Implications for increasing the soil carbon store: calculating the net greenhouse gas balance of no-till farming.

To investigate the effect of paddy-upland (PU) rotation system on greenhouse gas emissions, methane (CH4) and nitrous oxide (N2O) emissions were monitored for three years for a PU rotation field (four cultivations (wheat-soybean-rice-rice) over three years) and continuous paddy (CP) field on alluvial soil in western Japan. Soil carbon storage was also calculated using an improved Rothamsted Carbon (RothC) model. The net greenhouse gas balance was finally evaluated as the sum of CO2eq of the CH4, N2O and changes in soil carbon storage. The average CH4 emissions were significantly lower and the average N2O emissions were significantly higher in the PU field than those in the CP field (p < 0.01). On CO2 equivalent basis, CH4 emissions were much higher than N2O emission. In total, the average CO2eq emissions of CH4 plus N2O in the PU field (1.81 Mg CO2 ha−1 year−1) were significantly lower than those in the CP field (7.42 Mg CO2 ha−1 year−1) (p < 0.01). The RothC model revealed that the changes in soil carbon storage corresponded to CO2eq emissions of 0.57 and 0.09 Mg CO2 ha−1 year−1 in the both fields, respectively. Consequently, the net greenhouse gas balance in the PU and CP fields were estimated to be 2.38 and 7.51 Mg CO2 ha−1 year−1, respectively, suggesting a 68% reduction in the PU system. In conclusion, PU rotation system can be regarded as one type of the climate-smart soil management.

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Intercropping with Switchgrass Improves Net Greenhouse Gas Balance in Hybrid Poplar Plantations on a Sand Soil

Soil Science Society of America Journal ◽

10.2136/sssaj2017.09.0294 ◽

2017 ◽

Vol 81 (4) ◽

pp. 781

Author(s):

H.P. Collins ◽

P.A. Fay ◽

E. Kimura ◽

S. Fransen ◽

A. Himes

Keyword(s):

Greenhouse Gas ◽

Hybrid Poplar ◽

Sand Soil ◽

Greenhouse Gas Balance ◽

Poplar Plantations ◽

Gas Balance

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The growing season greenhouse gas balance of a continental tundra site in the Indigirka lowlands, NE Siberia

Biogeosciences ◽

10.5194/bg-4-985-2007 ◽

2007 ◽

Vol 4 (6) ◽

pp. 985-1003 ◽

Cited By ~ 84

Author(s):

M. K. van der Molen ◽

J. van Huissteden ◽

F. J. W. Parmentier ◽

A. M. R. Petrescu ◽

A. J. Dolman ◽

...

Keyword(s):

Carbon Dioxide ◽

Soil Temperature ◽

Greenhouse Gas ◽

Growing Season ◽

Light Limitation ◽

Greenhouse Gas Balance ◽

Area Index ◽

North East ◽

Methane Fluxes ◽

Gas Balance

Abstract. Carbon dioxide and methane fluxes were measured at a tundra site near Chokurdakh, in the lowlands of the Indigirka river in north-east Siberia. This site is one of the few stations on Russian tundra and it is different from most other tundra flux stations in its continentality. A suite of methods was applied to determine the fluxes of NEE, GPP, Reco and methane, including eddy covariance, chambers and leaf cuvettes. Net carbon dioxide fluxes were high compared with other tundra sites, with NEE=−92 g C m−2 yr−1, which is composed of an Reco=+141 g C m−2 yr−1 and GPP=−232 g C m−2 yr−1. This large carbon dioxide sink may be explained by the continental climate, that is reflected in low winter soil temperatures (−14°C), reducing the respiration rates, and short, relatively warm summers, stimulating high photosynthesis rates. Interannual variability in GPP was dominated by the frequency of light limitation (Rg<200 W m−2), whereas Reco depends most directly on soil temperature and time in the growing season, which serves as a proxy of the combined effects of active layer depth, leaf area index, soil moisture and substrate availability. The methane flux, in units of global warming potential, was +28 g C-CO2e m−2 yr−1, so that the greenhouse gas balance was −64 g C-CO2e m−2 yr−1. Methane fluxes depended only slightly on soil temperature and were highly sensitive to hydrological conditions and vegetation composition.

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