Response of Sorghum (Sorghum bicolor L. Moench) to Varying Plant Spacing under BRIS Soil Conditions

Global agriculture faces increasing pressure to sustain food production amid soil degradation, water scarcity, and climate change. Sorghum (Sorghum bicolor L. Moench), a stress-tolerant cereal, offers great potential for cultivation on marginal soils such as BRIS (Beach Ridges Interspersed with Swales) soils, which are sandy, acidic, and low in fertility. This study evaluated the effect of within-row plant spacing on sorghum growth and yield performance under BRIS soil conditions at the MARDI Bachok Research Station. The experiment employed a Randomized Complete Block Design (RCBD) with four spacing treatments (10, 15, 20, and 25 cm within rows) replicated five times. Results showed that plant spacing had a significant influence on several growth and yield parameters. Stem diameter increased significantly with wider spacing, while plant height and leaf number were not affected. Among yield components, 1000-grain weight, panicle weight per plant, and grain weight per plot were significantly influenced by spacing (p < 0.05). The 15 cm spacing (J2) produced the highest grain yield (4466.6 g plot- ¹) due to a favourable balance between plant competition and resource availability. Closer spacing (10 cm) caused intense competition, reducing grain size, whereas wider spacing (25 cm) reduced total yield per area. These findings indicate that moderate within-row spacing (15–20 cm) is most effective for optimizes sorghum growth and yield under BRIS soil conditions. The results provide practical recommendations for enhancing sorghum productivity and land-use efficiency on marginal coastal soils.