|PADILLA, JULIO - University Of Texas - El Paso|
|Van Pelt, Robert - Scott|
|GARDNER, TERRENCE - North Carolina State University|
|BADDOCK, MATTHEW - Griffiths University|
|NOVERON, JUAN - University Of Texas - El Paso|
Submitted to: Aeolian Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2014
Publication Date: 12/1/2014
Citation: Padilla, J., Calderon, F.J., Acosta Martinez, V., Van Pelt, R.S., Gardner, T., Baddock, M., Zobeck, T.M., Noveron, J.C. 2014. Diffuse-reflectance mid-infrared spectrocopy reveals chemical differences in soil organic matter carried in different size wind eroded sediments. Aeolian Research. 15:193-201.
Interpretive Summary: Wind erosion is a soil degrading process that threatens agricultural sustainability and environmental quality on a global basis. Little information is currently available regarding the C groups carried in wind eroded sediments and thus become lost from soil, the understanding of which will help determine how wind erosion affects soil quality and agricultural sustainability. An analysis method called Mid-infrared (MidIR) spectral interpretation was used on different types of wind tunnel-blown sediments eroded from a loam soil during the fallow period of different crop rotations and tillage management in Akron, Colorado. This method determines the absorbance of different light wavelengths of samples. The absorbance at different wavelengths can describe the mineral and chemical composition of the samples. The wind eroded sediments were separated into two fractions, fine dust (<35 µm mean dia.) and saltation-size material (<175 µm mean dia.). The fine dust fraction was characterized by strong clay and other mineral absorption, as well as aliphatic C chemical compounds associated with very mobile SOM. The saltation-size material fraction showed lower clay absorption than fine dust, while it showed greater absorption for other minerals. This study showed that there is a partition of C groups within wind eroded sediments of different sizes and that they can reflect the tillage management history of soil. It also demonstrated that finer dust sediments, which travel greater distances from the source soil compared to larger sized sediments (i.e., saltation size material), can carry away higher levels of aliphatic-carbon compounds and clays with potential negative impacts on soil processes and the future sustainability of these agroecosystems.
Technical Abstract: Soil organic matter (SOM) influences water holding capacity, aggregation, and diversity. Little information is available regarding the C functional groups carried in wind eroded sediments away from the source soil. Mid-infrared (MidIR) spectra was used on wind tunnel-blown sediments eroded from a loam soil during the fallow period of different cropping systems and tillage management in Akron, Colorado. The soil was managed as fallow-winter wheat (Triticum aestivum L.) under conventional tillage (F-Wct) or no tillage (F-Wnt) and fallowwheat-corn under no tillage (F-W-Cnt). Evaluation of the soil samples prior to the wind erosion simulations showed significantly greater organic C and total soil N under F-Wnt and F-W-Cnt than under F-Wct. Two wind eroded sediments were evaluated: fine dust (<35 µm mean dia.)and saltation-size material (<175 µm mean dia.). The fine dust presented higher absorbance at 2930 cm-1, indicating higher levels of aliphatic CH, and at 3690-3620 cm-1 indicating clays. The saltation-sized material showed higher absorbance for quartz from 1800-2000 cm-1 and a marked inversion band from 1250-1050 cm-1. Both wind eroded sediments showed higher absorbance for -OH groups and aliphatic CH from no-till soil. Our study showed that there is a partition of C groups within wind eroded sediments of different sizes and that they can reflect the tillage management history of soil. Finer dust sediments, which travel greater distances from the source soil than saltation size material, can carry away higher levels of aliphaticcarbon compounds and clays with potential negative impacts on SOM and the sustainability of these agroecosystems.