Push-pull farming system helps insure smallholder maize production under climate change

Abstract

Agroecological approaches harnessing in-field biodiversity have been highlighted as a sustainable way to reduce yield gaps, but long-term assessments of their ability to buffer production from weather extremes and increasing interannual and intraseasonal climate variability are scarce. Here, we analyze a 12-year dataset from 642 control vs. push-pull maize field pairs in western Kenya, where long-term climate trends include increasing temperatures and intensifying drought and rainfall. In push-pull, maize is intercropped with a fodder legume that improves soil fertility, suppresses weeds, and deters pests, and is bordered with fodder grasses attracting and suppressing the pests. We assess interactions between push-pull and climate effects on yields, stemborer pest damage and densities of parasitic weeds during the long and short rainy seasons, and how these drive push-pull effects on yield. Push-pull maize yields were always higher than control yields, but varying climate conditions affected the two field types differently. During the long rainy seasons, differences between push-pull and control yields were higher in years with high temperatures. Yield benefits of push-pull were also higher in years when dry spells were longer early in the long rainy season. During the short rainy seasons, push-pull increased yields, particularly when accumulated seasonal rainfall was optimal, while still doubling yield under very low or very high precipitation. Interactions between push-pull and climate variables were partly mediated by pests and weeds. Our results show that smallholder maize production using push-pull not only increases yields but also buffers adverse effects of weather extremes that are already becoming more frequent and intense.