| Autor: |
Hatala, Jaclyn A.1 jhatala@berkeley.edu, Detto, Matteo1,2, Sonnentag, Oliver1,3, Deverel, Steven J.4, Verfaillie, Joseph1, Baldocchi, Dennis D.1 |
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| Zdroj: |
Agriculture, Ecosystems & Environment. Mar2012, Vol. 150, p1-18. 18p. |
| Abstrakt: |
Abstract: The Sacramento-San Joaquin Delta in California was drained and converted to agriculture more than a century ago, and since then has experienced extreme rates of soil subsidence from peat oxidation. To reverse subsidence and capture carbon there is increasing interest in converting drained agricultural land-use types to flooded conditions. Rice agriculture is proposed as a flooded land-use type with CO2 sequestration potential for this region. We conducted two years of simultaneous eddy covariance measurements at a conventional drained and grazed degraded peatland and a newly converted rice paddy to evaluate the impact of drained to flooded land-use change on CO2, CH4, and evaporation fluxes. We found that the grazed degraded peatland emitted 175–299g-Cm−2 yr−1 as CO2 and 3.3g-Cm−2 yr−1 as CH4, while the rice paddy sequestered 84–283g-Cm−2 yr−1 of CO2 from the atmosphere and released 2.5–6.6g-Cm−2 yr−1 as CH4. The rice paddy evaporated 45–95% more water than the grazed degraded peatland. Annual photosynthesis was similar between sites, but flooding at the rice paddy inhibited ecosystem respiration, making it a net CO2 sink. The rice paddy had reduced rates of soil subsidence due to oxidation compared with the drained peatland, but did not completely reverse subsidence. [Copyright &y& Elsevier] |
| Databáze: |
GreenFILE |
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Full Text from ScienceDirect