Study On Soil Infiltration Law Of Artificial Forest Land On The North Slope Of Daqingshan

In this thesis,the north slope of Daqingshan,located in Hale Town,Wuchuan County,Inner Mongolia,was selected as the study area.Taking typical plantation tree species such as Pinus tabulaeformis,Caragana korshinskii and Hippophae rhamnoides Linn as the research object,and taking grassland as the control group,in order to improve the phenomenon of soil erosion and water and soil loss on the north slope of Daqingshan Mountain,Using the method of field sampling and indoor experiment,The research adopts the method of combining field sampling with indoor experiment to measure the characteristics of vegetation root system,soil physical and chemical properties and soil infiltration rate,and then analyzes the influence of the physical and chemical properties of soil under the forest and the parameters of vegetation root system characteristics on soil infiltration characteristics in the study area,and draws the following conclusions:(1)Except for the root biomass,the characteristic values of vegetation roots of all stands in the study area are that the value of Pinus tabulaeformis I forest is the smallest and the value of grassland is the largest.There are significant differences among different stands,The deepening of soil layer will reduce the eigenvalue of root system.The root length density is most affected by the 0-0.5mm grade among all diameter grades.There is a significant difference between grassland and forest land.The root surface area density was the highest in grassland and the lowest in Pinus tabulaeformis I.> 2.0mm diameter class has the greatest influence on the value of root bulk density.In > 2.0mm diameter class,the root bulk density of all kinds of land is grassland > Seabuckthorn I > Pinus tabulaeformis× Seabuckthorn > Seabuckthorn II > Pinus tabulaeformis × Caragana > Pinus tabulaeformis II> Pinus tabulaeformis I.(2)From the perspective of soil physical and chemical properties,the deeper the soil is,the greater the bulk density,the soil porosity and saturated water content were the highest in grassland and the lowest in Pinus tabulaeformis.The value of soil organic matter in mixed forest is the largest and that in grassland is the smallest,with a value range of8.23-32.39g/kg.The contents of available nitrogen,available phosphorus and available potassium in soil of all forest types decreased with the depth of soil layer,which were the highest in Pinus tabulaeformis I forest and the lowest in grassland.The characteristic values of roots in the study area have a very important impact on soil physical and chemical properties,and the soil bulk density is the most affected;The chemical properties are most affected by the density of root surface area and root length,and soil available phosphorus was most affected by roots.(3)The infiltration rate of the mixed forest of Pinus tabulaeformis and Hippophae rhamnoides was the highest,the infiltration rate is between 4.167-7.917mm/min.The average infiltration rate of soil in 0-10 cm is the highest.The average infiltration rate of soil is grassland,Seabuckthorn I forest,Seabuckthorn II forest and Pinus tabulaeformis from large to small × Seabuckthorn mixed forest and Pinus tabulaeformis × Caragana mixed forest,Pinus tabulaeformis I forest and Pinus tabulaeformis II forest.The difference of cumulative infiltration was significant,the value of pure forest of Pinus tabulaeformis was the smallest,and the value of grassland was the largest.The infiltration time of Seabuckthorn pure forest in 0-30 cm soil layer is the shortest,and that of Pinus tabulaeformis pure forest is longer.Kostiakov model has the best fitting result in the study area,and the correlation coefficient is as high as 0.895-0.938.(4)The correlation coefficient between root surface density and root bulk density was the highest,with a value of 0.990.The characteristic indexes of soil infiltration showed significant or extremely significant correlation except that the correlation between total infiltration and initial infiltration rate was not significant.The correlation between root surface density,root bulk density and soil infiltration characteristic parameters is the highest and the influence is the most important.Except for soil moisture content,soil physical properties have the most significant impact on the total infiltration,and soil porosity has a certain impact on the stable infiltration rate and average infiltration rate.Among the chemical properties,organic matter has the greatest influence on soil infiltration characteristics.