Abstract: Studies of runoff and soil loss have frequently been carried out on the plot scale, because this allows evaluation of the impact of natural conditions and land use management limiting the interaction of other factors such as topography, climate and varying soil properties. However, their size limits the study of other key erosion processes (such as gully or large scale deposition) as well as the interaction of complex topography or vegetation patterns and the effect of farm operations.

These erosion experiments on large plots or on the catchment scale are increasingly being used in studies beyond the mere evaluation of runoff and soil erosion processes, they are used on studies such as the biogeochemical cycle of nutrients and carbon, large scale dynamics of vegetation, and soil moisture and sediment redistribution. The continuous development of new technologies and techniques, e.g. sediment tracing, image analysis, etc., is enhancing possibilities of researchers for performing new experiments allowing the interpretation of the inter-actions and relationships among different processes and stakeholders; and providing more complexity than in the traditional studies of soil and hydrologic sciences.

This session is intended to bring together researchers in the field working of large plots or catchments to discuss:
1- Recent developments on technologies for evaluation of hydrologic and environmental processes on scale related to soil degradation.
2- Better ways to optimize the investment in this kind of studies.
3- Interaction with related disciples for the definition of new scientific objectives that might be pursued in this kind of experiments.

As a result of the session, we are planning to prepare a special issue with SOIL journal.