Improving Nutrient Use Efficiency and Soil Fertility of Aerobic Rice (Oryza sativa L.) under Integrated Nutrient Management and Micronutrient Foliar Spray in Calcareous Soils

Aerobic rice cultivation presents a promising water-saving alternative to conventional flooded systems but often faces challenges of reduced yield and nutrient efficiency, especially in calcareous soils. A field trial was conducted at Dr. Rajendra Prasad Central Agricultural University, Pusa, Bihar, during the 2018 and 2019 kharif seasons to evaluate the effects of integrated nutrient management (INM) and micronutrient foliar sprays on soil fertility and nutrient utilization efficiency in aerobic rice. The treatments involved combinations of organic nitrogen sources with chemical fertilizers, supplemented with foliar sprays of FeSO₄ and ZnSO₄. Results revealed that INM significantly enhanced post-harvest soil fertility, with the highest available N, P, and K observed under the treatment receiving 100% RDN from chemical fertilizers along with 25% RDN from vermicompost. The combination of 75% RDN through chemical fertilizers and 25% RDN from poultry manure improved partial factor productivity and nutrient balance, while farmyard manure increased internal utilization efficiency. Foliar applications of FeSO₄ and ZnSO₄ further enhanced yield performance without directly altering soil nutrient levels. Overall, integrating organic manures with chemical fertilizers and micronutrient sprays proved effective in improving soil fertility, nutrient efficiency, and yield, offering a sustainable approach for aerobic rice cultivation in calcareous soils.