1025 agronomic and environmental evaluation of a new approach for water-saving ground cover rice...
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Contributors: S Lin, K. Dittert, HB Tao1, KR Shen, YC Xu, SW Gao, XL Fan, MS Fan, SH Lu, LH Wu, FS Zhang. China Agriculture University, University of Kiel, Agricultural Bureau Hubei, Nanjing Agriculture University, Hunan Agricultural University, Sichuan Academy of Agricultural Sciences, Zhejiang UniversityTRANSCRIPT
Agronomic and environmental evaluation of a new approach for water-saving ground
cover rice production system (GCRPS)
S Lin1 、 K. Dittert2 、 HB Tao1 、 KR Shen3 、 YC
Xu4 、 SW Gao4 、 XL Fan5 、 MS Fan1 、 SH Lu6 、 LH Wu7 、FS Zhang1
1China Agriculture University, 2University of Kiel, 3Agricultural Bureau Hubei, 4Nanjing Agriculture
University, 5Hunan Agricultural University, 6Sichuan Academy of Agricultural Sciences,7Zhejiang University
Rice production is facing severe water scarcityeven in Southern China, in Guangdong with annual precipitation of 2000 mm
© www.irri.org/ipswar
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1000
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3000
4000
5000
6000
7000
76 78 80 82 84 86 88 90 92 94 96 98 00
Rice
Corn
Wheat
Yie
ld (
kg/
ha)
year
Average yield of rice, corn and wheat in China
Disadvantages of lowland rice production systems:
• High water demand , hence low water use efficiency
Wheat 500
Rice 1900
(Pimentel, 1997b)
Amount of water required (in liters) for the production of 1 kg grain
Water consumption for lowland productiondaily Season (150 d)mm d-1 mm
Land preparation 175 – 750Evapotranspiration wet season 4 – 5 600 – 750 dry season 6 – 7 900 – 1050Seepage heavy clays 1 – 5 150 – 750 loamy/sandy soil 25 – 30 3750 – 4500
Total season 925 – 5800 mmTypical 1500 – 2000 mm
(Bouman, 2001)
Disadvantages of lowland rice production systems:
• High water demand, and hence low water use efficiency
• Low N- fertiliser use efficiency
• High methane emission, and thus high global warming potential
Water-saving Ground Cover Rice Production System (GCRPS)
Strategy I: Rice is direct seeded, and soil is irrigated to approximately 80% of field water-holding capacity Strategy II: Rice plant is transplanted, and soil is irrigated to maintain soil water content near saturation
To reduce evaporation, the soil is covered by plastic film or by plant mulch with both strategies
Objectives of water-saving GCRPS
• Increase water and nutrient use efficiency
• Reduce emissions of CH4 and N2O
• Maintain and increase the grain yield
4000300020001600140012001000 800 600 400 200 100 50
Beijing, 600 mm
Nanjing, 1000 mm
Gaungzhou, 2000 mm
HubeiSichuan
Zhejiang
Distribution of precipitationGCRPS – direct seeding
GCRPS – transplanting
• GCRPS - direct seedingGCRPS - direct seeding
Seeding GCRPS-film
(15 cm pF < 10–15 kPa)
Lin, 2002
• GCRPS - transplanting
Lin, 2002
• Rice plant will be transplanted and soil is irrigated to maintain soil water content near saturation• To reduce evaporation, the soil is covered by plastic film or plant mulch.
Transplanting Lin, 2005
Land level & fertilization Film covering
Hole making
林杉 , 2005
Layout of the field experiment in Hubei
Evapo-transpiration plus leachingFree surface evaporation
Free surfaceevaporation
Evapo-transpiration
Free surface evapo-ration between rows
0
1000
2000
3000
Irri
gat
ion
wat
er (
mm
)
Amount of irrigation water used for paddy ground cover with plastic film and with straw
Paddy Film Straw
Beijing Nanjing Guangzhou
Paddy Film Straw Paddy Film Straw
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
WU
Ei
(kg
m-3)
Irrigation water use efficiency
Paddy Film Straw
Beijing Nanjing Guangzhou
Paddy Film Straw Paddy Film Straw
photo Lin
May we reduce CH4/N2O emission of traditional paddy rice?
Closed Chamber
15N balance
Water balance
Nitrate leaching
Water meter
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2000
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4000
20000
0
1000
2000
3000
4000
20000
0
1000
2000
3000
4000
20000
CH
4 (m
g m
-2)
CH4 emissions
Paddy Film Straw
Beijing Nanjing Guangzhou
Paddy Film Straw Paddy Film Straw
0
500
1000
1500
0
500
1000
1500
0
500
1000
1500
N2O
(mg
m-2)
N2O emissions
Paddy Film Straw
Beijing Nanjing Guangzhou
Paddy Film Straw Paddy Film Straw
0
200
400
0
200
400
0
200
400
Compared to CO2: CH4 by factor of 23, N2O by factor of 296 (IPCC 2001)
CO
2 eq
uiv
alen
t fl
ux
(g
m-2)
Global warming potential of CH4 and N2O
Paddy Film Straw
Beijing Nanjing Guangzhou
Paddy Film Straw Paddy Film Straw
Evaluation of water-saving alternatives with GCRPS
Comparison of rice grain yield, 2002
Beijing Nanjing Guangzhou
Regional yield level
Average grain yield (kg ha-1) of long-term experiments
Treatment Sichuan Hubei Nanjing Zhejiang (1999-2008) (2003-2008) (2001-2008) (2001-2008)
Paddy -N0 nd 3,180 4,631 nd
GCRPS-N0 5,011 4,657 4,330 6,318
Paddy -N150 5,998 6,059 7,294 8,216
GCRPS-N150 7,051 6,631 6,636 7,766
150 kg N/ha/yr for Sichuan, Hubei & Nanjing; 135 kg N/ha/yr for Zhejiang
+18% +10% -9% -5%
+46% -6%
Average grain yield, N uptake, NUE and C-fixation at Hubei , 2003-08
Treatment Yield N-uptake C-fix. NUE* (kg/ha) (kg N/ha) (kg C/ha) (%)
Paddy -N0 3,180 45 2,762
GCRPS-N0 3,657 50 3,388
Paddy -N150 6,059 111 5,663 44
GCRPS-N150 6,631 123 6,310 52
-- Difference method-- 150 kg N/ha/yr, n=18
Is there still some room for maneuver
for us to increase the rice grain yield
and reduce N2O emission of GCRPS by
improvement of fertilization method?
Average grain yield, N uptake, NUE and C-fixation at Hubei, 2003-08
Treatment Yield N-uptake C-fix. NUE* (kg/ha) (kg N/ha) (kg C/ha) (%)
Paddy -N0 3,180 45 2,762
GCRPS-N0 3,657 50 3,388
Paddy -N150 6,059 111 5,663 44
GCRPS-N150 6,631 123 6,310 52
GCRPS-CRF* 6,805 134 6,876 59
GCRPS-Ninhibitor** 6,945 133 6,550 59
• *Average for 5 years; ** Average for 4 years; • 150 kg N/ha/yr for all fertilized treatment
+13%
+24%
+18%
100%
Paddy _N225 0.05 c 123 c
GCRPS_N225 0.20 a 490 a
GCRPS_N150 0.12 b 293 b
GCRPS_CRF 0.07 c 160 c
AvdFlux Total
(mg.m-2.h-1) (mg.m-2)
Average daily N2O flux (AvdFlux) and total emission during the whole rice growth period (Total)
(Fan, unpub., pers. comm.)
Covering with plastic film
Hole-making with simple tool
Water-saving rice GCRPS in practice
GCRPS in Hubei
2005.5.7
GCRPS in Sichuan
2009.5.27
Conclusion
The system of water-saving ground cover rice production
can maintain food safety, improve resource use efficiency
(both for water & N), and increase C-fixation. Also, it can
also decrease global warming potential by reducing CH4
emissions and has the potential to reduce N2O emissions.
We believe GCRPS can harmonize the objectives of Countering Water Scarcity, Enhancing Food Safety, Achieving Resource Use Efficiency, and Abating Global Warming Potential
Thanks for your attention