Crop-Herbicide Sequences on a Southeastern Coastal Plain Soil

Abstract

Weeds in corn (Zea maysL.), cotton (Gossypium hirsutumL.), peanuts (Arachis hypogaeaL.), and soybeans (Glycine max(L.) Merr.), grown continuously or in rotation, were controlled with either cultural or herbicidal programs designed for broad-spectrum control. The herbicidal program initially selected for each group was used each year from 1968 to 1971. Herbicides controlled more weeds than cultural practices in all cropping sequences. Weeds were almost eliminated, judging by percent ground cover at harvest time, in five of the eight cropping sequences in each of the last three years of the experiment. Although several rotations drastically reduced the number of weeds, the composition of the weed population was not altered significantly. When cultural weed control practices were used, the cropping sequence and rainfall influenced the level of weeds present at harvest time. More weeds were present at harvest in corn grown continuously and in sequence than in the other crops. In addition to three or four cultivations, we used a yearly average of 86 manhours/ha of hand-hoeing in corn and 195 manhours/ha of hand-hoeing in cotton during the first 6-week period after planting to keep these crops weedfree until the last cultivation. The cropping sequence did not affect the amount of hand-hoeing required in these crops. In general, cropping sequence did not affect crop yield.