大气CO_2浓度升高对水稻土团聚体的分布与有机碳含量的影响  

Effects of Elevated CO_2 on Soil Aggregation and Soil Organic Carbon Allocation in a Rice Paddy Field

作　　者：徐乔[1,2] 朱建国[1] 朱春梧[1] 刘钢[1] 曾青[1] 

机构地区：[1]土壤与农业可持续发展国家重点实验室(中国科学院南京土壤研究所),南京210008 [2]中国科学院大学,北京100049

出　　处：《土壤》2014年第6期989-996,共8页Soils

基　　金：科技部国际合作和交流项目(2010DFA22770);国家自然科学基金国际(地区)合作与交流项目(31261140364);国家自然科学基金项目(41271310)资助

摘　　要：采取中国FACE（Free-air CO2 enrichment）平台9年试验区的土壤,采用干湿筛法获得水稳定性团聚体,研究高CO2浓度处理对水稻土团聚体组成、有机碳含量的影响。FACE试验设对照和高CO2浓度两个主处理,低氮和常氮两个施氮水平裂区。结果表明,经高CO2浓度连续9年处理后,小区土壤有机碳总量显著增加（年均1%）。高CO2浓度改变0-5 cm土层土壤团聚体的分布,大团聚体（〉250μm）含量有减少趋势,而微团聚体（250-53μm）含量平均增加27.49%（P=0.05）;常氮仅改变5-15 cm土层土壤粗大团聚体（〉2 000μm）含量,平均减少20.60%（P〈0.05）。分析表明,高CO2浓度使得0-5 cm土层土壤细大团聚体（2 000-250μm）有机碳含量平均降低9.67%（P〈0.01）,微团聚体有机碳含量平均增加31.30%（P〈0.05）,CO2和N交互有促进上述变化趋势。高CO2浓度增加5-15 cm土层土壤粗大团聚体有机碳含量（26.44%,P=0.05）,降低细大团聚体有机碳含量（6.83%,P〈0.01）;常氮减少5-15 cm土层土壤粗大团聚体有机碳含量（30.19%,P〈0.001）;CO2和N交互显著降低5-15 cm土层两级大团聚体有机碳含量。高CO2浓度降低耕层土壤（0-15 cm）细大团聚体有机碳储量（6.41%,P〈0.01）,增加微团聚体有机碳储量（15.09%,P〈0.05）;常氮显著降低两级大团聚体有机碳储量,且CO2和N交互降低细大团聚体有机碳储量（P〈0.05）。Based on dry and wet sieving sequences, water-stable aggregates were separated from bulk soils sampled at Chinese FACE（Free-air CO2 enrichment） Platform. The experiment was set as two main treatments： atmospheric CO2 and elevated CO2 and two sub-treatments： low amount of nitrogen fertilizer（LN） and normal amount of nitrogen fertilizer（NN）. The effects of elevated CO2 on soil aggregation, soil organic carbon contents（SOC） in aggregates were studied and analyzed. It showed that after 9 years, elevated CO2 increased soil organic carbon by 1% per year. At the 0 – 5 cm soil depth, macroaggregates（〉250 μm） tended to break down and thus forming more microaggregates（250 – 53μm）（27.49%, P = 0.05） under elevated CO2; NN decreased the amount of large macroaggregates（2 000 μm） of 5 – 15 cm soil by 20.60%（P〈0.05）. Elevated CO2 had a positive effect on SOC in microaggregates（31.30%, P〈0.05）, and a negative effect on SOC in small macroaggregates（2 000 – 250 μm）（9.67%, P〈0.01） at 0 – 5 cm soil depth; the interaction effect of CO2 and N had a trend to enhance such changes. Elevated CO2 increased SOC of large macroaggregates（26.44%, P = 0.05） and decreased SOC of small macroaggregates（6.83%, P〈0.01） at the 5 – 15 cm soil depth; NN decreased SOC in large macroaggregates at 5 – 15 cm soil depth by 30.19%（P〈0.001）; the interaction effect of CO2 and N decreased SOC in macroaggregates. Elevated CO2 decreased the storage of SOC in small macroaggregates（6.41%, P〈0.01） and increased the storage of SOC in microaggregates（15.09%, P〈0.05） of surface soil（0 – 15 cm）; NN decreased the storage of SOC in macroaggregates; the interaction effect of CO2 and N decreased the storage of SOC in small macroaggregates（P〈0.05）.

关 键 词：高CO2浓度 团聚体分级 有机碳 水稻土 

分 类 号：S152.3[农业科学—土壤学]