The value of pulverized refuse fines (PRF) as a substitute for topsoil in land reclamation .1. Field studies

1. The suitability of pulverized refuse fines (PRF) as a topsoil substitute in the reclamation of colliery spoil and urban clearance areas was studied in the field for 26 months. 2. Growth of ryegrass (Lolium perenne) was poor on untreated substrates. Fertilized or topsoiled substrates produced better yields. However, the highest yields were obtained from substrates spread with a 20-cm depth of PRF. 3. The concentration and uptake of nitrogen in the ryegrass was highest in the PRF plots. 4. Despite the relatively high C:N ratio (38) of PRF, mineralization of nitrogen occurred readily and supplied sufficient nitrogen for plant uptake within the study period, suggesting the organic nitrogen in PRF is in an easily decomposable form. The potential of PRF to supply available nitrogen was about 6-12 times that of the topsoil used.