【摘要】 【目的】研究稻田生态系统中土壤钙、镁元素生物地球化学循环对长期大气CO2浓度升高的响应。【方法】利用中国稻田FACE(free air carbon-dioxide enrichment)试验平台,包括Ambient(对照,自由大气CO2浓度约为370μmol·mol-1)和FACE(比对照大气CO2浓度高200μmol·mol-1)2个试验处理,在2004、2005和2007年稻季不同生育期原位采集5cm和15cm处土壤溶液并测定其中Ca、Mg浓度。【结果】在2004、2005和2007年,FACE处理5cm处土壤溶液Ca浓度分别是对照处理的125%、106%和72%,Mg浓度分别是对照处理的115%、104%和75%;FACE处理15cm处与5cm处土壤溶液Ca浓度的比值在2004、2005和2007年分别是对照处理的71%、114%和180%,Mg的比值分别是对照的74%、104%和159%;2007年FACE处理0-15cm耕层土壤溶液Ca、Mg浓度分别比对照处理低6.8%和4.6%。【结论】连续大气CO2浓度升高可改变土壤溶液中Ca、Mg元素在不同深度耕层的分布,提高15cm处与5cm处土壤溶液Ca、Mg浓度的比值,且这种影响存在一定的累积效应。稻田生态系统Ca、Mg循环对长期大气CO2浓度升高的响应值得深入研究。更多还原

【Abstract】 【Objective】The objective of this study was to understand the response of soil Ca and Mg geochemical recycle in rice paddy ecosystem to elevated atmospheric CO2.【Method】Field experiment was carried out at Experiment Station of FACE(free-air carbon dioxide enrichment) in China.There were two treatments,including ambient(the CO2 concentration was approximately 370μmol·mol -1 ) and FACE(the target CO2 concentration was 200μmol·mol -1 higher than that of ambient) .Soil solution samples were collected in situ at different stages during the 2004,2005 and 2007 rice growing seasons.Concentrations of Ca and Mg in soil solution were determined.【Result】The concentrations of Ca in soil solution at 5 cm depth in FACE treatment were 25%,6%and-28%higher than those in ambient treatment during the 2004,2005 and 2007 rice growing seasons,respectively.The ratios of 15cm/5cm of Ca and Mg in soil solution from FACE treatment were-29%,14%and 80%and-26%,4%and 59%higher than those from ambient treatment during the 2004,2005 and 2007 rice growing seasons,respectively.The concentrations of Ca and Mg in soil solution at 0-15 cm depth in FACE treatment were less than ambient treatment by 6.8%and 4.6%in the year of 2007,respectively.【Conclusion】Elevated atmospheric CO2 influenced the distributions of Ca and Mg in soil solution at different depths in arable layer and increased the ratios of 15 cm/5 cm of Ca and Mg in soil solution.This indicates that elevated atmospheric CO2 has a potential impact of soil Ca,Mg in the biogeochemical cycles,and may affect rice yield and quality.更多还原