Net and Gross Nitrogen Turnover in Soil Amended with Acidified and Differently Dried Solids from Biogas Digestate

Abstract

The use of dried digestate solids from biogas plants as organic fertilizers may be disadvantaged by considerable N losses during thermal treatment. Acidification can decrease NH3 emissions during drying, but little is known about the degradability and N release pattern of acidified and dried digestate solids. In a laboratory incubation, C mineralization and gross and net N mineralization from digestate solids subjected to acidification (to pH 5.5) and drying (70 or 160 degrees C) were monitored for 160 d at 15 degrees C. Gross N mineralization rates were determined using the N-15 isotopic pool dilution technique, and gross N transformation rates were calculated with the FLUAZ model. Irrespective of further treatment, acidified solids showed up to 50% reduced cumulative CO2-C respiration throughout the incubation and consequently decreased gross N mineralization rates compared with unacidified solids. Moreover, acidification of digestate solids delayed the nitrification dynamics during the first 3 wk of incubation. Throughout the experimental period, the acidified dried digestate solids had the highest inorganic N contents among all treatments. It was evident that acidification increased the stability of the organic matter and enhanced the availability of N on application to soil.

Published in

Soil Science Society of America Journal
2016, Volume: 80, number: 4, pages: 943-953 Publisher: SOIL SCI SOC AMER

UKÄ Subject classification

Soil Science


Publication identifier

DOI: https://doi.org/10.2136/sssaj2016.03.0059

Permanent link to this page (URI)

https://res.slu.se/id/publ/87473