Abstract/Contents: | "The Conservetion Reserve Program (CRP) has enrolled 2 million acres of highly erodible cropland in Kansas to be converted to permanent vegatative cover. Over 91% of the acres are being planted to native grass mixtures. The herbicides currently being used for weed control will not control most annual grassy weeds. A study was designed to evaluate the tolerance of native grasses to selected row crop herbicides that could be or are being used for weed control in CRP native grass establishment. Big bluestem, bluegramagrass, buffalograss, Indiangrass, little bluestem, sand lovegrass, sideoats gramagrass, switchgrass, and western wheatgrass were the native grass species tested. The herbicide treatments selected were alachlor (1.12, 2.24, 3.36 kg/ha), Atrazine (0.56, 0.84, 1.12 kg/ha), chlorsulfuron (17.5,26.25,35 g/ha), metolachlor (1.12, 1.68, 2.24 kg/ha), metribuzin (0.28, 0.56, 0.84 kg/ha), metsulfuron methyl (4.375, 8.75 g/ha), SD-95481 ( 35, 52.5, 70, 87.5 g/ha), and no herbicide. Applications were made on either June 24 or July 21, 1987. Injury ratings were made 8-10 days after herbicide application using a scale of 1 (normal plant) to 10 (dead plant). Seedlings per 0.1 m2 were determined 45-60 days after application. The statistical design was a randomized complete block with three replications. Preliminary results show all the herbicides will cause some degree of leaf injury to the native grasses. Terbutryn, metribuzin, and alachlor caused significant leaf injury. All herbicides caused leaf injury to big bluestem, switchgrass, blue gramagrass and buffalograss. Metolachlor, SD-95481, metsulfuron methyl, terbutryn and alachlor reduced the final establishment of all grasses. Sand bluestem establishment was increased by all herbicides while Indiangrass, sideoats gramagrass and buffalograss had lower establishment with all herbicides. Atrazine and chlorsulfuron appear to be the most useful for weed control during the seeding year while metolachlor, SD-95481, metsulfuron methyl, terbutryn and alachlor appear to have the least value." |