Johnsongrass (Sorghum halepense) Management Systems

Crop-herbicide systems for johnsongrass [ Sorghum halepense (L.) Pers. # SORHA] control were compared in a 5-yr study at two locations in central Ohio. Monocultures of corn ( Zea mays L.) and soybeans [ Glycine max (L.) Merr.] were compared with a 3-yr rotation of corn, soybeans, and winter wheat ( Triticum aestivum L.). Johnsongrass was controlled most effectively (over 95%) when glyphosate [ N -(phosphonomethyl) glycine] was applied to emerged johnsongrass, followed by moldboard plowing, preplant incorporated (PPI) application of trifluralin [2,6-dinitro- N,N -dipropyl-4-(trifluoromethyl)benzenamine], then soybean planting (MS-G-T). The second best control was in corn (over 90%) treated PPI with EPTC ( S -ethyl dipropylcarbamothioate) in the rotation (RC-E). Johnsongrass control was least in monocultured corn treated PPI with EPTC (MC-E) and in monocultured soybeans treated PPI with trifluralin (MS-T).