Context-dependent Associations of Push-Pull Cropping and Soil Properties with Striga Weeds and Pest Damage Across Four East African Countries

ABSTRACT Push-pull (PP) cropping is an ecological intensification strategy used in sub-Saharan African smallholder systems to manage lepidopteran pests and Striga weeds. However, outcomes may vary across environmental contexts, including soil conditions. This study examined how associations between cropping systems and soil conditions relate to Striga seed bank density and lepidopteran pest damage across PP and non-push-pull (NPP) fields in four East African countries. Data were collected from 128 smallholder fields cultivated with maize or sorghum. Soil physicochemical properties (pH, nitrogen, cation exchange capacity, water infiltration rate and soil penetration depth) were summarised using principal component analysis to represent soil gradients. Associations between PP and Striga seed density varied between countries. In Rwanda, Striga seed density was lower in PP than NPP fields only in fields characterised by low pH, nitrogen, CEC and physically constrained soils, suggesting that PP was more beneficial on poor soils. In Uganda, Striga seed density was consistently lower in PP, suggesting a strong association with the cropping systems alone. In contrast, neither cropping system nor soil variation was associated with Striga seed density in Ethiopia or Kenya. PP fields also showed lower pest damage in Ethiopia and Uganda, independent of soil variation, while no clear patterns were detected in Kenya or Rwanda. Overall, associations between PP cropping, soil conditions, Striga and pest damage are context-dependent; in Rwanda, PP was most effective under less fertile soil conditions. These results underscore the importance of considering local environmental conditions when evaluating ecological intensification strategies in smallholder systems.