No-tillage system is considered the most efficient system for erosion control in annual crop plantations. However, problems of erosion as development of rills and ravines under no-tillage have been observed, suggesting that mechanical practices, such as contouring and terraces are required for erosion control. The objective of this study was to determine if no-tillage system allows seeding direction following down slope and ramp length larger than the currently recommended. The experiment was conducted in a clayey Oxissol with a mean slope of 6% under no-tillage system for 6 years, cultivated with black oat and corn, in runoff plots with soil and water collector system. Two trials were conducted: one with three ramp lengths (25, 50 e 75 m) and other with two seeding direction (in contour and following down slope) and two ramp lengths (50 e 75 m). There was no sediment production under no-tillage system. Water losses were reduced in ramp length up to 75 m and were not influenced by seeding direction. The distance between terraces can be enlarged under no-tillage system for soil and slope studied.
no-tillage system; runoff; seeding direction; soil loss; terracing
