Ex-ante modeling analysis of maize yield
responses to nutrient management options in
Malawi:
Action Sites –Dedza & Ntcheu
Jawoo Koo (IFPRI)
Africa RISING Monitoring and Evaluation Meeting
Arusha, Tanzania, 13-14 November 2014

*DSSAT Cropping System Model Ver. 4.0.2.000 May 21, 2009; 16:32:33
*RUN 1 : RAINFED LOW NITROGEN
MODEL : MZCER040 - MAIZE
EXPERIMENT : UFGA8201 MZ NIT X IRR, GAINESVILLE 2N*3I
TREATMENT 1 : RAINFED LOW NITROGEN
CROP : MAIZE CULTIVAR : McCurdy 84aa ECOTYPE :IB0002
STARTING DATE : FEB 25 1982
PLANTING DATE : FEB 26 1982 PLANTS/m2 : 7.2 ROW SPACING : 61.cm
WEATHER : UFGA 1982
SOIL : IBMZ910014 TEXTURE : - Millhopper Fine Sand
SOIL INITIAL C : DEPTH:180cm EXTR. H2O:160.9mm NO3: 2.5kg/ha NH4: 12.9kg/ha
WATER BALANCE : IRRIGATE ON REPORTED DATE(S)
IRRIGATION : 13 mm IN 1 APPLICATIONS
NITROGEN BAL. : SOIL-N & N-UPTAKE SIMULATION; NO N-FIXATION
N-FERTILIZER : 116 kg/ha IN 3 APPLICATIONS
RESIDUE/MANURE : INITIAL : 1000 kg/ha ; 0 kg/ha IN 0 APPLICATIONS
ENVIRONM. OPT. : DAYL= 0.00 SRAD= 0.00 TMAX= 0.00 TMIN= 0.00
*DSSAT 10
Cropping System Model Ver. 4.0.2.000 May 21, 2009; 16:32:33
9
*RUN 1 : RAINFED LOW NITROGEN
MODEL : MZCER040 - MAIZE
EXPERIMENT : UFGA8201 MZ NIT X IRR, GAINESVILLE 2N*3I
TREATMENT 1 : RAINFED LOW NITROGEN
CROP : MAIZE CULTIVAR : McCurdy 84aa ECOTYPE :IB0002
STARTING DATE : FEB 25 1982
PLANTING DATE : FEB 26 1982 PLANTS/m2 : 7.2 ROW SPACING : 61.cm
WEATHER : UFGA 1982
SOIL : IBMZ910014 TEXTURE : - Millhopper Fine Sand
SOIL INITIAL C : DEPTH:180cm EXTR. H2O:160.9mm NO3: 2.5kg/ha NH4: 12.9kg/ha
WATER BALANCE : IRRIGATE ON REPORTED DATE(S)
IRRIGATION : 13 mm IN 1 APPLICATIONS
NITROGEN BAL. : SOIL-N & N-UPTAKE SIMULATION; NO N-FIXATION
N-FERTILIZER : 116 kg/ha IN 3 APPLICATIONS
RESIDUE/MANURE : INITIAL : 1000 kg/ha ; 0 kg/ha IN 0 APPLICATIONS
ENVIRONM. OPT. : DAYL= 0.00 SRAD= 0.00 TMAX= 0.00 TMIN= 0.00
OUTPUT
Phenology
8
7
6
5
4
3
2
1
SIMULATION OPT : WATER :Y NITROGEN:Y N-FIX:N PHOSPH :N PESTS :N
RAIN= 0.00 CO2 = R330.00 DEW = 0.00 WIND= 0.00
MANAGEMENT OPT : PLANTING:R IRRIG :R FERT :R RESIDUE:N HARVEST:M WTH:M
SIMULATION OPT : WATER :Y NITROGEN:Y N-FIX:N PHOSPH :N PESTS :N
*SUMMARY OF SOIL AND GENETIC INPUT PARAMETERS
PHOTO :C ET :R INFIL:S HYDROL :R SOM :G
MANAGEMENT OPT : PLANTING:R IRRIG :R FERT :R RESIDUE:N HARVEST:M WTH:M
*SUMMARY OF SOIL AND GENETIC INPUT PARAMETERS
SOIL LOWER UPPER SAT EXTR INIT ROOT BULK pH NO3 NH4 ORG
DEPTH LIMIT LIMIT SW SW SW DIST DENS C
cm cm3/cm3 cm3/cm3 cm3/cm3 g/cm3 ugN/g ugN/g %
SOIL LOWER UPPER SAT EXTR INIT ROOT BULK pH NO3 NH4 ORG
DEPTH LIMIT LIMIT SW SW SW DIST DENS C
cm cm3/cm3 cm3/cm3 cm3/cm3 g/cm3 ugN/g ugN/g %
flowering, grain/seed/tuber,
-------------------------------------------------------------------------------
0- 5 0.026 0.096 0.230 0.070 0.086 1.00 1.30 7.00 0.10 0.50 2.00
5- 15 0.025 0.086 0.230 0.061 0.086 1.00 1.30 7.00 0.10 0.50 1.00
15- 30 0.025 0.086 0.230 0.061 0.086 0.70 1.40 7.00 0.10 0.50 1.00
30- 45 0.025 0.086 0.230 0.061 0.086 0.30 1.40 7.00 0.10 0.50 0.50
45- 60 0.025 0.086 0.230 0.061 0.086 0.30 1.40 7.00 0.10 0.50 0.50
60- 90 0.028 0.090 0.230 0.062 0.076 0.05 1.45 7.00 0.10 0.60 0.10
90-120 0.028 0.090 0.230 0.062 0.076 0.03 1.45 7.00 0.10 0.50 0.10
120-150 0.029 0.130 0.230 0.101 0.130 0.00 1.45 7.00 0.10 0.50 0.04
150-180 0.070 0.258 0.360 0.188 0.258 0.00 1.20 7.00 0.10 0.50 0.24
-------------------------------------------------------------------------------
maturity
0- 5 0.026 0.096 0.230 0.070 0.086 1.00 1.30 7.00 0.10 0.50 2.00
5- 15 0.025 0.086 0.230 0.061 0.086 1.00 1.30 7.00 0.10 0.50 1.00
15- 30 0.025 0.086 0.230 0.061 0.086 0.70 1.40 7.00 0.10 0.50 1.00
30- 45 0.025 0.086 0.230 0.061 0.086 0.30 1.40 7.00 0.10 0.50 0.50
45- 60 0.025 0.086 0.230 0.061 0.086 60- 90 0.028 0.090 Yield 0.230 0.062 0.076 component
0.30 1.40 7.00 0.10 0.50 0.50
0.05 1.45 7.00 0.10 0.60 0.10
90-120 0.028 0.090 0.230 0.062 0.076 0.03 1.45 7.00 0.10 0.50 0.10
120-150 0.029 0.130 0.230 0.101 0.130 0.00 1.45 7.00 0.10 0.50 0.04
150-180 0.070 0.258 0.360 0.188 0.258 0.00 1.20 7.00 0.10 0.50 0.24
grain/seed/tuber, biomass, LAI
TOT-180 6.2 22.2 45.3 16.1 21.4 <--cm - kg/ha--> 2.5 12.9 87080
SOIL ALBEDO : 0.18 EVAPORATION LIMIT : 2.00 MIN. FACTOR : 1.00
RUNOFF CURVE # :60.00 DRAINAGE RATE : 0.65 FERT. FACTOR : 0.80
TOT-180 6.2 22.2 45.3 16.1 21.4 <--cm - kg/ha--> 2.5 12.9 87080
SOIL ALBEDO : 0.18 EVAPORATION LIMIT : 2.00 MIN. FACTOR : 1.00
RUNOFF CURVE # :60.00 DRAINAGE RATE : 0.65 FERT. FACTOR : 0.80
MAIZE CULTIVAR :IB0035-McCurdy 84aa ECOTYPE :IB0002
P1 : 265.00 P2 : 0.3000 P5 : 920.00
G2 : 990.00 G3 : 8.500 PHINT : 39.000
Growth
MAIZE CULTIVAR :IB0035-McCurdy 84aa ECOTYPE :IB0002
P1 : 265.00 P2 : 0.3000 P5 : 920.00
G2 : 990.00 G3 : 8.500 PHINT : 39.000
grain/seed/tuber, biomass, LAI
*SIMULATED CROP AND SOIL STATUS AT MAIN DEVELOPMENT STAGES
RUN NO. 1 RAINFED LOW NITROGEN
*SIMULATED CROP AND SOIL STATUS AT MAIN DEVELOPMENT STAGES
Soil
RUN NO. 1 RAINFED LOW NITROGEN
MANAGEMENT
• Planting window
• Planting density
• Irrigation
• Inorganic fertilizer
• Organic manure
• Tillage
• Residue
CULTIVAR
• Phenology
• Max # of kernels
• Kernel filling rate
*DSSAT Cropping System Model Ver. 4.0.2.000 May 21, 2009; 16:32:33
*RUN 1 : RAINFED LOW NITROGEN
MODEL : MZCER040 - MAIZE
EXPERIMENT : UFGA8201 MZ NIT X IRR, GAINESVILLE 2N*3I
TREATMENT 1 : RAINFED LOW NITROGEN
CROP : MAIZE CULTIVAR : McCurdy 84aa ECOTYPE :IB0002
STARTING DATE : FEB 25 1982
PLANTING DATE : FEB 26 1982 PLANTS/m2 : 7.2 ROW SPACING : 61.cm
WEATHER : UFGA 1982
SOIL : IBMZ910014 TEXTURE : - Millhopper Fine Sand
SOIL INITIAL C : DEPTH:180cm EXTR. H2O:160.9mm NO3: 2.5kg/ha NH4: 12.9kg/ha
WATER BALANCE : IRRIGATE ON REPORTED DATE(S)
IRRIGATION : 13 mm IN 1 APPLICATIONS
NITROGEN BAL. : SOIL-N & N-UPTAKE SIMULATION; NO N-FIXATION
N-FERTILIZER : 116 kg/ha IN 3 APPLICATIONS
RESIDUE/MANURE : INITIAL : 1000 kg/ha ; 0 kg/ha IN 0 APPLICATIONS
ENVIRONM. OPT. : DAYL= 0.00 SRAD= 0.00 TMAX= 0.00 TMIN= 0.00
RAIN= 0.00 CO2 = R330.00 DEW = 0.00 WIND= 0.00
SIMULATION OPT : WATER :Y NITROGEN:Y N-FIX:N PHOSPH :N PESTS :N
PHOTO :C ET :R INFIL:S HYDROL :R SOM :G
RAIN= 0.00 CO2 = R330.00 DEW = 0.00 WIND= 0.00
MANAGEMENT OPT : PLANTING:R IRRIG :R FERT :R RESIDUE:N HARVEST:M WTH:M
*SUMMARY OF SOIL AND GENETIC INPUT PARAMETERS
PHOTO :C ET :R INFIL:S HYDROL :R SOM :G
SOIL LOWER UPPER SAT EXTR INIT ROOT BULK pH NO3 NH4 ORG
DEPTH LIMIT LIMIT SW SW SW DIST DENS C
cm cm3/cm3 cm3/cm3 cm3/cm3 g/cm3 ugN/g ugN/g %
-------------------------------------------------------------------------------
0- 5 0.026 0.096 0.230 0.070 0.086 1.00 1.30 7.00 0.10 0.50 2.00
5- 15 0.025 0.086 0.230 0.061 0.086 1.00 1.30 7.00 0.10 0.50 1.00
15- 30 0.025 0.086 0.230 0.061 0.086 0.70 1.40 7.00 0.10 0.50 1.00
30- 45 0.025 0.086 0.230 0.061 0.086 0.30 1.40 7.00 0.10 0.50 0.50
45- 60 0.025 0.086 0.230 0.061 0.086 0.30 1.40 7.00 0.10 0.50 0.50
60- 90 0.028 0.090 0.230 0.062 0.076 0.05 1.45 7.00 0.10 0.60 0.10
90-120 0.028 0.090 0.230 0.062 0.076 0.03 1.45 7.00 0.10 0.50 0.10
120-150 0.029 0.130 0.230 0.101 0.130 0.00 1.45 7.00 0.10 0.50 0.04
150-180 0.070 0.258 0.360 0.188 0.258 0.00 1.20 7.00 0.10 0.50 0.24
TOT-180 6.2 22.2 45.3 16.1 21.4 <--cm - kg/ha--> 2.5 12.9 87080
SOIL ALBEDO : 0.18 EVAPORATION LIMIT : 2.00 MIN. FACTOR : 1.00
RUNOFF CURVE # :60.00 DRAINAGE RATE : 0.65 FERT. FACTOR : 0.80
MAIZE CULTIVAR :IB0035-McCurdy 84aa ECOTYPE :IB0002
P1 : 265.00 P2 : 0.3000 P5 : 920.00
G2 : 990.00 G3 : 8.500 PHINT : 39.000
*SIMULATED CROP AND SOIL STATUS AT MAIN DEVELOPMENT STAGES
RUN NO. 1 RAINFED LOW NITROGEN
CROP GROWTH BIOMASS CROP N STRESS
DATE AGE STAGE kg/ha LAI kg/ha % H2O N
------ --- ---------- ----- ----- --- --- ---- ----
25 FEB 0 Start Sim 0 0.00 0 0.0 0.00 0.00
26 FEB 0 Sowing 0 0.00 0 0.0 0.00 0.00
27 FEB 1 Germinate 0 0.00 0 0.0 0.00 0.00
9 MAR 11 Emergence 29 0.00 1 4.4 0.00 0.00
27 MAR 29 End Juveni 251 0.43 4 1.6 0.00 0.09
1 APR 34 Floral Ini 304 0.44 4 1.5 0.00 0.50
CROP GROWTH BIOMASS CROP N STRESS
DATE AGE STAGE kg/ha LAI kg/ha % H2O N
------ --- ---------- ----- ----- --- --- ---- ----
25 FEB 0 Start Sim 0 0.00 0 0.0 0.00 0.00
26 FEB 0 Sowing 0 0.00 0 0.0 0.00 0.00
27 FEB 1 Germinate 0 0.00 0 0.0 0.00 0.00
9 MAR 11 Emergence 29 0.00 1 4.4 0.00 0.00
27 MAR 29 End Juveni 251 0.43 4 1.6 0.00 0.09
1 APR 34 Floral Ini 304 0.44 4 1.5 0.00 0.50
CROP GROWTH BIOMASS CROP N STRESS
DATE AGE STAGE kg/ha LAI kg/ha % H2O N
nitrogen balance, water balance,
------ --- ---------- ----- ----- --- --- ---- ----
25 FEB 0 Start Sim 0 0.00 0 0.0 0.00 0.00
26 FEB 0 Sowing 0 0.00 0 0.0 0.00 0.00
27 FEB 1 Germinate carbon 0 0.00 balance
0 0.0 0.00 0.00
9 MAR 11 Emergence 29 0.00 1 4.4 0.00 0.00
27 MAR 29 End Juveni 251 0.43 4 1.6 0.00 0.09
1 APR 34 Floral Ini 304 0.44 4 1.5 0.00 0.50
0
0 50 100 150 200
Yield
(t/ha)
Fertilizer (kg[N]/ha)

Why (Ex-Ante) Model for AR?
 Better understanding of the current crop
production system’s sustainability
 Assess the potential of sustainable
intensification options and their scalability
beyond the study area and baseline survey
data

Data without models is chaos.
… but models without data is fantasy!
Source Unknown (but probably a crop modeler)

Hey, Jawoo!
We’ve got all these
baseline survey done!
What data do you need
for the modeling stuff?
White et al., 2013. Integrated description of agricultural field
experiments and production: The ICASA Version 2.0 data standards.
Computers and Electronics in Agriculture 96 (2013) 1–12

Come on, Jawoo!
That looks like too much
overwhelming! What are
the minimum data you
need?

What do we have for Dedza&Ntcheu?
From AR Baseline Survey + Docs + WUR Survey
 Site information
 Treatments (Innovations)
 Soil properties (Dedza: Loamy, Ntcheu: Sandy)
 Cropping calendar (Oct – Jan)
From HarvestChoice
 Soil profiles
 30-year daily weather (1980-2010; 0.5-deg grid)

* Simulated using 30-year historical weather data, first 3 years discarded for initialization spin-up, 13 years selected when maize was simulated

* Simulated using 30-year historical weather data, first 3 years discarded for initialization spin-up, 13 years selected when maize was simulated

* Simulated using 30-year historical weather data, first 3 years discarded for initialization spin-up, 13 years selected when maize was simulated

Seasonal
Yield & Rainfall

Soil Carbon
Sequestration

Soil Nitrogen
Leaching

Concluding Remarks
This is just the beginning;
many interesting ex-ante modeling
opportunities/applications ahead!
 Constraints analysis (What if…)
 Priority setting across innovation
options
 Cost-benefit/gross-margin analysis
 Climate-smart/proofing
 Identifying spaces for scaling-up

Thank You
Africa Research in Sustainable Intensification for the Next Generation
africa-rising.net
The presentation has a Creative Commons licence. You are free to re-use or distribute this work, provided credit is given to ILRI.