Estratégias para redução de perda de solo em área experimental no semiárido.

Abstract

The Brazilian semi-arid is a region that stands out for its peculiarities, mainly the climatic ones. Agropastoral activities are developed in the region with direct dependence on natural resources for their maintenance, however, they are not carried out with proper planning, which favors environmental degradation. In this sense, it is necessary to identify conservation strategies that favor the balance of biogeochemical cycles. This work aimed to evaluate the application of soil conservation practices in experimental plots as a strategy to recover degraded areas in the Brazilian semi - arid region. The study was developed in the Experimental Basin of São João do Cariri, PB, located in the semi-arid region of Paraíba. Two plots of 100 m², plots 1 (P1) and 2 (P2), with mean slopes of 3.6%, respectively, both with 4.55 m width and 22.0 m ramp length, were used. inserted 22 seedlings of 8 species native to the caatinga. It was carried out the reconstitution of seed bank and use of mulch of crushed corn residues (Zea Mays L.), being later replaced by residue of sugarcane (Saccharum officinarum). In order to evaluate the improvement of soil attributes as a function of the use of conservation practices, the values of organic matter, density, moisture and water infiltration rate in the soil were determined. After rainfall events with consequent runoff, sludge and soil loss were quantified. The results indicate the increase of soil organic matter, with a mean value of 23.1 g.kg-1 (P1) and 47.5 g.kg-1 (P2), the reduction of soil density, with a mean (P1) and 1.3 g.cm-3 (P2), the increase in soil moisture of 6.0 gg-1 (P1) and 6.6 gg- 1 (P2) and the reduction of infiltration rate, from 0.4 cm.min-1 in (P1) and 0.2 cm.min-1 in (P2). There was a reduction of the runoff (P2) relative to (P1), from 93.35% to 100% and from 96.4% to 100%, in sediment production. According to the results obtained, it was possible to conclude that the application of a combined conservationist practice favored the enrichment of the soil quality, indicated by the improvement of its attributes, which increases the productive capacity of the same, besides promoting the reduction of the blade drainage and sediment production. It is recommended to use this combined practice of soil conservation as a strategy for the recovery of degraded areas, without vegetation cover and intensive use of extensive low-yield livestock.