白洋淀沿湖农田施氮量对冬小麦产量和土壤硝态氮累积的影响

目的]研究白洋淀沿湖农田施氮量对冬小麦产量及土壤中硝态氮累积的影响。方法]选择2块具有代表性的农田进行田间小区试验,研究不同施氮量对该地区小麦产量构成因素、氮肥利用率及土壤硝态氮累积量的影响。结果]适宜施氮量可显著提高小麦的穗粒数、千粒重等产量构成因素及氮肥利用率。土壤硝态氮主要集中在0～30 cm土层,其含量随施氮量的增加而增加。随着小麦生育期的推移,0～90 cm土体中硝态氮累积量呈下降趋势。成熟期,当施氮量分别高于其适宜施氮量时,土体中硝态氮累积量随施氮量增加而显著增加,从而增加了硝态氮下移的风险。结论]综合考虑产量和环境效益,在该试验条件下,马堡和张六试验点冬小麦的适宜施氮量分别为225、90 kg/hm2。

Effect of Nitrogen Application on Winter Wheat Yields and Nitrate Nitrogen Accumulation in Soils of Surrounding Farmland in Baiyangdian Lake

Objective]The aim was to research the effect of nitrogen application on winter wheat yields and in soils of surrounding farmland inBaiyangdian lake.Method]The field experiment was carried out to study the effects of nitrogen application on yields of winter wheat,efficiencyof nitrogen fertilizer and nitrate nitrogen accumulation in soils of two representative agricultural fields.Result]The results showed that the opti-mum amount of nitrogen could improve the wheat grain number,grain weight and other yield components and efficiency of nitrogen fertilizersignificantly.The nitrate nitrogen mainly existed in 0 ～ 30 cm soil layer and their concentrations increased with the increases of nitrogen appli-cation levels.The accumulations of soil nitrate nitrogen decreased in 0 ～ 90 cm depth with the growth period passed.In mature stage,the accu-mulations rapidly increased the increases of nitrogen application levels when the nitrogen application rate was higher than the optimum amountof nitrogen.So the higher nitrogen application increased the risk of nitrate nitrogen transportation from soil surface layer to the deep layer.Conclusion]Considering the yield and environmental benefits,the optimum amounts of nitrogen were 225 kg/hm2 in MaPu and 90 kg/hm2 inZhangLiu fields respectively under the experimental conditions.