Herbicidal Enhancement of Dallisgrass Establishment1
- G. W. Evers2
Dallisgrass (Paspalum dilatatum Poir.), a desirable subtropical pasture grass, is difficult to establish because of its slow germination and seedling growth compared to annual weeds. Herbicides were evaluated for weed control and phytotoxicity to dallisgrass planted on a prapared seedbed each spring for 3 years by determining seedling density and forage production. All herbicides were applied in 154 liters of water/ha with a CO2 pressurized sprayer. Herbicides used were dicamba [3,6-dichloro-O-anisic acid], paraquat [l,1′-dimethyl-4,4′-bipyridinium ion], tebuthiuron [N-(5-(l,l-dimethylethyl)-l, 3,4-thiadiazol-2-yl)-N,N′-dimethylurea], diuron [3-(3,4-dichlorophenyl)-l,l-dimethylurea], simarine [2-chloro-4,6-bis (ethylamino)-s-triazine], bromacil [5-bromo-3-sec-butyl-6-methyluracil], glyphosate [N-(phosphonomethyl)glycine], hexazinone [3-cyclohexyl-6-(dimethylamino)-l-methyl-l,3,5-triazine-2,4(lH,3H)-dione], and metribuzin [4-amino-6-tert-(-butyl-3-(methylthio)-as-triazn-5(4H-one].
Dallisgrass production was increased 3, 30, and 8 fold for 1977, 1978, and 1979 respectively, by the best herbicide treatments. The most effective treatments were 1.1 kg/ha tebuthiuron; 0.6, 0.8, and 1.1 kg/ha metribuzin; and 2.2 kg/ha diuron. Lower rates of diuron failed to provide effective weed control. Tebuthiuron applied at 2.2 and 4.4 kg/ha resulted in some phytotoxicity to dallisgrass seedlings. Simazine increased seedling density and yield 2 out of 3 years when applied at 2.2 kg/ha but was ineffective at 1.1 kg/ha. The other herbicides failed to significantly increase seedling density or forage production.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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