Risk assessment of replacing conventional P fertilizers with biomass ash: residual effects on plant yield, nutrition, cadmium accumulation and mycorrhizal status

Research output: Contribution to journalJournal articleResearchpeer-review

Carla Cruz Paredes, Alvaro Lopez Garcia, Gitte H. Rubæk, Mads Frederik Hovmand, Peter Sørensen, Rasmus Kjøller

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.

Original languageEnglish
JournalScience of the Total Environment
Volume575
Pages (from-to)1168-1176
Number of pages9
ISSN0048-9697
DOIs
Publication statusPublished - 2017

ID: 168880169