The Study On CO₂ Of Karst Eco-system Of Vertical Zone In Jinfo Mountain In Summer

With the situation of global wanning caused by greenhouse becoming more hard, people begin to study greenhouse, especially CO2, more deeply. From the point of view of system, a series of researches about carbon cycle of earth' system and CO2's "source and sink" are done. At present , "Missing sink" is an important part in global carbon budget. Some researches have indicated that it existed in terrestrial eco-system. There is a close relation between terrestrial eco-system and human beings and terrestrial eco-system's carbon cycle plays an important role in global carbon balance. Therefore, the research about carbon cycle of terrestrial eco-system is profound.Some researchers had studied carbon cycle from the aspect of eco-system. But, from the aspect of vertical zone, the study is done rarely. We took the karst experimental site of Jinfo Mountain nature reserve area as example. We selected two experimental sites-forest land and bareland to carry out the research. The research including:CO2 concentration , temperature, air humidity and rainfall. We probed into the principle of carbon cycle in different elevation and the effect of vegetation to carbon cycle.The research results are as follows:(1) With the increasing of the height to the ground, the value of CO2 concentration in air become adding; The depth of soil profile more deeper, the value of CO2 concentration in soil more higher.(2) The temperature in the sample area, which is with high elevation, is higher than the temperature in the sample area, which is with low elevation.(3) The value of CO2 concentrations in air of two kinds of sample sites in high elevation area are all lower than the corresponding value in low elevation area. The case of CO2 in soil is opposite.(4) CO2 concentration in soil reached to maximum at 13 o'clock in forest land which is with both high elevation and low elevation, the curves are single kurtosis; CO2 concentration in soil reached to minimum at both 13 o'clock and 22 o'clock in the bare land which is with high elevation, the curve is double kurtosis, and that in the low elevation reached to maximum at 16 o'colck,its curve is single kurtosis.(5) CO2 in air and soil are all influenced by temperature. CO2's respond to the temperature in forest land is more moderate than that in the bareland, indicating vegetation's role of restraining to the carbon cycle.(6) CO2 concentration in soil is much higher than that in air, CO2 release makes soil to become a source of CO2 in air.the soil respiration has a distinct relation with temperature.(7) Rainfalls can "deposit "the CO2 in air, making it to take part in the process of karst, to dissolve and corrade carbonate rock. CO2 concentration in soil become lower after heavy rainfall and become higher after general rainfall.(8)The value of chemical characteristic of soil water in the high elevation area is lower than that in the low elevation area. That also indicates that the intensity of karst in high elevation area is weak.