| We used the method of combination field survey with the laboratory analysis and studied the response of desert community characteristics,stability and vegetation-soil nutrients to fencing in Anabasis salsa desert(6 years of enclosure),and to discuss the change rule of biochemical metrological characteristic of organic carbon(C),total nitrogen(N),total phosphorus(P)in A.salsa desert,which could provide a scientific basis and management for the local animal husbandry.The main results are showed as follows:(1)There are 3 more plant species in un-grazing in the A.salsa desert(Kochia prostrata,Ceratoides latens and Stipa glareosa).Seriphidium terrae-albae is dominant species in the fenced plot,but dominance of A.salsa decrease.A.salsa is dominant in the grazing plot.The height,diversity index,cover,biomass,richness index and evenness index of the grassland community and diversity increase significantly,which are significantly higher than those grazing plot in A.salsa desert,but the density decrease significantly.The height are highly significantly correlate with the coverage(0.578**),diversity index(0.723**),uniformity index(0.665**),and richness index(0.799**)(P<0.01),but height and density(-0.499**)have a very significant(P<0.01)negative correlation.The distances between the stable points are 30.66 and 31.86 in inside and outside in the A.salsa desert.Short-term enclosure is beneficial to community stability.Short-term un-grazing can significantly improve and maintain vegetation diversity and community stability in the A.salsa desert.(2)After un-grazing,aboveground biomass C content,the C/N,C/P andN/P of aboveground biomasssignificantly increase by 22.04%,25.92%,36.36%and 13.39%(P<0.05),but the aboveground biomass P content significantly decrease by 21.43%(P<0.05).The aboveground biomass C content and the P content(-0.798**)had a very significant(P<0.01)negative correlation and the aboveground biomass C content are highly significantly correlate with the C/N(0.951**)and C/P(0.960**)(P<0.01).(3)The root system is downward trend with increasing soil depthin inside and outside the fence.Root C content increase significantly by 14.73%and 15.76%in soil layer 0-5 cm and 70-100 cm after enclosure(P<0.05),while root C and P content decrease significantly in soil layer 10-20 cm 17.65%and 15.45%(P<0.05);in the same layer,the root K content increase significantly by 35.73%(P<0.05).The remaining differences are not significant.Root N/P in soil layer 0-100 cm after enclosure is significantly reduce by 34.11%(P<0.05),and root C/N and C/P are not significantly different(P>0.05).(4)There is no significant difference between the inside and outside of the soil bulk density and soil water content in fence(P>0.05),with the increase of soil depth,the soil water content increases first and then decreases,and the highest is 30-50 cm.Soil organic carbon and carbon density are increasing trend with increasing soil layer in A.salsa desert.The organic carbon content and storage in the soil layers of 50-70 cm and 70-100 cm are significantly higher than those in the other soil layers and after fence the organic carbon in 20-30 cm soil layer increase significantly by 43.49%(P<0.05).The total nitrogen content of the soil range from 0.14 to 0.37 g/kg,with an average value of 0.26 g/kg,and the total N content is lower than the average value of 1.60 g/kg for the N element in soil.In summary,the short-term un-grazing has a small response to the nutrient’s composition of soil in the desert of A.salsa. |
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