中文摘要：

采用FACE（Free air carbon dioxide enrichment）技术,研究了不同施氮水平下,大气CO2浓度升高对水稻/小麦轮作土壤速效钾的影响。结果表明,相对于对照处理,在不同氮水平下CO2浓度升高使作物生物量增加,导致作物生长季对土壤钾的吸收增加,但并没有降低作物主要生长期土壤（0—5、5—15 cm土层）速效钾的含量;CO2浓度升高使土壤速效钾增加的幅度在作物根际达6.3%～22.3%,在行间达3.7%～11.2%,且土壤速效钾增加的幅度在小麦季大于水稻季。表明根系对土壤速效钾的影响很大,因此,短期内土壤钾含量不会成为限制因素而影响作物对高CO2浓度的响应,反而会增加土壤钾的有效性。但在土壤肥力较低的土壤上可能会产生消极影响。

英文摘要：

The effect of elevated atmospheric CO2 on soil available K in paddy soil through FACE（Free air carbon dioxide enrichment）system was studied by comparing the contents of soil available K at different growth stages of the rice-wheat rotation system. The results show that compared to the ambient air treatment, K uptakes of the crops are increased by elevated CO2 due to significant increase of their biomass, while the contents of soil available K of both upper soil layer （0- 5 cm） and lower soil layer （5-15 cm） are not decreased. The increase magnitudes of soil available K due to elevated CO2 are 6.3 % - 22.3 % in root rhizosphere and 3.7 % - 11.2 % between crops lines. The increment of soil available K around wheat roots is higher than that of rice. These results indicate that root increased by elevated CO2 is beneficial to soil available K for crops, and K is not a limited factor for response of crops to elevated CO2 in a short time. However, this phenomenon may have negative effects for soils with poor fertility.