An overview on soil loss tolerance methods: challenges and opportunities

Tolerable soil erosion is the boundary between natural and accelerated erosion and is one of the most fundamental yet complex issues in soil erosion research. The tolerable erosion threshold is an essential criterion for awareness and judgment about the state of soil erosion and the extent of its potential economic, social and environmental risks and damages. Therefore, it is very important to determine it accurately and correctly using appropriate methods. For this purpose, various methods have been developed, which can be divided into three general groups including methods based on soil formation rate, methods based on agricultural soil productivity and methods based on off-site effects of erosion. First, the details of the various methodologies along with their disadvantages and advantages were examined, and finally, research challenges and opportunities in this field were presented. Various scientists in recent years have emphasized the need for comprehensiveness in determining tolerable thresholds, but existing methodologies have so far failed to achieve this, and are still at the beginning of the road. Thus, the main challenges and opportunities are mainly related to methodology and the presentation of new integrated and applied approaches to determine tolerable erosion.