Methane emissions from rice fields: Effect of plant height among several rice cultivars

The effect of rice cultivar and plant height on methane (CH4) emission from rice fields was studied from data of 8-year field experiments. Field experiments were conducted from 1989 to 1996 at the Texas A & M University Agricultural Research and Extension Center near Beaumont, Texas. Eleven rice cultivars and three soil types were involved. The results of this study showed the following: 1) Rice cultivar choice slightly influenced the day-to-day seasonal pattern of methane emission, but it had a significant effect on the seasonal total methane emission. The average seasonal methane emission is 22.8 g CH4 m−2 for high-emitting cultivars (Mars and Della), ranging from 8.0 to 41.0 g CH4 m−2 and 17.7 g CH4 m−2 for low-emitting cultivars (Lemont, Labelle, Lebonnet, Dawn, Katy, IR 36, Cypress, and Jasmine), ranging from 1.7 to 28.4 g CH4 m−2.) Seasonal methane emission has a positive linear correlation with postheading rice plant height. The correlation coefficient r2 is 0.736 (n = 24, and p < 0.05). In this paper we suggest that plant height may be a good criteria in choosing cultivars for mitigation of methane emission. More importantly, it provides a potential method for estimating methane emission from regional or global rice paddies as plant height can be evaluated by remotely sensed imagery.