大气O_3浓度升高对稻季耕层土壤溶液CaMg浓度的影响

利用中国稻/麦轮作系统O3-FACE（Ozone-Free Air Concentration Enrichment）试验平台,研究了大气O3浓度升高（比周围大气高50%）对稻季不同生育期耕层土壤溶液中Ca、Mg浓度的影响。结果表明,大气O3浓度升高对稻田0~15 cm耕层土壤溶液Ca浓度无明显影响,但Mg浓度呈现降低趋势;降低了15 cm处土壤溶液Ca、Mg浓度,其中对Mg浓度的降低幅度为20.97%,且达显著水平;大气O3浓度升高可改变耕层土壤溶液中Ca、Mg离子在不同深度的分布,降低15 cm处土壤溶液Ca、Mg浓度与5 cm处比值,降低幅度分别为13.50%、34.29%。文章指出大气O3浓度升高会对稻田生态系统土壤Ca、Mg元素地球化学循环产生重要影响,并可能因此影响稻米产量和品质。

Effect of O_3 Enrichment on Ca and Mg Concentration in Soil Solution at Arable Layer in the Rice Season

The objective of this study is to investigate the effects of atmospheric elevated O3 on concentrations of Ca,Mg in soil solution under the wheat-rice rotation.Ozone Free-air Concentration Enrichmen（tO3-FACE）system at Xiaoji town,Jiangdu County,Jiangsu Province,China（32°35′5′′N,119°42′0′′E）was used in this study.The target O3 for FACE plots was 50% higher than that in the ambient O3.Concen-trations of Ca and Mg in soil solution at different depths（5 cm and 15 cm）were determined under ambient and elevated ozone concentration treatment at different stages of the rice season in 2007.The results showed that elevated atmospheric O3 had no obvious influence on concen-tration of Ca in 0~15 cm soil solution,while had a trend to decrease the concentration of Mg in 0~15 cm soil solution.Elevated atmospheric O3 decreased the concentration of Ca in 15 cm soil solution,and significantly decreased the concentration of Mg in 15 cm soil solution with 20.97%（P=0.022）.Elevated atmospheric O3 changed the distribution of Ca,Mg in soil solution at different depths in arable layer,and de-creased the ratio of Ca,Mg concentration in soil solution at 15 cm depth to that at 5 cm depth.FACE treatment decreased the ratio of 15 cm/5 cm of Ca and Mg by 13.50% and 34.29%,respectively.It was indicated that elevated atmospheric O3 had a potential impact on soil Ca,Mg in the biogeochemical cycles,and might affect rice yield and quality.