开放式空气CO2浓度升高对水稻土壤可溶性C、N和P的影响

采用 FACE (Free air carbon dioxide enrichment)技术,研究了不同 N 施肥水平下,大气 CO2浓度升高对水稻/小麦轮作中水稻土壤可溶性 C、N、P 的影响。结果表明,CO2浓度升高使土壤表层可溶性 C 含量增加,土壤 5 ~ 15 cm 的可溶性 C 含量倾向于降低,增加 N 肥施用(常规 N 处理)更易于使土壤可溶性 C 含量降低。CO2浓度升高使水稻土壤中的可溶性 N 含量降低,在低 N 处理和土壤表层降低幅度较大,N 肥施用仍有提高的余地。CO2浓度升高使水稻成熟期土壤可溶性 P 含量增加,但是常规N 处理下会降低水稻生长前期和土壤表层的可溶性 P,增加 N 肥施用有利于水稻对 P 的吸收。

EFFECT OF FACE(FREE AIR CARBON-DIOXIDE ENRICHMENT) ON SOLUBLE C, N AND P IN SOIL DURING RICE GROWING

Effect of elevation of atmospheric CO2 on soluble C, N and P in paddy soil through a FACE(Free air carbon-dioxide enrichment)system was studied by comparing FACE with Ambient in content of soil soluble C, N and P, between different rice growing stages. The results show that compared to the treatment of ambient air, elevated CO2 results in increasing soluble C in the upper soil layer (0~1cm) and decreasing soluble C in the lower soil layer (5~15cm). With a higher rate of N fertilizer application, elevated CO2 is more likely to decrease the content of soluble C in the soil. Elevated CO2 decreases soluble N in paddy soil under different N levels by the most at 0-1cm soil layer and in LN treatment. The decreasing in the content of soluble N in the soil indicates that it is unadvisable to increase the application rate of N fertilizer under increasing atmospheric CO2 concentration. The content of soluble P increased due to elevated CO2 at the rice ripening stage. But it decreased at the tillering and jointing stages and in the soil layer of 0~1cm under NN treatment. The uptake of P by rice increased under higher N application rate (NN treatment) due to elevated CO2.