Abstract

To evaluate the efficiency of acidified (to pH 5.5) and dried digestate solids as a fertilization product in a pot experiment with ryegrass.The NH4-N pool of the solids was labelled with N-15 prior to acidification and drying to estimate plant N uptake efficiency. The effect of digestate solids on plant growth and N and P uptake was compared to the effect of different mineral N-P fertilization combinations.Non-acidified dried digestate solids showed inferior N fertilization performance compared to their raw and acidified counterparts, and higher drying temperature reduced solids N mineralization. More than 40% of the NH4-N in the raw, raw acidified and acidified dried solids treatments was recovered by the ryegrass over 5-months, similar to recovery with medium mineral N rates, resulting in mineral fertilizer equivalency of 32-41%. Digestate solids treatment altered the water extractable P of the solids, but less so the ryegrass P uptake, mainly due to the buffer capacity of the soil. However, ryegrass P uptake in non-acidified dried solids treatments was probably inhibited by poor growth due to low N availability.Acidification of digestate solids prior to drying may be an important treatment to maintain the solids fertilizing value while enhancing its manageability.

Keywords

Mechanical separation; Ammonia; pH; Drying method; Organic waste; Water-extractable phosphorus

Published in

Plant and Soil
2017, Volume: 421, number: 1-2, pages: 401-416
Publisher: SPRINGER

UKÄ Subject classification

Agricultural Science


Publication identifier

DOI: https://doi.org/10.1007/s11104-017-3463-y

Permanent link to this page (URI)

https://res.slu.se/id/publ/93697