Interactions of zinc with banded and broadcast phosphorus fertilizer on the concentration and uptake of P, Zn, Ca and Mg in plant tissue of oilseed flax

Abstract

Field experiments on four sites over 3 yr evaluated the effect of banded and broadcast applications of fertilizer P, with and without application of Zn on the tissue concentration and uptake by the plant of Zn, P, Ca, and Mg in oilseed flax (Linum usitatissimum L.). Residual effects of the P applications were also evaluated over five site-years. Banded applications of P tended to be more effective than either broadcast applications or residual P in increasing tissue concentration and uptake of P. Zinc application tended to decrease P concentration in the tissue where P levels were relatively high. When Zn was applied with banded P applications, it tended to reduce P uptake by the plant; when it was applied with broadcast P, it tended to increase P uptake by the plant. Changes in P uptake in response to Zn application generally reflected changes in dry matter production. When an increase in Zn concentration in the tissue or uptake by the plant occurred due to Zn applications, it was primarily when the Zn was applied with broadcast P fertilizer or where P had been broadcast the previous season. The increase in uptake of Zn generally reflected increased dry matter yield. Banded applications of P tended to produce lower tissue concentrations of Zn than did broadcast applications. Zinc concentration in the tissue also tended to be reduced by residual P from applications the previous season. Changes in Ca concentration in the tissue and uptake by the plant generally reflected changes in dry matter production. However, Mg concentration in the tissue and uptake by the plant were increased by P applications, particularly where P was banded. The increase in concentration in the tissue and uptake of Mg by the plant with application of P indicates that applications of P increase the ability of the plant to absorb Mg, presumably due to an effect on the absorption-translocation system within the plant. Key words: Flax, P placement, P, Zn, Ca, Mg