Effects of pH and phosphate status of a silty clay loam on manganese,zinc and copper concentrations in soil fractions and in clover

The field pH of a silty clay loam soil affected manganese, zinc and copper concentrations in the fraction extracted by DTPA; lower pH soils had higher metal concentrations. The soil pH also affected manganese and zinc but not copper concentrations in the soil solution, and in shoots of clover grown in pots. Metal concentrations in soil fractions were not affected by soil phosphate status, but zinc and copper concentrations in clover shoots were significantly lower when plants were grown on soils of high phosphate status. Manganese and zinc levels in shoots were predicted slightly more accurately by using soil solution data than by using concentrations extracted by DTPA.