Tillage and leaf colour chart-guided nitrogen management: Key to growth and yield improvement of winter maize in Chitwan, Nepal

Maize requires efficient nitrogen management to maximize productivity and sustainability. This research aimed to establish a critical Leaf Colour Chart (LCC) values for maize under zero tillage and conventional tillage. This research also focuses on evaluating LCC-based nitrogen management versus recommended practices. The experiment was conducted during the winter season of 2016-17 at the National Maize Research Program, Rampur, Chitwan, Nepal. The experiment was performed using a strip plot design with three replications. The main plot factor included two tillage methods (conventional and zero tillage) while the sub-plot factor comprised six nutrient management practices, namely nitrogen omission, recommended dose of nitrogen, nitrogen application at leaf color chart (LCC) values 3 (45 kg N/ha), LCC value 4 (88.33 kg N/ha), LCC value 5 (119.7 kg N/ha), and LCC value 6 (140 kg N/ha). Standard split nitrogen application and LCC-based nitrogen management at LCC 4, 5, and 6 critical values resulted in statistically similar LAI during all dates of observations; however, it was high at 90 days after sowing (DAS). Total dry matter accumulation was significantly higher under LCC-5 at 90 DAS. Grain yield was strongly influenced by nitrogen management, with LCC-5 achieving the highest yield (4814.26 kg ha-1), followed by LCC-6 (4511 kg ha-1). Conventional tillage slightly outperformed zero tillage in grain yield. According to the study, LCC threshold 5 is useful for real-time nitrogen application in maize. Therefore, maize farmers are encouraged to embrace LCC-based split nitrogen application rather than following standard nitrogen fixed schedules for sustainable and profitable production.