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在华西雨屏区天然常绿阔叶林中,通过野外原位试验,设置对照(CK)、减少降雨5%(W1)、减少降雨10%(W2)、减少降雨20%(W3)和减少降雨50%(W4)5个处理,采用LI-8100土壤碳通量分析系统(LI-COR Inc.,USA)测定土壤呼吸速率及其相应环境因子,并通过回归方程分析土壤呼吸速率与10 cm土壤温度和0-10 cm土壤水分间的关系,研究模拟减雨对华西雨屏区天然常绿阔叶林土壤呼吸的影响.结果表明:(1)W1处理对常绿阔叶林土壤呼吸无显著影响,W2处理显著促进了常绿阔叶林土壤呼吸,W3和W4处理显著抑制了常绿阔叶林土壤呼吸(P<0.05);(2)W1、W3和W4处理的年累计土壤呼吸分别比CK减少了3.03%、12.26%和26.67%,而W2处理比CK增加了11.17%;(3)W2处理使土壤呼吸的温度敏感性降低,而W1、W3和W4则提高了土壤呼吸的温度敏感性.综上所述,降雨减少显著影响了阔叶林土壤呼吸,改变了土壤呼吸的温度敏感性.(图4表1参28)
In the natural evergreen broad-leaved forest in the rain-screen area of western China, CK was set up in situ in the field to reduce the rainfall by 5% (W1), reduce the rainfall by 10% (W2), reduce the rainfall by 20% (W3) and reduce the rainfall by 50% (W4), the soil respiration rate and its corresponding environmental factors were determined by LI-8100 soil carbon flux analysis system (LI-COR Inc., USA), and the relationship between soil respiration rate and 10 cm soil temperature And 0-10 cm soil moisture, the effects of simulated rainfall on soil respiration in natural evergreen broad-leaved forest in the rain-screen area of Huaxi were studied.The results showed that: (1) W1 treatment had no significant effect on soil respiration in evergreen broad-leaved forest , W2 treatment significantly promoted soil respiration in evergreen broad-leaved forest, W3 and W4 treatment significantly inhibited soil respiration in evergreen broad-leaved forest (P <0.05); (2) The annual cumulative soil respiration rates of W1, W3 and W4 were CK decreased by 3.03%, 12.26% and 26.67%, while W2 increased by 11.17% compared with CK; (3) W2 decreased the temperature sensitivity of soil respiration, while W1, W3 and W4 increased the temperature sensitivity of soil respiration In summary, rainfall reduction significantly affected soil respiration in broad-leaved forests and altered the temperature sensitivity of soil respiration (Figure 4, Table 1, ref. 28)