Simulations of Cropping Systems

APSIM (Mc Cown et al. 1996), a cropping systems simulator capable of simulating several crops and cropping systems grown as sequential and intercrop systems in the project region, as well as "what if" management scenario analyses was used in this study. Daily-observed weather data from 1963 to 1998 for Anantapur, and from 1984 to 1998 for Nandyala were used for simulation input. Data sets available from experiments at RARS Nandyala, and ARS, Anantapur were used for cultivar parameterization to simulate crops. Cropping systems scenarios were simulated using observed daily weather data for all years as well as ENSO phase based analog years (Table 17.1) daily data to compare probable production estimates and the value of ENSO based seasonal forecasts was estimated to assess risks of loss/gain associated with cropping system in different phases. We could not use any optimization algorithm except arriving at the maximum mean of crop yield.

Fig. 17.12. a Peanut yield in intercrop as affected by rainfall in ENSO phases during 1950-2001 in Anantapur; b intercrop pigeonpea yield as affected by rainfall in ENSO phases during 1950-2001 in Anantapur

Fig. 17.12. a Peanut yield in intercrop as affected by rainfall in ENSO phases during 1950-2001 in Anantapur; b intercrop pigeonpea yield as affected by rainfall in ENSO phases during 1950-2001 in Anantapur

Table 17.2. Key issues in forecast that may lead farmers' decision options in Anantapur and Kurnool as against traditional/risk-averse decision cropping systems

Location/Forecast issue Forecast based decision options

Traditionally risk averse/ low input decisions

Anantapur

July rainfall Late/August rainfall

Kurnool

June rainfall and good seasonal rainfall

Late rainfall

Peanut/pigeonpea intercrop

Peanut/short duration pigeonpea intercrop

Mungari cotton, intercrops like peanut/pigeonpea, sunflower/pigeonpea, and sunflower + chickpea sequence

Late sunflower, late sorghum

September-October rainfall Sole sunflower, sole chickpea

Sole peanut

Sole peanut,SD pigeonpea, sorghum, horse gram

Mungbean + chickpea, foxtail millet/pigeonpea, mungbean + sorghum

Wait for September rains Sole rabi sorghum

Cropping systems scenarios include yield estimates of traditional practice of single crop systems for all seasons and optimized ENSO phase forecast based crop production estimates. Conceptualization of these system scenarios is based on the farmers' survey results as preferred and adoptable decision depending on seasonal forecast and soil conditions (Table 17.2) for Kurnool and Anantapur.

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