Nitrogen and phosphorus effects on winter maize in an irrigated agroecosystem in western Indo-Gangetic plains of India

摘要

Winter maize is an innovation in Indian cropping systems. It grows 50-60 days longer than rainy-season maize and is a heavy feeder cereal. It lacks proper management of nutrients, particularly nitrogen and phosphorous. N and P determine the photosynthetic and reproductive capacity of plants. The response of maize to these nutrients is season-dePendent and location-specific, but has seldom been studied in winter maize areas in India. This study was designed to evaluate the impact of N and P independently and interactively on winter maize. Maize yield was highest at 240 kg N ha(-1), but the yield obtained at 160 kg N ha(-1) was comparable. Every kg N applied produced 44.34 kg grain, and the N-use efficiency was reduced with increased N dose (67.4, 38.4, and 27.2 kg grain kg(-1) N for 80, 160, and 240 kg N ha(-1), respectively). Phosphorus application increased yield up to 26.4 kg ha(-1). A combination of 240 kg N ha(-1) and 26.4 kg P ha(-1), providing highest gross returns, net returns and net benefit: cost, was most profitable. The economic optimum dose for N and P was 196 kg N ha(-1) and 23.4 kg P ha(-1), respectively. This study shows that winter maize is responsive to higher levels of N up to 240 kg ha(-1) compared to 120 kg N ha(-1) recommended for rainy-season maize, but P application at 26.4 kg ha(-1) remains same for both the seasons. The study provides recommendation of N and P for winter maize based on economics. The data would be useful for fitting models and simulating yields across the doses of N and P.