Effects Of Enclosure On Degraded Grassland Community And Soil Characteristics In Etuokeqian Banner

In order to explore the effects of fencing measures on plant communities and soil characteristics of degraded grasslands,several representative natural grasslands in Etuokeqian Banner were selected as the research objects.Based on the collection of grassland survey data in the 1960 and 1980.In 2019,field investigation was conducted on five typical degraded grasslands,namely,Caragana tibetica-Artemisia frigida + Stipa breviflora grasslands,Glycyrrhiza uralensis + Pennisetum centrasiaticum + Agropyron mongolicum grasslands,Artemisia ordosica-Pennisetum centrasiaticum + forbs grassland,Artemisia ordosica-forbs grassland and C.intermedia + Artemisia ordosica-forbs grassland,which had been fenced for 4 years.The free grazing grassland was used as the control group,and the enclosed grassland was used as the experimental group.The effects of free grazing and enclosure on the plant community and soil characteristics of degraded grassland were compared.The results are as follows.(1)Fencing can increase the diversity of plant communities in degraded grassland.There were 8 – 28 species more plant species in fenced grassland community than in free grazing area,including increased by 28 species in Artemisia ordosica-forbs grassland community,increased by 26 species in Tibetan Caragana-Artemisia frigida + Stipa breviflora grassland type,increased by 14 species increase in Caragana intermedia +Artemisia ordosica-forbs grassland.The species composition of the three grasslands was significantly higher than that of free grazing grassland(p < 0.05).(2)Fencing can improve community coverage,grass yield,height and root biomass of degraded grassland.Under enclosure measures,the coverage,grass yield,root yield and height of five grassland communities were higher than those of free grazing grassland,and the coverage,grass yield and root yield were significantly higher than those of free grazing grassland(p < 0.05).The community height of Glycyrrhiza uralensis + Pennisetum centrasiaticum + Agropyron mongolicum community was significantly higher than that of free grazing grassland(p < 0.01).The community height of Artemisia ordosica-forbs grassland and Caragana intermedia + Artemisia ordosica-forbs grassland was significantly higher than that of free grazing grassland(p < 0.05).(3)The nitrogen-free extract content of plants under enclosure measures was higher than that of free grazing grassland;crude protein content of plants under enclosure measures was lower than free grazing grassland;crude fat content of plants under enclosure measures was lower than that of free grazing grassland except Artemisia ordosica-white grass + miscellaneous grassland;the crude fiber content of fenced Glycyrrhiza uralensis + Pennisetum centrasiaticum + Agropyron mongolicum community and Artemisia ordosica-white grass + forbs grassland were lower than that of free grazing grassland,and the crude fiber content of the other two grasslands were higher than that of free grazing grassland.The crude ash content of Caragana tibetica-Artemisia frigida +Stipa breviflora grassland and Artemisia ordosica-forbs grassland was significantly lower than that of free grazing grassland(p < 0.05).(4)Under the enclosure measures,the soil alkali-hydrolyzable nitrogen content of Caragana korshinskii-Artemisia frigida + Stipa breviflora grassland and Glycyrrhiza uralensis + White grass + Agropyron mongolicum grassland increased gradually with the deepening of soil layer,and the soil alkali-hydrolyzable nitrogen content of other grassland decreased gradually with the deepening of soil layer.The soil available P content in Artemisia ordosica-A.alboglabra + forbs grassland and Caragana tibetica-A.frigida +Stipa breviflora grassland decreased with the deepening of soil layer,and the available P content increased,and there was significantly difference in Caragana tibetica + Artemisia ordosica-forbs grassland(p < 0.05).Soil available K content in Caragana korshinskii-Artemisia frigida + Stipa breviflora grassland increased with the soil depth,and decreased in other grasslands.Soil p H decreased with the increase of soil depth.In summary,enclosure of degraded grassland can not only improve grassland yield,forage nutritional value and plant species,but also improve grassland soil.Therefore,enclosure is one of the effective measures for restoring degraded grassland.