Low spring soil temperatures may reduce iron, zinc or phosphorus uptake on some Manitoba soils, but deficiencies lessen once soils increase in temperature. Some bean varieties may be more susceptible than others to zinc deficiency. High phosphorus soil levels or applications as starter fertilizer may induce zinc deficiency. Visual symptoms first appear as yellowing between leaf veins of older leaves, and whitening and size reduction in new leaves. In severe deficiencies, bronzing and necrotic spots appear on leaves, internodes are shortened and plants appear stunted.
Severe deficiency can delay maturity and through aborted flowers, reduce yields.
Deficiencies of micronutrients, such as zinc, occur sporadically through the field, associated with the above suspect soil conditions. This uneven or delayed ripening may cause harvest delays or reductions in sample quality. Zinc levels in the soil can be measured using a DPTA extractant. Plant uptake of zinc is greatest from broadcast and incorporated applications. However, starter-banded applications are popular among growers.