Phosphorus availability from the solid fraction of pig slurry is altered by composting or thermal treatment

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The alteration of easily available phosphorus (P) from the separated solid fraction of pig slurry by composting and thermal processing (pyrolysis or combustion at 300-1000. °C) was investigated by water and acidic extractions and the diffusive gradients in thin films (DGT) technique. Temporal changes in P availability were monitored by repeated DGT application in three amended temperate soils over 16. weeks. P availability was found to decrease in the order: drying. >. composting. >. pyrolysis. >. combustion with increasing degree of processing. Water extractions suggested that no P would be available after pyrolysis above 700. °C or combustion above 400. °C, respectively, but during soil incubation, even char and ash, processed at 800. °C, increased P availability. Low-temperature pyrolysis vs. combustion was found to favor P availability as did application to acidic vs. neutral soil. Composting and thermal treatment produced a slow-release P fertilizer, with P availability being governed by abiotic and biotic mechanisms.

Original languageEnglish
JournalBioresource Technology
Pages (from-to)543-551
Number of pages9
Publication statusPublished - 2014

    Research areas

  • Combustion, Diffusive gradients in thin films (DGT), Digestate compost, Manure char, Slow pyrolysis

ID: 130100235