CH4 and N20 Emissions from Rice Fields in China:A meta-analysis
Rice paddies are important source of CH4 and N2O greenhouse gases. Researches on CH4 and N2O emissions from rice paddies have been carried out in recent 20 years in China. In order to quantify theses emissions and select mitigation options for GHG emission from rice paddies, 351 observations from 74 studies for CH4 emission, 120 observations from 32 studies for N2O emission from rice paddies, up to 2009, were collected from the China Journal Network, the Weipu S&T Journal Network, Science Direct Online, and Springer Link. Criteria for the selection of peered review papers in this study are as follows: 1) field measurements of CH4 and N2O emissions using chambers; 2) clearly defined the location, experiment design, water management regimes, and fertilization; 3) at least one rice growing season was covered by the experiment; 4) GHG emission sampling frequency is higher than once a week. A meta-analysis of CH4 and N2O emissions from rice paddies in China was conducted using the collected data from the papers. The conclusions are: 1) Water management regimes, including both in rice growing and non-rice growing seasons, are important factors to CH4 emission. During the rice growing season, compared to continuously flooded rice paddies (CF), flooding - midseason drainage - flooding (F-DF) , flooding - midseason drainage - flooding - wet irrigation (F-D-F-W) , and wet irrigation (W) could reduce CH4 emission by 45％, 59％ and 83％, respectively. Drainage during winter, rotation of rice and non-rice crops, rotation of double non-rice crops and rice, could reduce 42％ ~56％ of CH4 emission compared to pre-seasonal flooded rice paddies. 2) CH4 emission was affected by organic amendments and amount of synthetic nitrogen fertilizer significantly. CH4 emission flux of rice paddies with different organic amendments was in the order of: crop straw + farmyard manure (S+FM) > green manure (GM) > farmyard manure (FM) > crop straw (S) > composted farmyard manure and residue of biogas digester (CM). The CH4 emission decreased gradually with the increase of chemical nitrogen fertilizer application (N). When N was 0 < N <150 kg N ? ha2, 150 < N <250 kg N ? ha2 and N >250 kg N ? ha2, CH4 emission was reduced by 12％, 29％ and 65％ compared with treatment of non-fertilization. 3) Water management regimes both in rice growing and non-rice growing season and total nitrogen fertilizer input were important factors for N2O emission. Compared to CF, the N2O emission increased by 12％, 140％ and 478％ under F-D-F, F-D-F-W and W. The nitrogen fertilizer-induced N2O emission factors were estimated to be 0.43％ and 0.68％ for F-D-F and F-D-FM, respectively. The average N2O emission increased by 40％ ~110％ under drainage in winter season, rotation of rice and non-rice crops, and rotation of double non-rice crops and rice, compared to preseasonal flooded rice paddies. 4) Considering the global warming potential of CH4 and N2O, CH4 emission is major contributor to global warming. Mitigation options should focus on the CH4 mitigation. Mid-season drainage and fermented organic amendments were the recommended options for reducing GHG emissions from rice paddies.
Rice paddies CH4 N2O Meta-analysis Mitigation measurements
Yue Li Shengwei Shi Yunfan Wan Qingzhu Gao Shuo Liu XB Qin Xin Ma
Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, 100081, Beijing, China
国际会议
北京
英文
89
2010-06-27（万方平台首次上网日期，不代表论文的发表时间）