Large source of nitrate, a potential water contaminant, found in near-surface desert soils

The researchers note in the paper that desert land use – road construction, off-road vehicle use, and military training – often disrupts fragile land surfaces, increasing surface erosion by rain and wind. According to them, nitrogen-laden dust transported by wind from disturbed desert pavement soils may impact distant nitrogen-limited ecosystems, such as alpine lakes.

Furthermore, the researchers note that increased soil moisture resulting from climate change increases the potential for “denitrification” – a naturally-occurring process in soil, where bacteria break down nitrates to return nitrogen gas to the atmosphere. “Denitrification also produces nitrous oxide, a major greenhouse gas,” Graham said.

Next in their research, Graham and his colleagues will examine the spatial distribution of desert pavement throughout the Mojave Desert to explore how different levels of nitrate are associated with different kinds of desert pavement. Together with UCR’s David Parker, a professor of soil chemistry, they will look in the desert also for perchlorate, which may be associated with nitrate.

Graham was joined in the study by Daniel Hirmas, a doctoral candidate in the Department of Environmental Sciences at UCR; Christopher Amrhein, a professor of soil chemistry at UCR; and Yvonne Wood of the University of California Cooperative Extension, Inyo-Mono Counties, Bishop, Calif. The research was funded by the University of California Kearney Foundation of Soil Science.

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