不同氮水平下CO2浓度升高对小麦土壤可溶性C、N和P的影响

采用FACE(Freeaircarbondioxideenrichment)技术,研究了不同N施肥水平下,大气CO2浓度升高对稻/麦轮作小麦季土壤可溶性C、N、P的影响。结果表明,高CO2使土壤可溶性C在小麦前期和0~5cm土层降低,成熟期增加,对水稻和小麦不同轮作季土壤可溶性C的影响不同。在低N和常规N处理下,高CO2使小麦分蘖期土壤可溶性N含量分别增加17.2%和18.9%,在其他生长期,土壤可溶性N含量降低9.8%~63.0%,拔节期降低幅度最大分别为63.0%和50.4%,土层0~5cm降低幅度>5~15cm土层;小麦季和水稻季一样需要增加N肥施用量。CO2浓度升高增加了土壤可溶性P的含量,其中低N处理增加幅度高于常规N处理,研究表明小麦生长不会受到P养分的限制。

EFFECT OF FACE(FREE AIR CARBON-DIOXIDE ENRICHMENT)ON AVAILABLE C, N AND P IN SOIL UNDER WHEAT TREATED WITH DIFFERENT N LEVELS

Effect of elevated atmospheric CO2 on available C, N and P in the soil under winter wheat growing through FACE(free air carbon dioxide enrichment)system was studied, through comparison between FACE and the ambient in content of available C, N and P in the soil at different wheat growing stages. The results showed that elevated CO2 decreased the content of soil available C in the 0~5 cm soil layer before the heading stage, but increased at the ripening stage. The effect of elevated CO2 on soil available C differed between rice and winter wheat. Under LN and NN treatments, elevated CO2 increased soil available N by 17.2% and 18.9% at the tillering stage, but decreased by 9.8%-63.0% at others stages and the most at the heading stage, up to 63.0% and 50.4%, respectively. The results indicate that it is necessary to increase N fertilizer application level to both rice and winter wheat growing under elevated CO2] condition. The content of soil available P increased due to elevated CO2], more in the LN treatment than in the NN treatment. The study indicates that growth of winter wheat will not restricted by soil P under elevated CO2 condition.