Phosphorus availability in residues as fertilizers in organic agriculture


  • Bente Foereid Norwegian Institute of Bioeconomy Research


Phosphorous - organic waste – fertilizer - DGT


Phosphorus (P) should be recycled from organic wastes as much as possible, and input is needed in stockless organic agriculture. Seven organic residues were assessed and compared them to mineral P fertilizer and rock phosphate as fertilizer for barley. P availability in the mixtures and residual P availability were also assessed by diffusive gradients in thin films (DGT). The best availability was found in digested liquid manure followed by wood ash, fish sludge, composted solid manure and composted food waste. Meat and bone meal, the commercially available product Ladybug plus and rock phosphate had low P availability at the same level as no P. Only wood ash had significant P available for the next crop. The pH level of the soil did not affect P availability for any of the P sources. DGT predicted P availability moderately well, as it measures P supply over a short period without any biological factors.


Download data is not yet available.



How to Cite

Foereid, B. (2017). Phosphorus availability in residues as fertilizers in organic agriculture. Agricultural and Food Science, 26(1), 25–33.
Received 2016-09-21
Accepted 2017-01-04
Published 2017-04-04