Evaluating Leaf Color Chart-Based Nitrogen Management and Tillage Methods for Improved Maize Yield, Nitrogen Use Efficiency and Economic Returns in Chitwan, Nepal

Optimizing nitrogen management in maize is critical for enhancing yield and resource use efficiency, particularly in Nepal. This study evaluates the impact of real-time nitrogen management using a Leaf color chart (LCC) under different tillage practices in winter maize. The experiment was arranged in a strip plot design with three replications comprising two tillage methods (conventional tillage and zero tillage) as the main plot factor and six nutrient management practices namely nitrogen omission (0 kg N ha-1), recommended dose of nitrogen (120 kg N ha-1), nitrogen application through leaf color chart (LCC) values 3 (45 kg N ha-1), LCC values 4 (88.33 kg N ha-1, LCC values 5 (119.7 kg N ha-1) and LCC values 6 (140 kg N ha-1) as subplot factors. Results showed that LCC 5 (119.7 kg N ha⁻¹) achieved the highest grain yield (4,814.26 kg ha⁻¹) and economic returns (NRs 53,376.3 ha⁻¹ net return, B:C ratio 1.77). Grain yield from conventional tillage (3947 kg ha⁻¹) was somewhat higher than zero tillage (3326 kg ha⁻¹), but the differences were statistically insignificant. Nitrogen use efficiency and nitrogen uptake parameters were significantly influenced by nitrogen management, with LCC 5 exhibiting superior agronomic efficiency (28.60 kg grain kg-1 N) and recovery efficiency (0.77 kg N uptake kg-1 N applied). The LCC 5 treatment achieved the optimal balance between yield, nitrogen use efficiency, and economic returns, making it a suitable option for farmers aiming to optimize nitrogen use and maximize profits in maize cultivation. Thus, farmers should implement the LCC tool rather than relying on fixed schedules and quantities for nitrogen fertilizer application.