淹水胁迫对冬小麦-砂姜黑土土体单元碳通量的影响研究

近年来大气中二氧化碳(CO_2)含量的显著增加引起学者们广泛关注,生态系统碳平衡问题成为研究的热点和前沿问题。研究淹水胁迫对冬小麦碳通量的影响可为探究土体单元碳平衡关系提供理论基础。在五道沟实验站设立典型试验区,以冬小麦四个主要生长期为研究时段开展控制试验,设置淹水试验组和对照试验组,测量不同情景下冬小麦碳通量,并分析其变化趋势。研究结果表明:对照情景下,冬小麦碳通量表现为碳汇,日内碳通量曲线大致呈先降后升趋势,9时碳通量与13时的碳通量随生长期不断接近,晴天碳通量低于阴雨天,连续阴雨天后的初晴日碳通量大幅降低;淹水情景在拔节期、孕穗期会使碳通量降低,在抽穗期对碳通量影响较小,在扬花期会对碳通量产生正影响,应尽量避免淹水胁迫的发生。研究成果可为维持农田生态系统碳平衡和建设生态灌区提供科学依据。

Effects of flooding stress on carbon flux in winter wheat and ginger black soil

The significant increase of carbon dioxide ( CO2 ) in the atmosphere has attracted wide attention from scholars in recent years． Carbon balance of ecosystem has become a hot and cutting-edge issue． The study on the effect of flooding stress on carbon flux of winter wheat can provide a theoretical basis for exploring the carbon balance relationship of soil units． In this study,a typical test area was set up in Wudaogou Experimental Station． The controlled experiment was carried out with the four main growing periods of winter wheat and then took them as the research period． The water-flooding test group and the contrast test group were set up to measure the carbon flux of winter wheat under different scenarios and analyze their variation trends． The results show that the carbon flux of winter wheat reveals the carbon sink in the contrast situation． The curve of intra-day carbon flux roughly shows an uptrend first and then downturn． The carbon fluxes at 9 a． m． and 1p． m． are getting closer and closer along with the growth period． The carbon flux in sunny days is smaller than that in rainy days． The carbon flux of the first sunny day after continuous overcast and rainy days decreases significantly． The flooding reduces the carbon flux at the jointing stage and booting stage,but it has little effect on the carbon flux at the heading stage,and has a positive effect on the carbon flux at the flowering stage． The occurrence of flooding stress should be avoided as far as possible． The research results can provide scientific basis for maintaining carbon balance of farmland ecosystem and constructing ecological irrigation area．