Influence of Siduron and its Degradation Products on Soil Microflora

Abstract

The herbicide l-(2-methylcyclohexyl)-3-phenylurea (siduron) suppressed the growth of soil bacteria,Azotobacter sp.andChlorella vulgariswhereas siduron had no effect on actinomycetes, filamentous fungi, soil ciliates and other algae. Siduron had no effect upon the growth ofThiobacillus thioparus, Euglena gracilis, andStreptomyces griseus.The degradation product, 2-methylcyclohexylamine (hereinafter referred to as 2-MCHA) suppressed the growth ofAztobacter chroococcumand soil ciliates. Aniline, another degradation product of siduron, depressed the growth ofAspergillus versicolorandA. fischeri;however,A. ochraceus, A. candidus, A. clavatus, A. nidulans, A. flavus, Botrytis cinerea, andRhizopus nigricanswere not affected. None of these fungi was influenced in growth by 2-MCHA.Streptomyces griseusgrew significantly less in the presence of aniline. The growth ofChlamydomonas pyrenoidosa, C. radiata, Anabaena catenula, andRhizobium leguminosarumwere not influenced by 10 ppm aniline or 10 ppm 2-MCHA.