Erosión y desertificación.-Micro-Scale analytical approach in the study of a soil ecosystem affected by different levels of erosion

Abstract

ABSTRACT In this paper the evolution of the humic-enzyme complexes, characterized by analytical isoelectric focussing technique, have been investigated for characterizing three different soil degradation forms caused by the plant cover loss: I) a natural soil with a wide shrub-grass cover (Forest); II) a partially degraded soil with a scanty grass cover (Shrub); and III) a bare soil originated by landslides (Bare). Chemical (total organic carbon, total nitrogen, C/N ratio and water soluble carbon) and biochemical (dehydrogenase, biomass carbon, basal respiration and β-glucosidase) parameters only discriminate between the most degraded bare soil from the natural and partially degraded soils. A clear discrimination between the three soil ecosystems was given by the microbial cell constituent (ATP), humic carbon, extracellular β-glucosidase activity and humic carbon-bound β-glucosidase, which distributed the soils in a decrease order of degradation: natural (Forest), partially degraded (Shrub) and Bare. The results confirmed the previous findings that the biochemical properties of humic substances determined at microscale level, help in achieving a completeness of information capable of discriminating even little differences in soil ecosystem quality and functioning. The study was carried out in the framework of the European project “Indicators and threshold for desertification, soil quality and remediation” (INDEX- STREP n. 505450, 2004-06).