Performance of Push–Pull Technology in Low-Fertility Soils under Conventional and Conservation Agriculture Farming Systems in Malawi

Abstract

Push–pull technology (PPT) is one of the most viable low-cost agroecological practices that reduces the effects of insect pest infestations (e.g., stemborer) and parasitic weeds (e.g., Striga) in croplands. PPT was evaluated in low-fertility soils and two farming practices, minimum-tilled conservation agriculture practice (CA), and conventionally tilled practice (CP), in contrasting agroecological zones at the Chitedze, Mbawa, and Chitala stations in Malawi. Stemborer and Striga infestations were also investigated and the suitability levels of two Desmodium species. Farmers’ perceptions of PPT were gathered through a focus group discussion. The performance of PPT varied significantly between treatments, sites, and years on grain yields and the number of cobs that could be assigned to soil attributes. Significant variations were found in the number of exit holes, stemborer damage severity, and the number of Striga-affected plants with severe infestation. In Chitedze, CP recorded significantly shorter maize plants by 14.1, 11.6, and 5.8 cm than CP–PP, CA, and CA–PP, respectively, in 2016–2017. There were no significant differences in plant height between CP–PP, CA, and CA–PP. Similar results were also found in 2017–2018. Focus group discussions among farmers attested to up to 70% reductions in Striga weed and stemborer pests under PPT over the two seasons. Farmers who used push–pull technology reported a 45–50% yield increase. Push–pull was also perceived as a technology that improves soil fertility and controls soil erosion. The study presented the importance of soil physicochemical properties in the performance of the technology, as supported by the high occurrence of Striga asiatica in the country and the low suitability of Greenleaf Desmodium. Results reaffirmed the technology’s agronomic benefits in productivity, pest management, plant vigour, and Striga control. The cost of labour was described as a challenge, and research to identify more suitable Desmodium species is needed. The current study suggests the release of the technology in Malawi, emphasizing the inclusion of Desmodium and Brachiaria as animal fodder for the adoption of the technology.