Potential of Soybean (Glycine Max L.) as an Alternative Legume Cover Crop to Mucuna Bracteata for Enhancing Soil Chemical and Biological Properties and Growth Performance of Immature Oil Palm

Abstract

The use of cover crops contributes significantly to maintaining soil fertility and land sustainability during the immature phase of oil palm plantations. This study aimed to evaluate the potential of soybean (Glycine max L.) as a substitute for Mucuna bracteata in relation to soil chemical and biological properties, as well as the growth of immature oil palm. The research was conducted at Adolina Estate, PTPN IV, North Sumatra, using two treatments: oil palm with M. bracteata and oil palm intercropped with soybean, each replicated three times. Observed parameters included soil and leaf nutrient contents, functional microbial populations, leaf area, biomass, and vegetative growth of oil palm. The results indicated that soybean intercropping exerted a relatively comparable effect to M. bracteata on soil chemical properties and supported slightly higher vegetative growth of oil palm. However, populations of nitrogen-fixing, phosphorus-solubilizing, and potassium-solubilizing microbes were higher under the M. bracteata treatment. Overall, soybean has potential as an alternative cover crop that supports productivity and circular economy practices in immature oil palm plantations.