Publikationsdatum:
2012-02-08
Beschreibung:
Soils release more carbon, primarily as carbon dioxide, per annum than current global anthropogenic emissions (Luo and Zhou, 2006). Soils emit carbon dioxide through mineralization and decomposition of organic matter and respiration of roots and soil organisms (Houghton, 2007). Given this, the evaluation of the effects of abiotic factors on microbial activity is of major importance when considering the mitigation of greenhouse gases emissions. Previous studies demonstrate that soil CO 2 emission is significantly affected by temperature and soil water content. A limited number of studies have illustrated the importance of bulk density and soil surface characteristics as a result of exposure to rain on CO 2 emission, however, none examine their relative importance. Therefore, this study investigated the effects of soil compaction and exposure of the soil surface to rainfall and their interaction on CO 2 release. We conducted a factorial laboratory experiment with three soil types after sieving(clay, silt and sand soil), three different bulk densities (1.1 g cm -3 , 1.3 g cm -3 , 1.5 g cm -3 ) and three different exposures to rainfall (no rain, 30 minutes and 90 minutes of rainfall). The results demonstrated CO 2 release varied significantly with bulk density, exposure to rain and time. The relationship between rain exposure and CO 2 is positive: CO 2 emission was 53% and 42% greater for the 90 minutes and 30 minutes rainfall exposure, respectively, compared to those not exposed to rain. Bulk density exhibited a negative relationship with CO 2 emission: soil compacted to a bulk density of 1.1 g cm -3 emitted 32% more CO 2 than soil compacted to 1.5 g cm -3 . Furthermore we found that the magnitude of CO 2 effluxes depended on the interaction of these two abiotic factors. Given these results, understanding the influence of soil compaction and raindrop impact on CO 2 emission could lead to modified soil management practices which promote carbon sequestration. Copyright © 2012 John Wiley & Sons, Ltd.
Print ISSN:
0197-9337
Digitale ISSN:
1096-9837
Thema:
Geographie
,
Geologie und Paläontologie
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