Effects of elevated CO2 on soil C, P and K around the roots of rice and wheat MA Hong-Liang1,*, XU Yi-Jie1, ZHU Jian-Guo2, WU Yan-Hong1, XIE Zu-Bin2, LIU Gang2, GAO Ren1
摘 要 ：利用FACE(free air carbon dioxide enrichment)技术平台，在两种氮肥施用（低氮，LN和常规氮，NN）水平下，研究CO2浓度升高对水稻和小麦收获后根际和非根际土壤可溶性碳、有机磷、速效磷和速效钾的影响。结果表明，相对于对照CO2浓度处理，高CO2浓度处理在显著增加作物生物量的前提下，土壤速效磷和速效钾不但没有降低反而增加，增加幅度小麦季大于水稻季，根际大于非根际；水稻季土壤可溶性碳含量增加，且NN水平下水稻和小麦季进入土壤的可溶性碳增加，导致土壤有机磷降低幅度低于LN水平，且水稻季根际土壤大于非根际土壤，有机磷的降低是保证有效磷升高的一个重要因素，增加氮肥施用将有利于土壤有机磷的增加，对维持土壤磷的供给有积极作用，有利于作物对高CO2浓度的持续响应。
Abstract:The present study is conducted to determine effects of elevated atmospheric CO2 concentration on soil soluble C、available P and K, and organic P in rhizosphere and non-rhizosphere after crops harvested under two N levels with FACE(free air carbon dioxide enrichment) systems. The results showed that compared with ambient CO2, elevated CO2 did not decrease soil available P and K but increase them with increased biomass of rice and wheat and soil available P and K were increased more in wheat season than in rice one, more in root rhizosphere than in non-rhizosphere. Soil soluble C was increased by elevated CO2 and more carbon input to soil under NN treatment resulted in a more decrease of soil organic P at LN than at NN, in rhizosphere than in non-rhizosphere of rice. The decrease of organic P played an important role in the increase of soil available P. More N application, for example, NN treatment was beneficial to increase of soil organic P and then perform a positive function in keeping the soil P available, which could insure the continuously response of crops to elevated CO2.