@article{nwisrl451,
          volume = {30},
           title = {Fixation of Isotopic Nitrogen on a Semiarid Soil by Algal Crust Organisms},
          number = {1},
          author = {H.F. Mayland and T.H. McIntosh and W.H. Fuller},
         journal = {Soil Science Society of America Proceedings},
           pages = {56--60},
            year = {1966},
        abstract = {Semiarid desert algal crust organisms were found to fix N2
when exposed to an atomosphere which contained isotopically
enriched N. Significant quantities of the N isotope were detected
in the total crust N after 3 days of incubation under field-simulated
conditions.

Net N2 fixation rates by the algal crust organisms were 0.16
and 0.10 lb of N/acre of crust surface per day under continuous
wet and cycling wet-dry conditions, respectively. Net fixation of
N under field-simulated conditions adequately compensated for
the removal of N by livestock. The rate of N2 fixation under
field-simulated conditions increased linearly for at least 520 days.
The amount of N in the algal crust was doubled during this time.
No net N change was observed in dry crusts.

Growing algal crusts contained 1\% to 2\% of the total N as
extracellular NH4-N. Excretion of some fixed nitrogen was
suggested by the isotopic enrichment of the extracellular N fraction
and uptake of labeled N by grass seedlings (Artemesia sp.)
growing on incubated crusts.},
             url = {https://eprints.nwisrl.ars.usda.gov/id/eprint/451/}
}