Soil Respiration And Its Influencing Factors In Meadow Of Zhaosu Mountain Under Different Land Utilization

Grassland soil respiration is an important indicator of grassland ecosystem carbon budget,which is of great significance to terrestrial ecosystem carbon balance and global carbon balance,and also a measure of ecosystem health stress.In order to explore the effect of different land use patterns on soil respiration rate in mountainous meadow of Xinjiang Zhaosu Racecourse,the soil respiration measuring instrument?LI-8100 A?was used to replenish grassland?RG?natural grass?NG?and farmland?CR?soil respiration rate in the end of April and the end of September.The responses of grassland soil respiration to different disturbance and management methods and their main influencing factors were studied by measuring soil temperature and water content and soil microbial flora,microbial biomass carbon and soil enzyme activities in various periods,Below are key research findings:?1?The diurnal variation of soil respiration under different land use patterns showed the change of the first and the lower soils with the change of temperature,The peak value was at noon.?2?The monthly variation of soil respiration showed obvious seasonal variation.NG and CR showed double peaks in 2015,RG and LG showed single peak lines,and the treatments reached the maximum in wheat.In 2016,the peak time of each treatment was different.RG and LG reached the maximum at tillering stage of wheat,and NG and RC reached the maximum at flowering stage of wheat.During the monitoring period,the average soil respiration rate was from large to small:NG,RG,CR and LG.The cumulative CO₂ emissions from soil respiration in 2015were NG>CR>RG>LG.In 2016,the cumulative CO₂ emissions from soil respiration were NG>RG>LG>CR.?3?During the two-year monitoring period,the trend of soil temperature was basically the same,which showed that the temperature was low at the beginning of the growing season and the end of the growing season,and reached the maximum at 7,8 years;Soil water content showed"V"type throughout the monitoring period.Soil water content was higher at the beginning of growing season and at the end of growing season,and the water content decreased during the growing season.There was a significant correlation between soil temperature and soil respiration rate of RG,LG and NG,and there was no significant correlation with soil respiration rate;The fitting effect of soil respiration and temperature is:NG>RG>LG>CR.There was a significant linear correlation between soil respiration rate and soil water content?p<0.05?.The effect of soil respiration and soil water content was:NG>LG>RG>CR.The sensitivity index of soil respiration to temperature Q10 can reflect the sensitivity of soil respiration to temperature.The Q10 level of this study is NG>CR>RG>LG.?4?The number of soil microbes in different treatments was mainly bacteria,followed by actinomycetes,and fungi were the third,The total microbial biomass was:NG>RG>CR>LG..There was a significant linear correlation between soil respiration and bacteria and actinomycetes in LG soil?P<0.05?,and the soil respiration rate was significantly correlated with bacteria and actinomycetes?P<0.05?.The results showed that the respiration rate of RG and CR was significantly linearly correlated with the microbial biomass carbon?P<0.05?,and CR was very significant?P<0.01?.?5?The results of the four soil enzymes selected in this study are the largest farmland,followed by natural grassland,and finally for grass-legume mixture and replenishment of grassland.This may be due to the use of straw to improve the soil fertility,to provide a nutrient for soil microbes,and indirectly promote soil enzyme activity.Analysis of the relationship between enzyme activity and soil respiration showed that only protease and sucrase had a correlation with soil respiration,and sucrase had a greater effect on soil respiration.