Large near-surface nitrate pools in soils capped by desert pavement in the Mojave Desert, California
- 1Soil & Water Sciences Program, Department of Environmental Sciences, University of California–Riverside, Riverside, California 92521-0424, USA
- 2University of California Cooperative Extension, Inyo-Mono Counties, 207 West South Street, Bishop, California 93514, USA
- 3Soil & Water Sciences Program, Department of Environmental Sciences, University of California–Riverside, Riverside, California 92521-0424, USA
Abstract
We found exceptionally high nitrate levels (up to 12,750 kg ha−1) at shallow depths (≤1 m) in soils mantled by desert pavement, a common land-surface feature in arid regions. Nearby soils without desert pavement had nitrate contents that were one to two orders of magnitude lower. The soil conditions coincident with desert pavement (i.e., stability, antiquity, and virtually no leaching) favor the retention and accumulation of nitrate delivered by atmospheric deposition or in situ fixation. The nitrate stored in soils under desert pavement is a previously unrecognized pool of nitrogen that has the potential to increase the global nitrogen inventory for near-surface desert soils to five times previous estimates. Its near-surface occurrence makes this labile nitrogen pool particularly susceptible to mobilization by climate change or human disturbance, risking contamination of surface and groundwaters.
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- Accepted 27 November 2007.
- Received 6 August 2007.
- Revision received 21 November 2007.
- The Geological Society of America, Inc.
