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|Title:||Soil Persistence and Sorption Characteristics of Imazaquin, Imazethapyr, and Clomazone|
|Author(s):||Loux, Mark Monroe|
|Doctoral Committee Chair(s):||Slife, Fred W.|
|Department / Program:||Agronomy|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The soybean herbicides imazaquin (2- (4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl) -3-quinolinecarboxylic acid), imazethapyr (2- (4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl) -5-ethyl-3-pyridinecarboxylic acid), and clomazone (2-(2-chlorophenyl)methyl-4,4-dimethyl-3-isoxazolidinone) persist in some soils for periods of time sufficient to injure crops grown in rotation with soybeans (Glycine max L.). The relationship between soil type and sorption of these herbicides to soil colloids, one determinant of persistence, has not been documented. Field studies were conducted to characterize herbicide persistence and bioavailability in two soils differing greatly in sorption capacity. Laboratory studies were conducted to determine the influence of specific soil properties on herbicide sorption.
In field experiments, all three herbicides were more persistent in a Drummer silty clay loam with 5.8% organic matter than in a Cisne silt loam with 1.4% organic matter. Bioavailability was greater in the Cisne soil than in the Drummer soil. The potential for herbicide carryover and injury to crops grown in rotation with soybeans appears to be greater in soils with a high capacity for herbicide sorption.
In laboratory studies, sorption of clomazone on soils and sediments was correlated with organic carbon content. Clomazone had a strong affinity for pure clays, but soil clay content influenced sorption only when soil organic carbon content was low. Sorption on soil was attributed to hydrophobic bonding.
Multiple regression analysis of imazaquin sorption and soil properties showed soil pH, organic carbon, and clay content to determine the extent of sorption. Sorption of imazethapyr was influenced by soil pH and clay content. Mechanisms responsible for imazaquin and imazethapyr sorption appear to be typical of those for other acidic herbicides.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988.
|Date Available in IDEALS:||2014-12-16|