Assessment of soil erosion by compensatory hoeing tillage in a purple soil

Abstract

This study explores the role of a traditional tillage method, i.e., compensatory hoeing, for sustainable agro-ecosystem management in the hilly areas of the Chongqing municipality, south-western China. To validate the effects of compensatory tillage on the terraced slopes, the tillage method of noncompensatory hoeing was conducted on a linear slope. To acquire information about 137Cs inventories and soil texture, soil samples were collected by a core sampler with a 6.8-cm diameter at 5.0-m intervals along the toposequence and the linear slope in the dry season (March) of 2007. Meanwhile, a tillage erosion model was used for evaluating the spatial pattern of tillage erosion. The 137Cs data showed that on the terraced slope, soil was lost from the upper slope, and soil deposition occurred at the toe slope positions on each terrace. As a result, abrupt changes in the 137Cs inventories of soil were found over short distances between two sides of terrace boundaries. Results obtained from the tillage erosion model and the 137Cs data indicate that soil redistribution mainly results from tillage erosion in the terraced landscape. Consecutive non-compensatory tillage caused soil redistribution on the linear slope, resulting in thin soil profile disappearing at the top and soil accumulating at the bottom positions of the linear slope. This result further validates that compensatory tillage could avoid the complete erosion of the thin soil layer at the summit position. Therefore, this traditional tillage method, i.e., compensatory tillage, has maintained the soil quality at the summit of the slope in the past decades.