Effects of nitrogen application rate on summer maize (Zea mays L.) yield and water–nitrogen use efficiency under micro–sprinkling irrigation in the Huang–Huai–Hai Plain of China

Abstract

ABSTRACT To improve the grain yield (GY) and water–nitrogen (N) use efficiency of summer maize, a 2–year field experiment was conducted using micro–sprinkling irrigation water–fertilizer integration. Surface irrigation and N application methods were applied in the control (CK, irrigation at sowing; 300 kg N ha−1). Under water–fertilizer integration, N was applied at five rates (0, 120, 180, 240, and 300 kg N ha−1, N applied at sowing, jointing, and tasseling and ratio of 1:1:1; designated WN0, WN120, WN180, WN240, and WN300, respectively). The leaf area index and dry matter accumulation increased with increasing N application rate, with a slower rate of increase when N application rate ≥180 kg N ha−1. Compared with CK, the GY of WN300, WN240, WN180, and WN120 was not significantly different,but WN120 significantly decreased by 7.16% and 5.47% than WN240 and WN300.The evapotranspiration,irrigation amount,and N application rate in WN180 were 9.86%–16.40%, 47.11%–52.23%, and 40% lower,respectively,than in CK,while the water use efficiency and N partial factor productivity was 3.38%–15.14% and 32.04%–60.43% higher.Thus,application of 180 kg N ha−1 with water–fertilizer integration can achieve high GY and improve resource–use efficiency.