Agronomic responses of sweet sorghum to intercropping with Pongamia pinnata to improve land use

Abstract This study evaluated the impact of intercropping sweet sorghum ( Sorghum bicolor ) with pongamia ( Pongamia pinnata ) on growth performance and yield components, with a focus on practical implications for cultivation techniques in agroforestry systems. The experiment was conducted from March to June 2025 in the Jatigede Dam conservation area, Sumedang, West Java. Four treatments were applied: sorghum monoculture (SM) and intercropping with pongamia seedlings of short (SPS), medium (SPM), and tall (SPT) canopy heights. Sorghum was planted with a spacing of 70 × 20 cm between pongamia trees spaced 5 × 5 m, using 1–2 seeds per hole. The results showed that pongamia seedling height type has no significant effect to all the traits. However, the SPT treatment resulted in the tallest plants (232.26 cm), likely due to shade-modified growth dynamics. In contrast, the SM treatment produced the highest biomass, stem diameter, panicle weight, juice volume, and grain weight. Interestingly, the highest BRIX value (12.54%) was observed under the SPM treatment, indicating that moderate shading may enhance juice quality. Correlation analysis revealed strong positive relationships between stem biomass and juice volume (r = 0.74), and between panicle weight and seed yield (r = 0.92), underscoring the influence of cultivation practices on both vegetative and reproductive traits. These findings offer valuable insights for optimizing planting strategies and resource use efficiency in integrated agroforestry systems.