Influence of 2,4-D, Pronamide, and Simazine on Dry Matter Production and Botanical Composition of an Alfalfa-grass Sward1
- G. B. Triplett,
- R. W. Van Keuren and
- J. D. Walker2
Pronamide [3,5-dichloro (N-l,l-dimethyl-2-propynyl)-benzamide], simazine [2-chloro-4,6-bis(ethylamino)-s-triazine], and 2,4-D [(2,4-dichlorophenoxy)acetic acid] were evaluated for management of species composition in established swards of alfalfa (Medicago sativa L.) which had become colonized by orchardgrass (Dactylis glomerata L.), Kentucky bluegrass (Poa pratensis L.), and dandelion (Taraxicum officinale Weber). Dormant application of 2,4-D ester reduced s~edling dandelions, but did not affect mature dandelions, alfalfa stands, or yields. Simazine did not affect total yield or botanical composition of forage in this study. Pronamide application reduced bluegrass and total forage yield in the first harvest. The alfalfa component of the forage and total yield of alfalfa increased with pronamide treatments. Total forage yield for the season was the same for all treatments.
Counts of alfalfa plants per m2 were made for individual plots and multiple regression analysis was used to determine the association of percent alfalfa composition of the first harvest and plant density with alfalfa yield. In pronamide treated plots as few as 10 to 20 alfalfa plants per m~ utilized resources made available by reduction of other species and produced acceptable yields. These results contrast to the 50 to 60 plants per m2 commonly considered necessary for productive stands and suggest the possibility that herbicides may be used to extend the productive life of swards containing alfalfa.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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