Open AccessA laboratory study of soil conditions affecting emissions of nitrous oxide from packed cores subjected to freezing and thawing
Author(s) -
TenutaMario,
SparlingBrad
Publication year - 2011
Publication title -
canadian journal of soil science/canadian journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 67
eISSN - 1918-1841
pISSN - 0008-4271
DOI - 10.4141/cjss09051
Subject(s) - loam , nitrous oxide , soil water , denitrifying bacteria , chemistry , environmental chemistry , nitrate , soil test , environmental science , nitrogen , soil science , denitrification , organic chemistry
Tenuta, M. and Sparling, B. 2011. A laboratory study of soil conditions affecting emissions of nitrous oxide from packed cores subjected to freezing and thawing. Can. J. Soil Sci. 91: 223–233. A series of laboratory experiments using a packed core soil assay was carried out to test several soil conditions affecting the emission of N 2 O (nitrous oxide) during thawing of soil. The assay consisted of a sandy loam soil packed to 1.1 Mg m −3 , moistened to 80% water-filled pore space, and temperature treated to 4 or −20°C for 2.5 d; the emissions from thawing soil were then determined as the differences in N 2 O release rates of the temperature-treated soils when placed at 15°C. Nitrate addition to surface soil (0–10 cm) enhanced thaw emission. Thaw emissions, averaged for deeper collected soil (10–30 and 30–60 cm), was 0.3% with NO 3 − treatment and 1.2% without NO 3 − treatment of that for surface soil treated similarly. Higher thaw emission for surface soil was related to greater organic matter and microbial biomass C contents and denitrifying enzyme activity than deeper collections of soil. Increasing the bulk density of soil from 1.1, 1.2, and 1.25 Mg m −3 decreased thaw emission. A second freeze-thaw cycle of the highest compaction treatment resulted in an emission of 2.3% of the first freeze-thaw cycle. Acetylene increased thaw emission of N 2 O and more so for NO 3 − untreated than treated soil. Using the acetylene inhibition method, the N 2 O:N 2 ratio of gas produced was higher for frozen (0.17) than cold (0.07) treated soil, respectively, without the addition of NO 3 − . The addition of NO 3 − increased the N 2 O:N 2 ratio of gas produced with the ratio being 2.45 and 0.53 for frozen and cold-treated soil. The results are consistent with biological denitrification being a source of N 2 O with conditions promoting N 2 O production rather than consumption enhancing thaw emissions.