Fertility values of organic wastes in colliery spoil reclamation

Experiments were undertaken in the greenhouse to assess the effectiveness of various organic wastes as fertilisers in a wide range of colliery spoils. The dry weight yield of Lolium perenne grown on different treatments, its nutrient and heavy metal uptake were measured during four successive harvests, which took place at six week intervals. It was found that application of organic wastes significantly enhanced plant growth. The two animal manures, Chiguano and Poultry Manure, were superior to the two sewage sludges, Dewmus and Yorkshire Bounty. The plant growth also related to the spoil types. The neutral Thorne spoil had a lower yield than the two acidic Whitwood and Ashington spoils. The total N uptake by plants during the four harvests followed a similar trend as that found in the dry weight yield. Addition of organic wastes significantly increased the plant P concentration, especially in the poultry manure treatments. On the other hand, such treatments did not enhance the Zn and Mn concentration of plant tissues, and the amounts of plant Cd, Pb and Al were below the detection limits.