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Factors effecting the performance of metoxuron and chlortoluron in controlling blackgrass in winter wheat
Author(s) -
BANTING J. D.,
RICHARDSON W.G.,
HOLROYD J.
Publication year - 1976
Publication title -
weed research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.693
H-Index - 74
eISSN - 1365-3180
pISSN - 0043-1737
DOI - 10.1111/j.1365-3180.1976.tb00408.x
Subject(s) - loam , bioassay , leaching (pedology) , chemistry , horticulture , agronomy , soil water , biology , ecology
Summary: Blackgrass (Alopecurus myosuroides Huds.) was controlled by 2 kg/ha of metoxuron in glasshouse trials while winter wheat, cultivar Cappelle Desprez, tolerated 4 kg/ha. Blackgrass was controlled by 1.2 kg/ha of chlortoluron. Winter wheat previously damaged by freezing was injured by 2.5 kg/ha of chlortoluron applied at an early stage. Seedlings not exposed to freezing were not damaged by 2.5 kg/ha applied at the 4‐ and 5‐leaf stage. Breakdown of chlortoluron and metoxuron in the soil was attributed, in part, to microbial action. More than one‐third of the chlortoluron applied at 2 kg/ha disappeared in 6 weeks when applied in early spring while one half disappeared in 3 weeks when applied 2 months later. The bioassay, used to determine the amount of chlortoluron or metoxuron in the soil, was found to be adequate for metoxuron in only one of three soils. The bioassay results, for both herbicides, were affected by the addition of calcium carbonate to the soil, by sterilization of the soil, and by leaching. In comparisons of results in two sandy loams and a clay loam, the observed differences could not be altogether accounted for by differences in pH nor by changes in adsorption of metoxuron. When perennial ryegrass was grown in sandy loam, and treated with metoxuron before or after emergence, different watering regimes did not give any difference in weight of top growth.