Title: Fine dust emissions in sandy and silty agricultural soils Authors
Submitted to: International Conference on Aeolian Research
Publication Type: Abstract Only
Publication Acceptance Date: April 20, 2010
Publication Date: July 9, 2010
Citation: Zobeck, T.M., Baddock, M.C., Van Pelt, R.S., Schlegel, A., Cox, J.J. 2010. Fine dust emissions in sandy and silty agricultural soils[abstract]. International Conference on Aeolian Research. July 5-9, 2010, Santa Rosa, La Pampa, Argentina. p. 61. Technical Abstract: Dust emissions from strong winds are common in arid and semi-arid regions and occur under both natural and managed land systems. A portable field wind tunnel has been developed to allow measurements of dust emissions from soil surfaces to test the premise that dust concentrations are highly correlated with surface soil properties, as modified by land management. In this study, we report the effect of soil properties on fine dust emissions from differently textured soils prominent in major agricultural regions. In advance of the field experiments, the flow within the tunnel was conditioned to simulate a realistic wind above a smooth, level field surface. To investigate the intrinsic erodibility of each soil under the wind tunnel flow, all plots were prepared in the same manner. Existing variation in surface stability was removed by roto-tiller passes, followed by raking and finally rolling to establish a flattened, weakly crusted tilled field plot which the tunnel was run on. Dust samples were gathered through an isokinetic vertical slot sampler, with PM10 values of dust <25 microns obtained using a GRIMM spectrometer, plus analysis of suspended sediment collected on glass fiber filters. Larger saltating particles and some dust settled into a tray at the bottom of the slot sampler while smaller particles were pulled through a vacuum tube attached to the sampler. Under saltation in the wind tunnel, soils tend to a steady dust emission which represents their long term emission potential. The relationships between these characteristic PM10 release rates and aggregate strength, wet and dry stability, organic matter content and textural properties of each soil are presented.