Inhibition of biological hydrolysis of parathion in rice straw‐amended flooded soil and its reversal by nitrogen compounds and aerobic conditions

Abstract

Abstract The effect of nitrogen compounds and moisture regimes on the inhibition of the biological hydrolysis of parathion in rice straw‐amended soil under flooded conditions was studied. Single applications of rice straw, potassium nitrate or ammonium sulphate to the flooded soil, inoculated with parathion‐hydrolysing enrichment culture, inhibited the hydrolysis of the insecticide; the inhibition was reversed, however, in combined applications of rice straw with potassium nitrate or with ammonium sulphate. Aqueous extracts of rice straw‐amended soils incubated under flooded undisturbed conditions as well as at 100% moisture inhibited the hydrolysis. The inhibitory factor was not formed in rice straw‐amended flooded soils incubated at 50 and 75% moisture levels.