Evaluation of productivity and compatibility of sorghum with velvet bean and cowpea in intercrop system

Author

Ranjisi, Grevis

Title

Evaluation of productivity and compatibility of sorghum
with velvet bean and cowpea in intercrop system

Abstract

Addressing sustainable intensification in Zimbabwe's semi-arid regions (300-500 mm rainfall; sandy loam soils), this research evaluated sorghum-legume intercropping systems through field experiments, assessing three Sorghum bicolor cultivars (Dwarf Yellow Milo, Pioneer 84G62, Gandam) and two legumes (cowpea, velvet bean). The objectives of the study were to assess differential compatibility between velvet bean and cowpea when intercropped with sorghum; evaluating whether cereal-legume intercropping enhances the land equivalent ratio (LER) and examining how sorghum plant stature influences legume yield performance in intercrop systems. Employing a slope-blocked randomized design across 11 treatments with species-specific spacing (sorghum 75×5 cm; legumes 45×15 cm). Key findings revealed cowpea's exceptional compatibility with dwarf sorghum, yielding peak system productivity (1,357.9 kg/ha) and land efficiency (LER=1.52) through growth habit control and nitrogen facilitation. Conversely, velvet bean's competitive dominance (AI=+0.61) depressed outputs (1,087.7 kg/ha) via light interception and moisture rivalry, while dwarf sorghum minimized competition (height reduction to 114 cm). These results critically establish particularly cowpea-dwarf sorghum configurations as essential for climate-resilient smallholder agriculture, necessitating germplasm dissemination and seasonal alignment for scalable adoption.

Date

June 2025

Publisher

BUSE

Keywords

Sorghum

Velvet bean

Intercrop system.

Supervisor

Prof R. Mandumbu