Presentation made at the WCCA 2001 event in Brisbane, Australia.

1. InfoRCT: Simulation Tool for Conservation
Agriculture based Rice-Wheat Systems
Y.S. Saharawat
International Rice Research Institute
ysaharawat@cgiar.org

2. Challenges Facing the R-W System
Growing cereal demand vis-à-vis declining
harvest area.
Declining/stagnating productivity.
Degrading soil and water resource base.
Inefficiency associated with intensive tillage.
Adverse changes in micro-climate.
Inefficient nutrient management.
Growing labor shortage
Escalating fuel price.

3. Introduction
Various Conservation Agriculture based resource
conservation technologies (RCTs) are believed to be
resource use efficient, environment-friendly and
economically superior to conventional practices.
However, an accurate accounting of the ecology and
economics of such practices is lacking.
A decision support system (DSS) is required to quantify
the input-output budget, fluxes of N, and global
warming potential (GWP) along with detailed
cost/benefit analysis of the prominent RCTs in rice-
wheat systems.

4. CA based Resource conservation
technologies in rice-wheat systems
Conventional Unpuddled Raised bed Zero-tillage
Tillage
Transplanting Direct-drill-seeding
Crop
establishment

5. Quantitative Evaluation of CA based RCTs
Productivity
Resource use efficiency
Cost effectiveness
Environmental impact
N loss
Greenhouse gas emission
Biocide residue

6. InfoRCT Decision Support System (DSS):
The Concept
The DSS integrates bio-physical, agronomic and socio-
economic parameters to establish empirical input-output
relationships related to water, fertilizer, labour and biocide
uses, GHG emissions, biocide residue in soil and N fluxes in
rice-wheat system.
This is programmed in Microsoft Excel and inputs and outputs
are calculated on a seasonal basis using the target-oriented-
approach.
With this an optimal combination of inputs is identified to
realize a target yield based on the biophysical environment
and the production technique.
Outputs like GHG emissions, N losses, and biocide residue are
then calculated based on the amount of input used and the
related soil-plant processes.

7. Schematic overview of the InfoRCT decision support
system
Target yield
Soil organic C Seed
Nutrient Water
requirement requirement
Manure/residues Human labor
Soil supply Potential evapo-
transpiration
Root exudates Machine
Manure/residue
Precipitation Animal labor
Deposition Technology
Irrigation
Fertilizer N Biocides
Fertilizers
NH3 Denitrifi NO3 CH4 CO2 N2O Biocide
volatilization cation leaching emission emission emission residue
Global warming
potential
Legends: Model Outputs Factors
inputs
Saharawat et al. 2011 Pathak et al. 2006

8. Methane, nitrous oxide and carbon dioxide
emissions
Soil + organic/inorganic inputs + Technology
~ SOC ~ fertilizer ~ cont. flooding
~ bulk_density ~ root biomass ~ midseason drying
~ soil_depth ~ manure ~ alternate flooding
~ crop_duration ~ residues ~ zero tillage
Saharawat et al. 2011, Pathak et al. 2011

9. Global Warming Potential
GWP = CH4 * 21 +
N2O * 296 +
CO2 * 44/12

10. Biocide residue index (BRI)
BRI = Chemical use (g ha-1) *
Toxicity index *
Persistence index/100
<100 = Safe
100-200 = Permissible
>200 = Unsafe

11. Development and
Calibration of InfoRCT

12. Treatments in the Modipuram Experiment
Gathala et al. 2011 (a,b)

13. Simulated and observed yields of rice and
wheat in Modipuram
10 Rice 6 Wheat
Modi 2003 Modi 2003
Caculated yield (Mg ha )
-1
8
Caculated yield (Mg ha )
Modi 2004 Modi 2004
-1
Modi 2005 4 Modi 2005
6
4
2
2
0 0
0 2 4 6 8 10
0 2 4 6
-1 -1
Observed yield (Mg ha ) Observed yield (Mg ha )
Saharawat et al. 2011, Pathak et al. 2011

14. Sensitivity
analysis of
the InfoRCT
Saharawat et al. 2011, Pathak et al. 2011

15. Simulated yield and income in different RCTs
Technology Yield Total cost Net return Return compared
(Mg ha -1 ) (US $ ha -1 ) (US $ ha -1 ) with TP1
TP1 12.2 1137 482 1.00
TP2 12.0 1002 607 1.26
TP3 9.8 901 428 0.89
TP4 10.8 1012 435 0.90
TP5 11.1 910 572 1.19
TP6 11.6 1014 540 1.12
Yield of rice is more with puddled transplanting (TP1) but net returns
are higher with midseason drying (TP2) and double zero-till systems
(TP5 and TP6) due to reduced cost of irrigation in the former and
reduced cost of tillage in the latter.
Saharawat et al. 2011, Pathak et al. 2011

16. GWP in different RCTs in Modipuram
4000
Rice Wheat
GWP (kg CO2 equi. ha )
-1
3000
2000
1000
0
TP1 TP2 TP3 TP4 TP5 TP6
Calculated GWP is more in the conventional system because of more
methane emission in continuously submerged condition in rice and more
fuel consumption for tillage and irrigation.
Pathak et al. 2011

17. Biocide residue index (BRI) in different RCTs
250 Wheat
Rice
200
Biocide residue index
150
100
50
0
TP1 TP2 TP3 TP4 TP5 TP6
Biocide residue index in rice and wheat under
different technologies in rice-wheat system
Biocide residue index is at a safe limit in the puddled transplanted
systems, whereas it exceeds the safe limit in direct drill-seeded and raised
bed systems because of more herbicide use
Pathak et al. 2011

18. Validation and Evaluation of
InfoRCT at farmers’ fields

19. Study site
India
Haryana
Study site

20. Methodology
Experimental site
 10 Villages at Haryana, India
 76 Farmers
Survey methodology
 Social, economic and educational status
 Input use: seed, irrigation, tractor, labour,
fertilizer, and pesticides use
 Output: Grain and straw yield
Simulation
 InfoRCT- for estimation of global warming
potential

21. Rice yield under alternative tillage and crop
establishment methods
9.0
8.0
7.0
6.0
Yield (Mg/ha)
5.0
4.0
3.0
2.0
1.0
0.0
CTPR UPTPR CTPR BTPR CTPR DSR CTPR ZT TPR
o No significant differences in rice yield between conventional tillage/CE and
alternative tillage/CE.
o Aromatic rice (Basmati) had lower yield due to low genetic yield potential.
Saharawat et al. 2011

22. Economics
Conventional Alternate tillage Difference
Total Cost (US$) 518 379-473 45-139
Net income (US$) 275 345-377 70-102
Transplanting
5% Labour 22%
Threshing fixed cost Irrigation
Seed
5% 1% water
2% Labour 15%
8%
Harvest Land preparation
7% 37%
Weedicide/insectici 11
de
7% Land
preparation
77%
Fertilizers Irrigation
14% 22%
Input cost in conventional tillage/CE Saving in alternate tillage and CE
Saharawat et al. 2011

23. Simulated and observed net income in different
tillage and crop establishment methods
800
Simulated net income (US $)
700 y = 0.99x + 3.68
600 2
R = 0.95
500
400
300
200
100
0
0 100 200 300 400 500 600 700
Observed net income (US $)
Saharawat et al. 2011

24. Simulated greenhouse gas emissions in rice-wheat system with
different tillage and crop establishment practices
Techno Crop CH4 soil N2O soil N2O CO2 CO2 CO2 CO2 CO2 GWP
logy fertilizer machine fertilizer biocide fertilizer biocide (CO2
prod. prod. appli. appli. equi.)
kg ha-1 kg N ha - kg N ha- kg C ha- kg C ha- kg C ha- kg C ha- kg C ha- kg ha-1
1 1 1 1 1 1 1
T1 Rice 59 0.10 0.32 478 199 47 11 11 3286
Wheat 0 0.10 0.42 81 256 0.2 14 0 597
RW 59 0.20 0.74 559 455 47 25 11 3884
T2 Rice 48 0.11 0.36 507 197 47 10 11 3174
Wheat 0 0.11 0.47 66 256 0 14 0 576
RW 48 0.23 0.83 573 454 47 24 11 3750
T3 Rice 25 0.12 0.24 389 117 82 6 18 2209
Wheat 0 0.12 0.53 60 261 0 14 0 591
RW 25 0.24 0.77 450 378 82 19 18 2799
T4 Rice 25 0.12 0.37 446 182 69 9 15 2491
Wheat 0 0.12 0.46 59 222 0 11 0 542
RW 25 0.24 0.83 505 404 70 21 15 3033
T5 Rice 25 0.12 0.41 433 202 82 10 18 2482
Wheat 0 0.12 0.54 58 222 0 10 0 564
RW 25 0.24 0.95 501 466 82 25 18 3046
Saharawat et al. 2011

25. Conclusions
Double no-till rice-wheat system increases farm income;
saves water, labour and energy; and reduces global
warming potential.
The technology could be a viable alternative for the
conventional puddled transplanted rice- and intensive
tilled-wheat system.
The InfoRCT decision support system could capture the
major effects of tillage and crop management practices
and could be used for a comparative assessment of
different resource conservation technologies in rice-wheat
system.

27. Calculated input, uptake and losses of N in rice-wheat
system with different technologies in Modipuram
Technolo Crop Input Output
gya
Fertilizer Irrigation Rain Fixation Uptake Leachin Volatilizati Denitrificati Total
g on on loss
kg N ha-1
TP1 Rice 153 12 3 25 108 19 33 26 79
Wheat 173 1 1 5 113 11 31 4 46
RW 326 13 4 30 221 30 64 31 125
TP2 Rice 138 10 3 25 101 18 31 24 73
Wheat 188 1 1 5 121 11 34 5 49
RW 326 11 4 30 222 29 64 29 122
TP3 Rice 71 8 3 25 72 9 20 16 45
Wheat 176 1 1 5 114 9 32 4 45
RW 247 9 4 30 186 18 52 20 90
TP4 Rice 107 10 3 25 88 14 26 21 60
Wheat 171 1 1 5 112 9 31 4 44
RW 278 11 4 30 200 22 57 25 104
TP5 Rice 114 8 3 25 90 15 26 21 63
Wheat 178 1 1 5 116 10 32 4 47
RW 292 9 4 30 205 25 59 26 110
TP6 Rice 120 10 3 25 93 15 28 22 65
Wheat 191 1 1 5 122 11 34 5 50
RW 310 11 4 30 215 26 62 27 115

28. Conclusions
• Midseason drying and double zero-till systems
increased income whereas raised bed systems
decreased it compared with the conventional
system.
• Direct-seeding and double zero systems reduce
GWP but have a risk of high biocide residue. More
efficient and safer herbicides, therefore, need to be
developed.
• The InfoRCT decision support system could be used
for a comparative assessment of different RCTs for
productivity, income and environmental impact at
different scenarios of soil, climate and crop
management.

29. Area under zero-tillage
(million ha)
0.0
0.5
1.0
1.5
2.0
2.5
19 98
-9 9
19 99
-0 0
20 00
-0 1
20 01
-0 2
20 02
-0 3
20 03
-0 4
20 04
-0 5
Diffusion of zero tillage in wheat in the IGP
20 05
-0 6

30. Mechanistic Model vs. Decision Support Tool
Parameter Mechanistic model Decision Support Tool
(DNDC) (InfoRCT)
Overall purpose Computation of actual pools Comparison of technologies for
and fluxes yield, net income, N balance
and GHG emission
Scale Plot Farm
Basic concept Description of processes Description of processes
through algorithms and through empirical data and
empirical data algorithms
Programming C++ MS Excel
Inputs Detailed soil, climatic and Basic soil, climate,
management data management, and prices data
Outputs C and N budget (daily C and N budget (seasonal
records) records)
Socio-economic Indirect: Yields Direct: Net income
parameters

31. Simulated global warming potential
CTPR-CW UTPR-ZTW BTPR-Bed DSR-ZTW ZT TPR-ZTW
2500
2000 2400
Co 2 (kg/ha)
1500 1742
1697 1616
1514
1000
500
0
CTPR-CW UTPR-ZTW BTPR-Bed DSR-ZTW ZT TPR-ZTW
o Higher GWP in the conventional system was due to more fuel use for tillage, water
pumping and more methane emission in submerged condition.
o At the current price of C credit (US$ 30 Mg-1 CO2) double no till system fetches an
additional income of US$ 24 ha-1 compared to the conventional rice-wheat system.

34. Monthly total rainfall, mean maximum and minimum
temperatures and mean solar radiation in Modipuram
Rainfall
Max. temp.
40 Min. temp. 30
Solar radiation
Temperature (oC) and solar radiation (MJ m d-1)
35
25
-2
30
Total rainfall (mm)
20
25
20 15
15
10
10
05
05
00 00
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

35. Technologies Adopted by Farmers
Treatment Rice Wheat Number of
farmers
T1 Transplanted rice after Broadcasted wheat after 76
conventional puddling (FP), Conventional tillage (FP)
T2 Transplanted rice in Drill sown wheat after zero tillage 41
unpuddled fields (UP-TPR) (ZTW)
T3 Transplanted rice on raised Drill sown wheat on same beds 9
beds (BP-TPR) after reshaping (ZTW)
T4 Transplanted rice after zero Drill sown wheat after zero tillage 6
tillage (ZT-TPR) (ZTW)
T5 Direct-drill-seeded rice after Drill sown wheat after zero tillage 20
zero tillage (DSR) (ZTW)

36. Monthly total rainfall, mean maximum and minimum
temperatures and mean sunshine hour in Haryana
Rainfall
45 Max. temp. 250
Min. temp.
40
Sunshine hours
200
35
Average temp. (o C) and sunshine (hr d -1 )
30
Total rainfall (mm)
150
25
20
100
15
10
50
05
00 00
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec