High pH soils may have iron present hut unavailable to plants. Enzyme activityfor photosynthesis, respiration, and nitrogen metabolism. Brown, black, or gray spots appear next to veins. Plants in neutral or alkaline soils often show def. Immobile, easily leached.
Zinc deficiency leads to iron deficiency.
Lower pH can cause availability to the point of toxicity. Bound tightly in organic matter. May be deficient in highly organic soils. Not readily lost from soil but may he unavailable. Too much can cause toxicity.