The absorption, distribution and concentration of copper in white clover grown on a range of soils

Abstract

The absorption, distribution and concentration of Cu in white clover were examined in plants grown on 21 soils under controlled environment conditions, and the results compared with those from a previous study with perennial ryegrass. The clover absorbed more Cu and, in general, had higher concentrations in the shoots over six successive harvests than did the ryegrass. However, concentrations of Cu in the roots, and the proportion of the total plant Cu found in the roots were lower with the clover. The concentration of Cu in the shoots of the clover, and the total amount in shoots plus roots, respectively, were correlated with the concentration of Cu extracted from the soils by 0.05M EDTA (r=0.473 and 0.700), by 0.005M DTPA (r=0.610 and 0.638) and by 1.95 per cent HNO3 (r=0.627 and 0.699). Some of these correlations were improved slightly when the concentrations of extractable Cu were adjusted for soil pH. The exploration of the soils by root extension appeared to be less important in the acquisition of Cu by the clover than it was for the ryegrass.