Synergistic Effects of Integrated Nutrient Management through Green Manuring on Soil Fertility under Direct Seeded Rice Cultivation

Abstract

An experiment was conducted during the kharif season of 2024 at the College of Agriculture (Kaul) CCS Haryana Agricultural University, Hisar to ascertain the viablity of integrated nutrient management through green manuring on soil fertility under direct seeded rice (DSR). The experiment was laid out in a randomized block design with nine treatments comprising different combinations of green manuring crops (dhaincha and mungbean) and recommended dose of nitrogen (RDN). The treatments included T1 (control), T2 (Dhaincha), T3 (Mungbean), T4 (50% RDN + Dhaincha), T5 (50% RDN+ Mungbean), T6 (75% RDN), T7 (75% RDN + Dhaincha), T8 (75% RDN + Mungbean) and T9 (100% RDN), each replicated thrice. The treatments were evaluated for their effects on soil physico-chemical properties and availability of macro and micronutrients. Incorporation of dhaincha and mungbean significantly enhanced the availability of both macro (N, P, K) and micronutrients (Fe, Mn, Zn, Cu) while soil bulk density, pH, organic carbon, and electrical conductivity did not differ significantly among the treatments. A slight reduction in pH and bulk density, along with minute appraisal in organic carbon, was observed in green manured plots. The highest available nitrogen (139.3 kg ha⁻¹), phosphorus (27.2 kg ha⁻¹), and potassium (343.8 kg ha⁻¹) contents were recorded in the T7 treatment, which was statistically comparable with T8 and T9. Similarly, T7 also recorded the highest concentrations of DTPA-extractable zinc (2.05 mg kg-1), iron (14.62 mg kg-1), manganese (3.03 mg kg-1), and copper (1.54 mg kg-1). The results indicate that partial substitution of inorganic nitrogen with green manure crops can effectively enhance soil nutrient availability and improve soil fertility in direct seeded rice systems. Therefore, integration of green manuring with reduced fertilizer application can be considered a sustainable nutrient management strategy for maintaining soil fertility and productivity.