摘要
采用野外田间试验和定点监测的方法,通过研究滇中坡耕地地表径流中氮素流失方式、途径反映其流失特征。结果表明,产流量与降雨量相关系数达到0.8641(P<0.05),而土壤侵蚀量与降雨量没有表现出很好的相关关系。在相同降雨条件下,径流总氮、硝态氮、铵态氮浓度总体均表现为随着施氮量的增加,浓度逐渐增加,即CK<N1<N2<N3<N4<N5;降雨条件不同,3者最高值达到5.57,4.36,1.30mg/L。硝态氮在自然降雨条件下,占总氮浓度的21.62%～83.55%,铵态氮占1.02%～38.58%,硝态氮是氮素流失的主要形式。降雨径流的产生均伴随着土壤侵蚀,泥沙中总氮流失量也呈不规则波动。各处理全氮富集率在1.02～1.58之间变化。降雨强度最大时,富集率总体趋势最大,达到1.23～1.53。在相同降雨条件下,随着施肥量的增加,全氮富集率差异不明显,且随着时间的的推移逐渐降低。
Sentinel surveillance method was used to study patterns and means of nitrogen loss in sloping fields in the central Yunnan Province so as to reveal nitrogen loss characteristics.Results showed that the related coefficient between runoff and rainfall was 0.864 1,but soil erosion and rainfall did not show a good correlation.Under the same rainfall conditions,the amounts of TN,NO-3—N,and NH＋4—N were generally increased with the increased amount of nitrogen in the order of CK〈N1〈N2〈N3〈N4〈N5 and under different rainfall conditions,the values of the three chemicals reached 5.57,4.36,and 1.30 mg/L,respectively.The NO-3—N concentration accounted for 21.02%～83.55% in soluble nitrogen and NH＋4—N concentration was only about 1.02%～38.58% under natural rainfall conditions,indicating that NO-3—N was the main form of nitrogen loss.Rainfall runoff induced soil erosion and the amount of TN in sediment also showed irregular fluctuation.Nitrogen enrichment rate was about 1.02～1.58 in different treatments.When rainfall intensity was up to maximum,the enrichment rate of the overall trend increased and reached 1.23～1.53.Nitrogen enrichment rate was not significantly different with the increase of fertilizer under the same rainfall conditions and it decreased with time.
出处
《水土保持通报》
CSCD
北大核心
2010年第6期27-31,共5页
Bulletin of Soil and Water Conservation
基金
国家自然科学基金项目"微区域集水系统控制云南山区农业面源污染的机理研究"(30660037)
云南省自然科学基金项目(2006D0041M)
云南省科技计划项目(2006SG20)
西南林业大学水土保持重点学科
关键词
氮素
流失特征
自然降雨
坡耕地
滇中
nitrogen
loss characteristic
natural rainfall
sloping field
the central Yunnan Province
