摘要
为准确获取辽河三角洲水稻湿地CH4浓度与通量特征,分析水稻生长发育对CH4浓度与通量的影响,进一步估算稻田CH4排放量,基于采用涡度协方差法(Eddy Covariance Method,EC)获取的2013年4─10月辽河三角洲稻区近地层CH4监测资料,结合水稻生育期,分析了稻田CH4浓度与通量的时间变化规律。结果表明:水稻(Oryza sativa Linn)生长季内,近地层CH4的平均浓度是0.242 mmol·m-3,期间出现3个峰值,分别与泡田期、拔节-抽穗期和成熟期3个生育期相对应;CH4浓度较高时期,其日变化活跃,表现为日间浓度较低夜间浓度较高,日较差大,在其它浓度较低时期,日变化不大。CH4的月排放量在5月最大,为0.700 mol·m-2。CH4通量在水稻生长季内日平均为0.080μmol·m-2·s-1,通量峰值出现规律与浓度一致,其中泡田-移栽期较高,最高值出现在5月11日,为0.707μmol·m-2·s-1,返青期-分蘖期基本无CH4排放,拔节期-抽穗排放量再次升高,之后逐渐降低,在CH4通量较高时期,通量的日变化随气温升高而升高,温度达最大值之后逐渐降低。浓度与通量的日变化呈负相关关系。
In order to obtain accurately the characteristics of near surface CH4 concentration and flux in paddy field of the Liaohe Delta region, analyze the impacts of rice growth on CH4 concentration and flux and estimate the CH4 emissions of rice region, characteristics of CH4 concentration and flux during April and October of 2013 were analyzed by an eddy covariance method. The results indicate that the mean CH4 concentration near surface level is 0.242 mmol·m-3 in the rice (Oryza sativa Linn) growing season, and there are three peaks during this period, which are corresponding to the ponding, jointing-heading and maturity stages respectively. When the CH4 concentration is high, its diurnal variation is active, namely, its concentration is lower in daytime and higher in nighttime and diurnal concentration range is large, while its diurnal variation is inactive when the CH4 concentration is low. The monthly CH4 emission is largest in May, which is 0.700 mol·m-2. The daily mean CH4 flux is 0.080 μmol·m-2·s-1 during the growing season, and its variation rules are consistent with those of concentration. The CH4 flux over ponding stage is large, and the maximum is 0.707μmol·m-2·s-1 on May 11;there is nearly no CH4 emission during turning green-tillering stage, and then the CH4 emission rises again during jointing-heading stage, and the emission decreases gradually after that stage. When the CH4 flux is large, its diurnal variation rises with the increase of temperature and reaches the maximum value, and then decreases. There is a negative correlation between CH4 concentration and flux.
出处
《生态环境学报》
CSCD
北大核心
2015年第5期804-810,共7页
Ecology and Environmental Sciences
基金
国家自然科学基金项目(31270480
41375146
41405109)
国家重点基础研究发展规划(973)项目(2010CB951303
2004CB418507)
