内蒙古半干旱区土壤养分空间分异特征及影响因素分析OA

The semi-arid Loess Plateau in Inner Mongolia is a typical fragile area of ecological environment in China,and it is also one of the important areas for vegetation restoration and ecological construction.Taking the tributary basin of the Red River in Inner Mongolia as the research area,30 sampling points were evenly distributed by grid method for field monitoring and indoor analysis.The spatial distribution characteristics and influencing factors of surface soil nutrient content were analyzed by means of geostatistics,spatial autocorrelation Moran's I index,Kriging interpolation and redundancy analysis.It had important guiding significance for vegetation restoration and land use optimization in arid areas.The results showed that:(1)The soil in the Red River Basin was alkaline,the total potassium content was higher than the national average,and the other nutrient contents were relatively poor.(2)The spatial fitting of total potassium was a linear model,pH was a spherical model,total phosphorus was a Gaussian model,and total nitrogen and organic matter were exponential models.The total phosphorus content and pH value were circularly distributed.The total potassium content increased from southwest to northeast,and the total nitrogen and organic matter content increased from west to east.The four nutrients were high-high aggregation type in the eastern region and low-low aggregation type in the western region.High-high pH gathered in the middle of the study area,low-low gathered in the south of the study area.(3)Nutrients in the study area were mainly affected by silt content,elevation,slope,aspect and vegetation type.Except for the irregular change of total potassium content,the other three nutrient contents increased with the increase of elevation,and the content was the lowest in the middle and high slope,and the nutrient content in the sunny slope was higher than that in the shady slope.The nutrient content increased with the increase of silt content.The total potassium content in poplar-caragana mixed forest was the highest,and the total nitrogen,total phosphorus and organic matter contents were the highest in grassland,while the total nitrogen and organic matter contents in degraded farmland were the lowest.In the ecological restoration of semi-arid areas,measures such as the addition of nitrogen and phosphorus fertilizers and the return of crop residues can be taken to improve the nutrient deficiency.It is suggested that vegetation restoration should be based on the construction of mixed forests and natural restoration grasslands.