The value of pulverized refuse fines (PRF) as a substitute for topsoil in land reclamation. II. Lysimeter studies.
The pattern of growth and leaching losses from UK wasteland materials (colliery spoil and brick waste) fertilized, topsoiled, or covered with pulverized refuse fines (PRF) was investigated for 13 months using lysimeters. Leaching losses of N, P, K in the first 8 months corresponded to those of leachate volume. Initial losses of inorganic N were higher in PRF-amended substrates, particularly colliery spoil, probably because excess N, produced through mineralization, was removed in the leachate before grass [Lolium perenne] was established to capture the available nutrients. Subsequent losses declined to low levels. Phosphorus losses were greatest from fertilized lysimeters. Retention by adsorption accounted for the lower losses from topsoil or PRF treatment. Total leaching losses of N and P from PRF-covered substrates were lower than those from topsoiled lysimeters. This, combined with the sustained plant growth on PRF, suggested that PRF could supply adequate nutrients through mineralization and retain them effectively against leaching. It is therefore an effective soil amendment in land reclamation permitting the establishment of a fully functional and retentive ecosystem.