Effects of Herbicide-Crop Rotation on Nutsedge, Annual Weeds, and Crops

Abstract

In a 3 year herbicide-crop rotation involving corn (Zea maysL. ‘Coker 811A’), cotton (Gossypium hirsutumL. ‘Carolina Queen’), and peanuts (Arachis hypogaeaL. ‘Argentine’), uncontrolled yellow nutsedge (Cyperus esculentusL.) and annual weeds drastically reduced all crop yields. By the end of the rotation sequences, intensive cultivation throughout the rotation killed 97 to 99% of the nutsedge tubers, but this level of control depended on hand-weeding the cotton. Moderate application of herbicides killed from 78 to over 99% of the yellow nutsedge tubers, while intensive treatment with herbicides produced at least 99% kill. In addition, all annual weeds present when the experiment was initiated were controlled satisfactorily by intensive herbicide applications except Florida beggarweed [Desmodium tortuosum(Sw.) DC.] in peanuts. The major change in composition of the weed population was a reduction in yellow nutsedge and in the total number of weeds; however, certain other population shifts also seemed affected by the weed control treatments. Compared to intensive cultivation, the investment in intensive herbicide treatment produced maximum yields and highest gross profit per acre. None of the treatments affected the market grade or organoleptic characteristics of peanuts. The fatty acid content of corn and cotton changed significantly only in 1967.