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| Titel |
Soil quality, crop productivity and soil organic matter (SOM) priming in biochar and wood ash amended soils |
| VerfasserIn |
Eleanor (Swain) Reed, David Chadwick, Paul Hill, Davey Jones |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121705
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| Publikation (Nr.) |
 EGU/EGU2016-523.pdf |
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| Zusammenfassung |
| The application of energy production by-products as soil amendments to agricultural land is
rapidly growing in popularity, however the increasing body of literature on primarily biochar
but also wood ash have yielded contrary evidence of the range of these soil amendments
function sensitivity in soil. This study aims to assess the efficacy of two by-products; biochar
and wood ash to provide nutrients to grassland as well as the potential to improve
overall soil quality. The study of soil amendments at field scale are scarce, and the
agronomic benefits of biochar and wood ash in temperate soils remain unclear.
We used replicated field plots with three soil treatments (biochar, wood ash and
control) to measure the soil and crop properties over twelve months, including PLFA
analysis to quantify the total soil microbial biomass and community structure. After a
soil residency of one year, there were no significant differences in soil EC, total
N, dissolved organic N (DON), dissolved organic C (DOC), NO3-N and NH4-N
concentrations, between biochar amended, wood ash amended and un-amended soil.
In contrast, the application of biochar had a significant effect on soil moisture,
pH, PO4-P concentrations, soil organic carbon (SOC) and total organic carbon
(TOC), whilst the wood ash amendment resulted in an increase in soil pH only.
There were no significant treatment effects on the growth performance or nutrient
uptake of the grass. In a parallel laboratory incubation study, the effects of biochar
and wood ash on soil C priming was explored, in which soil with 14C-labelled
native SOC was amended with either biochar or wood ash at the same rate as the
field trial. The rates of 14CO2 (primed C) production was measured with a liquid
scintillation counter over a 50 day period. The 14CO2 that evolved during decomposition
likely originated from conversions in the (microbial) biomass. The results indicated
that biochar application did not prime for the loss of native SOC (i.e. there was no
acceleration of the decomposition of stable soil organic matter), whilst wood ash had a
negative priming effect (i.e. the decomposition of stable soil organic matter was
decelerated).
These two complimentary studies confirm the ability of biochar application to sequester
carbon even at relatively low application rates (10 t ha−1), however this is likely due to the
inherent carbon content of biochar rather than promoting negative soil C priming. The
potential for wood ash to repress native SOC turnover at low application rates (571 kg ha−1)
in the long term requires further investigation as this may be an additional tool for promoting
C sequestration in soil, whilst simultaneously generating greater quantities of energy from the
combustion of biomass to wood ash, as opposed to the pyrolysis of biomass to biochar. |
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