Data/hora: 05/06/2024 17:26:17

Provedor de dados: | 111
País: | China
Título: | Chamber measurement methods and aeration effect on greenhouse gas fluxes during composting
Autores: | Kyu-Hyun Park; Ngwa Martin Ngwabie; University of Guelph; Claudia Wagner-Riddle.
Data: | 2014-03-31
Ano: | 2014
Palavras-chave: | Chamber; Compost; Greenhouse gases; Aeration; Flux.
Resumo: | Composting has the potential to mitigate methane (CH4) and nitrous oxide (N2O) emissions from manure. &amp;nbsp;The heterogeneous nature of emitting surfaces makes it difficult to quantify these emissions. &amp;nbsp;CH4 and N2O fluxes measured using eight small chambers (0.72 m2) and a mega chamber (90 m2) were compared, and the effect of aeration on the fluxes during composting was studied. &amp;nbsp;Two batches of compost were placed in three channels and 2-3 small flux chambers were deployed on each channel. &amp;nbsp;The channels were enclosed by a building serving as a mega chamber. &amp;nbsp;Chamber location significantly affected gas fluxes, pointing to strong spatial heterogeneity. &amp;nbsp;Mean CH4 fluxes from the small chambers were similar or 1.4 times higher compared to the mega chamber. &amp;nbsp;Mean N2O fluxes from the small chambers were 50%-55% lower compared to the mega chamber. &amp;nbsp;Channel edges, not captured by the small chambers, were potentially significant &amp;lsquo;hot spots&amp;rsquo; for N2O production. &amp;nbsp;When only small chambers are used for flux measurements, a large number should be strategically positioned to cover different areas of the emitting surface so as to capture a representative flux. &amp;nbsp;On the other hand, if a few small chambers are used, they should be moved frequently to different locations on the emitting surface. &amp;nbsp;Temporal variations in CH4 and N2O fluxes were similar for all the chambers, including periods with active aeration. &amp;nbsp;Correlation of total aeration time with CH4 fluxes was insignificant (r = -0.097), but was positive with N2O (r = 0.556). &amp;nbsp;The flushing of stored CH4 at the onset of aeration, likely promoted fluxes, as opposed to the expected flux decrease with higher aeration time. &amp;nbsp;The purging of stored N2O enhanced the expected stimulation of N2O production at high aeration times, resulting in the positive trend observed for N2O fluxes. &amp;nbsp;Our results suggest that a mega chamber that covers a larger emitting surface area can avoid biases in flux estimates due to spatial variability of the source. &amp;nbsp; Keywords: chamber measurements, compost, greenhouse gases, aeration, flux
Idioma: | Inglês
Identificador: | http://www.cigrjournal.org/index.php/Ejounral/article/view/2467
Editor: | International Commission of Agricultural and Biosystems Engineering
Relação: | http://www.cigrjournal.org/index.php/Ejounral/article/download/2467/7334
Formato: | application/pdf
Fonte: | Agricultural Engineering International: CIGR Journal; Vol 16, No 1 (2014): CIGR Journal; 32-44
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