Weed control in barley (Hordeum vulgare) - no-till grain sorghum (Sorghum bicolor) production.

Field research to determine the influence of weed control systems in winter barley on subsequently notill-planted grain sorghum was conducted from 1985 to 1987 in northwest Georgia. Herbicide treatments applied to fully tillered winter barley included 2,4-D, dicamba, metribuzin, oryzalin, oryzalin plus metribuzin, fluorochloridone, or thiameturon. None of these herbicides affected barley grain yields compared to nontreated plots. Treatments containing oryzalin reduced johnsongrass fresh weights in the subsequently planted grain sorghum. Oryzalin plus metribuzin, in 1 of 2 yr, resulted in higher seed yields of subsequently planted grain sorghum compared to the other treatments except for oryzalin used alone. Treatments containing paraquat plus propazine plus metolachlor applied to grain sorghum provided good weed control when averaged across barley treatments and resulted in the highest grain sorghum yield. No grain sorghum injury from herbicides used in the previous winter barley crop was observed. Nomenclature: Dicamba, 3,6-dichloro-2-methoxybenzoic acid; fluorochloridone, 3-chloro 4 (chloromethyl) 1 [3 trifluoromethyl)phenyl] 2 pyrrolidinone; metribuzin, 4 amino 6 (1,1 dimethylethyl) 3 (methylthio) 1,2,4 triazin 5(4H)-one; oryzalin, 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide; thiameturon, 3-[[[[(4-methoxy-6-methyl1,3,5 triazin 2 yl)amino]carbonyl]amino]sulfonyl] 2-thiophenecarboxylic acid; 2,4-D, (2,4-dichlorophenoxy)acetic acid; paraquat, 1,1'-dimethyl-4,4'-bipyrid inium ion; propazine, 6-chloro-N,N'-bis (1-methylethyl)1,3,5-triazine-2,4-diamine; metolachlor, 2-chloro-N-(2ethyl 6 methylphenyl) N (2 methoxy 1 methylethyl)acetamide; barley, Hordeum vulgare L. 'Volbar'; grain sorghum, Sorghum bicolor (L.)Moench. 'Pioneer 8300'; johnsongrass, Sorghum halepense (L.)Pers. #3 SORHA. Additional index words: Conservation tillage, oryzalin, metribuzin, paraquat, thiameturon, propazine, metolachlor, dicamba, SORHA.