Data Set Citation:
When using this data, please cite the data package:
NCEAS 10645: Zhuang: Toward an adequate quantification of CH4 emissions from land ecosystems: Integrating field and in-situ observations, satellite data, and modeling , National Center for Ecological Analysis and Synthesis , and Khalil A. 2008.
Khalil:CH4 and N2O Emissions From Sub-tropical Rice Agriculture In China
nceas.883.4 (https://knb.ecoinformatics.org:443/knb/metacat/nceas.883.4/nceas)
General Information:
Title:Khalil:CH4 and N2O Emissions From Sub-tropical Rice Agriculture In China
Identifier:nceas.883
Abstract:
Emissions of methane and nitrous oxide, two significant greenhouse gases, were measured from rice fields at Qingyuan in Guangdong Province, China. The region has a sub-tropical climate which allows two crops of rice to be grown every year. The prevailing agricultural practices create a complex interaction between factors known to have a major effect on methane and nitrous oxide emissions from rice fields; namely intermittent flooding and use of organic fertilizers. In this region, the farmers depend on nitrogen fertilizers and, at least in recent years, have only intermittently flooded their fields during the growing seasons. These factors tend to reduce methane emissions. But the rice straw and crop residues from the first crop of the year are plowed into the fields providing a large addition of organic material under hot weather conditions favorable to quick decomposition during the second crop period. This, and the addition of farm yard manure, increases emissions of methane emissions from these fields. The results of the present study show that the effect of these competing factors and their timing lead to an average rate of emissions of 5 +/- 2 and 6 +/- 2 mg/m2/hr from the first crops for the two years when measurements were taken (2003 and 2004), and 12 +/- 8 and 13 +/- 8 mg/m2/hr from the second crop. Further, production measurements showed that during the two years of these experiments, the average production rates were about 27 mg/m2/hr for the first crop and 22 - 34 mg/m2/hr for the second crop, resulting in estimated oxidation rates of about 80%26#37; for the first crop and 50%26#37; - 60%26#37; for the second crop. The higher fluxes in the second crop therefore appear to be caused more by reduced oxidation than higher production. Nitrous oxide emissions, when they were detected, usually occurred within a few days after the application of nitrogen fertilizers. The seasonally averaged emissions were between 0.01 - 0.02 mg/m2/hr except in the first year when large emissions over one short period pushed the average upwards.
Keywords:None:
  • methane
  • nitrous oxide
  • rice agriculture
  • China
Publication Date:2008-02-14
Data Table, Image, and Other Data Details:
Metadata download: Ecological Metadata Language (EML) File
Other Data:2007JG000462-CH4data.txt ( View Metadata | Download File download)
Other Data:2007jg000462-CH4_production.txt ( View Metadata | Download File download)
Other Data:2007JG000462-N2Odata.txt ( View Metadata | Download File download)
Other Data:2007JG000462-Other.txt ( View Metadata | Download File download)

Involved Parties

Data Set Creators:
Organization:NCEAS 10645: Zhuang: Toward an adequate quantification of CH4 emissions from land ecosystems: Integrating field and in-situ observations, satellite data, and modeling
Organization:National Center for Ecological Analysis and Synthesis
Individual: Aslam Khalil
Organization:Porltand State University
Address:
Portland, Oregon 97201 USA
Phone:
1-503-725-8396 (voice)
Email Address:
khalilm@pdx.edu
Data Set Contacts:
Individual: Aslam Khalil
Organization:Porltand State University
Address:
Portland, Oregon 97201 USA
Phone:
1-503-725-8396 (voice)
Email Address:
khalilm@pdx.edu
Associated Parties:
Individual: Aslam Khalil
Metadata Providers:
Individual: Aslam Khalil

Data Set Characteristics

Geographic Region:
Geographic Description:Qingyuan,Guangdong Province, China, (23.68%26#194;%26#176; N latitude, 112.95%26#194;%26#176;E longitude), a city some 75 Km NNW from Guangzhou, the capital of Guangdong Province in China
Bounding Coordinates:
West:  112.9500  degrees
East:  112.9500  degrees
North:  23.6833  degrees
South:  23.6833  degrees
Time Period:
Begin:
2002-12-01
End:
2004-11-30

Sampling, Processing and Quality Control Methods

Step by Step Procedures
Step 1:  
Description:

Chamber studies

The fluxes of gases are measured by placing a chamber over a small prescribed section of the rice field in which a base has been embedded before the rice is planted. Access to plots away from the edge of the field is by a boardwalk that is installed to prevent agitation of the soil that may compromise the flux measurements. The chamber is sealed at the bottom by the water in the base. Air samples are taken periodically from the chamber at intervals of 3, 6, 9, and 12 minutes for methane measurements and at 0, 30 and 60 minutes for nitrous oxide measurements. Samples for methane analysis were taken in plastic syringes and were analyzed using a Gow Mac GC/FID instrument located at the nearby laboratory of the local meteorological bureau (Meteorological Agency, Chinese Meteorological Administration). There was no instrument available for the measurements of nitrous oxide. Air samples were taken by pumping air into 0.8L stainless steel containers that have been used for many years in our experiments. The flasks were sent back to the Trace Gas laboratory at the Oregon Graduate Institute where N2O was measured with a GC/ECD instrument.

Data Set Usage Rights

no restrictions
Access Control:
Auth System:knb
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Metadata download: Ecological Metadata Language (EML) File