Evaluation of nitrogen loss way in summer maize system under different fertilizer N managements

The objective of this study was to investigate nitrogen (N) loss from soil-crop systems under different fertilizer N managements, and to provide some suggestions on optimizing fertilizer management practices. The experiment was carried in high yield production area of Huantai county in Shandong province in 2009.Four kinds of fertilizer N application practices were designed, including CK, farmer practice (FP), optimizing fertilizer application (OPT) and controlled release fertilizer (CRT) for studying the fate of N during the maize growth season in 2009.The water and nitrogen management model (WNMM) was used to simulate the dynamics of soil water and N fate. The results indicated that the ratio of nitrate leaching and NH ₃ volatilization accounting of fertilizer N ranged from 6% to 18% and 5% to 34%, and their means were 12.7% and 20.7%, respectively. The amount of N leaching under OPT was 14.5 kg·hm ^-2, was the lowest in all treatments. The amount of NH ₃ volatilization under CRT was 7.6 kg·hm ^-2, respectively, was the lowest in all treatments. The order of total N loss under four treatments followed as: FP > OPT >CRF≈CK. Both OPT and CRT treatments are the best management practices considering their high grain yield, water and nitrogen use efficiencies, and environmental protection.