Fixation of Isotopic Nitrogen on a Semiarid Soil by Algal Crust Organisms

Mayland, H.F. and McIntosh, T.H. and Fuller, W.H. (1966) Fixation of Isotopic Nitrogen on a Semiarid Soil by Algal Crust Organisms. Soil Science Society of America Proceedings. 30(1):56-60.

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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.

Item Type:	Article
NWISRL Publication Number:	0056
Subjects:	Soil > Chemistry > Nitrogen Mass Import - autoclassified (may be erroneous)
Depositing User:	Dan Stieneke
Date Deposited:	20 Nov 2010 21:52
Last Modified:	13 Jan 2017 20:39
Item ID:	451
URI:	https://eprints.nwisrl.ars.usda.gov/id/eprint/451