Seasonal Variation in the Availability of Plant Nutrients in Acid Colliery Spoil

Abstract

The pH, percentage moisture, temperature of colliery spoil, the K, Ca, Mg, Na, Fe, Zn, Cu, Mn and Al concentration of saturation paste extracts of the spoil, were measured at frequent intervals for 2 yr. The effects of additions of limestone, shoddy and sewage sludge on these attributes were also studied [South Yorkshire, England]. Extractable Al, Mn, Cu, Zn and Fe was greater in the spoil in summer and autumn, while extractable K and pH were lower at those times. These seasonal variations are likely to have a considerable effect on plant establishment and growth on spoil. Addition of limestone significantly increased pH and reduced extractable Al, Mn and Zn. It also reduced extractable Zn, Fe and Cu and increased Ca, though these effects were not significant. Neither shoddy nor sewage sludge had any significant effect on any of the attributes measured and also had no significant effect upon the seasonal pattern of variation. Wide seasonal and diurnal variations in temperature were recorded at 1 cm depth and also, to a lesser extent, at greater depths in the spoil.