Factors affecting the accumulation of nitrogen in colliery spoil.
Abstract
Spoil N composition, DM yield, herbage N concentration and N yield were determined in Festuca rubra L. and Lolium perenne L. swards established on colliery spoil. The 7-year swards had been sown with white clover (Trifolium repens L.) or supplied with N fertilizer since establishment.newline˜DM yields, N concentration in the herbage, mineralizable spoil N and estimates of recently accumulated organic N were significantly greater on white clover than fertilized plots. DM yields and herbage N yields were also significantly greater on F. rubra plots than L. perenne plots. The converse was true of N concentration in the herbage, mineralizable N and an estimate of recently accumulated N. White clover plots and fertilized plots had accumulated 376 and 273 kg N ha-1 respectively and unameliorated spoil 58 kg N ha-1 since establishment. During this time fertilized plots had received 500 kg N ha-1. Spoil N components were significantly correlated with herbage yield and N components. The level of nitrogen accumulation was very low compared to soils but the rate of accumulation was similar to that found on other derelict land. The use of a legume is considered to be the most efficient way of accumulating nitrogen in colliery spoil.