Title: 24th WEDC Conference Sanitation and Water for All

Title: Weed Research

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: Impact Factor

Burns, I.G., Hayes, M.H.B. and Stacey, M. (1973), Some physico-chemical interactions of paraquat with soil organic materials and model compounds. II. Adsorption and desorption equilibria in aqueous suspensions. Weed Research, 13, 79-90.

Beltran, E., Fenet, H., Cooper, J.F. and Coste, C.M. (2002), Influence of the physical and chemical properties of soil on the retention process of isoxaflutole and its two main derivatives. Weed Research, 42 (5), 385-393.

Full Text: W\Wee Res42, 385.pdf

Abstract: Isoxaflutole is a new pre-emergence herbicide for use in maize and sugarcane. Its two main derivatives are a diketonitrile derivative, the 2-cyano-3-cyclopropyl-1-(2-methanesulfonyl-4-trifluoromethylphenyl)propan-1,3-dione, named DKN, and a benzoic acid derivative, the 2-methanesulfonyl-4-trifluoromethylbenzoic acid, named BA. The adsorption/desorption processes have never been studied for isoxaflutole (IFT) at high concentrations nor for BA, and the present work aimed at completing the knowledge of the behaviour of these three molecules in conditions close to those encountered in the context of agricultural use. The adsorption/desorption study was conducted on seven soils of different physical and chemical properties, using the batch equilibrium technique. During the experiments, IFT was chemically converted into DKN in a continuous manner. This reaction appeared to be dependent on the pH of the soil and was taken into account in the calculations of the adsorbed and desorbed amounts. The adsorption isotherms obtained were predominantly C-shaped for IFT and DKN and S-shaped for BA, but some differences appeared on a few soils. They fitted well the Freundlich equation, and the values of the Freundlich coefficient K_fa showed that, whatever the soil, IFT was more adsorbed than its two derivatives. The main parameter influencing the adsorption of IFT appeared to be the organic matter content, whereas this effect was not evident for DKN and BA. No correlation was found between the extent of adsorption and either clay content or pH of the soil, for the three molecules.

Khoury, R., Geahchan, A., Coste, C.M., Cooper, J.F. and Bobe, A. (2003), Retention and degradation of metribuzin in sandy loam and clay soils of Lebanon. Weed Research, 43 (4), 252-259.

Full Text: W\Wee Res43, 252.pdf

Abstract: The retention and degradation of metribuzin herbicide were studied under two environmental conditions. Field studies were carried out on two soils, a sandy loam soil (soil A)^-1 a clay soil (soil B). Metribuzin was applied with a jet sprayer at 1060 g a.i. ha^-1 and 1960 g a.i. ha^-1 on soils A and B respectively. Reconstituted soil columns were used to study the herbicide movement and metabolism in the two soils. Analyses of metribuzin and its metabolites were carried out using standardized methods. The results indicated a very weak capacity of adsorption of metribuzin in the two soils, and the weak adsorbed fraction is easily desorbed. Degradation and mobility of metribuzin in the field and laboratory soil columns were very intense and rapid. Soil A favoured reductive deamination whereas soil B favoured oxidative desulphuration and the respective metabolites deaminometribuzin and diketometribuzin yield the same product deaminodiketometribuzin. Both leaching by rainfall and degradation were important in the disappearance of metribuzin from the soils.

Keywords: Herbicide, Metribuzin, Mobility, Adsorption-Desorption, Metabolism, Soils, Degradation, Mobility, Atrazine, Adsorption, Rates, Fate, Metazachlor, Persistence, Dissipation, Herbicides, Metamitron

Title: Weed Science

ISO Abbreviated Title: Weed Sci.

JCR Abbreviated Title: Weed Sci

ISSN: 0043-1745

Issues/Year: 6

Journal Country/Territory: United States

Language: English

Publisher: Weed Sci Soc Amer

Publisher Address: 810 East 10th St, Lawrence, KS 66044-8897

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Agriculture Plant Sciences: Impact Factor

Schroeder, J. (1994), Chlorimuron and imazaquin persistence in selected southern soils under controlled conditions. Weed Science, 42 (4), 635-640.

Full Text: 1994\Wee Sci42, 635.pdf

Abstract: Growth chamber research was conducted to compare the persistence of chlorimuron or imazaquin in soils from 11 locations in the southern United States at 25°C. Chlorimuron at 30 ngg^-1 or imazaquin at 60 ngg^-1 of soil was incorporated throughout each soil and soils were watered to the water holding capacity and incubated in the dark. Soil samples were taken 0, 7, 14, 28, 60 and 90 d after treatment. Amount of chlorimuron or imazaquin remaining in each soil was quantified by sicklepod or corn root length bioassay, respectively. First order regression generally fit the concentration data for each herbicide. Bioactivity and persistence of chlorimuron in the soils was related primarily to soil organic matter content. Bioactivity and persistence of imazaquin was similar among the soils. Nomenclature: Chlorimuron, 2-[[[[ (4-chloro-6-methoxy-2-pyrimidinyl)amino] carbonyl] amino] sulfonyl] benzoic acid, imazaquin, 2-[4, 5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid, sicklepod, Cassia obtusifolia L.#3 CASOB, corn, Zea mays L. ‘Pioneer 3369A.