Restoration of drastically eroded land using coal fly ash and poultry biosolid

A 3-year field study was conducted at a 12 ha soil-borrow area adjacent to the Columbia Metropolitan Airport, South Carolina to investigate the restorative effects of co-application of coal fly ash (FA) and a poultry biosolid (PB). FA was applied at 0, 22, 280, 560 and 1120 Mg (tonne) ha−1, and PB at 5 and 10 Mg ha−1. The area was seeded with erosion-control species Atlantic Coastal panic grass (Panicum amarum var amarum L.), sericea (Lespedeza cuneata var. appalow [Dumont] G. Don.) and weeping love grass (Eragrostis curvula Wolf.). Plant biomass and elemental composition were analyzed in sequential harvests. Soil and groundwater quality characteristics including pH, EC and elemental composition were also monitored throughout the study. In addition, the effect of amendments on the water holding capacity and bulk density of the soil was investigated. Amendment addition significantly increased plant biomass production by a maximum of 26% using 1120 Mg ha−1 FA and 10 Mg ha−1 PB. Application of the highest rate of FA significantly increased the plant tissue concentrations of Mn, As, Se and B. Soil pH was initially increased from 4.6 to 6.1 by amendments. Soil salinity was increased in the initial year only. Amended soils had higher concentrations of Ca, Mg, P and K, higher organic matter content and water holding capacity than unamended soil. Concentrations of plant-essential trace elements (B, Cu and Zn) that were marginally deficient in the unamended eroded soil increased to within typical soil concentrations following amendment with FA and PB. Groundwater quality was unaffected throughout the study. The co-application of FA and PB successfully promoted the revegetation of the eroded borrow area with no apparent adverse environmental side effects.