Abstract

Climate change and population growth threaten sustainable food production, particularly in semi-arid regions such as Limpopo Province, South Africa. Conventional farming systems contribute to greenhouse gas emissions while failing to maintain soil fertility. Climate-Smart Agriculture (CSA) practices, including no-tillage and intercropping, offer potential solutions to enhance resilience and sustainability. This study assessed the growth, physiological responses, productivity, and carbon dynamics of grain sorghum–cowpea intercropping under no-till conditions at two sites (Syferkuil and Ofcolaco) during the 2018/19 and 2020/21 cropping seasons. A randomized complete block design (RCBD) in a 2 × 4 × 2 factorial arrangement evaluated cropping system (sole vs intercrop), cowpea density, and sorghum cultivar. Measurements included leaf gas exchange, leaf area index (LAI), aboveground biomass, grain yield, harvest index (HI) and land equivalent ratio (LER). Simulations by the Agricultural Production System Simulator (APSIM) were compared with field data for biomass and yield. Intercropping and cowpea density significantly (p ≤ 0.05) influenced physiological traits and cowpea yield, while sorghum yield was primarily cultivar-dependent. Enforcer and NS5511 were the highest-yielding sorghum cultivars, producing up to 4,338 kg ha⁻¹ at Syferkuil. Cowpea grain yield was substantially reduced under intercropping, with sole cropping outperforming intercrop by 77–96% across sites and seasons. High cowpea density improved yield and reduced CO₂ emissions compared to low density.  APSIM effectively captured biomass and yield dynamics but requires additional long-term data for robust scenario analysis. Sorghum–cowpea intercropping under no-till can improve soil fertility without compromising sorghum yield, supporting CSA adoption in semi-arid drylands.

Intercropping; Sorghum; Cowpea; Grain yield; APSIM modelling