Suppression effect of Crotalaria ochroleuca cover crop on Amaranthus deflexus emergence and development

Abstract

The weed infestation suppression by chemicals released by plants can occur due to crop residues left on the soil surface or through the incorporated straw in the soil. The aim of this study was to evaluate the suppression of Amaranthus deflexus as a result of cover crops and residue amounts of Crotalaria ochroleuca. The experiment was conducted in a greenhouse from May to August, 2014. The experimental design was a randomized block with four repetitions. The treatments were arranged in a factorial scheme (3 x 5) + 1, with the following factors: (A)-management of the cover crops (incorporated, incorporated + surface and soil surface); (B)-straw levels (3, 6, 9, 12 and 15 t ha -1) and a control treatment without the use of cover crop (control-0 t ha-1). The evaluated variables were: total number of emerged plants, emergence speed index, dry mass, leaf area, root dry mass and root volume. The management of different straw amounts was efficient, mainly when the incorporate+surface and surface in suppressing of A. deflexus forms were used.