Optimizing rice productivity through integrated nutrient management: Enhancing root development, nutrient uptake, and soil fertility

Abstract

A field experiment was conducted during the Navarai season of 2023–2024 at Annamalai University, Tamil Nadu, to evaluate the effect of various combinations of organic, inorganic, and microbial nutrient sources on root attributes, nutrient uptake, nitrogen use efficiency (NUE), and post-harvest soil fertility in rice (ADT 43). The experiment was laid out in a randomized block design with ten treatments and three replications. Results demonstrated that treatment T9 (25% N through farmyard manure + 25% N through green leaf manure + 50% RDN + microbial consortia) significantly enhanced root length (23.16 cm), root volume (26.49 cc hill⁻¹), and root dry weight (3.53 g hill⁻¹) compared to the 100% NPK control (T1), which recorded the lowest values (16.42 cm, 19.05 cc hill⁻¹, and 1.62 g hill⁻¹, respectively). Nutrient uptake under T9 increased by 26% for nitrogen (151.54 kg ha⁻¹), 35% for phosphorus (26.36 kg ha⁻¹), and 20% for potassium (128.42 kg ha⁻¹) over T1. Furthermore, NUE parameters, including agronomic efficiency (17.69 kg grain kg⁻¹ N), nitrogen efficiency ratio (88.19), apparent nitrogen recovery (31.36%), physiological efficiency (56.41 kg grain kg⁻¹ N uptake), and partial factor productivity (56.29 kg grain kg⁻¹ N applied), were highest in T9. Post-harvest soil nutrient availability of nitrogen (198.93 kg ha⁻¹), phosphorus (19.62 kg ha⁻¹), and potassium (235.73 kg ha⁻¹) was also significantly improved under INM treatments compared to sole chemical fertilization. These findings confirm that the synergistic integration of organic, inorganic, and microbial nutrient sources optimizes root development, enhances nutrient uptake and NUE, and improves soil fertility, thereby supporting sustainable and productive rice cultivation.