Fingerprinting Dust Blowing in the Wind

Valuable soil enzymes blown away in dust reveal both the dust's soil type and the farming practices used on the field from which it blew, according to Agricultural Research Service scientists.

ARS microbiologist Veronica Acosta-Martinez and soil scientist Ted Zobeck, both at the agency's Cropping System Research Laboratory in Lubbock, Texas measured three key enzymes in dust to match farm field soil samples with dust blown from the samples. They were also able to identify the type of tillage and the crop rotation used on the field.

The two scientists are providing a rare documentation of the wind-blown loss of enzymes that convert soil nutrients into plant-usable forms. These enzymes are essential to basic cycles such as the carbon, phosphorus and sulfur cycles.

In the lab, Acosta-Martinez and Zobeck put soil into a dust generator that Zobeck designed. Acosta-Martinez used biochemical tests to analyze soil for enzyme activity levels and adapted the tests for dust. In dust, the enzymes travel inside active microbes or as proteins attached to soil particles.

As more information becomes available on dust characteristics, the better able conservationists and land planners will be to pinpoint areas and practices that are causing most of an area's wind erosion. Adding enzyme and protein testing to the battery of tests currently performed on dust promises to expand understanding of the effects of wind erosion on soil and air quality.

A paper on this study appears in the current issue of the Journal of Environmental Quality.

ARS is the U.S. Department of Agriculture's chief scientific research agency.