INFLUENCE OF TERBACIL ON MICROBIOTA IN SOIL AND CULTURES

Abstract

Terbacil in concentrations up to 500 μg∙g−1 of sandy loam soil had little effect on populations of actinomycetes, bacteria, and fungi under laboratory and field conditions during a period of 5 mo. Concentrations up to 700 μg of terbacil∙mL−1 did not affect the in vitro growth of 111 strains of agriculturally important microorganisms, including effective, parasitic, and lysogenic rhizobia from seven cross-inoculation groups, pathogenic, attenuated, and saprophytic agrobacteria, azotobacters, and other bacteria, actinomycetes, and fungi. Terbacil inhibited the respiration of total soil microbiota, of bacteria, and of fungi at all concentrations tested. By contrast, it stimulated the respiration of actinomycetes at concentrations up to 500 μg∙mL−1 and partially inhibited it at 700 μg∙mL−1. Replication of bacterial and actinomycete isolates showed minimal inhibition by the extreme concentrations.