[Impacts of different vegetation types and soil properties on runoff chemical characteristics]

Chemical characteristics of surface runoff and groundwater in different vegetation types on Jinyunshan located in suburb of Chongqing were studied, and the relationship between runoff chemical characteristics and soil properties were analyzed. The vegetation types include coniferous broad-leaved mixed forest, evergreen broad-leaved forest, bamboo forest, shrubbery and bare soil. Results showed as follows: Chemical characteristics in surface runoff and groundwater were similar to that in rainfall, which Ca2+ was the dominant cation, Ca2+ > K+ > Na+ > Mg2+ > NH4+; and SO4(2-) was the dominant anion, SO4(2-) > NO; > Cl-. The concentration of Ca2+, Mg2+, K+, Na+, SO4(2-), Cl- in runoff were higher than that in rainfall, meanwhile Ca2+, Mg2+, SO4(2-), Cl- in groundwater were higher than that in surface runoff. pH of groundwater was obviously influenced by soil pH. Ca2+, Mg2+, K+, Na+ in groundwater showed a negative correlation to those properties in soil profile because cations were always absorbed by colloids in soils. Moreover, since anions were easy to be leaching, SO4(2-), NO3-, Cl- in groundwater displayed a positive correlation to that in soil profile.