Effect of ammonium or nitrate on nitrogen fixation by a terrestrial blue green alga
Rodgers, G.A.
Plant and Soil 64(2): 263-266
1982
ISSN/ISBN: 0032-079X
DOI: 10.1007/bf02184259
Accession: 005219756
The effects of ammonium or nitrate-N on biological N fixation by an algal [Nostoc muscorum] crust were compared. Nitrate-N up to 3.0 .mu.mol N g-1 sand/algal crust at 60% water holding capacity did not affect fixation, whereas an ammonium-N concentration of 0.2 .mu.mol N g-1 crust markedly depressed fixation. Consequences of these differential effects are considered.