Date of Graduation

1984

Document Type

Dissertation/Thesis

Abstract

A greenhouse investigation was conducted with corn and alfalfa to evaluate rock phosphate (rock-P) and fly ash as amendments to ameliorate toxic conditions in three acid mine soils. The extremely acid mine soils from Valley Point (VP), Westover (WO), and Lenox (LX) were each mixed with fly ash at a rate of 0%, 33% or 67%, and with rock-P at a rate of 0, 10, 20 or 40 g/kg soil in a factorial combination. In a corollary experiment, rock-P was replaced with fertilizer consisting of monocalcium phosphate (200 kg P/ha), KNO(,3) and KCl (112 kg/ha), calcium carbonate (225 kg Ca/ha), magnesium chloride (200 kg Mg/ha). Two crops of corn followed by three successive crops of alfalfa were grown on each mine soil fly ash mixture. Application of rock-P to the three mine soils alone gave significantly higher corn yield than those receiving both rock-P and fly ash. On the other hand, higher alfalfa yields were obtained when rock-P was applied along with fly ash compared to rock-P alone. Similar trends in yields of corn and alfalfa grown on the three mine soils treated with fertilizer and fly ash, were obtained as in the case of rock-P and fly ash mix. However, dry matter yield of both crops were lower than those obtained on rock-P/fly ash mix. Application of both rock-P and fly ash probably reduced the concentration of Mn and Al in corn and alfalfa crops. However, application of fly ash increased B concentrations in some cases to toxic levels in both corn and alfalfa crops. Application of rock-P increased available P in the pots without fly ash, however, the increase was somewhat lower in pots treated with both fly ash and rock-P. The concentrations of exchangeable Al in the three mine soils decreased with application of rock-P and fly ash. Phosphate fractionation indicated that, application of rock-P increased Calcium-P (Ca-P) in all three mine soils. With time, the rock-P was initially transferred to Al-P and then to Fe-P. However, application of fly ash to the three mine soils resulted in the conversion of rock-P to Al-P, due to the high Al content of fly ash. This study suggests that application of fly ash alone or in combination with rock-P may be used for reclamation of strip mine soils provided crops like alfalfa are grown.

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