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Herbicide Efficacy for Various Application Times in Doublecrop Wheat and Soybean
Author(s) -
Higgins Jeffery M.,
Whitwell Ted,
Toler Joe E.
Publication year - 1988
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/agronj1988.00021962008000030017x
Subject(s) - oryzalin , pendimethalin , agronomy , loam , weed control , sowing , panicum , acetochlor , weed , biology , poaceae , tillage , pesticide , soil water , microtubule , ecology , microbiology and biotechnology
Effective weed management is essential in reduced tillage doublecrop wheat ( Triticum aestivum L.) and soybean [ Glycine max Merr.] production. Field experiments were conducted on a Hartsells fine sandy loam soil (fine loamy, silaceous, thermic Typic Hapludalfs) near Crossville, AL, from 1981 to 1983 to determine the influence of application time on herbicidal efficacy of oryzalin [4‐(dipropylamino)‐3,5‐dinitrobenzenesulfonamide], pendimethalin [ N ‐(1‐ethylpropyl)‐3,4‐dimethyl‐2,6‐dinitrobenzenamine], and oryzalin + 2,4‐D [(2,4‐dichlorophenoxy)acetic acid] for weed control. Herbicides were applied early preplant (EP) to fully tillered wheat, and preemergence (PRE) at soybean planting. Paraquat (1,1'‐dimethyl‐4,4'‐bipyridinium ion) was applied separately at 0.3 kg ha −1 at the time of PRE applications to ail plots that received other herbicide applications (EP or PRE) and alone as a check treatment. Early preplant treatments did not reduce wheat seed yields in 2 of 3 yr compared to the untreated control. Fall panicum ( Panicum dichotomiflorum Michx.) and prickly sida ( Sida spinosa L.) control were similar with EP and PRE applications of all herbicides. Fall panicum control ranged from 63 to 100%, and prickly sida control from 20 to 87%. Early preplant applications provided greater Pennsylvania smartweed ( Polygonum pensylvanicum L.) control than PRE applications. Pennsylvania smartweed control was 5 to 70% greater with EP applications compared to PRE applications. Preemergence applications of oryzalin + 2,4‐D produced moderate (20%) soybean injury in 1982 and 1983. Soybean seed yields were similar with EP and PRE applications in 1981 and 1982; however, seed yields were from 26 to 103% greater with EP applications than PRE applications in 1983.