Abstract:
Nitrous oxide (N2O) is one of the longest-lived greenhouse gases (GHGs) with a
global warming potential which is 298 times higher than that of carbon dioxide.
Different sources affect on GHGs emissions. Among them, soil physical conditions
such as compaction and moisture content affect GHGs emissions from soil.
Conditioners or amendments applied into soils may affect terrestrial N2O emissions.
Autoclaved lightweight aerated concrete (ALC) is used as a soil amendment and
conditioner. In this study, we examine the effects of soil compaction, moisture
content, and ALC (Inenica, Clion Co., Ltd, Japan) addition on N2O emissions from
soils. Laboratory experiments were conducted using a paddy soil amended with and
without ALC (0% or 5%), under two levels of compaction (compacted and non-compacted), and two soil moisture contents (60% and 100% water holding capacity:
WHC) in 200-mL glass bottles. All samples were incubated at 25°C for 21 days under
aerobic conditions. Emissions of N2O were determined at 0, 1, 3-, 7-, 14- and 21-days
using gas chromatography with thermal conductivity detector. Higher moisture
content (100% WHC) and the addition of ALC significantly decreased N2O
emissions. Soil compaction significantly increased N2O emissions from soil. The
interaction between ALC addition with compaction and ALC addition with moisture
content on cumulative N2O emissions was statistically significant (p<0.05). Results
revealed that ALC addition suppressed the N2O emissions from soil, which was more
effective at non-compacted and 100% WHC. Our study suggested implementing the
precise dosage (5%) of ALC, along with an adequate moisture (100% WHC) and
non-compacted conditions actively contribute the suppression of N2O emissions from
soil while creating an ideal soil environment.
