Effect of concentration, sorption, and microbial biomass on degradation of the herbicide fluometuron in surface and subsurface soils

Mueller, Thomas C.; Moorman, Thomas B.; Snipes, Charles E.

doi:10.1021/jf00024a035

Cited by 60 publications

(56 citation statements)

References 23 publications

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Section: Kinetic Analysis¯uometuron Degradationcontrasting

confidence: 67%

“…The degradation constants observed in 0± 5 cm CT surface soils (0.060±0.075) in our studies are somewhat higher than those reported by others (0.010±0.037) under controlled conditions (Mueller et al, 1992;Brown et al, 1994). However, ®rst-order constants at the 10±25 cm depths of CT and NT soils were much lower than that reported for a 15±30 cm depth of a Beulah silt loam (Mueller et al, 1992). When degradation constants were calculated on a basis of¯uometuron concentration in solution,¯uo-meturon degradation proceeded more rapidly in the NT 0±2 cm soil depth than other depths (Table 5), as would be expected with the greater microbial biomass and activity.…”

Section: Kinetic Analysis¯uometuron Degradationcontrasting

confidence: 67%

“…Concentrations of¯uometuron (up to 20 mg l À1 ) and its major metabolite, desmethyl¯uometuron (up to 5 mg l À1 ) have been detected in Mississippi Delta surface waters (Zablotowicz et al, 2000). Mueller et al (1992) showed that¯uometuron was more readily degraded in the surface of a Mississippi Delta soil (Beulah silt loam) with decreasing degradation rates at lower soil depths that correlated with reduced microbial biomass. The interactions of a hairy vetch cover crop and tillage on¯uometuron degradation were assessed by Brown et al (1994Brown et al ( , 1996.…”

Section: Introductionmentioning

confidence: 98%

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Interactions of tillage and soil depth on fluometuron degradation in a Dundee silt loam soil

Zablotowicz¹,

Locke²,

Gaston³

et al. 2000

Soil and Tillage Research

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Fluometuron (N,N-dimethyl-NH -[3-(tri¯uoromethyl)phenyl]urea) is the most widely used soil applied herbicide in cotton (Gossypium hirsutum) production in the Southeastern United States. Thus, there is a need to understand the persistence of this herbicide under various crop management systems in regards to both herbicide ef®ciency and environmental fate. The effects of long-term no-tillage practices on¯uometuron degradation were studied in a Dundee silt loam under laboratory conditions. Soil was collected at four depths (0±2, 2±5, 5±10, and 10±25 cm) from ®eld plots following 11 years of continuous no-tillage (NT) or conventional tillage (CT). Organic carbon content, microbial biomass, and¯uorescein diacetate (FDA)-hydrolytic activity were 48, 106, and 127% greater, respectively, in the upper 2 cm of NT soil compared to CT soil. Microbial biomass and FDA-hydrolytic activity were 39±66 and 34±99% greater in the CT compared to NT soil, respectively, in the 2±5 and 5± 10 cm depths. Fluometuron degradation was assessed under laboratory conditions using 14 C-ring labeled¯uometuron. Fluometuron was degraded more rapidly at depths between 0 and 10 cm of the CT soil relative to the NT soil. Fluometuron degradation was described as ®rst-order (k 0X0754, 0.0608, 0.0273, and 0.0074 per day in the 0±2, 2±5, 5±10, and 10±25 cm depths of CT soils compared to 0.035, 0.0368, 0.0145, and 0.0138 per day in respective depths of NT soil). Although the surface 0±2 cm of the NT soil had greater microbial activity and biomass, higher¯uometuron sorption in the surface 0±2 cm NT soil compared to CT (Freundlich coef®cient K f NT 7X12 versus CT 1X88) reduced¯uometuron solution concentration in NT soil and may have impeded degradation. Interactions between soil biological activity and¯uometuron soil solution concentrations, mediated by sorption, may determine the potential for¯uometuron degradation in soils under long-term NT practices. Published by Elsevier Science B.V.

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Section: Kinetic Analysis¯uometuron Degradationcontrasting

confidence: 67%

Section: Kinetic Analysis¯uometuron Degradationcontrasting

confidence: 67%

Section: Introductionmentioning

confidence: 98%

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Interactions of tillage and soil depth on fluometuron degradation in a Dundee silt loam soil

Zablotowicz¹,

Locke²,

Gaston³

et al. 2000

Soil and Tillage Research

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“…Fluometuron easily leaches from soils. As was the case with atrazine, adsorption coefficients for fluometuron are strongly correlated with soil organic content (21, 29). One field study found that adsorption of fluometuron in the field was a function of depth, tillage practice, and cover crop (10).…”

Section: Migration Through Soilmentioning

confidence: 98%

“…Compared with organic matter and clay, sand and silt have minimal CEC. Numerous studies have shown that movement of organic herbicides through soil is dominated by the organic content of the soil (28)(29)(30).…”

Section: Migration Through Soilmentioning

confidence: 99%

Degradation of Persistent Herbicides in Riparian Wetlands

Stoeckel¹,

Mudd²,

Entry³

1997

Phytoremediation of Soil and Water Contaminants

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Rate of bentazone transformation in four layers of a humic sandy soil profile with fluctuating water table

Leistra¹,

Smelt²,

Matser³

et al. 2001

Pest Management Science

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The rate of transformation of a pesticide as a function of the depth in the soil is needed as an input into computations on the risk of residues leaching to groundwater. The herbicide bentazone was incubated at 15 degrees C in soil materials derived from four layers at depths of up to 2.5 m in a humic sandy soil profile with a fluctuating water table (0.8 to 1.4 m), while simulating the redox conditions existing in the field. Gamma-irradiation experiments indicated that bentazone is mainly transformed by microbial activity in the soil. The rate constant for transformation was highest in the humic sandy top layer; it decreased with depth in the sandy vadose subsoil. However, material from the top of the phreatic aquifer had a higher rate constant than that from the layers just above. The presence of fossil organic material in the fluviatile water-saturated sediment probably stimulated microbial activity and bentazone transformation. The changes in the transformation rate constant with depth showed the same trend as those in some soil factors, viz organic carbon content, water-extractable phosphorus and microbial density as measured by fluorescence counts. However, the (low) concentration of dissolved organic carbon (DOC) in the top of the aquifer did not fit the trend. The rate constant for bentazone transformation in the layers was higher at lower initial contents of the herbicide.

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Effect of concentration, sorption, and microbial biomass on degradation of the herbicide fluometuron in surface and subsurface soils

Cited by 60 publications

References 23 publications

Interactions of tillage and soil depth on fluometuron degradation in a Dundee silt loam soil

Interactions of tillage and soil depth on fluometuron degradation in a Dundee silt loam soil

Degradation of Persistent Herbicides in Riparian Wetlands

Rate of bentazone transformation in four layers of a humic sandy soil profile with fluctuating water table

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