EFFECTIVENESS OF MUNG BEAN (Vigna radiata L.) AS A COVER CROP IN IMPROVING SOIL CHEMICAL PROPERTIES ON DEGRADED AGRICULTURAL LAND

Abstract

Degraded agricultural land is a serious issue, particularly due to the loss of topsoil, which significantly reduces soil fertility. This study aims to analyze the effectiveness of mung bean (Vigna radiata L.) as a cover crop in improving the chemical properties of soil on degraded farmland in Rumah Kabanjahe Village, Kabanjahe District, Karo Regency. The research was conducted from November 2024 to March 2025 using a descriptive method by collecting soil samples before and after mung bean planting, which were then analyzed in a laboratory. Observed parameters included organic carbon (C- organic), total nitrogen (N), available phosphorus (P), exchangeable potassium (K), soil pH, and cation exchange capacity (CEC). The results showed increases in C-organic from 0.15% to 1.36%, total N from 0.10% to 0.18%, K from 0.49 me/100g to 2.38 me/100g, and CEC from 10.89 to 26.04 me/100g. However, available P decreased from 10.08 ppm to 2.98 ppm, and pH declined from 6.70 to 6.34. These findings indicate that mung bean is effective in enhancing soil fertility through organic matter input and biological activity, particularly nitrogen fixation. Nevertheless, the decline in phosphorus and pH values suggests the need for supplementary treatments to maintain soil nutrient balance. Thus, mung bean has strong potential as a cover crop for sustainable rehabilitation of degraded agricultural lands.