Study On The Structure Characteristics Of Soil Macropores In The Riparian Zone Of Baiyangdian-Daqing River Basin

In recent years,serious water and soil erosion caused by rainfall often occurs in the river/gully bank of Baiyangdian-Daqing River Basin.The riparian connectivity is not only related to the slope connectivity,but also important to the whole riparian connectivity.In this paper,the connectivity of soil macropores in the slope is used to represent the whole riparian connectivity.Through the comparative analysis of the structural characteristics and connectivity of soil macropores in six different riparian rivers in the Baiyangdian-Daqing River basin,the riparian zones with good soil macropores and high connectivity and vegetation types in the current riparian zones are determined,so as to provide theoretical support for the selection of vegetation restoration in the later riparian zones.The vegetation types selected by planting are of great significance to improve the soil macropore structure,increase precipitation infiltration and enhance the connectivity of the riparian zone.Compared with the traditional imaging technology,CT imaging technology has the advantages of high resolution and 3D nondestructive imaging,which can carry out 3d visualization imaging of soil macropore structure and achieve quantitative characterization of soil macropore structure and connectivity.Therefore,CT scanning technology was used to study the structural characteristics(macroporosity,pore size,roundness,fractal dimension)and three-dimensional connectivity of macropores in soil in different riparian zones.The influence of different texture and land use types on the structure characteristics and connectivity of soil macropores is analyzed.The main conclusions are as follows:(1)In the riparian zone with different soil types,loam had the highest macroporosity of 0.72 and the three-dimensional connectivity density of macropores was also higher of 74.5,which was conducive to the growth of vegetation roots and was the optimal soil texture for the development of soil macropores.(2)In the riparian zone of different land use types(including forest land,grassland and cultivated land),the soil macropore structure and connectivity of forest land are obviously better than that of grassland and cultivated land.Economic forest of peach trees in the forest and Japanese persimmon Lin of riparian zone,the soil large porosity,high connectivity,high density value,but because of the economic forest management process easy to cause the pollution of water,so you should choose better soil macropore structure,higher connectivity and has a certain ecological and protective benefits of Luan Shu He locust tree planting in the zone,to improve the connectivity riparian zone,reduce the bank slope of soil and water loss.Moreover,paniculata and sophora paniculata grow well in the riparian zone.(3)The effects of three different herb communities in persimmon forest and poplar forest on soil macropores in the forestland riparian zone with the same stand and different herb communities were analyzed through two situations,respectively taking persimmon forest and poplar forest as examples.In the riparine zone where persimmon tree and different herbaceous plant communities were combined,the order of the connectivity density of macropores was as follows.Matang group;Therefore,the soil macropores formed by the combination of sedge group,chensinensis group and doxoryza bunge group are conducive to the infiltration of water and can improve the connectivity of the riparian zone.In the riparine zone where poplar and different herb communities were combined,the macroporous surface combined by chenopodia + codtail cluster had good porosity distribution and high connectivity,which was the most favorable combination for water infiltration among several herb communities.(4)In the riparietal zone of different herb communities,the macroporosity and connectivity density of artemisia annua + Ceratosus group were 0.57,46.5,0.37 and 19 respectively.By analyzing the structural characteristic values of the macropores and the 3d connectivity density,it can be seen that the macroporosity of the Quinoa group is higher and the 3D connectivity is better.It is beneficial to increase the water seepage and enhance the connectivity of the riverbank..