While the causes of iron chlorosis are complex, the general yellowing of leaves due to iron deficiency is hard to miss. In some cases, the leaves of a tree or plant turn yellow while its veins remain green (this is called interveinal chlorosis). In more severe cases, entire leaves turn yellow or white while their outer edges turn crispy and brown.<\/p>\n

Frequently, iron chlorosis can be found in plants growing in soils that have a pH level greater than 7.0 (alkaline) and are rich in lime. Interestingly, while there may be sufficient iron in the soil itself, the high pH levels create a reaction that ties up the iron and makes it unavailable to plant roots\u2014hence, iron deficiency.<\/p>\n

High Bicarbonate in Irrigation Water<\/h3>\n

Bicarbonate is also a frequent cause of iron chlorosis, particularly in irrigated soils throughout the West. High bicarbonate levels in irrigation water react with calcium to form calcium carbonate, or lime. Bicarbonate ties up essential nutrients and makes them unavailable to plants (not to mention that it plugs up sprinkler heads and is the leading cause of crusting of soils).<\/p>\n

In the following video, agronomist Rich Affeldt explains how high bicarbonate in irrigation water contributed to iron chlorosis in a pear orchard in California and how mineral-rich Cascade Minerals Remineralizing Soil Booster<\/strong> is being tested as a way to treat its symptoms:<\/p>\n