Reduction of Excessive Bioavailable Phosphorus in Soils by Using Municipal and Industrial Wastes
Poultry and swine production has created both economic growth in Oklahoma and concern over the effect of excessive land application of animal manure on water quality. The objectives of this study were to evaluate the ability of two drinking water treatment alum hydrosolids (HS1, HS2), cement kiln dust (CKD), and treated bauxite red mud (RM) to reduce excessive amounts of bioavailable P in soil and to determine potential environmental impacts from these treatments. Two soils that contained 553 and 296 mg kg−1 Mehlich III-extractable P, as a result of prior treatment with poultry litter or dairy manure, were mixed with amendments at the rate of 30 and 100 g kg−1 soil and incubated at 25°C for 9 wk. Reductions in Mehlich III-extractable P from 553 mg kg−1 to 250 mg kg−1 followed the trend HS2, CKD ≥ HS1 ≥ RM in the slightly acidic Dickson soil (fine-silty, siliceous, Thermic Glossic Fragiudult). Reductions in Mehlich III-extractable P from 296 mg kg−1 to 110 mg kg−1 followed the trend HS2 > HS1 > RM > CKD in the calcareous Keokuk soil (coarse-silty, mixed, Thermic Fluventic Haplustoll). Reduction of soluble P followed similar trends. Most treatments did not result in excessive soil pH or increases in soil salinity, in extractable Al, or in heavy metals in soils. Application of alum hydrosolids to soils with excessive amounts of bioavailable P in sensitive watersheds may improve drinking water quality and provide financial savings for municipalities.
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