干旱区生态环境知识资源中心

Recent studies on alkaline soils of arid areas suggest a possible contribution of abiotic exchange to soil CO2 flux (F-c). However, both the overall contribution of abiotic CO2 exchange and its drivers remain unknown. Here we analyzed the environmental variables suggested as possible drivers by previous studies and constructed a function of these variables to model the contribution of abiotic exchange to F-c in alkaline soils of arid areas. An automated flux system was employed to measure F-c in the Manas River Basin of Xinjiang Uygur autonomous region, China. Soil pH, soil temperature at 0-5 cm (T-s), soil volumetric water content at 0-5 cm (theta(s)) and air temperature at 10 cm above the soil surface (T-as) were simultaneously analyzed. Results highlight reduced sensitivity of F-c to T-s and good prediction of F-c by the model F-c=R(10)Q(10)((Tas-10)/10)+r(7)q(7)((pH-7))+lambda T-as+mu theta(s)+e which represents F-c as a sum of biotic and abiotic components. This presents an approximate method to quantify the contribution of soil abiotic CO2 exchange to F-c in alkaline soils of arid areas.