Effects of different soil types on the foliar δ13C values of common local plant species in karst rocky desertification area in central Guizhou Province

By measuring the foliar δ13C values of common local plant species grown in different soil types in Wangjiazhai catchments,a typical karst desertification area in Qingzhen City,Central Guizhou,we studied the impact of soil type and rocky desertification grade on the foliar δ13C values. The results showed that the foliar δ13C values were more negative in yellow soil area than those in black calcareous area and there was no obvious difference in foliar δ13C values between these two soil types. The distribution interval of foliarδ13C values in yellow soil area was narrower than those in black calcareous area and the variation coefficient of foliar δ13C values in yellow soil area were smaller than those in black calcareous area. With increasing degree of karst rocky desertification,the foliar δ13C values of plant community in black calcareous area increased,whereas those in yellow soil area first increased and then decreased. The result of multiple comparison showed that the difference in foliar δ13C values of plant community among rocky desertification grade was not obvious in yellow soil area,but it was obvious in black calcareous area. Correlation analysis between the foliar δ13C values of plant species and the main environmental factors indicated that slope and soil thickness were the main factors which affected the foliar δ13C values of plants in yellow soil area and soil water contant was the main factor in black calcareous area. The impact of soil on the foliarδ13C values was realized by adjusting the soil moisture in study area.