Understanding the effects of contour hedgerow and terracing hedgerow on soil and water conservation in the remote mountainous regions of Southwest China

Abstract

BackgroundSoil and water loss is a serious worldwide environmental problem, for example, soil loss from the sloping cultivated lands in the remote mountainous regions of Southwest China due to the abundant precipitation and steep sloping cultivated lands in these areas. Various soil protection techniques have been adopted to prevent soil loess, the local people did not admire the introduced contour hedgerow measurement from abroad; however, they have been actively accepted another traditional one, the terracing hedgerow. The purpose of this work is to understand the differences on soil and water conservation between contour hedgerow and terracing hedgerow. MethodsThe different structure between four treatments of contour hedgerow and terracing hedgerow were analysed. Meanwhile, three heights (0 cm, 10 cm, and 15 cm) of lynchet were set, and the soil erosion module, runoff efficiency, ratio of output and input, economic effects among the different treatments were compared. The soil anti-scourability was calculated using the equation, and analysis of variance (ANOVA) was performed with SPSS 11.5 and Microsoft Excel software. ResultsThe obvious difference was that terracing hedgerow with a certain height of walkway was more convenient for farming activities and effectively reduced soil and water loss. The treatment of terracing hedgerow 2 (H15H) reduced runoff 55.56%±6.25% and reduced erosion modulus 79.26%±3.50% when compared to the sloping cultivated land plots with no lynchet and no hedgerow (CK). The contributions of the independent variables on runoff, soil erosion reduction and soil anti-scouring were in the following order: terracing hedgerow 2 (H15H) > terracing hedgerow 1 (H10H) > contour hedgerow (H0H) > non-hedgerow (CK). The value of ratio of output to input of H15H treatment was 1.52, which was the highest value among different treatments. ConclusionsAlthough the treatment of terracing hedgerow 2 (H15H) needs more labour force, however, results in the higher hedgerow yield and ratio of output to input than other treatments as well as stronger anti-scourability. Thus, the traditional terracing hedgerow with 15 cm lynchet is recommended in the remote mountainous regions of Southwest China, even should be recommended often and used extensively in the similar climatic regions in other countries.