Using a crop/soil simulation model and GIS techniques to assess methane emissions from rice fields in Asia. III. Databases

As part of a series of papers describing the use of a simulation model to e xtrapolate experimental measurements of methane (CH4) emissions from rice f ields in Asia and to evaluate the large-scale effect of various mitigation strategies, the collation and derivation of the spatial databases used are described. Daily weather data, including solar radiation, minimum and maxim um temperatures, and rainfall were collated from 46 weather stations from t he five countries in the study, namely China, India, Indonesia, Philippines , and Thailand. Quantitative soil data relevant to the input requirements o f the model were derived by combining data from the World Inventory of Soil Emissions (WISE) database, the ISIS database, and the FAO Digital Soil Map of the World (FAO-DSMW). These data included soil pH; organic carbon conte nt; sand, silt, and clay fractions; and iron content for top and subsoil la yers, and average values of bulk density and available water capacity for t he whole profile. Data on the areas allocated to irrigated, rainfed, upland , and deepwater rice at the province or district level were derived from th e Huke & Huke (1997) database developed at IRRI. Using a geographical infor mation system (GIS), a series of georeferenced data sets on climate, soils, and land use were derived for each country, at the province or district le vel. A summary of the soil-related derived databases is presented and their applicationn for use in global change modeling discussed.