The Effect of Herbicides and Insecticides on Some of Soil Eco-physiological and Chemical Indices

In order to study the effect of pesticides on soil biological quality, three herbicides and insecticides with the highest consumption rates, on soil eco-physiological and chemical indices were investigated.

The experiment was carried out as factorial in a completely randomized design with seven treatments of which were triplicated. The pesticides were applied as constructed by the manufacturer and then the pots maintained in a greenhouse condition for two months. Then, some of the soil eco-physiological and chemical indices were measured after one month and also after two months.

The results showed that in comparison with the application of the pesticides caused a significant decrease in soil bacterial and fungal population, basal respiration, substrate-induced respiration, microbial biomass carbon, microbial biomass nitrogen, and microbial quotient and a significant increase in soil metabolic quotient. The results also showed that the application of the pesticides has no significant effect on soil organic carbon. The results showed that, although soil eco-physiological indices decreased after one month, the indices increased after two months reaching the level that was before application of the pesticides. The results also showed that 2, 4-D had the highest and Chloropyrifos had the lowest adverse effects on the indices.

It could be concluded that application of the pesticides which are used in this work decreased soil biological quality short terms.