North American Fruit Explorers mailing list at ibiblio

["Martha L. Davis" <martha_davis@earthlink.net>]

Back when I was in high clay, high pH soils near Chicago I understood that 
gypsum was not useful in loosening clay in our soils because they already had 
lots of calcium.  However, if there were clay soil problems due to road salt 
it would help.  I have forgotten the exact mechanism that was explained by 
the soil scientist by now. Maybe this is useful.

Martha