The influence of some chlorinated hydrocarbon insecticides on the mineralization of N fertilizers and plant growth

Abstract

The variable effects, previously observed under field and laboratory conditions, resulting from the application of the widely used chlorinated hydrocarbon insecticides has stimulated further investigations. Because of the possible cumulative harmful effects of the insecticides on the activities of soil micro-organisms, several investigations tlave been concerned with the influence of these insecticides on the conversion of ammonia to nitrate.The present investigation is concerned with the relationship between the deleterious effect of certain pesticides on the activities of the soil microflora and the use of nitrogenous fertilizers; an aspect of the problem which has not previously been considered.The results of the investigation may allow the anomalous effects of the insecticides in the laboratory and in the field to be understood.The observations indicate that the basis of the effects of hexachlorocyclohexane on soils is as an inhibitor of nitrification.

A Review of the Effects of Pesticides on Microbial Activity in Soils

“…Organophosphorus insecticides can, however, cause a slight depression in nitrate production when applied at 10 and 100 p g per g soil, but the concentrations of the ion in treated soils quickly return to normal, probably as the result of rapid breakdown of the insecticide (Tu, 1970). Verstraeten and Vlassak (1973) found that lindane inhibited the nitrification o f added fertiliser N[(NH4)2S04 and urea] but that aldrin and heptachlor did not. The importance of the formulation was highlighted by Kuseske et ul.…”