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Leaching and transformation of glufosinate‐ammonium and its main metabolite in a layered soil column
Author(s) -
Behrendt H.,
Matthies M.,
Gildemeister H.,
Görlitz G.
Publication year - 1990
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620090502
Subject(s) - ammonium , glufosinate , leaching (pedology) , sorption , loam , metabolite , chemistry , environmental chemistry , nitrification , soil water , nitrogen , soil science , agronomy , environmental science , adsorption , biology , organic chemistry , glyphosate , biochemistry
Results from a long‐term study on leaching and transformation of the herbicide glufosinate‐ammonium (ammonium‐DL‐homoanalin‐4‐yl (methyl)phosphinate) in a layered soil column were compared with model calculations. Soil columns with layers of loamy sand and sand were treated with 3 kg/ha glufosinate‐ammonium, applied to the soil surface. The soils were irrigated and the leachate was monitored for glufosinate‐ammonium and the main metabolite 3‐methylphosphinico‐propionic acid during a period of 256 d. Calculations for glufosinate‐ammonium and the metabolite were performed with the soil column model EXSOL. Linear equilibrium sorption coefficients ( K d ) and first‐order half‐lives were used for fitting effluent curves for both the herbicide and the metabolite. Sorption coefficients were compared with those values estimated from a relation to the clay content derived from batch studies. Fitted half‐lives were compared with the results from die‐away and 14 CO 2 evolution studies of both the parent and the daughter compound. The observed leaching of glufosinate‐ammonium could be well simulated using K d (0.5 cm 3 /g) and half‐life (11.2 d). The half‐life fitted for the metabolite (10–30 d) was a factor 2 to 3 smaller than that measured with batch degradation experiments. This may be the result of using degradation data estimated by 14 CO 2 evolution, which only indirectly indicates the disappearance of the compound.