TRACE ELEMENTS IN AGRICULTURAL SOILS OF NORTHWESTERN ALBERTA

Abstract

Fifty-two surface soils and 11 subsoils collected from agricultural soils of the Peace River region of northwestern Alberta were analyzed for total and extractable contents of Cd, Cr, Cu, Mn, Ni, Pb and Zn. The purpose of this survey was to build up a data base on trace element contents of agricultural and environmental concerns for soils of this region. Extractable amounts were determined by DTPA-ammonium bicarbonate, 0.05 M EDTA, 0.1 M HCl and saturation extractions. Total Cd, Cr, Cu, Mn and Pb concentrations were similar to average values for "world" soils; Ni was less than and Zn greater than "world" average. Total Cr was higher and total Pb lower than average values reported for Canadian soils. Total Cd, Cu, Ni, Pb and Zn were similar in surface and subsurface soils. Extractable Cd, Mn, Ni and Zn tended to be greater in surface soils compared to subsoils; Cu and Pb were higher in the clay-enriched subsoils. Among the surface soils, soils with higher amounts of organic matter contained greater amounts of total and extractable metals with few exceptions. Clay content was also closely correlated with the distribution and content of Cu, Pb and Cr. Few, if any, of the soils would be expected to be deficient in Cu, Mn or Zn for the production of crops. Key words: Cadmium, copper, chromium, manganese, nickel, lead, zinc