The Primary Study On CO₂ And CH₄ Emission From Soil-Plant Systems Of 'Black Soil Patch' Degraded Alpine Meadow In The Source Area Of Yellow River

Using static chamber-GC method,a primary study on CO2 emission and CH4 emission from Soil-Plant Systems of'Black soil patch'degraded alpine meadow and the relevant analysis of CO2 and CH4 emission with soil surface temperature,5 cm depth soil temperature, soil water content indicated that:1. The diurnal variation of CO2 emission rate of three different treatments of'Black soil patch'degraded alpine meadow—the respiration rate of soil -plant system(BC),Soil respiration rate(BJ) and Soil microbial respiration rate (BL) were similar. They all had the evident characteristics of "unimodal curve". The maximum rate appeared around 15:00, and the minimum rate appeared around 4:00.The CO2 emission rate presented the ascending tendency from 4:00 to 15:00 and it dropped from 15:00 to 4:00 of the next day. Seasonal dynamic of the CO2 emission rate was pretty remarkable,and the trend of three different treatments were consistent. The CO2 emission rate increased gradually from the beginning of July to the middle of August, and and it dropped down. The CO2 emission rate given off,did not absorb. In the period of observation, the CO2 emission rate varied with different treatments showing an order of BC>BJ>BL,and the average rates were 460.41±167.74,327.97±108.61 and 238.44±94.50 mg/(m2·h). Seasonal dynamic of the CO2 emission rate of plants, overground part of plants and underground part of plants were pretty distinct. The CO2 emission rate increased gradually from the beginning of July to the middle of August, and it dropped down swift later, it went on rising in the beginning of September and continued to drop finally.2. The both of the diurnal variation and seasonal dymanic of the CH4 emission rate of three different treatments of'Black soil patch'degraded alpine meadow were not prominent. CH4 emission is at the absorption condition in a great measure time. In the experiment perio,the CH4 emission rate varied with different treatments showing an order of BC>BJ>BL, and their average rates were -28±26,-38±21 and -43±25 ug/(m2·h). Seasonal dynamic of the CH4 emission rate of plants,overground part of plants and underground part of plants were not pretty distinct. The CH4 emission rate was positive. The CH4 emission rate indicated plants > overground part of plants > underground part of plants. 3. There was a extreme significant correlation between soil surface temperature and the CO2 emission rate of soil -plant system(BC),soil respiration rate(BJ) and soil microbial respiration rate (BL) of'Black soil patch'degraded alpine meadow. The correlation coefficients were 0.907,0.877 and 0.928. There was a extreme significant correlation between soil temperature at 5cm depth and the CO2 emission rate of soil -plant system(BC),Soil respiration rate(BJ) and Soil microbial respiration rate (BL) of'Black soil patch'degraded alpine meadow. The correlation coefficients were 0.811,0.813 and 0.968. The correlation between the CO2 emission rate of soil -plant system and 10~20 cm , 20~30cm soil water content was not significant. But there existed a significant correlation between the CO2 emission rate of soil–plant system and 0~10cm soil water content. The correlation coefficient was 0.670. There was a significant correlation between the CH4 emission rate of over ground part of plants and aboveground phytomass. The correlation coefficient was 0.987.4. The correlation between soil surface temperature and the CH4 emission rate of soil -plant system (BC) was not significant. There was a significant correlation between soil surface temperature and the CH4 emission rate of soil respiration rate(BJ) and soil microbial respiration rate (BL) of'Black soil patch'degraded alpine meadow. The correlation coefficients were 0.694,0.705. There was an extreme significant correlation between soil temperature at 5cm depth and the CH4 emission rate of Soil microbial respiration rate (BL) of'Black soil patch'degraded alpine meadow. The correlation coefficient was 0.698. There existed an extreme significant correlation between the CH4 emission rate of soil -plant system and 0~10cm soil water content. The correlation coefficient was 0.949. There existed a significant correlation between the CH4 emission rate of soil -plant system and 10~20cm soil water content. The correlation coefficient was 0.741.The correlation between the CH4 emission rate of soil -plant system and 20~30 cm soil water content was not significant.