Efficacy and Economics of Weed Control Methods in Cotton (Gossypium hirsutum)

Four cultivations of cotton [Gossypium hirsutumL. ‘Stoneville 213′] alone failed to reduce green weed biomass or increase seed cotton yields above that of the no weed control treatment, and thus resulted in a negative net return (−200 to −450 $/ha) all 4 yr. Two cultivations plus two hand-hoeings reduced green weed biomass and increased seed cotton yields 3 out of 4 yr, thus a positive net return was produced for 3 yr ranging from 300 to 640 $/ha. Fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] alone was the most effective treatment in reducing green weed biomass and increasing seed cotton yields, and produced the highest net return, 280 to 420 $/ha for the 4-yr period. The addition of cultivation did not improve the fluometuron treatment. However, diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea)] required three supplementary cultivations to equal the single fluometuron treatment. Trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) plus three cultivations did not equal the single fluometuron treatment, although a positive net return was obtained every year. The addition of trifluralin to fluometuron also failed to improve weed control or net return over that of fluometuron alone.