Assessing the suitability of soil and water conservation practices in Southwestern China.

摘要

The suitability of soil and water conservation (SWC) practices is the basis of their implementation, and determining their suitability is an important concern in the field of SWC studies. However, little research has been performed to assess the suitability of SWC approaches. In this study, we propose and demonstrate a method to assess the suitability of SWC practices and to assist decision makers in choosing the most appropriate SWC practices. Data from long-term research and community surveys in Linyuan village in Yanting County and Qunli village in Suining County, both in Southwestern China, were used to validate the method. The suitability of an SWC practice was defined as its objective adequacy under a particular set of natural and social conditions and the subjective satisfaction of local people with respect to their expectations and perceptions in a particular region and period. A dual-set paired-criterion system that examines input requirements and output expectations consisting of 'supply-requirement' and 'output-expectation' criteria was developed to evaluate the suitability of SWC approaches more thoroughly. An approach for assessing the suitability of SWC practices was also developed. This approach introduces membership functions and categorical values to address quantitative, qualitative and uncertain data and relies on ratio calculations of each set of paired assessment criteria. In this calculation, the numerical values of the 'supply-requirement' and 'output-expectation' ratios in the model were added together. When several SWC practices were compared, the highest value obtained by pairwise addition of these two criterion ratios indicated the most suitable practice. This approach was applied to compare the suitability of the following four practices in the two villages: terracing, contour tillage (CT), conversion to forestland (CFL) and conversion to grassland (CGL). The results indicated that terracing was the least suitable practice under local conditions, while CGL is the most suitable practice due to its highest economic efficiency. This conclusion reflects the reality that terraces have become more difficult to implement than in the past because of a shortage of labour and investment in the region. This result was consistent with those obtained using the general multiple-criteria analysis (MCA) method. Therefore, the new method proposed here is a highly effective and simple means of assessing the suitability of SWC practices in hilly areas of Southwestern China.