Effects of Different Environmental Factors on Soil CO2 and Its Significance to Groundwater Hydrochemistry: A Field Experimental Study in the Qi-Longwan Village in Laiwu City, China

Different environmental conditions lead to different soil CO2 distribution characteristics, which will have different effects on the biological, physical and chemical processes in the soil. In terms to study the characteristics of soil CO2 distribution and to discuss the effects of soil CO2 on the evolution of groundwater chemical, soil CO2 of 20 experimental quadrats were detected and chemical compositions of 1 rainwater sample and 3 mixed water samples were analyzed. Results that the soil CO2 concentration with mixed vegetation was higher than that with a single vegetation type and the variation in soil CO2 concentrations with different slopes followed the order of 10° > 15° > 20° > 25° > 30°. The soil CO2 concentration in winter was much lower than that in summer. The chemical parameters such as K+, Na+, Ca2+, Mg2+, SO₄^2 - , HCO₃⁻ , Cl–, NO₃⁻ , fCO2, TDS and pH in the water samples were increased with increasing soil CO2, which indicated that the soil CO2 was participated in the evolution of the chemical compositions from rainwater to groundwater and played a positive role in the formation of groundwater chemical components in the precipitation infiltration process.