Effects of land use on soil properties and run-off in a colombian Orinoco water basin

Abstract

his study evaluate the effects of land use on the Camoa water basin in Meta by quantifying the effect of soil organic matter content (SOMC), bulk density and water content. These variables were evaluated by extracting ground cores from riparian forests and grasslands of different litter cover. We also evaluated the relationship between the SOMC and the water volume deficit using regressions. Likewise, using pitfall traps we identified the trophic organization of soil-superficial arthropods. Due to its higher SOMC (> 5%), the soils of highly productive forest (high litter content) had significantly higher water contents than soils from less productive forests and grasslands (p < 0.05 in both cases). The water content found among the studied soil cover types suggests that the role of run-off in forest has been underestimated. Water basin management should encourage the establishment of productive riparian forests with CMOE values higher than 5% in order to promote volume and continuity in water offer from rivers due to the generation of constant subsurface flow and the regulation of sporadic superficial run-offs. The variety of functions and interactions accomplished by arthropods in forest soils suggests that a highly structured trophic organization favors conversion of simple and complex compounds in humus and therefore would favor soil water retention capacity.

Keywords

• caño Camoa, humedad del suelo, Llanos Orientales, manejo de cuencas, materia orgánica, regulación hídrica