Effect of harrowing before corn planting on weed control

Abstract

The objective of this research was to study the effects of the time elapsed after disk harrowing and com planting on weed infestation, and on crop yield components. The experiments were conducted in the counties of Lavras and Sete Lagoas, MG, Brazil, in 1991/92 and 1992193, in random blocks in a split-plot design, with flaur replications. The plots were formed by three disk harrowing times (0, 15, and 30 days before corn planting) and, in the sub-plots, by six treatinerits of weed control (no control, control by manual hoeing, two treatments with animal traction cultivation, and two chemical control treatments). Disk harrowing fifteen and thirty days before com planting promotes reduction of crop development and grain yield, mainly in Sete Lagoas. Independent of the disk harrowing time, the best options for weed control are: control by manual hoeing and chemical control with atrazine + metholachlor. The animal traction cultivation process is more efficient in the plots with harrowing conducted simultaneously with the com planting.