不同施氮量对小麦、玉米产量和土壤养分分布的影响

在河北省中西部黄壁庄水库上游流域,通过田间试验,分析不同施氮量对该区小麦和玉米产量、氮肥偏生产力、农户纯收益和土壤中氮素累积的影响,以期为该区农业的施肥管理和防治农业非点源污染的技术策略提供科学依据。试验结果表明,中肥施氮水平,冬小麦产量和农户收益最高。不同施氮水平对夏玉米产量影响差异不显著。高肥水平,春玉米产量和农户收益最高。在冬小麦和夏玉米轮作农田,硝态氮在90cm土层出现累积。在春玉米农田,硝态氮在50cm土层出现累积。另外,随着施氮量的提高,100cm土体硝态氮储量在2010年和2011年间出现盈余。综合分析试验结果,在该区合理灌溉的前提下,冬小麦合理施氮量为225kg/hm2左右,夏玉米合理施氮量为180kg/hm2左右,春玉米合理施氮量为225kg/hm2左右。

Effects of Nitrogen Application on the Yields of Wheat and Maize and the Distribution of Soil Nutrients

Field experiments were carried out to investigate the effects of different nitrogen(N) application rates on the grain yields,the nitrogen partial productivities,the net incomes of peasant households,and the accumulations of NO3——N content in the soil layers in the upper stream of the Huangbizhuang Reservoir in the Midwest of Hebei Province,and the results were expected to provide scientific references for the management of the agricultural fertilization and the controlling measures of agricultural non-point source pollution in this area.The results showed that the middle level of nitrogen application results in the highest yield of winter wheat and the corresponding net income of farmers;the level of nitrogen application has an insignificant impact on the yield of summer maize;and the high level of nitrogen application leads to the highest yield of spring maize and the corresponding net income of farmers.For the rotation farmland of winter wheat and summer maize,NO3——N accumulated in the depth of 90 cm of the soil layer.For the spring maize farmland,NO3——N accumulated in the depth of 50 cm of the soil layer.Furthermore,the NO3——N contents in the depth of 100 cm of the soil layer increased in 2010 and 2011 with the increasing of the nitrogen application.As a result,the reasonable nitrogen application rates were 225,180,and 225 kg/hm2 for the winter wheat,summer maize,and spring maize,respectively.