Effects Of Fence Enclosure On The Stoichiometric Characteristics Of Grassland Ecosystem In Inner Mongolia

Due to natural causes and the impact of human activities,grassland degradation and desertification in Inner Mongolia has become more and more serious.Reversing pasture degradation is an important goal of grassland management but also a challenge for recovery technologies.Fence enclosure is widely recognized as one of the effective measures to restore degraded grasslands.In this paper,the meadow steppe,typical steppe and desert steppe in the Inner Mongolia are studied.The community composition of the vegetation,biodiversity,plant,root and soil nutrient content and their stoichiometric characteristics inside and outside the fence were studied.The conclusions are as follows:1.Plant height and aboveground biomass in the fence are significantly increased compared with the outside of the fence.The number of plant species,plant cover and density in the fence are increased compared with the outside of the fence,but don’t reach a significant level.At the same time,the grassland community diversity index has changed to varying degrees.This shows that enclosure fencing can generally make the grassland community develop benign.2.Fence enclosure increases the plant organic carbon content in desert steppe and meadow steppe.For root organic carbon content,the organic carbon content of 0-10 cm and 10-30 cm roots in meadow steppe is inside the fence > outside the fence.The desert steppe and typical steppe are the opposite.The total nitrogen content,soil organic carbon content and total nitrogen content of the plants inside the fence are larger than those outside the fence.For the total phosphorus content of plants,it is generally expressed as outside the fence> inside the fence.The total phosphorus content of 0-10 cm layer soil in the desert steppe and meadow steppe are expressed as outside the fence > inside the fence,while the typical steppe is inside the fence > outside the fence.The total phosphorus content of 10-30 cm soil layer in the typical steppe and meadow steppe are expressed as inside the fence >outside the fence,while the desert steppe is outside the fence > inside the fence.3.Plant C:N appears as outside the fence > inside the fence,0-10 cm and 10-30 cm root C:N appears inside the fence > outside the fence in the typical steppe and meadow steppe.Plant and root C:P and N:P are all represented inside the fence > outside the fence of three grassland types.The soil C:N is expressed as inside the fence > outside the fence.The trends of soil C:P and N:P are basically similar.Among the three grassland types,except for 0-10 cm soil C:P in the typical steppe,the other soil C:P and N:P of differentgrasslands are all inside the fence > outside the fence.4.There are no significant correlations between Vegetation community species diversity,aboveground biomass,plant organic carbon content,total nitrogen content,total phosphorus content,C:N,N:P,soil total phosphorus content,C:N,C:P and N:P and environmental factors.There is a significant positive correlation between total nitrogen content and N:P of root,and soil organic carbon content is significantly negatively correlated with altitude.Root N:P is significantly positively correlated with annual mean temperature.Plant C:P,root C:P and root N:P are significantly negatively correlated with annual precipitation.Soil organic carbon content and total nitrogen content are significantly positively correlated with annual precipitation.The underground biomass,total phosphorus content,soil organic carbon content and total nitrogen content are positively correlated with drought index.Root N:P and C:P are significantly negatively correlated with drought index.