title: Evaluation of fertilization-to-planting and fertilization-to-harvest intervals for safe use of noncomposted bovine manure in Wisconsin vegetable production.
abstract: Fresh bovine manure was mechanically incorporated into loamy sand and silty clay loam Wisconsin soils in April 2004. At varying fertilization-to-planting intervals, radish, lettuce, and carrot seeds were planted; crops were harvested 90, 100, 110 or 111, and 120 days after manure application. As an indicator of potential contamination with fecal pathogens, levels of Escherichia coli in the manure-fertilized soil and presence of E. coli on harvested vegetables were monitored. From initial levels of 4.0 to 4.2 log CFU/g, E. coli levels in both manure-fertilized soils decreased by 2.4 to 2.5 log CFU/g during the first 7 weeks. However, E. coli was consistently detected from enriched soil samples through week 17, perhaps as a result of contamination by birds and other wildlife. In the higher clay silty clay loam soil, the fertilization-to-planting interval affected the prevalence of E. coli on lettuce but not on radishes and carrots. Root crop contamination was consistent across different fertilization-to-harvest intervals in silty clay loam, including the National Organic Program minimum fertilization-to-harvest interval of 120 days. However, lettuce contamination in silty clay loam was significantly (P < 0.10) affected by fertilization-to-harvest interval. Increasing the fertilization-to-planting interval in the lower clay loamy sand soil decreased the prevalence of E. coli on root crops. The fertilization-to-harvest interval had no clear effect on vegetable contamination in loamy sand. Overall, these results do not provide grounds for reducing the National Organic Program minimum fertilization-to-harvest interval from the current 120-day standard.
authors.affiliation: Department of Food Science, University of Wisconsin-Madison, Madison, Wisconsin 53706-1565, USA. scingham@wisc.edu
authors.forename: Steven C
authors.initials: SC
authors.lastname: Ingham
authors.forename: Melody A
authors.initials: MA
authors.lastname: Fanslau
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Engel
authors.forename: Jeffry R
authors.initials: JR
authors.lastname: Breuer
authors.forename: Jane E
authors.initials: JE
authors.lastname: Breuer
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Wright
authors.forename: Judith K
authors.initials: JK
authors.lastname: Reith-Rozelle
authors.forename: Jun
authors.initials: J
authors.lastname: Zhu
mesh_terms: D000383:Agriculture / Q000379:methods* / Q000592:standards*; D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D018552:Daucus carota / Q000382:microbiology; D004926:Escherichia coli / Q000254:growth & development / Q000302:isolation & purification*; D005306:Fertilization; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D006801:Humans; D018545:Lactuca / Q000382:microbiology; D008372:Manure / Q000382:microbiology*; D031224:Raphanus / Q000382:microbiology; D012988:Soil Microbiology; D013997:Time Factors; D014675:Vegetables / Q000382:microbiology*; D014922:Wisconsin
chemical_list: D008372:Manure