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Tebuthiuron Distribution in Soil following Application of Pellets
Author(s) -
Whisenant Steven G.,
Clary Warren P.
Publication year - 1987
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1987.00472425001600040018x
Subject(s) - loam , agronomy , soil water , chemistry , zoology , environmental science , biology , soil science
Persistence, activity, and distribution of tebuthiuron { N ‐[5‐(1,1 dimethylethyl)‐1,3,4‐thiadiazol‐2‐yl]‐ N,N ′‐dimethylurea} in two soils were studied following application of 40% active ingredients (a.i.) extruded pellets. Tebuthiuron dissipation from the surface 3 cm and within 2 cm of the point of pellet placement was best explained by the nonlinear regression equation: Y = bX a , where Y is the tebuthiuron concentration in milligrams per kilogram, b is 7.05 × 10 6 , X is time (d) after pellet placement, and a is −2.272 ( r 2 = 0.97). Applications of 40% tebuthiuron pellets at 0.6 or 1.1 kg ha −1 left a detectable residue on 9 to 21 and 17 to 38% of the treated areas, respectively. The lower percentages were on a loam soil with 47 g kg −1 soil organic carbon (OC) content and the higher percentages were on loam soils with 17 and 18 g kg −1 OC. Crested wheatgrass [ Agropyron cristatum (L.) Gaertn.] seedling growth was reduced 50% (GR 50 ) by tebuthiuron concentrations of 0.04 to 0.20 mg kg −1 , depending on soil OC content. Two years after application of 0.6 kg ha −1 , 40% tebuthiuron pellets to a big sagebrush ( Artemisia tridentata Nutt.) community, with a loam soil that had a 30% shrub cover (17 g kg −1 OC in interspaces and 48 g kg −1 OC under former shrub canopies), <20% of the surface soil contained the crested wheatgrass GR 50 .