针对青藏高原湟水流域氮肥不合理施用引起的土壤有效态氮淋溶损失等问题，设置5个处理0(N0)、78(N78)、156(N156)、234(N234)和312(N312)kg/hm2进行田间试验，结果表明:①随施氮量增加，0～100 cm 土壤硝态氮含量逐渐增加，土壤铵态氮含量无显著变化;②施氮量达到234 kg/hm2之前，土壤硝态氮主要积累在0～40 cm 土层;施氮量超过234 kg/hm2，土壤硝态氮主要积累在60～100 cm 土层;施氮量超过156 kg/hm2，土壤中氮素开始盈余，并随施氮量的增加而增加;③随施氮量的增加，春小麦的产量先升高后降低，2 a施氮量分别为241 kg/hm2，246 kg/hm2时，产量达到最高为8 623 kg/hm2，8 435 kg/hm2。综合产量、环境及经济效益，最佳施氮量为240 kg/hm2。
Effect of Exogenous Nitrogen on Nitrogen Uptake and Utilization and Soil Inorganic Nitrogen by Spring Wheat in Huangshui Basin
In the Huangshui Basin of the Qinghai-Tibet Plateau,inappropriate application of nitrogen fertilizer has resulted in significant leaching losses of soil available nitrogen,To address this issue,a field study was conducted with five nitrogen application rates:0(N0),78(N78),156(N156),234(N234)and 312(N312)kg/hm2.The results showed that nitrate nitrogen(NO3--N)content in the 0-100 cm soil layer increased with nitrogen application,while ammonium nitrogen(NH4+-N)content remained unchanged;Within the 0-100 cm soil profile,nitrogen application rates below 234 kg/hm2 led to a slow increase in soil NO3--N,with the main accumulation occurring in the 0-40 cm layer.However,at application rates exceeding 234 kg/hm2,the NO3--N accumulation shifted to the 60-100 cm layer.A surplus of soil nitrogen emerged at an application rate of 156 kg/hm2and increased with further ni-trogen input.Spring wheat yield initially increased and then slightly decreased,with the highest yield of 8 623 kg/hm2 and 8 435 kg/hm2 achieved at 241 kg/hm2 and 246 kg/hm2,respectively.Considering yield,environmental sustainability,and economic efficiency,the optimal economic nitrogen applica-tion rate is 240 kg/hm2.
Huangshui River BasinSpring wheatYieldNitrate nitrogenAmmonium nitrogen
万方数据
维普
