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Forage Legume Response to Dicamba and 2,4‐D Applications1
Author(s) -
Griffin J. L.,
Watson V. H.,
Knight W. E.,
Cole A. W.
Publication year - 1984
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1984.00021962007600030029x
Subject(s) - dicamba , vicia villosa , trifolium subterraneum , red clover , agronomy , legume , tifton , trifolium repens , vicia sativa , loam , biology , cynodon dactylon , weed , forage , horticulture , cover crop , weed control , pasture , soil water , ecology
Weed control options in pastures containing legumes are limited due to herbicide selectivity. A field study was conducted for 2 years in northeast Mississippi on a Leeper fine sandy loam (fine, montmorillonitic, nonacid, thermic Vertic Haplaquept) soil to evaluate tolerance of subterranean ( Trifolium subterraneum L.), white ( T. repens L.), crimson ( T. incarnatum L.), red ( T. pratense L.), and arrowleaf ( T. vesiculosum Savi) clovers and vetch ( Vicia sativa L.) to dicamba (3,6‐dichloro‐ o ‐anisic acid), 2,4‐D [(2,4‐dichlorophenoxy) acetic acid], and a 3:l (W:W) mixture of 2,4‐D + dicamba. Stands of all clover species were generally reduced where dicamba at 0.56 kg ha −1 and where 2,4‐D + dicamba at 0.42 + 0.14 or 0.84 + 0.28 kg ha −1 were applied. Forty‐five days after herbicide application legume yields, with the exception of crimson clover, were reduced at least 24% when treated with dicamba. Yields of all clover species were severely reduced where 2,4‐D + dicamba was applied ranging from 50% for subterranean to 84% for red clover. Subterranean clover yield was not affected and white clover yield was only slightly reduced (28%) where 2,4‐D at 1.12 kg ha −1 was applied; yields of other clover species were markedly reduced. Vetch was killed with all herbicides applied. To determine residual activity, bermudagrass [ Cynodon dactylon (L.) Pers.] sod was treated with dicamba and 2,4‐D + dicamba 120, 90, 60, 30, and 15 days prior to overseeding crimson and white clover on 1 October. The study was conducted for 2 years on a Leeper fine sandy loam soil. Application time of dicamba at 0.28 kg ha ‐1 and 2,4‐D + dicamba at 0.42 + 0.14 kg ha −1 did not affect crimson or white clover yields measured in mid‐May. However, crimson and white clover yields were reduced an average of 39 and 55% where dicamba was applied at 0.56 and 1.12 kg ha −1 , respectively, and 37% when 2,4‐D + dicamba was applied at 1.68 + 0.56 kg ha −1 15 days prior to overseeding compared to 30 days. Selective broadleaf control can be obtained by using 2,4‐D at 1.12 kg ha −1 in pastures containing subterranean and white clover. Dicamba at 0.56 kg ha −1 or 2,4‐D + dicamba at 1.68 + 0.56 kg ha −1 should be applied to warm‐season grass pasture at least 30 days prior to overseeding in order to avoid residual activity on overseeded legumes.