Transformation and mineralization of metribuzin in surface and subsurface horizons of a Mississippi Delta soil

Journal Article · · Journal of Environmental Quality; (USA)

DOI:https://doi.org/10.2134/jeq1989.00472425001800030011x· OSTI ID:7166506

Moorman, T B; Harper, S S ^[1]

---

1. Agricultural Research Service, Stoneville, MS (USA)

The rates of degradation and mineralization of metribuzin (4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5(4H)-one) were determined in the surface and subsurface horizons of a Dundee silty clay loam soil (Aeric Ochraqualf) from the Mississippi Delta. Residual metribuzin and metabolites were measured by HPLC or TLC methods during or after 91-d incubations of treated soil in the laboratory. Metribuzin degradation was faster in the surface soil than in the subsurface soils. Degradation in the surface and the subsurface horizons were not described by first-order kinetics. Degradation was a second-order process in the surface soil, but only a half-order process in the subsurface horizons. Considerably more mineralization of {sup 14}C-metribuzin occurred in the surface (0- to 10-cm depth) soil, with 15 to 20% evolved as {sup 14}CO{sub 2} after 91 d, vs. 5% from the subsurface soils. Substantial amounts of {sup 14}C-bound residues were formed in both surface and subsurface horizons. Reduced microbial populations and activity corresponded to the reduced degradation of metribuzin in the subsoils.

• OSTI ID: 7166506
• Journal Information: Journal of Environmental Quality; (USA), Journal Name: Journal of Environmental Quality; (USA) Vol. 18:3; ISSN JEVQA; ISSN 0047-2425
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540211* -- Environment
Terrestrial-- Basic Studies-- Radiometric Techniques-- (1990-)
BIODEGRADATION
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
DECOMPOSITION
FEDERAL REGION IV
HERBICIDES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
METABOLITES
MINERALIZATION
MISSISSIPPI
NORTH AMERICA
OXIDES
OXYGEN COMPOUNDS
PESTICIDES
SOILS
TRACER TECHNIQUES
USA