Effects Of Climatic Factors And Production Modes On Vegetation Change Of Typical Grassland

In order to determine the degradation causes of typical steppe in Xilingol during the past 40 years,the vegetation data of grassland census in 1978-1982 and 2009-2010 were used as background and compared with the measured grassland growth status in 2019-2021.The climate change,stocking rate and animal husbandry mode of grassland in recent 40 years were investigated and analyzed.At the same time,experiments with different rest periods and different grazing patterns were set up in the typical steppe in central Xilingol from 2019 to 2021 to analyze the effects of different production patterns on grassland vegetation height and coverage,grassland productivity,plant community structure and α-diversity index,so as to determine the effects of climate change and production patterns on grassland degradation.The results are as follows:1.Compared with 1978-1982 and 2009-2010,grassland vegetation height and coverage,aboveground biomass,relative biomass of perennial gramineae,Margalef index,Simpson index and Pielou index showed a decreasing trend from 2019 to 2021,indicating grassland degradation.2.Based on the analysis of climate change and its impact on grassland in recent 40 years,it is found that the precipitation in typical grassland in central Xilin Gol has a decreasing trend in recent 40 years,while the average annual temperature has a rising trend.Precipitation had a significant positive correlation with vegetation height and aboveground biomass of perennial gramineous plants(P < 0.05),but had no significant effect on other grassland indexes.Average annual temperature was negatively correlated with vegetation height,aboveground biomass and Margalef index(P < 0.05).The stocking rate of grassland was negatively correlated with vegetation height,aboveground biomass and Margalef index(P < 0.01).Grassland stocking rate has a greater impact on grassland degradation than climate change.3.The results showed that the vegetation height,coverage,aboveground biomass andα-diversity index of perennial graminaceous plants were significantly decreased(P < 0.05),and the plant community composition was worse than that of seasonal rotation grazing.Hugh grazing compared to two months to take 1 months and 4 months,the grassland vegetation height,coverage,aboveground biomass and perennial grasses of alpha diversity index has increased significantly(P < 0.05),plant community structure is more reasonable,spring grazing 2 months and seasonal rotational grazing on the grassland has obvious function recovery.To sum up,in the context of typical grassland degradation in Xilingol in the past 40 years,the analysis of degradation causes shows that although climate factors to a certain extent lead to grassland degradation,overgrazing caused by the increase of grassland stocking rate and unreasonable production mode are the main reasons for grassland degradation.On the basis of this study,it can be concluded that reasonable rest time and scientific grazing system are beneficial to grassland restoration.The results of this study showed that the growth of grassland was best in spring(April-May)when grazing was suspended for 2 months.Under the system of resting grazing in spring and rotating grazing in summer and autumn,it can not only meet the demand of livestock for feeding but also maintain the normal development of grassland vegetation.It is a key measure to curb grassland degradation and ensure the sustainable utilization of grassland by strictly controlling the stocking rate of grassland and implementing reasonable resting grazing and rotating grazing system.