Application of different release duration controlled-release coated urea combined with conventional urea on summer maize

Field experiments were performed to study the effects of different amount controlled-release coated urea of 60 d release duration combined with conventional urea used as basal on grain yield of summer maize, nitrogen utilization efficiency, nitrogen accumulation, and economic benefit. Comparative analysis of nitrogen release characteristics under field and 25℃ static water conditions was carried as well. The results show that when the same dosage nitrogen is applied, the summer maize yields are increased under different amounts of controlled-release coated urea of 60 d release duration combined with conventional urea used as basal. Total nitrogen accumulation and maize kernel nitrogen accumulation are obviously higher than those of the traditional nitrogen application treatment. Compared to the traditional nitrogen application treatment, nitrogen utilization efficiencies are increased by 5.86%-11.39%. The net incomes are increased by 1303.2-1715.2 yuan/ha. The net income in the controlled-release coated urea of 60 d release duration combined with conventional urea is the highest. Nitrogen release characteristics under field and 25℃ static water conditions of controlled-release coated urea of 60 d release duration are similar. The controlled-release coated urea of 60 d release duration combined with conventional urea as basal accords with nitrogen absorption rule of summer maize.