The maintenance of grassland on smelter wastes in the Lower Swansea Valley. I. Blast furnace slag.
Large-scale revegetation trials on blast furnace slag in the Lower Swansea Valley were observed from 1965 to 1970. A mixed sward grew best in the long-term. The final contribution of the species was in the decreasing order: Dactylis glomerata, Festuca rubra, Phleum pratense, Trifolium repens and Lolium perenne. Pure swards of Festuca rubra grew well and improved, in relation to the other swards, with time. Pure swards of Agrostis tenuis grew poorly and were invaded by weeds and adjacent swards. Additions of sewage sludge, and to a lesser extent domestic refuse, improved initial establishment but had less effect in the long-term. Annual applications of fertilizer were essential to ensure long-term success of the swards. There was little or no advantage in using pulverized fuel ash as a substitute for organic matter.