Diversidade de ácaros edáficos e minhocas em área de integração lavoura pecuária no centro oeste do Rio Grande do Sul

Abstract

The Crop Livestock Integration System (ILP) is based on diversification, rotation, intercropping and/or succession of agriculture and livestock activities within the rural property. The aim of the study was to evaluated if different grazing intensities applied in the ILP change soil fauna diversity and activity, thus identifying soil quality indicators in soils under ILP systems. The experimental area consisted of 14 plots, where treatments are based on four grazing intensities (10, 20, 30 and 40 cm) regulated from the pasture height and distributed in an experimental design of randomized blocks. It was used three replicates, and two areas of ungrazed blocks as reference areas. Sampling was performed by five points to mites and nine points for the eartworms in each plot, pre-set by the use locations on a grid, with the same measurements, regardless of the size of plots, after grazing of cattle and after soybean harvest. Funnel Berleze-Tullgren Modified was assessed to verify the presence of edaphic mites. The Tropical Soil Biology and Fertility methodology (TSBF) was carried out to collected earthworms. The total mites density is favored by the 20cm height in after grazing of cattle in ILP system. In the assessment, there is a greater diversity of mites families (Upododidae, Pachilaelapidae, Nothridae, Phthiracaridae, Galumnidae, Oribatidae, Trombiculidae, Cunaxidae four unidentified) after soybean cultivation. The presence of earthworms were highest after soybean cultivation and of in 10-20cm deep layer on Integration Livestock System. The presence of two families of Glossoscolecidae and Ocnerodrilidae worms were verified in ILP area, with different grazing intensities. Moreover, the first occurrence of the species Eukerria michaelsen was recorded in the Rio Grande do Sul state, Brazil.