title: Risk assessment of replacing conventional P fertilizers with biomass ash: Residual effects on plant yield, nutrition, cadmium accumulation and mycorrhizal status.
abstract: Reutilizing biomass ashes in agriculture can substitute inputs of P from finite primary sources. However, recycling of ashes is disputed due to their content of toxic substances such as heavy metals. This study evaluates the potential risk of replacing easily soluble inorganic P fertilizer with P in biomass ashes in a barley crop grown on soil with adequate P status. Two contrasting doses of three different types of ashes were applied to an agricultural field with spring barley and compared to similar doses of triple-superphosphate fertilizer. In the second growing season after biomass ash application, grain, straw and root dry matter yield, and P and Cd uptake were determined. Resin-extractable P was measured in soil and the symbiotic arbuscular mycorrhizal fungal activity, colonization, and community composition were assessed. Crop yield was not affected by ash application, while P-uptake and mycorrhizal status were slightly enhanced with high ash applications. Changes to the mycorrhizal community composition were evident with high ash doses. Cadmium uptake in aboveground plant tissue was unaffected by ash treatments, but increased in roots with increasing doses. Consequently, we conclude that fertilization with biomass ashes can replace conventional fertilizers without risk to barley crops in the short term.
authors.affiliation: Department of Biology, Section for Terrestrial Ecology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark. Electronic address: carla.paredes@bio.ku.dk.
authors.forename: Carla
authors.initials: C
authors.lastname: Cruz-Paredes
authors.affiliation: Department of Biology, Section for Terrestrial Ecology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: López-García
authors.affiliation: Department of Agroecology, Aarhus University, 8830 Tjele, Denmark.
authors.forename: Gitte H
authors.initials: GH
authors.lastname: Rubæk
authors.affiliation: Department of Biology, Section for Terrestrial Ecology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark.
authors.forename: Mads F
authors.initials: MF
authors.lastname: Hovmand
authors.affiliation: Department of Agroecology, Aarhus University, 8830 Tjele, Denmark.
authors.forename: Peter
authors.initials: P
authors.lastname: Sørensen
authors.affiliation: Department of Biology, Section for Terrestrial Ecology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen Ø, Denmark.
authors.forename: Rasmus
authors.initials: R
authors.lastname: Kjøller
mesh_terms: D018533:Biomass; D002104:Cadmium / Q000378:metabolism*; D005308:Fertilizers; D001467:Hordeum / Q000254:growth & development* / Q000378:metabolism; D038821:Mycorrhizae; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D018570:Risk Assessment; D012987:Soil / Q000737:chemistry
chemical_list: D005308:Fertilizers; D012987:Soil; D002104:Cadmium
keywords: Arbuscular mycorrhizal fungi; Barley; Biomass ash; Cadmium; Fertilization; Phosphorus