title: Changes in soil chemical properties and microbial activities in response to the fungicide Ridomil Gold plus copper.
abstract: The purpose of the study was to investigate changes of soil chemical and biological properties changes resulting from a single application of the fungicide Ridomil Gold plus copper (Ridomil Gold plus)(mefenoxam 6% + copper oxide 60%) at the following rates 0.25, 0.5, 1, 2, and 10 g m(-2). Selected chemical properties generally differed between fungicide rates over longer incubation periods. Microbial activity indices (available N, ammonification rates and specific enzymatic systems) were more sensitive indicators of change. Values of these indicators generally increased with incubation period and decreased or increased at high rates. Significant changes in P availability occurred after 90 days of incubation at rates > or = 1 g m(-2). Incorporation of the fungicide significantly increased NH4+ levels in soil after 75 days of incubation. These changes stimulated soil microbial activity as evidenced by increased ammonification rates especially at long-term exposure. Of the enzyme activities studied, dehydrogenase and beta-glucosidase activities were the most sensitive to ridomil gold plus. This sensitivity was more pronounced with the dehydrogenase activity.
authors.affiliation: Laboratory of General Biology, Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde I, Republic of Cameroon.
authors.forename: Joseph
authors.initials: J
authors.lastname: Demanou
authors.forename: Adolphe
authors.initials: A
authors.lastname: Monkiéjé
authors.forename: Thomas
authors.initials: T
authors.lastname: Njin
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Foto
authors.forename: Moise
authors.initials: M
authors.lastname: Nola
authors.forename: Serges H Zebaze
authors.initials: SH
authors.lastname: Togouet
authors.forename: Norbert
authors.initials: N
authors.lastname: Kemka
mesh_terms: D000135:Acid Phosphatase; D000409:Alanine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D000469:Alkaline Phosphatase; D003300:Copper / Q000737:chemistry / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005659:Fungicides, Industrial / Q000737:chemistry / Q000494:pharmacology*; D009584:Nitrogen; D010088:Oxidoreductases; D010758:Phosphorus; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D013997:Time Factors; D001617:beta-Glucosidase
chemical_list: D005659:Fungicides, Industrial; D012987:Soil; D010758:Phosphorus; D003300:Copper; D010088:Oxidoreductases; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D001617:beta-Glucosidase; C473256:mefenoxam; D009584:Nitrogen; D000409:Alanine