Effects of gypsum and sewage sludge amendment on physical properties of fine bauxite refining residue

Wong, J.W.C. and Ho, G.E. (1991) Effects of gypsum and sewage sludge amendment on physical properties of fine bauxite refining residue. Soil Science, 152 (5). pp. 326-332.

Abstract

Fine bauxite refining residue (red mud) was amended with gypsum and sewage sludge to evaluate their effects on soil physical properties in a field experiment. Sewage sludge amendment significantly reduced soil bulk density (25%) and particle density (9%), and increased the total porosity of red mud (8%). Both sewage sludge and gypsum contributed to the increases in hydraulic conductivity after one growing season. Enhanced plant growth was due to improved soil structure and hydraulic conductivity. An application of 77 t/ha gypsum and 144 t/ha sewage sludge exerted the maximum effect on soil physical properties of red mud and should ensure the initial establishment of plants.