A recent study by Agricultural Research Service (ARS) soil scientist Martin J. Shipitalo in Ohio found that more may be better when it comes to applying paper mill sludge to reclaim soils of surface-c…
A recent study by Agricultural Research Service (ARS) soil scientist Martin J. Shipitalo in Ohio found that more may be better when it comes to applying paper mill sludge to reclaim soils of surface-coal mined areas.
Over a 10-week period, Shipitalo and his colleagues applied paper mill sludge to recently surface-mined plots located on steep slopes in southeast Ohio at two rates: the standard 100 tonne per acre rate and at 300 tonnes per acre. Grass was planted on the slopes following the 10-week application period.
While the application of the sludge at both rates reduced runoff and erosion, especially before the grass was planted, the higher 300 tonne per acre rate reduced soil loss eight-fold after the grass was planted and the soil had stabilised. Both application rates reduced runoff from three-to six-fold in the same period after the grass was planted.
The 300 tonne per acre rate also increased soil carbon levels, soil pH and calcium more than the lower sludge application rate did. There were other positive results the research supported: the improved soil quality could help plant growth and continue reducing runoff and erosion. Less runoff and erosion could also lead to a reduction in sediment pond sizes, resulting in lower reclamation costs.
There was one negative effect, though: oxygen levels in the runoff water were reduced temporarily -for about 10 weeks -but total runoff was reduced.
Source: United States Department of Agriculture/Agriculture Research Service
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