Effects of Soil Chemical Properties on Quartz Reststrahlen Band Response.

Effects of soil chemical properties on quartz reststrahlen band response

Matthew A. Middleton, Josh L. LeMonte, and Brandon J. Lafferty

Two soil components that tend to exhibit a disproportionately large effect on soil chemical behavior are SOM and iron oxides. Like quartz, both SOM and iron oxides are present in a wide range of soils. Also, SOM and iron oxides are especially predominant in non-desert soils around the world. It is probable that iron oxides and SOM can have a profound effect on QRB response by decreasing its intensity. It is known that some types of organic matter (OM) can almost completely attenuate infrared signal such that it is impossible to collect any infrared data on these materials (Nakamoto, 1986). When these materials are present in soils it is possible that they could completely inhibit the use of infrared spectroscopy for detection of disturbed soil. Also, both iron oxides and SOM are known to be present in soils as both discrete particles and particle coatings (Schwertmann and Cornell, 2000). As discussed previously, research has shown that coating of sand grains with clay minerals can drastically change QRB intensity, thus, it is probably that iron oxides and SOM coatings on quartz grains in soil could also decrease QRB intensity. On the other hand, SOM and iron oxides that exist in soils as discrete particles might have a much smaller effect on QRB response. It is important to better understand the effects that these two soil chemical properties (SOM and iron oxide content) have on QRB response because of the prevalence of these soil components in non-desert soils.