P. Perucci et al., Rimsulfuron in a silty clay loam soil: effects upon microbiological and biochemical properties under varying microcosm conditions, SOIL BIOL B, 31(2), 1999, pp. 195-204
The effects of rimsulfuron, a sulfonylurea herbicide, on the growth and act
ivity of soil microbial biomass have been investigated, under laboratory co
nditions, at varying conditions of temperature and humidity in a silty clay
loam soil. Rimsulfuron was incorporated at the recommended field dose for
maize weed control (25 g a.i. ha(-1)) and at 10-fold and 100-fold higher co
ncentrations. No adverse effects on microbiological processes were observed
at the field dose. Decreases in the microbial biomass-C content, ATP conte
nts and dehydrogenase activity, and increases in the global hydrolytic capa
city, catalase and nitrogenase activity, in comparison with the untreated s
oil control, were found at the higher dosages. The onset and magnitude of t
hese effects were dependent on temperature and humidity conditions, however
, they were generally slight and transitory, These findings are discussed i
n terms of rimsulfuron toxicity to the soil microbial biomass and any conse
quent release of endocellular enzymes from the dead micro-organisms, (C) 19
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