Plant and Soil

, Volume 71, Issue 1, pp 445–454

Effects of ammonium and nitrate on growth and nitrogen uptake by mycorrhizal Douglas-fir seedlings


  • Caroline S. Bledsoe
    • College of Forest Resources AR-10University of Washington
  • R. J. Zasoski
    • College of Forest Resources AR-10University of Washington

DOI: 10.1007/BF02182685

Cite this article as:
Bledsoe, C.S. & Zasoski, R.J. Plant Soil (1983) 71: 445. doi:10.1007/BF02182685


In a greenhouse pot study, mycorrhizal and non-mycorrhizal Douglas-fir seedling were grown in a forest soil amended with clays and ammonium or nitrate fertilizer. Mycorrhizal seedlings grew taller, increased root and shoot dry weight more, and accumulated more nitrogen and phosphorus than non-mycorrhizal seedlings. Mycorrhizal effects were most pronounced in the nitrate treatment. Ammonium enhancement of phosphorus uptake was demonstrated for both mycorrhizal and control seedlings. Rhizosphere pH was altered by nitrogen source and the presence of mycorrhizas. Ammonium fertilization decreased pH, while nitrate fertilization increased pH.

Key words

Clay typeCECDouglas-firHebeloma crustuliniformeMycorrhizasNitrogen PhosphorusPseudotsuga menziesiiRhizospherepHRoot-soil interface

Copyright information

© Martinus Nijhoff/Dr W. Junk Publishers 1983