Effects of different nitrogen fertilizer types and application rates on maize yield and nitrogen use efficiency in Loess Plateau of China

Abstract

After excessive application of chemical fertilizer in farmland can cause serious impact on the environment. Therefore, it is urgent to explore the optimal application rate of maize yield and nitrogen use efficiency (NUE) in order to maintain the sustainable use of cultivated land. The objective of this study was to quantify the interaction effect of fertilizer type and N fertilizer application rate on maize grain yield, N uptake, N translocation, and N translocation efficiency. The experiment was arranged in a randomized complete block design with two factors (2 N fertilizer types × 5 N fertilizer application rates) in 2018, 2019, and 2020. The two N fertilizer types were urea and slow-release N fertilizer. The five N fertilizer application rates were 90 (N1), 120 (N2), 180 (N3), 240 (N4), and 300 (N5) kg N ha–1. The mean grain yield in slow-release N fertilizer was 21.3%, 25%, and 16.2% higher than that with urea fertilizer in 2018, 2019, and 2020, respectively. Total plant N uptake in slow-release N fertilizer was 2.3%, 5.5%, and 3.3% higher than that with urea fertilizer at silking stage in 2018, 2019, and 2020, respectively. Total N translocation under slow-release N fertilizer averaged over N fertilizer application rates and years was 9.3%, 22.9%, and 17.8% lower than observed under urea fertilizer in 2018, 2019 and 2020, respectively. Fertilizer type and N fertilizer application rate had significant effects on maize grain yield, N uptake, N translocation, and N translocation efficiency. The combination of slow-release N fertilizer and moderate N fertilizer application rate (180 kg N ha–1) was the optimal strategy for increasing maize grain yield.