Percent calcium carbonate equivalent (neutralizing value) of five fly ash samples ranged from 34 to 41. Field soils at three sites were treated with fly ash at rates that ranged from 1 to 6 tons per acre. Fly ash applications had opposite effects on extractable P, B, Fe, and Cu at Sites 1 and 2. A three-fold increase in total B occurred in wheat plants taken from one field treated with fly ash. At Site 3 test results of soil samples collected three, six, nine and twelve months after treatment showed that 2 tons of agricultural limestone was equivalent to 4 to 6 tons of fly ash in raising soil pH. Most of the chemical changes occurred in the upper 2.5 cm of soil and within three months after treatment.
Chapman, Stanley L.
"Fly Ash as a Fertilizer and Lime Source in Arkansas,"
Journal of the Arkansas Academy of Science: Vol. 38
, Article 7.
Available at: http://scholarworks.uark.edu/jaas/vol38/iss1/7