity BAM B.A.M. Bouman C S il d W t S i Di i i Crop, Soil and Water Sciences Division International Rice Research Institute

2 600 million tonnes for 2.6 billion people Despite declining population growth rate and changing diets, more rice needed in future Projected increase in demand for rice, East Asia -3% Southeast Asia 11% South thasia 13% Central and West Asia 36% Sub-Saharan Africa 49% Latin America 17% World 10%

3 While much better off than 25 years ago, over one billion remain desperately poor (LivingonlessthanUS$1perday) and most live in Asia!

4 Poor rural rice producers need increased income while the urban poor demand cheap rice supplies.

5 Increase food security Strategy Alleviate poverty net rice consumers Stimulate macro-economy Alleviate poverty rice producers Increase yield => keep price low Increase factor productivity => reduce costs Reduce environmental externalities

6 Some challenges ahead Increasing rice demand, decreasing production growth => Decrease world rice stocks Volatile prices Labor shortages and high wages Land shortage (land converted to other use, erosion) Water issues: Shortage Uncontrollable flooding Salinity Climate change and variability

7 The problem of not enough water Projected water scarcity in 2025 IWMI Global Water Scarcity Study, 2000 Irrigation: >80% of the freshwater resources in Asia By 2025, million ha of irrigated rice will suffer some degree of water scarcity Asia dry-season irrigated rice IRRI database (GIS laboratory)

8 Yield (t ha -1 ) Technologies to reduce water input Furrow, Flush, Sprinkler Irrigation AWD SSC Soil Management, Reduced d water depth Traditional upland rice system Aerobic rice system Lowland rice system ΔY = f (variety, management) Low Water availability High Aerobic Flooded FC Soil Condition Saturated

9 Field water dep pth (mm) transp. Early Late PI to complete grain filling Maturity recovery tillering tillering flowering Days after Transplanting Alternate wetting and drying (AWD) Intermittent irrigation (II) Controlled Irrigation (CI) One of key components in SRI

10 Safe AWD practice using simple tool 1. Start 10 DAT or 20 DAS 2. Irrigate when water is cm deep (simple tool) 3. Keep 5-cm flooded at flowering Main idea to convey: Water is there even when you can t see it Create confidence by farmers Farmers then to experiment with threshold value No recipe for soil type, hydrology, variety,..

11 Average number of pumping irrigation in water saving and non-water saving fields by district, An Giang Province, Vietnam (2006) N An Phu Chau Phu Cha hau Thanh Cho Moi Phu Tan Tan Chau Thoai Son Tinh Bien Long Xuyen water saving non-water saving Tri Ton

12 Yield under saving and non-water saving fields by district, An Giang Province, Vietnam (2006) Tons/ha Water saving Non saving Long An Phú Thoại Tri Tôn Phú Tân Tân Châu Châu Chợ Tịnh Xuyên Sơn Châu Phú Thànhh Mới Biên District

13 Aerobic rice Key characteristics: no puddling, no standing water, no soil saturation, dry land preparation, direct dry seeding, high inputs => high yields, special aerobic rice varieties Target domain: water-short irrigated lands, favorable uplands and rainfed lowlands (where water is Insufficient to grow flooded rice)

14 Upland rice Breeding: Aerobic soil Drought tolerant Weed competitive Adverse soil conditions Low inputs (!) => Stable but low yields Unfavorable uplands

15 Different idea of rice like upland crop Breeding: from upland rice Aerobic soil Input responsive Lodging resistant Weed competitive => Stable and high yields Lowland HYV traits Water-short t irrigated areas Favorable uplands

16 Beijing (CAU): Three varieties: Aerobic rice Han Dao 502 and 297 Lowland rice (check): Jin Dao 305 Lowland site: conventional lowland practice Aerobic site: five irrigation treatments

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18 Water input (rainfall + irrigation) mm Flood W W W W W

19 Yield (t ha -1 ) of HD Flood W W W W W

20 10 Yield (t ha -1 ) Flooded soil 9 Aerobic soil 8 7 Target domain Black = HD297 (plus HD502) White = lowland variety Water input (mm)

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22 MEANS OF CROPS 2002 Lowland rice Aerobic rice Maize Cotton Field size (ha) Grain yield (t/ha) Irrigation (mm) Rainfall (mm) Total water (I + R; mm) WP (g grain/ kg total water) Input cost ($/ha) fertilizer seeds herbicide and pesticide harvest fuel (except irrigation) irrigation (water, fuel) Total input cost ($/ha) Production value ($/ha) Net income ($/ha) Hired labor (d/ha) Own labor (d/ha) Net income, labor included

23 Comparative profitability (US $) of rice production, 2005 Aerobic Rice Lowland Rice Difference # of samples (n) Production Value 967 1,316 (349) *** Total Cost Fertilizer Cost Pesticide Cost Labor Cost Irrigation Cost Other Cost Gross Margin Other cost include seed, power and food cost (232) (41) 5 (175) (18) (3) (116) *** ** ** ***

24 Comparative profitability (US $) of other crops Corn Soybean Cotton Peanut # of samples (n) Production Value ,249 1,315 Total Cost Fertilizer Cost Pesticide Cost Labor Cost Other Cost Gross Margin Other cost include seed, power and food cost

25 Comparing different varieties under flooded and aerobic conditions, Tokyo, Osaka 2007, 2008

26 Aerobic Direct seeded Flooded transplanted Flooded Direct seeded

27 Conclusions Need to increase rice productivity Water scarcity increasing and affecting rice growing areas Response options available some ready to go (AWD) some require further research (AR)

28 50% of worlds hungry are net staple food consumers and stand to loose 50% smallholders stand to gain (depending on cost/benefit ratio) Urban Uba 20% Other rural Small farmers 10% 50% Rural landless 20% Estimates, Millennium Project, Task Force Hunger, 2005)

29 A balancing act

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31 Dissemination in Vietnam, Red River Delta: Yên Mỹ district, Hưng Yên( Xuân crop) & Văn Giang district, Hưng Yên (Mùa crop). Central North: Hưng Nguyên district, Nghệ An & Đông Sơn district, Thanh Hoá (Mùa crop) 3 Central Coast: La Hà corporative, Quảng Ngãi & Quế Xuân 1 corporative, Quảng Nam (AS crop) 4 MRD: Mỹ Thới, Long Xuyên, An ỹ, g y, Giang & Gò Công Tây, Tiền Giang (AS crop)

32 Different amount and timing irrigation Irrigation (mm) sowing emergence 44 d W1 W1 PI FL M Day number Rainfall (mm) Rain Day number Irrigation (mm) W5 W Day number Rainfall (mm) Rain Day number 2001

33 Destroyed cotton and maize fields by flooding, 2004 Destroyed sesame and maize fields by flooding, 2002

34 Yield of aerobic rice, various sites N China Tons/ha n=4 n=11 n=9 n=

35 Soil moisture tension (kpa) PI FL Very dry soil! 60 Soil moisture 50 tension at 20 cm; Day number Soil moisture tension (kpa) PI Day number FL Field capacity W1, W2 W3, W5