Demanda de tração em hastes sulcadoras de adubo para semeadura direta afetada por rotação de culturas, fonte de nutrientes e tráfego de rodados.

Abstract

An experiment in complete randomized split plots with four replications was carried out in Eldorado do Sul, Brazil, to assess the combined effects of crop rotation and nutrient source on draft requirement of fertilizer chisel-type furrow openers, considering two traffic conditions. Treatments consisted of two nutrient sources (mineral and organic), two crop rotation systems (soybean/wheat/ corn/oat and soybean/oat + vetch/corn) and two traffic conditions (with and without traffic). Treatments were compared with two controls; one of them was kept uncovered during winter and the other was kept without cover all year round; a subdivision in trafficked and no-trafficked rows. Results showed that when using organic nutrient sources and crop rotation systems keeping soil covered in winter and summer, draft requirements by fertilizer shanks increased significantly. These results may be related to higher organic matter addition in these treatments, resulting in increased soil shear strength. Draft requirements were lower on trafficked zones, owing to lower furrow depth.