极端干旱区增雨对泡泡刺(Nitraria sphaerocarpa)群落土壤呼吸的影响

Effect of Rain Supplementation on Soil Respiration of Nitraria sphaerocarpa Community in Hyperarid Area of Dunhuang,China

在极端干旱区(敦煌)以泡泡刺群落为研究对象,测定分析了生长季内增雨对泡泡刺灌丛和裸地土壤呼吸速率的影响。结果表明:增雨增加了灌丛和裸地的土壤呼吸速率,且增雨越多,增量越大,对土壤呼吸影响的持续时间也越长;以月为单位,每增雨16mm和24mm分别使裸地土壤呼吸速率显著增加90%和106%(p<0.01),增雨8mm、16mm和24mm则分别使灌丛土壤呼吸速率显著增加68%、157%和205%(p<0.01);裸地和灌丛土壤呼吸对增雨响应的时间不同步,且灌丛土壤呼吸对增雨的响应量比裸地快118%;整个生长季土壤呼吸速率和土壤含水量有明显的正相关关系(p<0.01),并且每增雨1mm,裸地和灌丛土壤呼吸速率分别增加0.01μmol.m-2.s-1和0.04μmol.m-2.s-1。

In order to analyze the effect of rain supplementation on soil respiration rate of Nitraria sphaero- carpa community, we measured soil respiration rate in bare and vegetated area in hyperarid area （Dunhuang, Gansu, China） during the growing season. The results showed that the rain supplementation in the growing season promoted the carbon flux of bare soil and vegetated soil to change dramatically. The more the rain supplementation, the greater the increment and the longer duration time effect to soil respiration rate. Compared with the controlled treatment, the rain supplementation by 100 %, 200 % and 300 % respectively made the soil respiration rate of bare soil to increase by 34 %, 90 % and 106 % respectively, and made the soil respiration rate of shrub soil to increase by 68 %, 157 % and 205 % respectively. The response time of bare and vegetated soil respiration to rain supplementation was asynchronous. Response variable of soil respiration in vegetated soil was higher 118% than soil respiration in bare soil. There was significant positive correlation between soil respiration rate and soil water content during the growing season （p〈0.01）. For the rain supplementation of lmm, the soil respiration rates of the bare soil and shrub soil respectively increased by 0.01μmol.m-2.s-1 and 0.04μmol.m-2.s-1.