Impact of organic nutrient management on nutrient uptake and soil health in traditional rice varieties

Abstract

A field investigation was undertaken during the Kuruvai season (June-September) of 2024 at the Experimental Farm, Department of Agronomy, Faculty of Agriculture, Annamalai University, Chidambaram, Tamil Nadu. The study was laid out in a split-plot design with three replications. The main plot treatments comprised of four traditional rice varieties: Aruvatham Kuruvai, Poongar, Navara, and Ottu Kichilli. The sub-plot treatments included five organic nutrient management practices: farmyard manure (FYM) @ 12.5 t ha-1 + 5% jeevamrutham, vermicompost @ 5 t ha-1 + 5% jeevamrutham, enriched FYM @ 0.75 t ha-1 + 5% jeevamrutham, urban compost @ 10 t ha-1 ¹ + 5% jeevamrutham, and an untreated control (no manure). Among the treatments, application of vermicompost @ 5 t ha-1 combined with 5% jeevamrutham significantly enhanced the uptake of nitrogen (90.52 kg ha⁻¹), phosphorus (22.58 kg ha-1), and potassium (115.62 kg ha-1), as well as the availability of soil nitrogen (223.0 kg ha-1), phosphorus (24.6 kg ha-1), potassium (283.5 kg ha⁻¹), and organic carbon (0.60%) in the post-harvest soil. Additionally, the highest microbial populations viz.,bacteria (38.05 × 106 CFU g-1), fungi (14.13 × 103 CFU g-1), and actinomycetes (7.01 × 104 CFU g-1), were observed under this treatment. Based on these findings, the combination of the traditional variety Poongar with vermicompost @ 5 t ha-1 + 5% jeevamrutham proved to be the most effective in improving soil nutrient status and microbial populations after harvest.