Desempenho de plantas de cobertura no controle da erosão hídrica no Sul de Minas Gerais

Abstract

The erosion initiates with the impact of the raindrop on the soil surface, causing the transport of sediment, nutrients and organic matter. To reduce this erosion, the use of conservation practices, such as proper management and planting of cover crops that reduce these losses, is essential. The objective of this study was to evaluate the potential of plant coverage and weather conditions in the South region of Minas Gerais, aimed at soil conservation. The experiment was carried out on the campus of the Federal University of Lavras, in the municipality of Lavras-MG. The treatments consisted of cover crops - sunn hemp, jackbean and millet using two spacings - 0.25 m and 0.50 m. We evaluated the coverage by a horizontal bar, with nineteen holes 9 mm in diameter, and the device placed diagonally on the plant cover. To quantify the production of green mass, we used a 1 m2 wooden frame, being randomly placed on cover crops, which were cut close to the ground. To determine the dry matter content 500 g fresh weight were weighed and placed in an oven at 65 °C until stable constant weight. Based on the dry matter content, the matter in t ha-1 was obtained. The chemical and physical attributes were determined in the Soil Fertility and Physics Analysis Laboratories, located at UFLA. The rainfall erosivity was calculated as the product of kinetic energy with the maximum precipitation of a single rain. To quantify the soil, water and nutrient loss, we used plots prepared for this type of assessment. We also quantified the loss of nutrients, the potential soil sediment drag and the runoff enrichment rate. The sunn hemp had the highest yield of green mass and dry matter. The spacing does not influence the productivity of sunn hemp green mass. Among the cover plant species studied, the jackbean had the lowest soil, water and nutrient losses, due to its efficiency as a ground cover.