title: Effect of monocrotophos and quinalphos on soil population and nitrogen-fixing activity of Azospirillum sp.
abstract: The effects of monocrotophos and quinalphos on population and nitrogen-fixing activity of Azospirillum sp. in four agricultural soils were determined in a laboratory study. Concentrations of the two insecticides up to a 5 kg ha-1 level were either stimulatory or innocuous to the population of Azospirillum in the soils. Four successive applications of the insecticides to soils resulted in a significant increase in the population density. Cultures of Azospirillum sp., isolated from insecticide-treated soils, exhibited greater nitrogen-fixing activity. Three consecutive subculturings of the isolates from insecticide-treated soils had no effect on their nitrogen-fixing activity.
authors.affiliation: Department of Microbiology, Sri Krishnadevaraya University, Anantapur, India.
authors.forename: V
authors.initials: V
authors.lastname: Rangaswamy
authors.forename: P B
authors.initials: PB
authors.lastname: Charyulu
authors.forename: K
authors.initials: K
authors.lastname: Venkateswarlu
mesh_terms: D001419:Bacteria / Q000187:drug effects*; D007306:Insecticides / Q000633:toxicity*; D008999:Monocrotophos / Q000633:toxicity*; D009586:Nitrogen Fixation / Q000187:drug effects*; D009946:Organothiophosphorus Compounds / Q000633:toxicity*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000633:toxicity*
chemical_list: D007306:Insecticides; D009946:Organothiophosphorus Compounds; D012989:Soil Pollutants; C009145:quinalphos; D008999:Monocrotophos