CH4 emission from various rice fields in P.R. China

Timing of midseason aeration to reduce CH4and N2O emissions from double rice cultivation in China

“…High emission of CH 4 was observed at the early growth stage of late rice (Fig. 1), which was consistent with previous reports (Wang and Shangguan 1996;Lu et al 2000;Khalil et al 2008). This pattern might be related to the following factors involved in CH 4 production and emission: Firstly, late rice was transplanted immediately after the harvest of early rice, and the stubble left from the previous crop in the soil could provide a large amount of substrate for CH 4 generation.…”

“…However, considerable quantities of CH 4 were emitted from the middle to the late growth stage of early rice (Fig. 1), a result similar to findings reported earlier Wang and Shangguan 1996;Lu et al 2000;Khalil et al 2008). The precipitation in Jiangxi was mainly concentrated in the months from April to June when intensive rainfall and frequent storms account for about 46% of the annual precipitation (Jin 2009).…”

“…1), thus favoring CH 4 production and transport (Nouchi et al 1994;Bodegom and Stams 1999;Hulzen et al 1999). Finally, ebullition was the major transport pathway when rice plants were still too young to play an important role in transporting produced CH 4 to the atmosphere, and reoxidation of CH 4 was obviously lower when CH 4 was emitted through ebullition rather than by plant-mediated transport (Schü tz et al 1989;Shangguan et al 1993;Wang and Shangguan 1996). Both high CH 4 production and high CH 4 transport efficiency happened during the early growth stage of late rice, thus leading to the occurrence of about 56-72% of the total seasonal CH 4 emissions in the period (Fig.…”

“…All these observed data are related only to single rice cultivation, and little to the effect of timing of MSA on CH 4 and N 2 O emissions from double rice cultivation. The general trends of CH 4 flux patterns for early and late rice differed from those for single rice Wang and Shangguan 1996;Yan et al 2003). Accordingly, the proper time to start MSA in double rice fields to achieve the minimum GWP (CH 4 þ N 2 O) may differ from that in single rice fields.…”

Emission Laws and Influence Factors of Greenhouse Gases in Saline-Alkali Paddy Fields

“…China is one of the most important rice-producing countries in the world. In China, the areas dedicated to rice harvests (3.2ˆ10 7 ha) account for 22% of the world's total area (14.3ˆ10 7 ha), and rice production in the country accounts for 38% of the total global yield [14]. Thus far, massive efforts have been made to quantify the GHG emissions of paddy fields in China, such as the study of winter paddy fields in hilly areas of Southwest China and wetlands in Sanjiang Plain of northeast China [15][16][17].…”