Plant and Soil

, Volume 134, Issue 2, pp 209–219

Relative importance of the effect of 2,4-D, glyphosate, and environmental variables on the soil microbial biomass

  • D. A. Wardle
  • D. Parkinson

DOI: 10.1007/BF00012038

Cite this article as:
Wardle, D.A. & Parkinson, D. Plant Soil (1991) 134: 209. doi:10.1007/BF00012038


Two post-emergence herbicides (glyphosate and 2,4-D) were applied at field application levels to tilled field plots in a mixed cropping area in south-central Alberta. The effects of these chemicals on certain variables associated with microbial biomass and activity were monitored in these plots (as well as corresponding control plots) for 45 days. Glyphosate did not influence any of the microbial variables tested. Addition of 2,4-D significantly influenced all microbial variables investigated but these effects were transient, being detectable only within the first 1–5 days of herbicide addition. The effects of 2,4-D addition on the microbial variables tested, even when significant, were typically small and probably of little ecological consequence especially when spatial and temporal variation in these variables is taken into account.

Key words

bacterial fungal ratio basal respiration 2,4-D glyphosate herbicide microbial biomass selective inhibition substrate-induced respiration 

Copyright information

© Kluwer Academic Publishers 1991

Authors and Affiliations

  • D. A. Wardle
    • 1
  • D. Parkinson
    • 1
  1. 1.Department of Biological SciencesUniversity of CalgaryCalgaryCanada
  2. 2.Ruakura Agricultural CentreHamiltonNew Zealand