The distribution of prairie soil resources along a topographic gradient in the loess hills of northwest Missouri using portable x-ray fluorescence (PXRF)

Background/Question/Methods

The loess hills along the Missouri River are a unique ecosystem group encompassing forested habitats on northeast and northwest facing slopes and prairies on southeast and southwest slopes.  Without disturbance of fire or grazing, prairies are encroached upon by woody plants, eventually reverting to forested environments.  Because of possible slope and aspect differences, we sought to quantify the elemental composition of various locations of the loess hills.  We used a Bruker Tracer III SD portable X-ray fluorescence spectrometer to identify and relatively quantify the elements in soil taken from 120 grid locations.  Samples were collected from the top 10 cm of the soil profile, air dried, and homogenized before analysis.

Results/Conclusions

Detectable elements included the following: Al, Ca, Cr, Fe, K, Mn, Mo, Nb, P, Pb, Rb, Si, Sn, Sr, Ti, Y, and Zr.  Ca and K demonstrated greater quantities in prairie versus forest habitats.  Ca, Fe, and Mn demonstrated differences based on elevation.  K was positively correlated with Si, and Al was positively correlated with K and Si.  These data will be used as a multivariate, chemical element description of the loess hills and to associate elemental correlations with herbaceous and woody plant distributions.