Nitrogen fertilization and cultivar synergy under rainfed conditions: effect on maize productivity, nutrient use efficiency and soil properties

Rational nitrogen (N) management is essential for improving maize productivity and nitrogen use efficiency (NUE) particularly under rainfed conditions. Therefore, a two-year field-experiment was conducted in a split-plot design to evaluate two hybrids (PMH 1 and PMH 13) and two composites (JC 4 and JC 12) under four N rates (N0, N60, N80 and N100). Hybrids generally outperformed composites with PMH 13 recording superior growth, yield attributes, grain yield, N uptake and economic returns. Mean grain yield of PMH 13 was 13.6-85.8% higher than all the cultivars with the highest net returns (₹32,757ha−1) and benefit-cost ratio (1.94). For majority of the growth parameters and yield attributes, N100 significantly outperformed the lower N rates. PMH 13 exhibited the highest N uptake and N100 significantly increased N uptake than other treatments across the years. However, agronomic, apparent recovery and physiological efficiencies did not increase proportionally with N rate indicating a trade-off between yield maximization and efficient N utilization. Across years, N100 increased mean net returns by ₹2,865ha−1 compared with the recommended N80 with a benefit-cost-ratio of 1.86. Significant cultivar and N interactions for growth, yield and N uptake demonstrated cultivar-specific responses to N availability. Nutrient application increased post-harvest soil N, P and K. Quadratic response functions indicated lower optimum-N rates for the composites and higher estimates for hybrids; however, the estimates for hybrids exceeded the highest experimentally tested rate necessitating further validation. Overall, cultivar-specific N management, particularly for high-yielding hybrids like PMH 13, can improve maize productivity and N-utilization under rainfed conditions.