摘要
冻融作用与水力侵蚀的复合作用更容易使土壤发生侵蚀,进而加剧土壤养分的流失,为了揭示冻融作用下土壤可蚀性对坡面养分流失的影响,该文采用室内模拟降雨试验,研究了不同土壤含水率(SWC)下坡面的降雨产流产沙及养分流失特征,并分析了土壤可蚀性对坡面全氮(TN)和全磷(TP)流失的影响。结果表明:产流率与产沙率之间呈现正线性相关关系,相关方程斜率的绝对值可作为土壤可蚀性指标。径流中氮磷的流失主要受径流率控制,受土壤可蚀性影响较小(P>0.05);而土壤可蚀性显著影响着泥沙中氮磷和总的氮磷流失(P<0.01)。土壤可蚀性对黄土坡面氮素流失的影响与冻融作用有关,而土壤可蚀性对坡面磷素流失的影响与冻融作用无关,磷素的流失随着土壤可蚀性增加而增加。因此,在黄土地区,应当采取一系列的生态建设措施来控制水土流失,降低土壤可蚀性,从而减少坡面养分的流失。该研究结果为冻融条件下黄土坡面水-土和氮磷等养分流失机制提供了有效指导。
The freeze-thaw processes affect an area of46.3%in China.The process of soil nutrient loss under freezing and thawing was seldom been studied.Under the condition of rainfall simulation,the characteristics of soil and nutrients loss under different soil water content(SWC)conditions were studied.The effects of freeze-thaw and erodibility on total nitrogen(TN)and total phosphorus(TP)losses on the loess slope were analyzed.Loess slope(LS)and freeze-thawed slope(FTS)were set,and we studied five SWCs,between10%and30%.The results showed that there was a significant difference in runoff/sediment associated TN and TP concentrations under different SWCs for two slopes(P<0.05).Largest runoff-associated TN and TP losses were found when the SWC was30%and the largest sediment-associated TN and TP losses were found when the SWC was10%in the two slopes.The sediment-associated nutrient losses dominated the total nutrient loss in all treatments,and when the SWC was20%,average sediment-associated TN and TP losses occupied99%of totals in the LS and FTS.The K values decreased firstly and then increased in both LS and FTS and in low SWC area.FTS soil erodibility was greater than that of the LS with an average ratio of1.4.The influence of runoff on sediment was positively linear.The absolute slope of the regression line between runoff rate and sediment yield rate was suitable as a soil erodibility indicator.The runoff-associated and sediment-associated total TN and TP loss rates increased linearly with runoff rate and sediment yield rate under different SWCs for the two slopes.The runoff-associated TN and TP losses were mainly influenced by runoff rate,and were weakly affected by soil erodibility(P>0.05).However,soil erodibility significantly influenced sediment-associated TN and TP losses.Since the sediment-associated TN and TP losses dominated the total TN and TP losses for the two slopes,soil erodibility also exhibited a significant influence on total TN and TP losses.The freeze-thaw effect increased total loss of TN by1.6times when the SWC was10%.It increased total TP losses by5and1.9times when the SWC was10%and15%,respectively.Considering the SWC in the loess region was generally no more than15%,the freeze-thaw would promote the loss of nitrogen and phosphorus in the loess region.The effect of soil erodibility on nitrogen loss was relevant to freezing and thawing.The nitrogen loss increased first and then decreased with the increase of soil erodibility before freezing and thawing.The nitrogen loss increased with the soil erodibility increased after freezing and thawing.While the effect of soil erodibility on phosphorus loss showed no relationship with freeze-thawing.The loss of phosphorus always increased with the soil erodibility increased.Therefore,a series of ecological construction measures should take to control soil erosion and reduce soil erodibility in order to reduce the nutrients loss in the loess region.The results provide a better understanding of soil and nutrient loss mechanisms under freeze-thaw conditions in the loess slope.
作者
成玉婷
李鹏
徐国策
李占斌
王添
Cheng Yuting;Li Peng;Xu Guoce;Li Zhanbin;Wang Tian(State Key Laboratory Base of Eco-hydraulic Engineering in Arid Area, Xi'an University of Technology, Xi'an, 710048, China;State Key Laboratory of Soil Erosion and Dry-land Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yang ling 712100, China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2017年第24期141-149,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家自然科学基金(Nos.41330858
41401316
41471226)
西安理工大学校基金(Nos.310-252071604)联合资助
关键词
土壤含水率
侵蚀
氮
磷
冻融
土壤可蚀性
soil water content
erosion
nitrogen
phosphorus
freeze-thaw
soil erodibility
