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Soil incubation study showed biogas digestate to cause higher and more variable short‐term N 2 O and N 2 fluxes than mineral‐N
Author(s) -
Buchen-Tschiskale Caroline,
Hagemann Ulrike,
Augustin Jürgen
Publication year - 2020
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.201900075
Subject(s) - digestate , biogas , fertilizer , chemistry , soil water , agronomy , environmental chemistry , zoology , environmental science , anaerobic digestion , soil science , waste management , methane , organic chemistry , engineering , biology
Today, a large share of mineral fertilizer is substituted by biogas digestates. Biogas digestates are known to promote N 2 O production, compared to mineral fertilizer. In particular, the initial phase following fertilizer application is crucial for the N gas release as N 2 O and also N 2 . However, this period impact has been rarely investigated, especially not across various field sites. Thus, undisturbed soil cores from two fertilizer types (biogas digestate vs . mineral fertilizer) at five sites with different site characteristics were investigated in a short‐term laboratory experiment under N 2 ‐free helium–oxygen incubation atmosphere. Across sites, biogas digestate soil cores showed significantly higher absolute N 2 O fluxes compared to mineral fertilizer soil cores, even though this effect was dominated by samples from one site (Dornburg with the highest biogas digestate fertilization rate). Also relative N 2 O fluxes showed a similar tendency. On average, absolute and relative N 2 fluxes differed between the two fertilizer types, while N 2 fluxes were highest at the Dornburg site. A N 2 O/(N 2 O+N 2 ) ratio of denitrification below or equal to 0.5 clearly highlighted the importance of N 2 O reduction to N 2 for three of five the biogas digestate soil cores. Soil characteristics like bulk density and water‐filled pore space as proxies for gas diffusivity in soil, as well as N availability (NO 3-,NH 4+), significantly affected the N 2 O and N 2 fluxes from the biogas digestate soil cores. While this study presents data on short‐term N 2 O and N 2 fluxes, there is a need for further studies in order to investigate the dynamics, the duration of the observed effects and their significance at the field scale.