Ammonia volatilization from Chihuahuan Desert habitats - 1988

Ammonia volatilization was measured at three sites in the
Chihuahuan Desert of southern New Mexico, U.S.A. In dry
soils, ammonia volatilization ranged from 9 to 11 micrograms
of nitrogen per square meter per day, but rates increased to
95 micrograms of nitrogen per square meter per day in a
shrubland site after an experimental addition of water.
Ammonia volatilization also increased with experimental
additions of NH4Cl and decreased with additions of sucrose.
Competition by nitrifiers for available NH4+ had little
effect on NH3 volatilization: N-Serve, added to inhibit
nitrification, decreased NH3 volatilization in a grassland
site and had little effect at other sites. We suggest that
NH3 volatilization is controlled by the rate of
mineralization of NH4+ from soil organic matter, and
mineralization is stimulated by rainfall. Overall rates of
NH3 volatilization from undisturbed desert ecosystems appear
to be much lower than those reported for rangeland and
agricultural soils.

The data set shows ammonia volatilization from grassland,
cresotebush, and playa habitats in response to a variety of
experimental treatments chosen to elucidate the processes
controlling the volatilization under dry and post-rainfall
conditions. Ammonia is collected in weak acid in scintillation
vials placed inside PVC chambers in the field. The rate of
ammonia volatilized per unit area ugN/m2/day) is found by
mulitplying the concentration in the acid by 1250 to account
for volume and area corrections.