Bioavailability of diuron, imazapic and isoxaflutole in soils of contrasting textures.

Miriam H Inoue, Rubem S Oliveira, Jamil Constantin, Diego G Alonso, Cássio A Tormena

Department of Agronomy, State University of Mato Grosso, Tangará da Serra, Brazil.

Journal of environmental science and health. Part. B, Pesticides, food contaminants, and agricultural wastes 2009 Nov

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This research was aimed at understanding the dynamics of the herbicides diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], imazapic [2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)-5-methylnicotinic acid] and isoxaflutole [5-cyclopropyl-4-(2-methanesulfonyl-4-trifluoromethyl benzoyl)isoxazole] in two soils of different physico-chemical properties. To accomplish such intent, several greenhouse experiments were run. The bioavailability of diuron (0; 1.6 and 3.2 kg ha(-1)), imazapic (0; 98 and 122.5 g ha(-1)) and isoxaflutole (0; 35 and 70 g ha(-1)) was measured in samples from a sandy loam soil and a clay soil, by sowing a bioindicator (Brachiaria decumbens), at 0, 25, 50, 75 and 100 days after herbicides application (DAA). Diuron was very stable in clay soil, providing control equal to or higher than 92% of bioindicator, up to 100 DAA, as assumed by biomass accumulation. No differential effect was observed in sandy loam soil, even when 2x labeled rate were applied. Imazapic provided a short bioavailability in relation to B. decumbens, independent of rates applied. The persistence of isoxaflutole was longer in clay soil (28 to 30 days).

Citation

Miriam H Inoue, Rubem S Oliveira, Jamil Constantin, Diego G Alonso, Cássio A Tormena. Bioavailability of diuron, imazapic and isoxaflutole in soils of contrasting textures. Journal of environmental science and health. Part. B, Pesticides, food contaminants, and agricultural wastes. 2009 Nov;44(8):757-63