Trace element (TE) concentrations intopsoil of Swedish arable soils and grain of winter wheat, spring barley and oatsare regularly monitored. Data on Co, Cr, Cu, Mn, Mo, Ni and Zn were analysed inthis study, in order to determine spatial patterns of geographical variation inconcentrations and their correlations with soil parent material and bedrockgeology, and to identify areas with possible TE deficiency or excesswith regard to crop and livestock production and product quality. The resultsshowed that pseudo-total (7 M HNO3 extraction) concentrations of Co, Cr, Cu, Niand Zn were elevated in heavy clay soils. Areas influenced bysedimentary rock containing alum shale clearly showed elevated concentrationsof various TEs, but otherwise it was difficult to find a clear correlation between soil TEconcentration and bedrock geology. This may be because in the recently glaciatedSwedish landscape, the ice sheet itself and the melt water from the decliningice sheet have transported soil material over large distances and/or because oflow sampling density in many parts of the country. Despite weak correlationsfor individual elements, there was a general correlation between concentrationin soil and concentration in cereal grain for many of the elements studied. Oneexception was Mn, for which pH was much more important than the concentrationin soil. However, there was large variation in TE concentrations within shortdistances, indicating that soils with high and low concentrations can existside by side. Nevertheless, for most TE, the risk of low concentrations in cropplants appeared to be greatest on coarse-textured soils on felsic rock and onsoils on sedimentary rock (other than alum shale) in southern Sweden. Whilesoils in this region generally have lower concentrations of Co, Cr, Cu, Mn, Niand Zn than soils in most of western and central Europe, it was difficult to find documented deficiency of elementsother than Cu and Mn among those that are essential to plants. Comparing thedata on cereal grain presented on this study with suggested critical values indicatespossible Cu and Ni deficiency. For the cationic TEs, the generally lower pH in arablesoils in Sweden may be one explanation for the modest deficiency problemsobserved despite rather low soil concentrations. No excessive TE concentrationsin crops were recorded, but on clayey soils in eastern Sweden theconcentrations were higher than the national average. |
