USING THE 137CS TECHNIQUE TO STUDY THE EFFECT OF SOIL REDISTRIBUTION ON SOIL ORGANIC CARBON AND TOTAL NITROGEN STOCKS IN AN AGRICULTURAL CATCHMENT OF NORTHEAST CHINA

Soil organic carbon (SOC) and total nitrogen (TN) stocks can be affected by soil erosion and this is of great significance in relation to global environmental concern about environmental change. This study investigated the spatial patterns of Cs-137, SOC and TN as well as their relationships for an agricultural catchment and presents a budget analysis of the redistributions of SOC and TN for the period 1954-2010. Cs-137, SOC and TN inventories were found to be significantly correlated, and the application of the(137)Cs technique proved to be useful for evaluating SOC and TN dynamics in the Luvic Phaeozem soil typical of the Chinese black soil region. Spatial patterns of soil, SOC and TN were greatly influenced by shelterbelts/windbreaks within the study catchment. Higher Cs-137, SOC and TN stocks were generally found upwind of the shelterbelts and at the study catchment outlet, whereas lower stocks of Cs-137, SOC and TN occurred behind the shelterbelts (i.e. in the lee). The total net losses of SOC and TN over the past 56 years were approximately 152 and 11 t respectively, with 47 and 38 per cent of the eroded SOC and TN in soils redeposited within the study catchment, respectively. Based on the relationships of soil, SOC and TN in the investigated catchment, erosion-induced SOC and TN losses per year are around 1.2 x 10(6) and 0.1 x 10(6) t for the typical black soil region of Northeast China. Copyright (C) 2012 John Wiley & Sons, Ltd.