Abstract:
The effect of rice varieties' diversity in Rajburi on methane emission using the application of geographic information system was conducted in three parts: study on the diversity of rice varieties, study methane emitted form various varieties of rice, and evaluate the methane emission from various rice varieties grown in Rajburi. The study of the diversity of ricc varietics was performed by using the questionnaires. There are 9 districts in Rajburi . The total area was 3,247,789 rai, the agricultural land was 1,471,140 rai and the area for growing rice was 396,608 rai. The soil in Rajburi consisted of 48 soil map units, most of soil texture used in agriculture were clay, sandy silt and sandy clay. It was also found that in the past rice grown in this area consisted of 43 varieties; 16 native and 17 extended varieties. Recently, there were only 20 and 5 varieties of rice grown in rainy and dry season, respectively. In the study of methane emission using the 5 abundant varieties grown in Rajburi. The methane was collected by using static box at 6 interval diurnal times; 8.00, 10.00, 12.00, 14.00, 16.00 and 18.00. Five replicated samples were taken at 0, 10,20,30,40 minutes. The methane gas was analyzed by Gas Chromatography. The results showed that the methane emission of 5 various varieties was significantly different (p < 0.01). The emission rate of Kao Dok Mali 105 (KDML 105) was highest. In addition, the emission rate of Supanburi 60, Kor Khor 23, Chainat 1, and Homsupan were ranged lower, respectively. Furthermore, all varieties , not including KDML 105 rice , showed the samc methane cmission trend line. The methane emission was high at 8.00-10.00 and then decreased slowly. The ratc of emission was high again at 16.00-18.00. The results also showed that there was an interaction between mcthane emission rate and inner temperature of the box on 2 rice varieties; KDML 105 and Supanburi 60. In the evaluation of methane emission of various rice varieties , the were stildied using multi-criteria decision making technique from 4 main factors; soil, rice varieties, cultural practice, and ambient temperature was using. The results showed that 3 varieties of rice; KDML 105, Supanburi 60, and Supanburi 90 had the high methane emission. However, 12 of rice varieties; Chainat 1, Hormsupan, Kor Khor 23, Leuangprathiew 123, Supanburi 1, Kor Khor 6, 15,21, 11, Kao ?'a Hang , Klong Luang and Pin Kaow showed moderate suitable for methane emission. Two rice varieties; Luang Ee Duaon and Luang Tu Rian showed slightly suitable for methane emission. Finally, 3 varieties, Khao Ka Rieng, Ee Wong, and Ree Saw did not show any suitable for methane emission. According to the evaluation study, it was also found that the high emission area was in the right side of Rajburi consisting of 5 districts; Banpong, Banpae, Damnernsaduak, Wat Pleng, and Potaram. The moderate suitable for methane emission was at the life side of Rajburi consisting of 4 districts; Jombueng, pak Toh, Mueng, and Suan Pueng.