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Northwest A&F University (2021)

Key Processes of Water Cycle in Check Dams in the Wind-Water Erosion Crisscross Region

袁鸿猷

Titre : Key Processes of Water Cycle in Check Dams in the Wind-Water Erosion Crisscross Region

Auteur : 袁鸿猷

Grade : Master 2021

Université : Northwest A&F University

Résumé partiel
Check dam is an important part of water cycle in small watershed and a significant area for food production in Loess Plateau,it is of great significance to accurately understand grasp the space-time characteristics of soil moisture shallow groundwater under different land uses in check dam,to clarify the soil water supply capacity of check dam scientifically guide the agricultural production regional ecological restoration of check dam.In this study,we choosed two check dams(A and B dams)in Liudaogou watershed,the spatial distribution of soil resistivity in check dam was explored by electrical resistivity tomography,the spatial distribution of shallow groundwater in check dam was analyzed after the relationship with soil moisture content was established,we also studied the dynamic change process of shallow groundwater in check dam ground and estimated shallow groundwater storage.By monitoring the change of soil moisture content in different land use types(cropland,grassland shrubland)in the check dam,explored the spatial temporal distribution characteristics of soil moisture in three land use types,calculated the soil water storage,analyzed the soil moisture consumption supplementary depth under three different land use types,determined the profit loss degree of soil moisture.At the same time,combined with meteorological data soil moisture data,the main water consumption depth of Salix matsudana was analyzed,the sap flow characteristics of Salix matsudana and Populus simonii Carr were explored by thermal diffusion method in check dam and the responses to environmental factors were analyzed.The conclusions of the study are as follows :(1)The soil resistivity of the check dam has increasesd,then decreased,then increased with depths.The upper soil resistivity is higher than the lower one,the upper soil resistivity has greater variability ;the soil resistivity and soil moisture content showed a significant power function relationship.In the vertical direction,the soil moisture content of the shallow surface layer of the check dam showed that the upper layer is lower than the lower layer,the overall trend is to first decrease then increase with stratification.In the horizontal direction,the shallow surface groundwater content is gully tail>gully head>the middle.The groundwater storage in A and B check dams were seasonal changes,the end of winter to the following summer for soil moisture consumption period,late summer early winter for the accumulation period,summer water storage is the smallest,the value is 85,949,94,196m3,the winter water storage value reached the largest,its value is 93,486,99,309 m3.The groundwater storage in check dam is changing seasonally,the water storage is decreasing gradually from late winter to summer,the water storage is increasing sharply in late summer early autumn,the water storage in summer is the smallest,the water storage is the largest in winter.(2)The soil moisture content of farmland,grassland and shrubland in the check dam has obvious seasonal variation characteristics,which is synchronous with the change of precipitation has a certain lag.The order of soil water storage of the three land use types was farmland>grassland>shrubland.In normal water years,the water consumption of 0-200 cm soil was shrubland>grassland>farmland.In dry years,the consumption of soil water storage was grassland>farmland>shrubland.However,in the past two years,the soil water storage of all land use was negative.

Mots clés : water-wind crisscross erosion region ;check dam ;water;soil resistivity ;depletion infiltration ;evapotranspiration;

Présentation (CNKI)

Page publiée le 13 novembre 2021