Organic matter and parathion degradation in flooded soil

The effect of rice straw on parathion degradation in a flooded alluvial soil was investigated. In soils inoculated with an enrichment culture which exhibited an exceptionally high ability to hydrolyze parathion, rice straw amendments inhibited parathion hydrolysis to p-nitrophenol and diethyl thiophosphoric acid. On the other hand, in uninoculated soils, rice straw enhanced the degradation of parathion via nitro reduction. During the enhanced breakdown of parathion in uninoculated soils amended with rice straw, aminoparathion and an unidentified metabolite evidently possessing a P=S bond were detected. Thus, the influence of organic matter on the persistence of parathion in flooded soil is governed by the metabolic pathway involved in the degradation

Foliar sprays of growth regulators and rhizosphere effect in Cajanus cajan Millsp. I. Quantitative changes

Foliar sprays of growth regulators brought forth attendant changes in the rhizosphere of pigeon pea (Cajanus cajan Millsp.). Sprays of NAA boosted up fungi in the rhizosphere, regardless of its concentration and age of the plants. Significant increases in bacterial numbers were recorded in the rhizosphere of 2,4-D-treated plants and this effect was again independent of the concentration employed and the age levels. Gibberellin and MH sprays generally lowered microbial numbers in the rhizosphere. Reductions in microbial numbers with MH sprays were not necessarily apparent when combined with other growth regulators

Effects of HCH, carbaryl, benomyl, and atrazine on the dehydrogenase activity in a flooded soil

This article does not have an abstract

Inhibition of heterotrophic and autotrophic nitrification in bacterial cultures by carbaryl and 1-naphthol

A carbamate insecticide, carbaryl, and its hydrolysis product, 1-naphthol, inhibited nitrification by a heterotrophic bacterium, a Pseudomonas sp., at a concentration of 50 µg/ml and by chemoautotrophic bacteria, a Nitrosomonas sp. and a Nitrobacter sp., at a concentration of 10 µg/ml, in pure cultures

Degradation of carbofuran by Azospirillum lipoferum and Streptomyces spp. isolated from flooded alluvial soil

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Stimulation of Autotrophic Ammonium Oxidation in Rice Rhizosphere Soil by the Insecticide Carbofuran

The application of the insecticide carbofuran (technical or formulated) to rice rhizosphere soil suspensions at 10 and 100 ppm (μg/ml) of active ingredient distinctly stimulated the autotrophic oxidation of ammonium. Evidence suggested that Nitrosomonas sp. was enriched in the presence of carbofuran. Formulated carbofuran (Furadan 3G) exhibited a more pronounced stimulation of ammonium oxidation than that exhibited by technical-grade (99.5%) carbofuran, a result which was attributed to the CaCO(3) present in the formulation