Short-term soil, growth and yield responses to Lablab intercropped with maize and sorghum in dryland agroecological zone of Tanzania

Abstract

Smallholder farmers in semi-arid regions of Tanzania face multiple challenges, including erratic rainfall, prolonged droughts, and soil degradation, which threaten both crop yields and food security. Cereal-legume intercropping has been proposed as a sustainable strategy to enhance soil health, nutrient availability, and productivity under these conditions. This study evaluated the potential of intercropping maize (Zea mays) and sorghum (Sorghum bicolor) with three legumes Lablab purpureus, cowpea (Vigna unguiculata), and common bean (Phaseolus vulgaris) at TARI Makutupora, Dodoma, Tanzania. A randomized complete block design with three replications was used to assess effects on soil physical and chemical properties, microbial abundance, and crop performance. Intercropping systems significantly improved soil nitrogen (up to 0.17%), microbial populations (up to 4.8 × 10 5 CFU g −1 ), and soil moisture (up to 14%) compared with sole cereal crops. Path analysis indicated that soil moisture (β = 0.419) and nitrogen (β = 0.345) were the most influential factors for productivity. Among legumes, Lablab-based intercrops consistently enhanced soil fertility and crop yield, achieving land equivalent ratios above 1.5 and outperforming other legume intercrops. These findings demonstrate that cereal-legume intercropping, particularly with Lablab, can revitalize semi-arid soils, improve water and nutrient use efficiency, and enhance food security. This approach provides a scalable, climate-resilient strategy for sustainable intensification in Tanzania’s drylands.