Incorporating Herbicides on Sandy Soil for Dryland Cotton 1

Studies were conducted for 2 yr in the field, comparing the effectiveness of a spring‐toothed harrow and a tandem disk for incorporating preplant cotton ( Gossypium hirsutum L.) herbicides under dryland cropping, on a Miles loamy fine sand soil (fine‐loamy, mixed, thermic Udic Palvestalf) that is subject to wind erosion. Herbicides 3 used were trifluralin [2,6‐dinitro‐ N , N ‐dipropyl‐4‐(trifluoromenthyl)benzenamine], nitralin [4‐(methylsulfonyl)‐2,6‐dinitro‐N,N‐dipropylbenzenamine], butralin [4‐(1,1‐dimethylethyl)‐ N ‐(l‐methylpropyl)‐2,6‐dinitrobenzenamine], profluralin [N‐(cyclopropylmethyl)‐ 2,6‐dinitro‐ N ‐propyl‐4‐(trifluoromethyl) benzenamine], fluchloralin [N‐(2‐chloroethyl)‐2,6‐dinitro‐ N ‐propyl‐4‐(trifluoromethyl) benzenamine] and dinitramine (N 3 , N 3 ‐diethyl‐2,4‐dinitro‐6‐ (trifluoromethyl)‐1,3‐benzenediamine]. Weeds encountered were redroot pigweed ( Amaranthus retrofexus L.), green carpetweed ( Mollugo verticillata L.), large crabgrass [ Digitaria sanguinulis (L.) Scop.], and field sandbur ( Cenchrus incertus M.A. Curtis). No appreciable difference in weed control was noted either year between the disk and spring‐toothed harrow. The first year, cotton yields were not affected by incorporation methods. The second year, incorporating the herbicides with a spring‐toothed harrow resulted in higher yield than incorporating with a tandem disk. Because the spring‐toothed harrow leaves the soil cloddy and less subject to wind erosion and gives equivalent weed control along with equal or better cotton yields, it is a better implement than a tandem disk for incorporating preplant cotton herbicides on sandy soil in dry areas.