Sustainable Intensification of Smallholder Farming Systems Using Push-Pull Technology as a Template

Abstract

Sustainable intensification is essential for increasing food production on shrinking smallholder farms while reducing environmental risks. In western Kenya, farmers use practices such as intercropping, crop rotation, agroforestry, crop-livestock integration, and push-pull technology to address constraints such as low soil fertility, pests, diseases, and limited land for production. Push-pull technology, which combines cereal crops with repellent and trap companion crops, is effective in managing striga weed, stem borer, and fall armyworm, but its adoption remains limited because it is mainly cereal-based and its companion crops are not edible. This study aimed to identify farmers’ preferred sustainable intensification options for integration into push-pull systems and to assess the effects of the selected option on soil fertility, pests, natural enemies, and maize productivity in Kisumu, Siaya, and Vihiga counties. Farmers’ preferred intensification practices were identified through participatory research involving focus group discussions, key informant interviews, and validation with farmers. Integration of Cajanus cajan (pigeon pea) into push-pull technology was selected as a priority option because pigeon pea provides additional benefits, including food, feed, and fuelwood. Field trials were then established on farmers’ plots during the long and short rainy seasons of 2021, 2022, and 2023 using four treatments: push-pull, push-pull with pigeon pea, maize with pigeon pea, and maize monocrop. Subplots were used to monitor crop growth, striga weed density, fall armyworm, stem borer, and natural enemies. Equally, soil physical and chemical properties, maize grain and stover yield, pigeon pea productivity, Brachiaria biomass, and desmodium biomass were measured in the same plot. Data were analyzed using analysis of variance, and treatment means were separated using Tukey’s Honestly Significant Difference test. Farmers identified several sustainable intensification options for integration into push-pull systems, with intercropping, crop rotation, crop-livestock integration, and agroforestry ranked as the most preferred. Their main motivations were food diversification, fuelwood and fodder provision, soil improvement, and pest management. Soil fertility varied across counties, ranging from low in Vihiga to moderate in Kisumu and Siaya. Major nutrients, particularly nitrogen, phosphorus, and potassium, were generally below critical levels, while micronutrients such as zinc and manganese were sufficient. Integrating pigeon pea improved nitrogen, phosphorus, and potassium levels in the tested soils, indicating its potential to support soil fertility improvement in maize-based systems. Maize monocrop recorded the highest striga density and the greatest infestation by fall armyworm and stem borer, whereas maize with pigeon pea had significantly lower striga density. Maize grain yield did not differ significantly for treatments across sites and seasons, indicating that intensified systems-maintained productivity. However, maize monocrop produced the highest stover yield, followed by push-pull, maize + pigeon pea, and push-pull + pigeon pea. Pigeon pea also contributed additional benefits, including food, fodder, and fuelwood, while supporting striga suppression and maintaining maize productivity. The findings show that integrating pigeon pea into push-pull and other maize-based farming systems can diversify farm benefits without compromising crop productivity. The study recommends the integration of pigeon pea into push-pull and maize-based systems in Kisumu, Siaya, and Vihiga counties as one of the practical strategies for improving soil fertility, suppressing striga weed, maintaining crop production, and providing additional farm products such as food, fodder, and fuelwood.