Factors Influencing Microbial Degradation of¹⁴C-Glyphosate to¹⁴CO₂in Soil

Abstract

14C-glyphosate [N-(phosphonomethyl)glycine] degradation to14CO2was examined in a Spinks sandy loam, Collamer silt loam, and a Norfolk loamy sand. After 32 days, 40, 9.5, and 3% of the14C-glyphosate was recovered as14CO2in the three soils, respectively. The degradation was primarily microbial. Phosphate additions stimulated14C-glyphosate degradation to a limited extent in the Collamer silt loam but not in the Norfolk loamy sand. Additions of Fe+++and Al+++ions reduced degradation in the Spinks sandy loam. It is postulated that formation of colloidal Fe and Al precipitates in modified soils with concomitant adsorption of14C-glyphosate is responsible for decreased availability of14C-glyphosate to microorganisms. Mn++additions were found to increase degradation. Spinks soil and carbon substrate amendments failed to substantially increase degradation rates in both soils with low degradation rates.

Respiração microbiana do solo sob doses de glyphosate e de imazapyr

“…Normalmente, é observada uma taxa de decomposição inicialmente rápida, seguida por prolongada e lenta decomposição (Moshier & Penner, 1978). Esse comportamento reflete a facilidade com que a molécula é metabolizada pela microbiota do solo (Torstensson & Aamisepp, 1977;Dick & Quinn, 1995).…”

Herbicide Sulcotrione

“…Sandy loam and clay has the strongest adsorption capacity for sulcotrione, followed by sandy clay and sandy soil. After adsorption by soil, sulcotrione is gradually released and does not disappear easily [17]. The sulcotrione soil residual level is affected by many factors.…”

Mineralization and sorption of 14C-glyphosate in samples from three soil types collected in El Espinal, Colombia

“…Rice Forest Grass (1977) and Moshier & Penner (1978) found that 28 days were required to degrade 45% to 48% of the original glyphosate in the soil.…”