华北平原冬小麦-夏玉米轮作体系秋季一次基施牛粪氮素损失与利用研究

摘要

为对我国华北平原冬小麦-夏玉米轮作体系秋季一次基施有机肥的氮素环境效应提供评估依据,本文分别在山东陵县和天津蓟县以不施肥、分次施用硫酸铵为对照,对秋季一次基施牛粪的产量水平、氮素损失及利用等进行研究.其中,山东陵县试验采用15N示踪技术.结果表明,在冬小麦-夏玉米轮作周期施氮量为N 300和N 450kg/hm2条件下,秋季一次基施牛粪15N损失率为30%～38%,与分次施用硫酸铵15N损失率无显著差异.牛粪氮施用N 300kg/hm2时,损失量为N 89 kg/hm2;增施50%牛粪氮,氮损失量增加91%.冬小麦、夏玉米收获后,施牛粪处理0-80 cm土壤硝态氮含量在山东陵县分别为N 38～40和18～23 kg/hm2,在天津蓟县N 300kg/hm2施氮条件下分别为N 95和28 kg/hm2,均低于分次施用硫酸铵处理.长期施用有机肥农田,秋季一次基施牛粪处理冬小麦、夏玉米子粒产量与分次施硫酸铵处理也无显著差异,因此从环境角度分析,秋季一次基施有机肥可继续应用和大力推广,但施用量以不超过N 300kg/hm2为宜.%Cattle manure was applied to a winter wheat-summer maize cropping system on the North China Plain in autumn as a single basal application (MOAA).In order to provide parameters for evaluation of environmental effects of MOAA, experiments employing no fertilizer application and split application of ammonium sulfate (SAAS) and MOAA as N 300 kg/ha were carried out in Ji county, Tianjin City; as N 300 and 450 kg/ha and was also adopted 15N tracer technology in Ling county, Shandong province, to study nitrogen (N) utilization and 15N loss.In the winter wheat-summer maize cropping system, 30％-38％ of the total manure 15N was lost, which did not differ significantly from SAAS 15 N loss.Manure N loss was N 89 kg/ha following N 300 kg/ha manure N application, and N loss sharply increased by 91％ when manure N application increased by 50％.After winter wheat harvest, the amount of soil NO3- -N at 0-80 cm depths in MOAA was N 38 -40 kg/ha in Ling county and N 95 kg/ha in Ji county, and decreased to N 18 -23 and 18 kg/ha after summer maize harvest, respatively; in both instances, the values were lower than those of SAAS.In farmland with long-term application of manure, there were no significant differences in winter wheat and summer maize grain yields between MOAA and SAAS.From an environmental point of view, it is concluded that MOAA is an appropriate application but the amount of N should not exceed N 300 kg/ha.