EVALUATION OF FLY-ASH AS A SOIL AMENDMENT FOR THE ATLANTIC COASTAL-PLAIN .1. SOIL HYDRAULIC-PROPERTIES AND ELEMENTAL LEACHING

A major limitation to crop yields in the Atlantic Coastal Plain is dro ught stress caused by the low moisture-holding capacities of the coars e-textured soils common to the area. Because coal fly ash is comprised primarily of silt and clay-sized particles, it has the potential, if applied at high enough rates, to permanently change soil texture and i ncrease moisture holding capacity. A series of soil column studies wer e conducted to evaluate the effects of high rates of fly ash on soil h ydraulic properties and elemental leaching of trace metals and boron, Fly ash from two Delaware power plants (EM=Edgemoor and IR=Indian Rive r) was incorporated in a Hammonton loamy sand (fine-loamy, siliceous, mesic, Typic Hapludults) at six rates (0, 5, 10, 20, 30, and 40%, by w eight). The effect of fly ash on soil moisture holding capacity, hydra ulic conductivity, and wetting front velocity was determined. Leachate s from columns amended with 30% fly ash were analyzed for B, Cd, Ni, P b, Cu, and Zn. Soil moisture holding capacity was increased from 12% i n the soil alone to 25% in the soil amended with 30% fly ash. Boron an d soluble salts leached rapidly from ash amended soils while only trac e quantities of Cd, Ni, Pb, Cu, and Zn were detected in column leachat es.