title: Influence of soil structure on contaminant leaching from injected slurry.
abstract: Animal manure application to agricultural land provides beneficial organic matter and nutrients but can spread harmful contaminants to the environment. Contamination of fresh produce, surface water and shallow groundwater with the manure-borne pollutants can be a critical concern. Leaching and persistence of nitrogen, microorganisms (bacteriophage, E. coli, and Enterococcus) and a group of steroid hormone (estrogens) were investigated after injection of swine slurry into either intact (structured) or disturbed (homogeneous repacked) soil. The slurry was injected into hexaplicate soil columns at a rate of 50 t ha-1and followed with four irrigation events: 3.5-h period at 10 mm h-1after 1, 2, 3, and 4 weeks. The disturbed columns delayed the leaching of a conservative tracer and microorganisms in the first irrigation event compared to the intact columns due to the effect of disturbed macropore flow paths. The slurry constituents that ended up in or near the macropore flow paths of the intact soil were presumably washed out relatively quickly in the first event. For the last three events the intact soil leached fewer microorganisms than the disturbed soil due to the bypassing effect of water through the macropore flow path in the intact soil. Estrogen leached from the intact soil in the first event only, but for the disturbed soil it was detected in the leachates of last two events also. Leaching from the later events was attributed to higher colloid transport from the disturbed soils. In contrast, NO3-N leaching from the intact soil was higher for all events except the first event, probably due to a lower nitrification rate in the disturbed soil. A week after the last irrigation event, the redistribution of all slurry constituents except NO3-N in most of the sections of the soil column was higher for the disturbed soil. Total recovery of E. coli was significantly higher from the disturbed soil and total leaching of mineral nitrogen was significantly lower from the disturbed soil. Results demonstrate how manure-borne constituents injected into undisturbed soil columns respond more as expected in the field, in terms of leaching and persistence, than do the same constituents injected into typically constructed columns of disturbed soil.
authors.affiliation: Department of Agroecology, Faculty of Science and Technology, Aarhus University, Blichers Alle 20, DK-8830, Tjele, Denmark; Department of Irrigation and Water Management, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh. Electronic address: mostofa.amin@bau.edu.bd.
authors.forename: M G Mostofa
authors.initials: MGM
authors.lastname: Amin
authors.affiliation: Danish Technological Institute, Kongsvang Allé 29, DK-8000, Aarhus C, Denmark.
authors.forename: Christina Østerballe
authors.initials: CØ
authors.lastname: Pedersen
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, 1870, Frederiksberg C, Denmark; National Veterinary Institute, Technical University of Denmark, 1870, Frederiksberg C, Denmark.
authors.forename: Anita
authors.initials: A
authors.lastname: Forslund
authors.affiliation: USDA-ARS, 3702 Curtin Road, University Park, PA, 16802, USA.
authors.forename: Tamie L
authors.initials: TL
authors.lastname: Veith
authors.affiliation: Department of Agroecology, Faculty of Science and Technology, Aarhus University, Blichers Alle 20, DK-8830, Tjele, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Laegdsmand
mesh_terms: D000383:Agriculture / Q000379:methods; D000818:Animals; D002244:Carbon / Q000032:analysis; D003102:Colloids / Q000737:chemistry; D016983:Enterococcus; D004926:Escherichia coli; D004967:Estrogens / Q000032:analysis; D060587:Groundwater; D008372:Manure / Q000032:analysis / Q000382:microbiology; D009584:Nitrogen / Q000032:analysis; D012483:Salmonella Phages; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000032:analysis*; D013552:Swine; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D003102:Colloids; D004967:Estrogens; D008372:Manure; D012987:Soil; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D002244:Carbon; D009584:Nitrogen
keywords: Contaminants fate; Estrogen; Manure management; Microorganisms; Nitrogen; Repacked column