Nutrient deficiencies and the aftercare of reclaimed derelict land.
Fourteen grass swards which had been reclaimed from colliery spoil and urban clearance materials 1-7 years previously were dressed with nitrogen, phosphorus and potassium in factorial combination. Examination of grass yields showed that N deficiency was the major factor limiting plant growth. There was no effect of P, K or lime on plant growth at any site. Retreatment in the subsequent year showed a continued major need for nitrogen and some deficiency of phosphorus on the colliery spoil. Considerable nitrogen deficiency was also found on two urban sites where topsoil had been used. Some of the colliery spoil sites had become very acid due to oxidation of pyrite, but surface limestone treatments failed to penetrate and therefore failed to have any effect. It is concluded that there is need for legumes and appropriate aftercare in reclaimed sites to build up nutrients to levels allowing adequate cycling.