Municipal sewage sludge and phosphorus as soil amendments for enhancing wildlife habitat on reclaimed surface mines

The purpose of this study was to evaluate the benefit of municipal sewage sludge and/or phosphorus as soil amendments for enhancing wildlife habitat on reclaimed surface mined land. Five forage seed mixtures beneficial to wildlife were tested: 1) Ladino clover and timothy 2) switchgrass, indiangrass, and little bluestem 3) kobe lespedeza and orchardgrass 4) korean lespedeza and orchardgrass 5) A. U. lotan lespedeza and orchardgrass. An unseeded control was included. The objectives of the experiment were 1) to compare species viability and plant productivity on surface mined land amended with and without sludge and/or phosphorus, 2) to evaluate minesoil acidity, fertility, and heavy metal content before and after soil amendment, and 3) to evaluate, over a two-year period, the dynamics of species composition of plots within the different amendments and seed mixtures.

Minesoil exhibited increased fertility levels with all soil amendments. Minesoil amended with sludge had the greatest increase in fertility. Amended minesoil had greater vegetation percent cover and stand height compared with the unamended control and there were significant differences in cover among soil amendments. Differences occurred in density of vegetative cover and stand height due to type of seed mix present. Stem counts of the individual species in the seed mixtures and the volunteer grassy and broad-leaf species differed depending on the type of soil amendment and on the type of seed mix present.

Municipal sewage sludge effectively enhanced soil fertility and organic content of minesoil and aided establishment of vegetation. Phosphorus aided in the rapid establishment of vegetation, particularly legumes, on limed but otherwise unamended minesoil. A combination of sewage sludge and phosphorus fertilizer had a negative impact on some vegetative responses compared to sludge alone. Plants chosen to enhance wildlife habitat were successfully established and provided acceptable cover on surface minesoil.