Background China is among the countries that suffer most serious soil erosion in the world. During the process of soil erosion control, various methods were developed to evaluate the benefits of soil and water conservation measures. However, it is difficult to select a method from so many for specific context due to lack of a systemic summary of the evaluation methods to clarify and compare the advantages and scope of application of existing methods.

Methods Based on literature survey, we summarized the characteristics, strengths and weaknesses and scope of application of the existing evaluation methods. The information of the methods was collected from 33 core papers out of 892 papers published in Chinese in the past 20 years with the keywords of "soil and water conservation" and "benefits evaluation".

Results Eleven methods were widely used to evaluate the benefits of soil and water conservation at present, including empirical evaluation method, BP artificial neural network method, genetic algorithm, double-set assessment indexes system method, fuzzy comprehensive evaluation method, grey correlation analysis method, TOPSIS method, ontology knowledge base method, matter-element extension model, weighted summation formula method, and comprehensive evaluation methods. There are different scopes of application for different methods according to their characteristics, advantages and limitations. Weighted summation method is mainly suitable for evaluation in large-scale region or watershed as it has no requirements on the number of indicators and takes the relationships among the indicators into consideration. Genetic algorithm and TOPSIS method are more suitable for comparison of benefits among different soil and water conservation measures and measures selection; because these two methods could be used to calculate the optimal solution for the benefits obtained from different soil and water conservation measures. Fuzzy comprehensive evaluation method and grey correlation analysis are suitable for areas with complex environments where data are scarce or difficult to acquire, which had lower requirements for data and could generate more objective evaluation results.

Conclusions In the future, researches should be focused on the exploration and application of new methods by combining computer technology and artificial intelligence, integrating theories with multiple methods, and modeling, etc. In order to improve the benefits of soil and water conservation projects, the application of evaluation methods should be selected according to local physical and socio-economic conditions with long-term monitoring and timely adjustment. Besides, relevant departments should draft general criteria for benefits evaluation of soil and water conservation, which could be used among different soil erosion prevention areas across the country to facilitate comparison among different areas, and promote the performance of soil and water conservation projects in China.