Canadian Forest Service Publications
In vitro allelopathic inhibition of nitrification by balsam poplar and balsam fir. 1982. Thibault, J.-R.; Fortin, J.A.; Smirnoff, W.A. American Journal of Botany 69: 676-679.
Issued by: Laurentian Forestry Centre
Catalog ID: 14433
CFS Availability: PDF (request by e-mail)
A soil percolation apparatus was used to study the effect of plant extracts on nitrification. Foliar leachates, leaf extracts, and bud extracts of balsam fir (Abies balsamea) and balsam poplar (Populus balsamifera) were added to the ammonium percolation solution. Color tests and quantitative measurement of residual ammonium and formed nitrate were applied. Foliar leachates of balsam fir strongly inhibited nitrification; leachates of balsam poplar were slightly less inhibitory. Balsam fir needle and balsam poplar dormant bud extracts (5% w/v) completely prevented the oxidation of ammonium. The same estracts (2% w/v) still prevented the oxidation of ammonium to nitrate to a large extent. Once again balsam fir extracts inhibited the process more strongly than balsam poplar. No evidence was obtained for the presence of a specific inhibitor of nitrifier microorganisms.