不同施氮水平对华北平原冬小麦土壤CO_2通量的影响

Effect of different nitrogen levels on soil CO_2 fluxes of winter wheat in north China plain

针对当前碳、氮循环对生态环境影响以及碳源/汇问题的客观实际,设计了N0、75、150、225、300kg·hm-25个氮处理,对冬小麦(TriticumaestivumL.)返青期、拔节期、孕穗期、灌浆期和成熟期进行了土壤呼吸速率的测定,探讨了不同氮肥用量对华北平原潮褐土区冬小麦农田土壤CO2释放的影响。结果表明:土壤呼吸释放CO2与气温二次相关,25℃左右土壤呼吸速率达到最大,增幅随气温升高而减小,低于25℃时增幅较明显;随着氮肥用量增加土壤呼吸增强,土壤呼吸强度在N150达到最大;施用氮肥的冬小麦农田土壤CO2释放主要集中在孕穗、灌浆期;不施氮的则主要集中在灌浆、成熟期。

According to the effect of carbon and nitrogen cycle on ecological environment, especially the carbon source/sink problem, five N-treatments（ N0, N75, N150, N225, N300（ kg N·hm^2 ） ）were designed, and soil respiration rate of winter wheat （Triticum aestivum L.）, including Turning green stage, Jointing stage, Booting stage, Filling stage and Maturing stage） were measured. The effect of different nitrogen application on meadow cinnamon soil CO,, emission of winter wheat in North China Plain was further discussed. The results showed that CO2 emission coining from soil respiration quadratically con-elated to the temperature, the maximum soil respiration rate was at about 25℃, the amplitude minished with the increase of temperature, and the amplitude under 25 ℃ was more significant; soil respiration increased with the increase of nitrogen amount, the maximum soil respiration rate was at N150 level; soil CO2 emission of the fields in which nitrogen applied mainly concentrated on the booting and filling stages, while no nitrogen applied ones mainly concentrated on the grouting and maturity stages.