1. Bilski J J, Alva A K and Sajwan K S 1995 Fly ash. In Soil Amendments and Environmental Quality. Ed. J E Rechcigl. pp 327–363. Lewis Publishers, Boca Raton, FL, USA.
2. Chang M L and Thomas G W 1963 A suggested mechanism for sulfate adsorption by soils. Soil Sci. Soc. Am. Proc. 27, 281–283.
3. Ernani P R and Barber S A 1993 Composition of the soil solution and cation leaching as affected by addition of calcium chloride or calcium sulfate to an acid soil. Rev. Bras. Ci. Solo, Campinas, 17, 41–46 (In Portuguese).
4. Jones Jr. J B, Wolf B and Mills H A 1991 Plant Analysis Handbook. Micro-Macro Publishing Inc., Athens, GA, USA.
5. Kemper W D, Nicks A D and Corey A T 1994 Accumulation of water in soils under gravel and sand mulches. Soil Sci. Soc. Am. J. 58, 56–63.