Economic considerations in the revegetation of an abandoned coal washing settlement pond

A study was established on an abandoned coal washing settlement pond to examine the biological effectiveness and economic efficiency of four organic soil amendments on the growth of herbaceous cover and the survival and growth of black locust (Robinia pseudoacacia L.). The site had a pH of 1.8 and as devoid of vegetation at the time of study establishment. Materials tested included hardwood bark, a mixture of bark, sawdust and manure, a mixture of composted sewage sludge and kiln dust, and a mixture of straw and manure. After six growing seasons, the mixture of bark, sawdust and manure and the mixture of sewage sludge and kiln dust produced the most herbaceous cover. All treatments were equally effective in promoting tree survival and growth except for the sewage sludge and kiln dust, which was significantly worse. In economic terms, however, the control, which was limed and fertilized, was the most cost effective in all cases. The soil amendments simply did not result in a biological response sufficient to offset their substantially higher establishment costs.