Spatial Variation Of Soil Nutrients In Alpine Grassland Based On Multiple Data

Soil nutrients are an important component of soil fertility and have an important impact on alpine grassland meadow ecosystems.In this study,the subtropical beach in Xinghai Basin was selected as the research area,and the alpine grassland and alpine meadow were taken as research objects.The combination of geoscience and geochemistry theory,combined with the radionuclide tracing method by RS and GIS,extracted different alpine grassland areas.Vegetation information and soil erosion information,estimate soil erosion intensity and determine soil nutrient content in seven types of soil,study spatial distribution characteristics and changes of soil nutrients.?1?The OM?organic matter?content of the study area is 13.96-76.01 g.kg^-1,the TN?total nitrogen?content is 1.23-4.95 g.kg^-1,and the EXT-N?alkali nitrogen?content is 52.01-297.50mg.kg^-1.EXT-P?available phosphorus?content is 1.38-11.85 mg.kg^-1,TP?total phosphorus?content is 0.82-1.82 g.kg^-1,and TK?total potassium?content is 19.63-28.57 g.kg-¹,EXT-K?available potash?content is 76.11-248.80 mg.kg^-1.?2?The alpine meadow is covered with a dense layer of planted felt,which can effectively protect the surface soil nutrients from being eroded;The alpine grassland vegetation has no felt layer,which is vulnerable to wind and water erosion,which causes the loss of soil nutrients on the surface soil.Therefore,the soil nutrient content of alpine meadow is higher than that of alpine grassland.It is embodied in the average content of OM(45.58 g.kg^-1 in alpine meadow>35.82 g.kg^-1 in alpine grassland)and the average content of TN(2.97 g.kg^-1in alpine meadow>2.58 g.kg^-1 in alpine grassland),EXT-N average content(alpine meadow151.29 g.kg^-1>alpine grassland 123.41 g.kg^-1),EXT-K average content(alpine meadow 180.43mg.kg^-1>alpine grassland 163.75 g.kg^-1),EXT-P average content(alpine meadow 5.64 mg.kg^-1>alpine grassland 5.20 g.kg^-1).?3?NDVI gradually decreases from west to east in the study area,NDVI and OM,TN,EXT-N,EXT-K was a significant positive correlation?P<0.01?,and EXT-P showed a significant positive correlation?P<0.05?,The higher the surface vegetation coverage,the easier the OM,TN and EXT-N content to accumulate in the soil surface,providing nutrients for vegetation growth.?4?There is no grade difference in TN,TP,TK and EXT-P content under three soil erosion types in the study area.The primary and secondary content distribution areas of OM in hydraulic erosion area accounted for 59.92%and 39.18%of the area,and the secondary EXT-N accounted for 86.73%.The secondary EXT-K accounted for 91.73%;the OM secondary content distribution area of the wind erosion zone accounted for 49.53%of the area,and the OM level accounted for 42.44%.EXT-N Level 1,Level 2 and Level 3 accounted for 21.44%,45.09%and 33.58% respectively.EXT-K level accounts for 81.01%of the region.The primary and secondary content distribution areas of OM in the freeze-thaw erosion zone accounted for45.75%and 44.32%of the area,EXT-N level II and III accounted for 67.24%and 17.76%,respectively,and secondary EXT-K accounted for 93.09%.?5?The soil erosion intensity of OM,TN,EXT-N and EXT-P in the study area was negatively correlated?p<0.05?,indicating that soil nutrient OM,TN,EXT-N and EXT-P were lost during soil erosion.The research conclusions obtained by the above methods and means may provide reference for the ecological environmental protection work in the alpine grassland area,and provide scientific suggestions for the ecological civilization construction in the alpine grassland area.