Improving Soil Health and Weed Control through Dhaincha (Sesbania aculeata) Green Manuring under Semi-Arid Conditions

Abstract

Aims: Green manuring is a sustainable agricultural practice that enhances soil fertility and aids in weed management, particularly in organic farming systems. The study aimed to assess the effect of green manure incorporation on soil physicochemical properties and weed density. The experimental soil, classified as sandy clay loam, showed significant improvement in fertility parameters after the incorporation of dhaincha biomass. Methodology: This study was conducted at the Agricultural College and Research Institute, Madurai, to evaluate the impact of dhaincha (Sesbania aculeata) green manuring on soil physicochemical properties and weed dynamics. The experimental soil, classified as sandy clay loam (Typic Udic Hapludalf), was assessed before and after the incorporation of green manure. Results: The results revealed that green manuring significantly improved key soil parameters. The soil pH decreased from 7.8 to 7.5, indicating a favourable shift toward neutral conditions, while electrical conductivity increased from 0.33 to 0.47 dS/m, suggesting enhanced nutrient availability. Organic carbon content rose slightly from 1.26% to 1.29%, highlighting improved microbial activity and organic matter status. Available nitrogen increased from 225.79 to 235.00 kg/ha, phosphorus from 31.36 to 33.60 kg/ha, and potassium from 251.00 to 256.12 kg/ha due to the nutrient-rich biomass and nitrogen-fixing ability of dhaincha. Additionally, green manuring exerted a suppressive effect on weed populations, especially broadleaf species, due to allelopathic interactions and shading. Weed density for broadleaf weeds decreased markedly from 56 to 8 plants/m² after dhaincha incorporation. Conclusion: The findings support the value of green manuring in improving soil fertility, enhancing nutrient cycling, and managing weed infestations sustainably. Incorporating dhaincha as a green manure crop can thus serve as an effective strategy for maintaining soil health and supporting organic crop production.