Greenhouse Gases Emission From Typical Ranches In Qinghai-Tibet Plateau

Ranch is the basic unit of human-rangeland coupled system. Regulating and controlling greenhouse gases emission reducing is the lead and hotspot of many course researches. This thesis takes typical ranches in Qinghai-Tibet Plateau as study objects, invents the method of piled-up two pots pile which is successfully used in the experiment, together with static boxes-greenhouse gases analyzer and household investigation, so as to show the characters of greenhouse gases emission of rangeland, livestock and habitation with the view of ranch system. Followings are the main experiment results:Firstly, the emission flux of CO2 with exuberant pasture period is much higher than with turning green and withering period in each subsystem of ranch (p<0.05). The rangeland in turning green and exuberant period has the function of collecting CH4, while freeze and thaw in withering period makes the rangeland discharge CH4; subsystem of livestock and habitation is the source of CH4. Ranch is the source of N2O as a whole and the emission of N2O in each subsystem is different due to season changing.Secondly, the emission flux of CO2 in pasture turning green and exuberant period takes up 92.62% and 93.76% respectively of the total greenhouse gases emission; there are no big differences between the emission flux of CO2 and N2O in withering period, but their emission fluxs are both much higher than the emission flux of CH4 (p<0.05). In livestock subsystem, CH4 with manure and N2O with pen have a higher emission flux; the emissions flux of N2O in pasture turning green and withering period and CO2 in exuberant period are both higher with pen. In habitation subsystem, the emissions flux of CO2 by dung combustion is much higher than by other activities (p<0.05); the emissions flux of CO2 in cold season is much higher than in other seasons (p<0.05).Thirdly, the rangeland greenhouse gases emission with ranch in pasture turning green, exuberant and withering period takes up 79.05%,92.38%,62.80% respectively of the total greenhouse gases emission; habitation takes up 1.95%,0.55%,5.75% respectively. In ranch system, the emission flux of CO2 in pasture turning green, exuberant and withering period is 75.29%,87.24%, and 33.98% respectively; CH4is 18.54%,6.92%, and 31.85% respectively; N2O is 6.17%,5.84%,34.16% respectively.Finally, in the three interfaces with ranch system, grass-soil interface has the biggest contribution to ranch greenhouse gases emission (p<0.05). Ranch is the collection of greenhouse gases as a whole.The results can provide scientific evidences for greenhouse gases emission reducing in Qinghai-Tibet Plateau and clean energy mechanism building.