Local Soil Degradation Assessment
Many local land and soil degradation assessment are undertaken worldwide. To cite only a few examples, twenty one site specific investigations were carried out in 6 countries in three different continents under the LADA project (Argentina, China, Cuba, Senegal South Africa and Tunisia). The DeSurvey project investigated six local sites in Algeria, Chile, China, Morocco, Tunisia and Senegal. The GEF is presently co-funding three large initiatives with a local component in Patagonia, China and in the Central Asian countries.
Soil properties and health assessment tools
The tools for assessing soil properties and health are taken from the VS-Fast methodology (McGarry, 2006) and selected VSA methods of Shepherd (2000). The emphasis is on the assessment, both qualitative and quantitative, of soil physical condition conducted during field visits. The core set of indicators used provides a robust, yet rapid and inexpensive approach to assessing the following soil characteristics and rating them and a scorecard established for the overall assessment of soil health:
- description of the soil sample (depth, texture, structure, colour, layering);
- aggregate size distribution;
- soil crust;
- tillage and other pans;
- biota (particularly earthworms and roots);
- slaking and dispersion;
- water infiltration;
- organic carbon;
- soil and water salinity
Local Soil Erosion Assessment
The presence of soil erosion in arable, forest and pasturelands is a prime indicator of soil degradation by water or by wind; often caused by a reduction in protective vegetation cover. Soil erosion through topsoil loss is an indicator and cause of reduced land fertility, and hence potential productivity. It may also hinder access to land for crop/forest production. Moreover, the transported sediments and nutrients may cause problems downstream in terms of sediment deposits and reduced water quality. Despite the recognized importance of controlling and reversing soil erosion through soil and water conservation practices, there are few attempts to systematically observe and measure soil erosion as part of an integrated assessment of degradation and management (soil, vegetation, water and ecosystems) with the notable exception of the LADA local manual. The following steps are undertaken in the field when assessing soil erosion:
- sketch map land use - erosion features;
- describe and Assess Erosion Types;
- describe Erosion state;
- Assess Erosion Extent;
- Assess Erosion Severity.
On the basis of the above a score card is established to evaluate soil erosion.