Characterization, utilization, and remediation of derelict poultry house pad soils.

摘要

Delaware has been a major poultry producer (>70 years) and many obsolete production facilities have become derelict. Research on derelict poultry house pad soils was conducted to characterize nutrient, metal, and salt loading; evaluate pad soil fertilizer value; and assess soil remediation methods. Twenty-five derelict poultry house sites were sampled at depths from 5 to 150 cm and analyzed for salts, mineral nutrients, and metals. Nitrogen (N) was conserved in intact houses as nitrate-N (NO3-N) and ammonium-N (NH4-N). Mean inorganic N was 3342 mg kg-1 at 0 to 60 cm depth. Surface soil (30 cm) contained 83% of the N and 92% of the N was found at 0 to 60 cm depth. Potassium (K) also accumulated, but in lower amounts. Salts were high in surface soil; predominantly NO3-, NH4+, K+, and sodium (Na+ ). There was a significant linear relationship between electrical conductivity (EC) and NO3-N in pad soils (R2 = 0.96). Phosphorus accumulation was limited to surface soil. Zinc, copper and arsenic did not accumulate to levels of concern. When exposed to weathering, large N losses were found at sandy pad sites within a 5-year period.;A pad site was excavated and 21 field trials were conducted in crops and turfgrass where nitrogen from fertilizer was replaced with pad soil up to 120 kg ha-1 N equivalent. There were no differences in yield or quality measurements in any trials when fertilizer was replaced by pad soil.;In salt tolerance tests, none of the 15 common crop and 41 salt tolerant species tested grew in non-amended pad soil; however, when amended with sawdust as a carbon source (C), germination was enhanced >80%. In three pad site remediation field studies, soil EC was reduced four-fold with C addition, annual species performance (growth and N uptake) was superior to perennial crops; and Sorghum species and small grains had the highest dry weights and N removal.;This research suggests dual remediation strategies for pad soils: (1) excavation of surface soil to spread as fertilizer and (2) adding high C:N materials followed by planting successive annual crops with high N removal potential.