Effects Of Vegetation On Soil Water Storage And Soil Dry Layer In The Loess Plateau

The soil erosion in the Loess Plateau is serious and the ecological environment has been seriously damaged.In order to restore the ecological environment of the Loess Plateau,the project of returning farmland to forest and grassland is carried out in the area.Because of the lack of precipitation and the evaporation is strong,the soil moisture in the Loess Plateau is seriously deficient,which is the main limiting factor of vegetation restoration and ecological environment reconstruction in this area.At the same time,vegetation growth strongly consumes soil moisture due to the significantly reduce of the soil water storage capacity.Soil dry layer is the negative impact of unreasonable vegetation construction.A large number of scholars have done a lot of research on the vegetation of soil water storage and soil dry layer in the Loess Plateau after returning farmland to forest and grass.But most of the literature only studies a region or a factor.In order to systematically and comprehensively study the vegetation effect of soil water storage and soil dry layer in the Loess Plateau,in this paper,I use the method of integration analysis,based on the study of many scholars.We will study the infiltration depth of precipitation under different land use patterns in different climatic zones as a prerequisite,and comprehensively analysis the vegetation effect of the soil water storage capacity and soil dry layerfrom both vegetation growth period and vegetation type.The main conclusions of this study are as follows:1.The infiltration depth of precipitation in Pianguan is about 1.5m,the infiltration depth of precipitation in Shenmu is about 1.3m,the infiltration depth of precipitation in Ansai is about 1.6m,the infiltration depth of precipitation in Jingchuan is about 2.3m,the infiltration depth of precipitation in Qianyang is below 2m.For the entire Loess Plateau,there is a significant regional difference of the infiltration depth.In the semi-arid area,the average infiltration depth is 1.5m.In sub-humid areas,the infiltration depth is more than 2m.And the difference between different vegetation types at the same location was small.2.The soil dry layer of alfalfa grassland in Ningxia is 10a> 7a> 3a,and the soil dry layer of 3-year-old alfalfa grassland has reached 7m,7-year-old and 10-year-old alfalfa grassland is more than 10 m.Ningxia Guyuan 1-year-old alfalfa grassland soil dry layer Depth of 5.8m,5-year-old,8-year-old and 12-year-old alfalfa grassland reached 10 m depth.The relationship between the intensity of soil dry layer was 20a> 14a> 11a> 4a in semi-humid areas,The soil dry layer depth of the 5-year-old apple forest land in Changwu of Shaanxi was 3.2m,and the soil dry layer depth of the 10-year-old apple forest land was 6m and 15 years old was below 6m.The soil dryness of the original 3-year-old alfalfa grassland in Gansu was the smallest and the depth was about 3.8m,8-year-old 5m,18-year-old alfalfa grassland soil dry layer depth of up to 10 m.For the whole Loess Plateau region,the vegetation growth period has a similar law on the soil dry layer:with the increase of vegetation growth period,the strength of soil dry layer gradually increased,the depth gradually deepened.And the intensity of soil dry layer in semi-arid area is obviously higher than that in semi-humid area.3.The relationship between the intensity of the dry layer of 20-year-old vegetation is seabuckthorn> Caragana korshinskii> Robinia pseudoacacia;The relationship between the intensity of 8-year-old vegetation dry layer is Robinia pseudoacacia> Caragana korshinskii;The relationship between the intensity of soil dry layer in 30-year-old vegetation was Caragana korshinskii> Alfalfa;The relationship between the soil dry layer intensity of three-year-old vegetation is alfalfa> Caragana korshinskii;The relationship between the dry layer strength of 10-year-old vegetation soil is Robinia pseudoacacia> alfalfa.For the entire loess plateau area,vegetation growth is strong for soil moisture consumption,the soil water storage capacity of farmland and desert slope is obviously larger than that of other vegetation types.There were obvious soil dry layer phenomena in different vegetation types.The relationship between the size of dry layer increases with the increase of vegetation growth period.