Bao Xueyan, Wen Xuefa, Sun Xiaomin, Zhao Fenghua, Wang Yuying
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
PLoS One. 2014 Oct 14;9(10):e110021. doi: 10.1371/journal.pone.0110021. eCollection 2014.
Interannual variation in plant phenology can lead to major modifications in the interannual variation of net ecosystem production (NEP) and net biome production (NBP) as a result of recent climate change in croplands. Continuous measurements of carbon flux using the eddy covariance technique were conducted in two winter wheat and summer maize double-cropped croplands during 2003-2012 in Yucheng and during 2007-2012 in Luancheng on the North China Plain. Our results showed that the difference between the NEP and the NBP, i.e., the crop economic yield, was conservative even though the NEP and the NBP for both sites exhibited marked fluctuations during the years of observation. A significant and positive relationship was found between the annual carbon uptake period (CUP) and the NEP as well as the NBP. The NEP and the NBP would increase by 14.8±5.2 and 14.7±6.6 g C m(-2) yr(-1), respectively, if one CUP-day was extended. A positive relationship also existed between the CUP and the NEP as well as the NBP for winter wheat and summer maize, respectively. The annual air temperature, through its negative effect on the start date of the CUP, determined the length of the CUP. The spring temperature was the main indirect factor controlling the annual carbon sequestration when a one-season crop (winter wheat) was considered. Thus, global warming can be expected to extend the length of the CUP and thus increase carbon sequestration in croplands.
由于农田近期的气候变化，植物物候的年际变化可能导致净生态系统生产力（NEP）和净生物群系生产力（NBP）的年际变化发生重大改变。利用涡度协方差技术对碳通量进行了连续测量，测量地点分别是2003 - 2012年位于禹城的两块冬小麦和夏玉米一年两熟农田，以及2007 - 2012年位于华北平原栾城的两块农田。我们的结果表明，尽管在观测年份中两个地点的NEP和NBP均表现出明显波动，但NEP与NBP之间的差值，即作物经济产量，是保守的。研究发现年碳吸收期（CUP）与NEP以及NBP之间存在显著的正相关关系。如果CUP天数延长一天，NEP和NBP将分别增加14.8±5.2和14.7±6.6 g C m(-2) yr(-1)。CUP与冬小麦和夏玉米各自的NEP以及NBP之间也分别存在正相关关系。年气温通过对CUP开始日期产生负面影响，决定了CUP的长度。当考虑单季作物（冬小麦）时，春季温度是控制年度碳固存的主要间接因素。因此，可以预期全球变暖将延长CUP的长度，从而增加农田的碳固存。
