Title: A review of land degradation assessment methods

Land degradation is an increasing problem in many parts of the world. Success in fighting land degradation requires an improved understanding of its causes, impact, degree and acquaintance with climate, soil, water, land cover and socio-economic factors. Therefore, land degradation assessment is a primary goal in a decision support system for reversing degradation. Fortunately, scientists around the world started long ago to look at the problem and have developed assessment and monitoring methods. This study, aimed at exploring and reviewing existing assessment methods, used a global, regional, local and field/farm levels in an attempt to assess land degradation issues. This paper discusses and describes various methods for assessing land degradation and its processes. The study concludes that there are plenty of different approaches for assessing land degradation worldwide. Expert opinions, field measurements, field observations, land user’s opinions, productivity changes, remote sensing and modelling methods act as a backbone for many approaches to assess land degradation at different levels. Moreover, the first distinction that has to be made is land use and land types and scale. Significantly, methods or techniques need to be critically selected, taking into account their suitability, applicability and adaptability to local conditions. This helps in comparing areas and involving stakeholders as much as possible as aids in land use and restoration planning and prioritizing projects. It is also important to integrate local knowledge with scientific knowledge, but care should be taken in interpreting local knowledge and interests, which can be complex. Furthermore, use of statistical methods, ordination, and modelling approaches are costly, complicated, and time consuming. The lack of experienced people and availability of resources are some of the main barriers to successful assessment. This review revealed very few failures in using different assessment methods, which is somewhat surprising. Does this mean that everything works?