Soil Property Responses to Push-Pull Cropping in East Africa

Abstract

ABSTRACT Push-pull technology is increasingly promoted in sub-Saharan Africa, particularly for pest management and enhancing crop productivity. However, its influence on soil properties remains understudied, despite its potential implications for soil health and sustainable soil fertility management. This study examines soil properties in push-pull and conventional non-push-pull cropping systems. Soil samples were collected from push-pull and conventional plots in Ethiopia, Kenya, Rwanda, and Uganda. We examined the associations between soil physicochemical properties and cropping systems, along with key components of push-pull, namely Desmodium coverage and plot age, and manure and mineral fertiliser application. Overall, there were a few differences in soil properties between push-pull and conventional cultivation. In Kenya and Uganda, where Desmodium cover varied considerably, higher cover was positively associated with soil organic matter, cation-exchange capacity, and multiple nutrients. In Rwanda, Desmodium cover was positively associated only with phosphorus. Plot age in Kenya was negatively associated with pH and potassium, suggesting acidification from N2 fixation and potassium mining in the system. In Kenya, manure application was negatively associated with soil pH, CEC and several nutrients, while in Uganda, it was positively associated with calcium, sodium and zinc. In Ethiopia, manure application was positively associated with potassium and zinc, but only when testing the pushpull systems separately. Mineral fertiliser use was negatively associated with potassium and pH in Kenya, the only country with considerable use of mineral fertilisers. The data highlight a need for adaptive soil and crop management, including affordable non-acidifying N fertilisers and liming products for long-term sustainability of the push-pull system. The complexity in farmer adoption and practices, and the underlying soil and climate conditions, limit our ability to disentangle the contribution of system components to the effects of the push-pull system. Nevertheless, our findings highlight the complex and context-dependent associations of push-pull cropping and soil properties, underscoring the need for site-specific management to sustain soil health and crop productivity across sub-Saharan Africa.