Erosão hídrica em semeadura direta de milho e soja nas direções da pendente e em contorno ao declive, comparada ao solo sem cultivo e descoberto

Abstract

Soil and water loss data from rainfall erosion studies are fundamental for the planning of soil conservation. Despite the implantation of no-tillage systems, introduced in the 1970s, conservation practices, e.g., contour cropping and terracing, are still required for an effective control of rainfall erosion, especially in areas with high rainfall amounts. Another alternative for erosion control is the planting of cover crops for soil protection. The objective of this study was to quantify water and soil losses by rainfall erosion from a soil under no-tillage soybean and maize, sown along and perpendicularly to the slope contour lines. The experiment was conducted on an Inceptisol, in the 2010/2011 growing season, with application of four simulated rainfall tests. There were five treatments, in two replications: soybean sown perpendicularly to the contour lines (SD); soybean along the contour lines (SC); maize perpendicular to the contour lines (MD); maize along the contour lines (MC); and control - no crop and bare soil (T). The crops were planted on wheat crop residues in the no tillage system. Soybean along the contour lines was more effective in controlling soil loss than soybean perpendicular to the contour. Maize was more effective in controlling soil loss than soybean, regardless of the form of seeding, and both were more effective than the control. Water losses were only influenced by the form of sowing and negatively correlated with soil moisture before the onset of the rains and the beginning of runoff.