title: Isotope characteristics of vegetables and wheat from conventional and organic production.
abstract: Multielement isotope ratio analysis was checked for its suitability as a means for the discrimination between agricultural products from integrated/conventional or organic production, respectively. Differences were mainly found for delta15N-values. Paprika and tomatoes from organic production in greenhouses showed delta15N-values above+7 per thousand, whereas corresponding products from conventional cultivation had delta15N-values near 0 per thousand. Lettuce, onions, cabbage and Chinese cabbage from field production had delta15N-values in the range of+5 to+6 and+5.5 to+7.5 per thousand, respectively (conventional and organic production); these overlapping differences do not permit a reliable discrimination. The same is true for wheat, showing average delta15N-values of+2.3+/-1.0 and+3.6+/-1.6 per thousand, respectively. The unexpected relative high 15N-enrichments of vegetables from integrated production are discussed as originating, at least partially, from 15N-enrichment in the soil by NH3 evaporation and denitrification.
authors.affiliation: isolab GmbH, Woelkestr. 9/1, 85301, Schweitenkirchen, Germany. hlschmidt@web.de
authors.forename: Hanns-Ludwig
authors.initials: HL
authors.lastname: Schmidt
authors.forename: Andreas
authors.initials: A
authors.lastname: Rossmann
authors.forename: Susanne
authors.initials: S
authors.lastname: Voerkelius
authors.forename: Wilfried H
authors.initials: WH
authors.lastname: Schnitzler
authors.forename: Michael
authors.initials: M
authors.lastname: Georgi
authors.forename: Johanna
authors.initials: J
authors.lastname: Grassmann
authors.forename: Gerhard
authors.initials: G
authors.lastname: Zimmermann
authors.forename: Ralf
authors.initials: R
authors.lastname: Winkler
mesh_terms: D000641:Ammonia / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D058870:Food, Organic / Q000032:analysis*; D007554:Isotopes / Q000032:analysis*; D017942:Nitric Acid / Q000737:chemistry / Q000378:metabolism; D009587:Nitrogen Isotopes / Q000032:analysis; D010103:Oxygen Isotopes / Q000032:analysis; D013460:Sulfur Isotopes / Q000032:analysis; D014908:Triticum / Q000737:chemistry* / Q000254:growth & development; D014675:Vegetables / Q000737:chemistry* / Q000254:growth & development
chemical_list: D007554:Isotopes; D009587:Nitrogen Isotopes; D010103:Oxygen Isotopes; D013460:Sulfur Isotopes; D017942:Nitric Acid; D000641:Ammonia