Influence of black-oats chemical management periods on the incidence of weeds and productive performance of maize

Abstract

Maize sowing in succession to the cultivation of black oat is a practice widely adopted in southern Brazil, especially in no-tillage system. The time management of oats in relation to the sowing of corn is a determining factor, because it depends on the residence time of oat straw on the ground and may even interfere with the productivity of successor culture. In this sense, the objective was to evaluate the influence of time of chemical management of black oat on yield components of maize. The experiment was conducted at the experimental unit PUCPR – Campus Toledo, in the 2008/2009 and 2009/2010 agricultural years. The experimental design was randomized blocks with five treatments (maize sowing at 0, 7, 14, 21 and 28 days after chemical management of black oat) with four replications. For each treatment, black-oats was sown weekly, and later in the flowering stage managed chemically with 48 g L-1 a.i. of glyphosate at a dosage of 2.0 L ha-1 of the commercial product, using a spray volume of 150 L ha-1, the plants were left intact at the maize sowing period. The variables evaluated were black oat dry matter production, weed incidence, percentage of emerged plants, height of ear insertion, stem diameter, ear length and diameter, number of rows of kernels per ear, weight of 1000 and grain yield. The incidence of weeds decreased gradually decreasing the time between the management of black oat and maize sowing in both agriculture years. The time management of black oat did not affect most yield components of maize, especially productivity.