title: Phosphorus and nitrogen sorption to soils in the presence of poultry litter-derived dissolved organic matter.
abstract: Two environmental aspects associated with land application of poultry litter that have not been comprehensively evaluated are (i) the competition of dissolved organic matter (DOM) and P for soil sorption sites, and (ii) the sorption of dissolved organic nitrogen (DON) relative to inorganic nitrogen species (e.g., NO(3)(-) and NH(4)(+)) and dissolved organic carbon (DOC). The competition between DOM and P for sorption sites has often been assumed to increase the amount of P available for plant growth; however, elevating DOM concentrations may also increase P available for transport to water resources. Batch sorption experiments were conducted to (i) evaluate soil properties governing P sorption to benchmark soils of Southwestern Missouri, (ii) elucidate the impact of poultry litter-derived DOM on P sorption, and (iii) investigate DON retention relative to inorganic N species and DOC. Soils were reacted for 24 h with inorganic P (0-60 mg L(-1)) in the presence and absence of DOM (145 mg C L(-1)) using a background electrolyte solution comparable to DOM extracts (I = 10.8 mmol L(-1); pH 7.7). Soil P sorption was positively correlated with metal oxide (r(2) = 0.70) and clay content (r(2) = 0.79) and negatively correlated with Bray-1 extractable P (r(2) = 0.79). Poultry litter-derived DOM had no significant negative impact on P sorption. Dissolved organic nitrogen was preferentially removed from solution relative to (NO(3)(-)-N + NO(2)(-)-N), NH(4)(+)-N, and DOC. This research indicates that poultry litter-derived DOM is not likely to enhance inorganic P transport which contradicts the assumption that DOM released from organic wastes increases plant-available P when organic amendments and fertilizer P are co-applied. Additionally, this work demonstrates the need to further evaluate the fate and transport of DON in agroecosystem soils receiving poultry litter applications.
authors.affiliation: Dep. of Soil, Environmental, and Atmospheric Sciences, University of Missouri, Columbia, MO 65211-7250, USA. goynek@missouri.edu
authors.forename: Keith W
authors.initials: KW
authors.lastname: Goyne
authors.forename: Hee-Joong
authors.initials: HJ
authors.lastname: Jun
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Anderson
authors.forename: Peter P
authors.initials: PP
authors.lastname: Motavalli
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000032:analysis; D000818:Animals; D002244:Carbon / Q000032:analysis; D000077215:Clay; D005308:Fertilizers; D008372:Manure / Q000032:analysis*; D008670:Metals / Q000032:analysis; D008923:Missouri; D009566:Nitrates / Q000032:analysis; D009584:Nitrogen / Q000032:analysis / Q000737:chemistry*; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry*; D011200:Poultry; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D012995:Solubility
chemical_list: D000538:Aluminum Silicates; D005308:Fertilizers; D008372:Manure; D008670:Metals; D009566:Nitrates; D000644:Quaternary Ammonium Compounds; D012989:Soil Pollutants; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen; D000077215:Clay