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Labile carbon matters more than temperature for enzyme activity in paddy soil.
- Source :
-
Soil Biology & Biochemistry . Aug2019, Vol. 135, p134-143. 10p. - Publication Year :
- 2019
-
Abstract
- Global warming increases belowground carbon (C) input as plant litterfall, root biomass and rhizodeposition, which influences the stocks and dynamics of soil organic matter. To clarify the effects of labile C availability (biochemical factor) and temperature (environmental factor) on enzyme activities, we incubated typical paddy soil for 75 d at four temperatures (5, 15, 25, and 35 °C) under anaerobic conditions. Acetate was used as the source of labile C and methane. The potential activities of three hydrolases (β -glucosidase, chitinase, and xylanase) were analysed on days 3, 15, and 75 after acetate addition. Activity of β -glucosidase and chitinase in soil without acetate addition was 2.1–2.7 times higher than that with acetate. Xylanase activity increased with temperature and incubation period. The enzymes involved in the C cycle were sensitive to temperature, whereas chitinase (responsible for N cycle) activity became temperature sensitive only after acetate addition (Q 10 - V max ≥ 1). Organic C mineralisation (CO 2 release) was more sensitive at low temperature with Q 10 values 1.1–3.4 times higher at 5–15 °C than at 25–35 °C. The Q 10 values for methane (CH 4) emission were 2.8–13.5 times higher at 5–15 °C than at 25–35 °C. Organic matter decomposition in paddy soil was more sensitive to temperature (Q 10 of CO 2 and CH 4 emission ≥ 1) than enzyme activities. Comparison of abiotic (temperature) and biochemical (C availability) effects indicated that warming has limited effects on hydrolase activities in paddy soil. The increase in labile C remarkably stimulated microbial activity and soil organic matter turnover. We conclude that: i) enzyme activities are more sensitive to C addition than to temperature; ii) and SOM decomposition is accelerated by both C input and warming, especially at low temperatures. Image 1 • Labile C affects the response of extracellular enzyme activities to soil warming. • The higher the labile C content, the less enzymes are produced by soil microorganisms. • Labile C addition affects microbial biomass and induces enzymatic N mining from SOM. • Acetate input increases temperature sensitivity of CO 2 and CH 4 emission below 15 °C. [ABSTRACT FROM AUTHOR]
- Subjects :
- *HUMUS
*EXTRACELLULAR enzymes
*SOIL dynamics
*SOIL heating
*ENZYMES
*SOIL air
Subjects
Details
- Language :
- English
- ISSN :
- 00380717
- Volume :
- 135
- Database :
- Academic Search Index
- Journal :
- Soil Biology & Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 137417034
- Full Text :
- https://doi.org/10.1016/j.soilbio.2019.04.016