Climate change and ecological intensification of agriculture in sub-Saharan Africa – a systems approach to predict maize yield in push-pull technology

Description

‘Push-pull’ technology (PPT) is a poly-cropping design developed in eastern Africa that utilizes plant chemicals to mediate plant–insect interactions. PPT application increases crop productivity, by bolstering soil fertility and reducing pest damage caused by arthropods and parasitic weeds. As climate change effects are species- and/or context-specific, there is need to elucidate how, in interaction with biotic factors, projected climate conditions are likely to influence future functioning of PPT. Here, we first review how changes in temperature, precipitation and atmospheric CO2 concentration can directly influence PPT components (land use, soils, crops, weeds, diseases, pests and their natural enemies) across sub-Saharan Africa (SSA). We then impose anticipated responses on a landscape-scale qualitative mathematical model of maize production in eastern Africa, to predict cumulative, system-mediated impacts of climate change on maize yield. The review suggests variable direct impacts of climate change on PPT components in SSA by the end of the 21st century, including reduced soil fertility, increased weed and arthropod pest pressure and increased prevalence of crop diseases, but also increased biological control by pests’ natural enemies. The model predicts predominantly negative cumulative impacts of climate change on maize yield in eastern Africa. Nevertheless, maize yields can be sustained or increased by higher PPT adoption, preservation of field edge density and agricultural diversification beyond cereal crops. Our predictions can help guide management, policy-making and future research around PPT. Ultimately, we aim to provide the knowledge and methodological basis for reliable predictions of climate change impacts on ecological intensification across SSA and beyond.

Period	2023 Sept 28
Event title	Agri4D 2023: Building resilient food systems in uncertain times
Event type	Conference
Degree of Recognition	International