| Abstract/Contents: | "Field experiments were conducted to evaluate the effects of selected herbicides on rooting and tensile strength of established centipedegrass [Eremochloa ophiuroides (Munro.) Hack], bermudagrass [Cynodon dactylon (L.) Pers.], and zoysiagrass [Zoysia matrella (L.) Merr.] sod. Herbicides included atrazine, tridiphane, bensulide, chlorimuron, DCPA, DPX-6313, imazapyr, imazaquin, napropamide, oxadiazon, pendimethalin, sethoxydim, simazine, and sulfometuron. These were applied in 225 L/ha of water to mature sods which were maintained under normal sod production conditions of frequent irrigation and moderate nitrogen fertility. Soil type of the centipedegrass sod was leaf silt loam, while the zoysiagrass and bermudagrass were grown on Dothan loamy sand. At 2,4, and 8 weeks after application, tensile strength of each sod was determined in the field. None of the herbicides materially reduced the tensile strength of mature sods below that of the untreated control at any of the three sampling periods. After tensile strength was measured, blocks of sod (929 cm2) were allowed to root on irrigated sand beds for 7 to 10 days, at which time root densities and lenghts were determined. Napropamide (2.24 and 4.48 kg/ha) and imazapyr (0.12 and 0.25 kg/ha) decreased root density and length at 2, 4, and 8 weeks, while bensulide (13.45 kg/ha), sulfometuron (0.06 kg/ha), atrazine (3.3 kg/ha), and tridiphane (0.56 kg/ha) reduced only the number of roots of zoysiagrass sod at 2 weeks. Chlorimuron (0.01 and 0.03 kg/ha), DCPA (13.45 kg/ha), pendimethalin (1.68 and 3.36 kg/ha), DPX-6313 (0.03 and 0.07 kg/ha), sulfometuron (0.01 and 0.03 kg/ha), oxadiazon (2.24 and 4.48 kg/ha), sethoxydim ( 0.28 and 0.56 kg/ha), simazine (2.24 and 3.36 kg/ha), and imazaquin ( 0.28, 0.41, and 0.56 kg/ha) did not significantly affect rooting. Centipedegrass rooting density and length were decreased by bensulide and imazapyr. Napropamide at 2.24 kg/ha and atrazine at 3.36 kg/ha decreased the number of roots at 2 weeks only, while the 4.48 kg/ha rate decreased both numbers and lengths of roots at 2 and 4 weeks but not at 8 weeks. Sulfometuron (0.03 and 0.07 kg/ha) reduced both density and length at 2 weeks, while the 0.01 kg/ha rate reduced only the length. Chlorimuron, DCPA, DPX-6313, imazaquin, and sethoxydim (0.28 and 0.56 kg/ha), atrazine (2.24 kg/ha), tridiphane (0.56 kg/ha), oxadiazon ( 2.24 and 4.48 kg/ha), pendimethalin ( 1.68 and 3.36 kg/ha), and simazine ( 2.24 and 3.36 kg/ha did not affect rooting. Rooting of bermudagrass sod was decreased at all rates and intervals by imazapyr. Sod treated with bensulide and napropamide recovered at the 8-week date. Sethoxydim and sulfometuron initially suppressed rooting of sod, but it strongly recovered at 8 weeks. Chlorimuron, DPX-6313, imazaquin, atrazine, tridiphane, DCPA, oxadiazon, pendimethalin, and simazine produced no change in rooting compared to the control after initially being suppressed." |
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