Effects Of Grazing On Biomass And Soil Physical And Chemical Properties Of Artificial Caragana Korshinskii Forest In Wuchuan County

Artificial Caragana forest is an important afforestation vegetation in the arid area of Northwest China,which plays an important role in windbreak and sand fixation,soil and water conservation and so on.Wuchuan County of Inner Mongolia is a typical arid area with extremely harsh ecological environment.The forestry department implemented the construction project of ten thousand mu Caragana korshinskii forest in 2014,and the local ecological and environmental benefits improved significantly after the implementation of the project.In order to alleviate the pressure of local animal husbandry and improve the well-being of herdsmen,it is necessary to determine the reuse mode and intensity of artificial Caragana woodland.In this study,the well-growing areas of Caragana korshinskii forest were selected,and three methods of enclosure(no grazing),semi-free grazing(low intensity)and free grazing(high intensity)were set up to study the effects of different grazing on the growth status of Caragana korshinskii,soil physical and chemical properties and atmospheric environment,in order to provide a theoretical basis for the later moderate utilization of Caragana korshinskii forest.The results show that :1.The atmospheric temperature of Caragana korshinskii forest reached the highest in July,and the atmospheric humidity reached the highest in August.Atmospheric temperature and humidity decreased with increasing height.The atmospheric temperature of free grazing treatment was significantly higher than that of semi-free grazing and enclosure treatment,while the surface humidity was significantly lower than that of the other two treatments.The soil temperature of Caragana korshinskii forest reached the highest in July,the soil moisture of 0-10 cm was the highest in June,and the soil moisture of 10-20 cm was the highest in July.With the increase of soil depth,soil temperature decreased and soil moisture increased.The soil temperature of the free grazing area of the two soil layers was higher than that of the semi-free grazing and enclosure treatments,and the soil moisture was lower than the other two treatments.2.Grazing increased soil bulk density,and soil bulk density in free grazing area was significantly higher than that in semi-free grazing and enclosure treatment.The soil porosity decreased with the increase of grazing intensity.The soil porosity was the smallest under free grazing condition and the largest under enclosure treatment.The soil water storage decreased with the increase of grazing effect,and increased with the increase of soil depth.The proportion of soil sand(1～0.05mm)in the two soil layers was the highest.With the increase of grazing intensity,the content of soil sand increased,and the content of clay and silt decreased.3.The surface soil p H of the enclosure treatment was significantly lower than that of the other two treatments,and there was no difference in the lower soil.The contents of soil organic carbon,total nitrogen and total phosphorus were the highest in semi-free grazing,and increased with the increase of soil depth.The content of soil available potassium was the highest in the free grazing area and increased with the increase of soil depth.There was no significant difference in soil available nitrogen and available phosphorus content between different grazing treatments and soil layers.4.Caragana korshinskii grew slowly from May to July,and the fast-growing period was from July to September.The height and crown growth of Caragana korshinskii under enclosure and semi-free grazing treatments were both increasing.The average number of branches increased in the order of semi-free grazing > enclosure > free grazing.The edible parts(leaves,annual branches)of Caragana korshinskii in semi-free grazing area were more than those in enclosed area and free grazing area.The total biomass of Caragana korshinskii shrubland was in the order of enclosure > semi-free grazing > free grazing.Appropriate grazing in the growing season can promote the branching of artificial Caragana forest,improve the growth status of Caragana,improve the utilization rate of Caragana,promote the enrichment of soil nutrients,and improve the economic benefits of local herdsmen.