The reclamation of acidic colliery spoil. II. The use of lime wastes.
The effects of 3 different lime wastes at rates of 10-200 t/ha in combination with 45-220 kg superphosphate/ha on reclamation of acid mine spoil by (a) perennial ryegrass and (b) white clover were studied at Leigh and Coppull in N. England. All treatments increased growth of (a) and there was a significant interaction between liming material and rate of application. The opt. treatment was 10 t dried calcareous slurry/ha. Application of 10 t limestone/ha gave yields comparable to 50 t Leblanc waste/ha. There was no interaction of lime with P fertilizer. Establishment of (b) was very slow and Leblanc waste was as effective as limestone in promoting its yield, but slurry gave the highest yields. Growth of (b) was decreased by application of >20 t limestone/ha, >10 t slurry/ha and >50 t Leblanc waste/ha. There was also an interaction between P and lime effects on (b). When limestone was applied to (a) yields decreased with increasing particle size at rates of 20 and 50 t/ha but increased at 100 t/ha. At 20 t/ha yields decreased with increasing particle size of Leblanc waste but not at 50 or 100 t/ha.