Research On The Correlativity Between Forage Grass Nutrition And Soil Characteristics In Degeneration Grassland

Setting experimental sample plots of natural grassland under different degeneration gradients in meadow steppe and typical steppe, with the methods of field survey and the laboratory carrying the analysis on its vegetation characteristics, the diversity and the content of forage grass nutrition , meanwhile carrying on the physical and chemical analysis to the degenerated grassland soil .In this foundation, making separate research on the relationship between forage grass nutrition , species diversity of plant community and soil characteristics . The conclusion as follows;(1) With the intensifying of degeneration degree, the grassland population standing crop, vegetation coverage on grassland present decreasing tendency, the species diversity of plant community conforms to the moderate disturbance hypothesis; (2) With the intensifying of degeneration degree, the content of forage grass crude fiber reduces gradually, the content of crude protein increases gradually. Namely the degree of degeneration is higher, the quality of plant community nutrition is better;(3) The content of soil nutrient (organic matter, the entire nitrogen, alkaline hydrolysis nitrogen) in unemployed area is higher than the severe degeneration area, moreover with the increase of soil depth, the content of nutrient present the drop tendency;(4) The soil electrical conductivity reduces along with the degeneration intensifying. The soil density of control area of every soil layers of four sample plots in the meadow steppe and typical steppe is lower than the severe degeneration area; (5) The total dissolved nitrogen of forage on natural grasslands and organic matter,total nitrogen and alkaline nitrogen in 10—30cm soil layer shows positive correlation, the correlation coefficient were 0.9319,0.8271 and 0.8423 respectively .Besides, the total dissolved nitrogen of forage grass in meadow steppe and typical steppe all show negative correlation with soil density, the correlation coefficient were -0.9607 and -0.9914 respectively; (6) There is obvious negative correlation between the species diversity of plant community of the meadow steppe and the pH value and the electrical conductivity; In the soil, the increased nutrient content can promote the increase of index of diversity of typical steppe, in the degree, the soil density restricts the development of diversity of typical steppe.