We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Measurement and simulation of the movement of thiazafluron, clopyralid and metamitron in soil columns.
- Authors
Cox, L.; Walker, A.; Hermosin, M. C.; Cornejo, J.
- Abstract
Adsorption and leaching of the herbicides thiazafluron (1,3-dimethyl-1(5-trifluoromethyl-3,4-thiadiazol-2-yl)urea), metamitron (4-amino-4,5-dihydro-3-methyl-6-phenyl-1,2,4-triazin-5-one) and clopyralid (3,6-dichloropicolinic acid) were studied in one sandy and two silty-clay soils. Equilibrium adsorption coefficients (Kd) were measured using a batch equilibration procedure, and mobility was studied in repacked columns of the soils under fluctuating saturated/ unsaturated flow conditions. Breakthrough curves (BTCs) were consistent with an inverse relationship between leaching and adsorption with greater mobility of the weakly-adsorbed clopyralid than the more strongly adsorbed thiazafluron or metamitron. The BTC data were used to evaluate the LEACHP simulation model. Following model calibration with respect to hydrological parameters and some of the herbicide degradation rates, the best fits between predicted and observed data were with the less adsorptive and highly mobile clopyralid. In general, the model gave acceptable predictions of the timing of the concentration maxima and the shapes of the BTCs, although earlier breakthrough than that observed was predicted with the less mobile herbicides, thiazafluron and metamitron, in the silty-clay soils. For metamitron, the total amounts leached were not predicted accurately, suggesting more rapid degradation of the herbicide in the soil columns than in the kinetic studies performed in a 1:1 soil:solution ratio shaken system.
- Subjects
HERBICIDES; WEED control; SOIL absorption &; adsorption; SOIL leaching; HERBICIDE content of soils; SOIL testing
- Publication
Weed Research, 1996, Vol 36, Issue 5, p419
- ISSN
0043-1737
- Publication type
Article
- DOI
10.1111/j.1365-3180.1996.tb01671.x