Effects of maize cowpea intercropping on yield stability and production risk in central Malawi: A modeling study

Smallholder farmers in Malawi face growing challenges from increasingly variable weather and scarce resources. We used the Agricultural Production Systems Simulator (APSIM) to investigate yield stability and production risk in maize cowpea intercrop and maize and cowpea monocrop systems at three locations in central Malawi. This was done as part of an ongoing farmer participatory research project, with a household survey and field trials providing context for the modeling study. Models were calibrated and validated based on field trials, and cropping systems were simulated for 26 seasons. Simulations were run in two soils at each site, under unfertilized conditions and with the addition of 69 kg N / ha. We determined calorie and protein yields of intercrop and monocrop systems in relation to household needs, and used stability analysis to contrast yields across a range of environmental conditions.;Calorie and protein yields tended to be higher in intercrops than in monocrops, except at one location where unfertilized maize yields were suppressed in intercrop with cowpea. Calorie and protein yields of intercrops also tended to be more variable than monocrops, largely due to the high performance of intercrops under favorable conditions. Maize cowpea intercrop systems demonstrated a greater chance of meeting household calorie and protein needs than maize and cowpea monocrops in 83% of cases. This suggests that maize cowpea intercropping is generally advantageous for smallholder farmers in Malawi, but yields may be suppressed in environments where cowpea is a strong competitor with maize. This study is unique in that it addresses risk to farmers and compares system performance across a range of growing conditions and seasons.