模拟增温及施氮对荒漠草原土壤呼吸的影响

Response of soil respiration to simulated warming and N addition in the desert steppe

以内蒙古高原四子王旗短花针茅建群的荒漠草原为研究对象,通过野外自然条件下进行的模拟增温和增施氮肥实验,研究了增温、施氮及增温+施氮情况下土壤呼吸强度的变化。三年的研究结果表明:1)增温对各年内土壤呼吸没有产生显著影响,但土壤呼吸有明显的季节变化,而且与增温显著相关(P<0.05)。2)施氮对荒漠草地的影响程度与自然条件有密切关系,其中降雨量多少是施氮对荒漠草地土壤呼吸影响程度的重要制约因素,降雨量越高氮素对土壤呼吸作用愈加明显。3)施氮显著增加了植物群落的地下生物量(P<0.05),土壤呼吸与地下生物量呈显著的正相关(P<0.001)。

We studied the effect of warming, nitrogen fertilizer and their interaction of the warming and the nitrogen fertilizer on soil respiration of the communities of the Stipa breviflora desert steppe in Inner Mongolia. Three years＂ study showed the evident temperature was linearly and positively correlated with mean soil respiration in three years, however, elevated temperature had not impact on soil respiration. Secondly, there were close relationships between the natural conditions and the effect of the nitrogen fertilizer to the desert grassland, among them the rainfall was the main factor which had a positive effect to the nitrogen fertilizer. In high precipitation season, N addition promoted soil respiration. N addition significant increased underground biomass of the plants, and a significantly positive correlation was detected between under - ground biomass and soil respiration （P 〈0.001）.