title: Optimization of pig slurry application to heavy metal polluted soils monitoring nitrification processes.
abstract: Nitrification is often negatively affected by heavy metal pollution in soils, this limiting land revegetation. Thus, the potential use of pig slurry as a nitrogen-rich organic amendment in different heavy metal contaminated soils has been evaluated; this also being a way of recycling this waste. In order to identify the factors affecting nitrification processes in heavy metal polluted soils (soil pH, heavy metal solubility and the N source), incubation experiments were run using two polluted soils with different pH values (5.0 and 7.1) and a non-contaminated soil (pH 8.2). Ammonium was added as pig slurry or as ammonium sulphate for comparison (both added at 150 mg NH(4)(+)-N kg(-1) of soil). Pig slurry provoked higher nitrification rates and N-immobilisation than ammonium sulphate, especially in the neutral-polluted soil, reflecting an improvement of the microbial activity in the soil. The microbial immobilisation of N led to an inverse relationship between the amount of N added and nitrate conversion in the neutral-polluted soil and in the non-contaminated soil amended with different pig slurry dosages (75, 150 and 225mg NH(4)(+)-N kg(-1) of soil). Low rates of nitrification and N-immobilisation were found in the acidic soil. Pig slurry addition to metal polluted soils enhanced soil nitrification, especially when metals were in low-solubility forms.
authors.affiliation: Department of Soil and Water Conservation and Organic Waste Management, Centro de Edafología y Biología Aplicada del Segura, CSIC. P.O. Box 164, 30100 Murcia, Spain. cfsaez@cebas.csic.es
authors.forename: Carlos
authors.initials: C
authors.lastname: de la Fuente
authors.forename: Rafael
authors.initials: R
authors.lastname: Clemente
authors.forename: José
authors.initials: J
authors.lastname: Martinez
authors.forename: M
authors.initials: M
authors.lastname: Pilar Bernal
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D006863:Hydrogen-Ion Concentration; D008372:Manure; D019216:Metals, Heavy / Q000032:analysis / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*; D013552:Swine
chemical_list: D008372:Manure; D019216:Metals, Heavy; D000644:Quaternary Ammonium Compounds; D012989:Soil Pollutants; D009584:Nitrogen