Nutrient uptake efficiency in ryegrass fertilized with dried digestate solids as affected by acidification and drying temperature

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

SLU Authors

• Pantelopoulos, Athanasios

  • University of Copenhagen

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