Reclamation of colliery spoil: the effect of amendments and grass species on grass yield and soil development

Results are presented of a field trial in which various methods for the reclamation of coarse colliery waste were tested. The site was divided into three blocks and each block received a different level of deep cultivation; however, these treatments appeared to have no long-term significant effect on grass yield. Within each cultivation block a number of treatments were superimposed. These included: amendments of soil and organic materials, deep placement of P fertilizer, and the use of different grass seed mixtures. Grass yield was measured annually for 6 years. At the end of that period soil samples were taken for analysis and tests were conducted in the field to measure the effects of treatments on the developing soil conditions. There was a general decline in grass yields during the course of the experiment. However, the rate of decline varied with the different treatments, being lower on amended spoil (i.e. treated with soil or organic materials) and on treatments sown with a seeds mixture containing S143 cocksfoot (Dactylis glomerata). Differences in the soil conditions resulting from the use of amendments were detected; in particular, the soil-amended plots had higher pH and exchangeable Ca and greater penetrability.