Tradeoffs in land and water productivity of rice with
establishment method and irrigation schedule Sudhir Yadav and Liz
Humphreys
Slide 2
Outline Establishment method of rice Performance of DSR and AWD
field experiment Model simulation Conclusion Research need
Slide 3
Rice agriculture is the engine of growth for rural and urban
economiesand maintaining peace
Slide 4
Conventional practice of growing Rice Nursery raising Puddling
Transplanting
Slide 5
Issues and Concerns Labour cost and availability Ground water
depletion/deterioration Energy requirement to pump groundwater
Productivity of rice Soil and environmental health *Some of these
problems can be handled by changing establishment method of
rice
Slide 6
Other practices of establishing Rice Establishment method of
rice Transplanting Puddled Manual Mechanical Unpuddled After dry
Tillage After Zero Tillage Direct seeding Wet seeding Puddled field
Broadcasting Line sowing Unpuddled field Broadcasting Line sowing
Dry seeding After dry tillage After Zero tillage (+M/-M)
Slide 7
Direct seeding
Slide 8
Mechanical transplanting, WSR & DSR labour saving- reduced
costs - timely establishment DSR beneficial to non-rice crops in
the rotation (e.g. wheat & maize) due to avoidance of puddling
= improved soil) opportunity to introduce conservation agriculture
in rice upland rotations e.g. rice-wheat (zero tillage, surface
residue retention = mulch) Drivers of different establishment
method
Slide 9
Performance of DSR in IGP DSR is considered as a water saving
technology but the fact is- it is just an establishment method
Slide 10
Regardless of establishment method, rice very sensitive to soil
drying With more water stress (>20 kPa), yield penalty was
higher in DSR than PTR. Water requirement of DSR vs puddled
transplanted rice (PTR) Punjab, India (clay loam, deep watertable)
4 irrigation treatments - daily or soil water tension 20, 40 or 70
kPa at 15-20 cm
Slide 13
for potential, water-limited, and/or nitrogen-limited
conditions (lowland, aerobic rice) Effects of weather, irrigation,
nitrogen fertilizer, general management, variety characteristics,
soil type (hydrological, native N supply) version 2.0, 2004; and
2.13, 2009 Fully documented User-friendly interface (FSEWin)
Tutorial available Standard evaluation methodology Standard data
sets available www.knowledgebank.irri.org/oryza2000/ Oryza2000: a
rice growth simulation model
Slide 14
Application of ORYZA Calibration: from 2 year field experiment
data Evaluation: 4 irrigation regime each year Simulation: 40 years
(1970-2009) past weather data of Ludhiana, India Irrigation
threshold First 30 DAS: 2-d after disappearance of water After 30
DAS: SWT based (10,20,..........70kPa)
Slide 15
Performance of ORYZA2000 to predict grain yield PTR DSR 2008
2009
Slide 16
Performance of ORYZA2000 to predict water balance
components
Slide 17
Simulation with 40 years past weather data
Slide 18
Grain yield and IW input with different irrigation
schedule
Slide 19
Where is the water saving? (Percolation+Seepage) Can we count
it under water saving
Slide 20
Safe AWD- PTR vs DSR Stage 1 Stage 2 Stage 3 y = 4.14x - 396.1
R = 0.97 y = 3.24x - 424.3 R = 0.98
Slide 21
Cracking in soil
Slide 22
SWT and Cracking intensity* *measurement with WinDIAS
Sofware
Slide 23
Water productivity: PTR vs DSR
Slide 24
TargetTechnologyPredicted outcome Yield (t ha -1 ) WP I (g kg
-1 ) WP ET (g kg -1 ) ET mm Maximizing yieldDSR-CF9.80.371.39705
Maximizing WP I DSR-30 kPa8.21.811.41586 Maximizing WP ET PTR-20
kPa8.51.191.66518 Minimizing ETPTR-60 kPa7.21.301.45497 Selection
of establishment method and irrigation schedule
Slide 25
25 The biggest gains in irrigation water saving are from
adoption of safe AWD (establishment method is of secondary
importance) Safe AWD reduced runoff, percolation & seepage (no
effect on ET) (i.e. it will not make more water available for other
uses where runoff & deep drainage can be used elsewhere)
reduced irrigation requirement for DSR by ~30% compared with PTR in
Punjab, India (needs to be evaluated in other situations) requires
ability to deliver water when needed (because of sensitivity of
rice to soil drying) Significance of above for irrigation system
managers
Slide 26
irrigation scheduling for DSR o can we reduce frequency of
irrigation during some crop stages & further reduce irrigation
input without reducing yield? o how is this affected by soil type,
climate, varietal duration etc? o develop farmer friendly
techniques for AWD Field water tube (shallow water table)
Tensiometer (deep water table) does adoption of zero tillage &
mulching in a rice- upland cropping system increase total system
yield, WPi & WP of depleted water? what are the real water
savings at higher spatial scales (irrigation schemes, catchments,
river basins)? Research needs for AWD & DSR
Slide 27
Acknowledgement Gurjeet Gill, The University of Adelaide,
Australia Liz Humphreys, International Rice Research Institute,
Philippines Tao Li, International Rice Research Institute,
Philippines S.S.Kukal, Punjab Agricultural University, India