Lâmina escoada e produção de sedimentos em microbacias do semiárido paraibano.

Abstract

Erosion is a natural phenomenon where the earth's surface is worn and shaped by physical, chemical and biological processes for the removal being probably the most serious form of landscape degradation around the globe. Humans are considered the main causative agents of erosion on the planet and this can result in many environmental impacts and the loss of arable land. Civil society faces a major challenge is the search for balance between development and sustainability. The use of inappropriate management practices of water and soil had a strong impact on the conservation of natural resources in the semi-arid region. There are increasingly interested in the study and evaluate according to the local characteristics of each region, respecting the culture and tradition, the best ways to use the remaining natural resources. In this sense it is essential to know the behavior of degraded areas and the level of degradation consequences that is each area. This work is the main problem of research a qualitative evaluation of runoff and sediment yield when mechanical soil conservation practices are used in rural micro-basins in the Brazilian semi-arid region. The aim of this study is to evaluate the marketed blade and sediment yield in watersheds of Paraiba semi-arid, and the experimental objectives are to assess the marketed blade and sediment yield in nested experimental watersheds and investigate the influence of mechanical practices for soil conservation in an experimental catchment. The hypothesis that guides the work is that mechanical soil conservation practices may favor the maintenance of wetlands and higher productivity which would help the cast of alternative land use and occupation in rural areas besides favoring man's relations with the environment, thus resulting in a higher possibility of identification of conservation strategies. Data from three watersheds with 1.0 ha magnitude, two of them nested, were used to analyze the efficiency of mechanical soil conservation practices and the effect of scale. The results indicate in range of 19.3% to 97.9% reduction in annual sediment yield observed in the watershed 3 for 01 watershed and 23.4% to 63.7% compared to 02 watershed in the period from 2002 to 2007. The reduction in annual of runoff watershed 03 ranged from 4.6% to 98.1% when compared to watersheds 01 and 02. There is a linear relationship between rain, runoff and sediment yield and disposed between the runoff and the sediment yield. The use of rock barriers as soil conservation practice is presented as a successful and cost-effective alternative to the use of land plots for agricultural use or recovery of degraded areas in the semi-arid region.