A laboratory study of the mineralization and binding of 14C-labeled herbicide rimsulfuron in a rendzina soil.
The fate of pyrimidine-2-14C-rimsulfuron in a rendzina soil was investigated using a laboratory microcosm approach. Measurement of CO2 evolution suggested that rimsulfuron applied at 5 times the recommended dose did not affect soil respiration. Under abiotic conditions, no mineralization of 14C-rimsulfuron into 14C-CO2 occurred and under biotic ones it was very low reaching 0.75% of the applied 14C-rimsulfuron after 246 days of incubation. The analysis of data showed that a three-half order model provided the best fit for the mineralization curve. Extractable 14C-residues decreased over time to 70-80% of the applied 14C-rimsulfuron at the end of the incubation. After 246 days of incubation, non extractable residues (NER) accounted for up to 24.7% of the applied 14C-rimsulfuron and were distributed according to organic carbon in soil size fractions, suggesting a progressive incorporation process of NER to soil humus.
Metzger
L O
LO
CPB-CNRS, Vandoeuvre-les-Nancy, France.
Munier-Lamy
C
C
Belgy
M J
MJ
Andreux
F
F
Chone
T
T
Védy
J C
JC
D002250:Carbon Radioisotopes; D006540:Herbicides / Q000737:chemistry / Q000378:metabolism*; D008903:Minerals / Q000378:metabolism; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D014508:Urea / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism
D002250:Carbon Radioisotopes; D006540:Herbicides; D008903:Minerals; D012987:Soil; D012989:Soil Pollutants; C113968:DPX E9636; D014508:Urea