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Ding Y.,Northwest Agriculture and Forestry University | Ding Y.,Key Laboratory of Plant Nutrition and the Agri environmental in Northwest China Ministry of Agriculture | Yang X.,Northwest Agriculture and Forestry University | Yang X.,Key Laboratory of Plant Nutrition and the Agri environmental in Northwest China Ministry of Agriculture | And 8 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae

A six-year field experiment, using the Lysimeter method, was conducted in Guanzhong Plain of Shaanxi Province to investigate the effects of nitrogen (N) fertilizer application amount on N loss characteristics and N budget in the soil profile at 90 cm depth under winter wheat-summer maize cropping system. Results showed that N leaching mainly occurred in August and September, the rainy period of maize growing season. In the monitoring period, the average annual loss of total N and nitrate (NO3--N) were 2.72~23.07 kg·hm-2 and 1.53~18.72 kg·hm-2, respectively, and the average annual leaching rate from fertilizer for total N and NO3--N were 0.65%~3.44% and 0.82%~3.32%, respectively. N leached from the soil were mostly in the form of NO3--N comprising with 56.00%~81.00% of total N, whereas ratio of NO3--N decreased with low N fertilizers. Thus, different N fertilizer amounts affected the forms of nitrogen loss from the soil. The nitrogen budget result illustrated that the nitrogen application significantly enhanced N surplus and nitrate accumulation in the 90 cm depth of soil profile. The annual residual NO3--N and N surplus had a positive relationship with the annual N fertilizer inputs. Continuous N application resulted in N loss rate of 32.60%~55.20% and annual residual NO3--N in the 90 cm depth of soil of -0.17%~8.20%. According to the multi-year monitoring results, OPT treatment showed less nitrogen leaching amounts at high yield and better N use efficiency, reduced potential environmental risks and saved N fertilizer resources. ©, 2015, Science Press. All right reserved. Source

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