Acidic iron oxide waste as a conditioner for calcareous soils
Date
2002
Authors
Campbell R.
O'Brien R.D.
Fey M.V.
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Abstract
A fine-grained iron oxide (hematite, (α-Fe2O3), containing 1.2% hydrochloric acid by mass, is the main by-product of an acid recovery plant at Saldanha Bay. The alkalinity of calcareous soils in this semi-arid region causes plant deficiencies in many trace elements, including iron. The use of the acidic waste to decrease the pH of two sandy soils (one non-calcareous and the other containing 1.9% CaCO3) was evaluated in a pot trial. No significant differences were observed in the yield of young wheat in either soil treated with 0, 5 or 25 g iron oxide per kg soil. An application rate of 50 g/kg, however, suppressed wheat growth in both soils by about 40%. This was interpreted as being due to soil salinity in both soils (electrical conductivity, ECe, increased to about 10 dS m-1) and to acidification of the non-calcareous soil to pHKCI4.04 (the calcareous soil remained buffered at pH 7).
Description
Keywords
acidification, calcareous soil, iron oxide, waste, South Africa, Triticum aestivum
Citation
South African Journal of Plant and Soil
19
4
19
4