Several soils have been identified in the
Intermountain West which contain excessive amounts of
extractable potassium (K). A "normal" ammonium acetate
extractable potassium level may be from 200 to 500 parts
per million (ppm), while the high potassium soils contain
1,000 to over 7,000 ppm. Initial observation of crops
grown on these soils continually showed poor crop yield,
general chlorosis and failure to respond to fertilizer
additions.
While not widely reported in the literature, these soils
have been identified at sites in Idaho, Montana, Oregon,
Utah and Wyoming. Their discovery suggests a need to
further explore the distribution and origin of high
extractable K soils. We may also be able to define steps
to improve crop and livestock productivity on the sites.
This paper presents what we know about excess-K soils and
outlines current efforts to determine their origin,
chemistry and impacts on crops and livestock
