Pedosphere 9(1): 11--24, 1999
ISSN 1002-0160/CN 32-1315/P
©1999 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Modeling methane emission from rice paddy soils: Ⅱ. Model validation and application |
| HUANG Yao1, R. L. SASS2 and F. M. FISHER2 |
1 College of Resources and Environmental Sciences, Nanjing Agricultural University,Nanjing 210095 (China);
2 Department of Ecology and Evolutionary Biology, Rice University, Houston, TX 77005-1892 (USA) |
| ABSTRACT |
| A simulation model developed by the authors (Huang et al., 1999) was validated against independent field measurements of methane emission from rice paddy soils in Texas of USA, Tuzu of China and Vercelli of Italy. A simplified version of the simulation model was further validated against methane emission measurements from various regions of the world, including Italy, China, Indonesia, Philippines and the United States. Model validation suggested that the seasonal variation of methane emission was mainly regulated by rice growth and development and that methane emission could be predicted from rice net productivity, cultivar character, soil texture and temperature, and organic matter amendments. Model simulations in general agreed with the observations. The comparison between computed and measured methane emission resulted in correlation coefficients r2 values from 0.450 to 0.952, significant at 0.01~0.001 probability level. On the basis of available information on rice cultivated area, growth duration, grain yield, soil texture and temperature, methane emission from rice paddy soils of mainland China was estimated for 28 rice cultivated provinces/municipal cities by employing the validated model. The calculated daily methane emission rates, on a provincial scale, ranged from 0.12 to 0.71 g m-2 with an average of 0.26 g m-2. A total amount of 7.92 Tg CH4 per year, ranging from 5.89 to 11.17 Tg year-1, was estimated to be released from Chinese rice paddy soils. Of the total, 45% was emitted from the single-rice growing season, and 19% and 36% were from the early-rice and the late-rice growing seasons, respectively. Approximately 70% of the total was emitted in the region located at latitude between 25° and 32° N. The emissions from rice fields in Sichuan and Hunan provinces were calculated to be 2.34 Tg year-1, accounting for approximately 30% of the total. |
| Key Words: CH4 emission, China, model estimates, model validation, rice paddy soils |
| Citation: Huang, Y., Sass, R. L. and Fisher, F. M. 1999. Modeling methane emission from rice paddy soils: Ⅱ. Model validation and application. Pedosphere. 9(1): 11-24. |
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