Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)




No-till and minimum tillage agriculture limits preplant incorporated herbicides and cultivation for weed control in soybeans. Furthermore, reduced tillage leaves crop residue on the soil surface, thereby al so limiting the effectiveness of many preemergence herbicides. A reduced tillage system with the utilization of postemergence weed control practices may reduce soil erosion and production costs while increasing weed control, water infiltration, moisture conservation, and crop yields. Postemergence herbicides are less affected by soil type and moisture than soil applied herbicides. However, the effectiveness of postemergence herbicides may be reduced when rain occurs too soon after treatment. Quackgrass [Agropyron repens (L.) Beauv.], foxtail spp. [Setaria spp.], and corn (Zea mays L.) are problem weeds in the corn-soybean rotation of the northern corn belt. The presence of these grassy weeds in soybean fields is unsightly and often results in severe yield reductions. Fluazifop butyl {2-[4-[5-(trifluoromethyl -2-pyridinyloxy)] phenoxy]propanoate}, CGA 82725 {2-propynyl 2-(4-[3,5-dichloro-2pyridinyl )oxy]phenoxy]propionate}, Dowco 453 {methyl 2-4-[3-chloro-5(trifluoromethyl )-2-pyridinyl]oxy]phenoxy]propanoate}, and RO 13-8895, are being developed as postemergence herbicides to control several grass species in soybeans. The purpose of these studies was to evaluate and compare fluazifop butyl, CGA 82725, Dowco 453, and RO 13-8895 as late-season rescue treatments for annual grass and quackgrass control in soybeans and to determine the effect of rainfall on the control of weeds by these herbicides.

Library of Congress Subject Headings

Soybean -- Weed control


South Dakota State University Theses



Number of Pages



South Dakota State University