Micronutrient supplying power of pyrite and fly ash

Abstract

Bush bean plants (Phaseolus vulgaris L. cv Improved Tendergreen) were grown in nutrient solution with added waste mine tailings pyrite and also coal fly ash to test their ability to supply micronutrients to plants. The ability of fly ash to supply K was also tested. The pyrite was a satisfactory source of Fe, Mn, Zn, B and Cu to the solution cultures. The pyrite also supplied Ca. The fly ash supplied inadequate Fe and Mn but adequate quantities of Zn, B and Cu. It supplied adequate Ca and inadequate K. Both pyrite and fly ash supplied some Cd (when solution was acid), Cr and Pb to roots but not in detectable amounts to shoots. In another experiment, fly ash also failed to supply K to bush bean plants and failed to supply Zn. Iron, B, Si, Cu, Mo, Sr, Ba and some Ni and Cr were supplied to leaves; Si, Sr, Ba, Ni and Cr were supplied to roots by the fly ash. None of these elements seemed to result in phytotoxicity. A suggestion is made that fly ash and pyrite could be blended for soil application of some micronutrients where soil pH change is not needed.

Key words:

• Pyrite
• fly ash
• waste management
• solid wastes
• trace metals
• coal
• soil amendments