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    杜琳垚, 刘千慧, 申璇璇, 王绮彤, 王艺霖, 张峰, 于海群, 贾昕. 降雨减少对油松人工林凋落叶分解的影响[J]. 北京林业大学学报, 2020, 42(7): 68-76. DOI: 10.12171/j.1000-1522.20190211
    引用本文: 杜琳垚, 刘千慧, 申璇璇, 王绮彤, 王艺霖, 张峰, 于海群, 贾昕. 降雨减少对油松人工林凋落叶分解的影响[J]. 北京林业大学学报, 2020, 42(7): 68-76. DOI: 10.12171/j.1000-1522.20190211
    Du Linyao, Liu Qianhui, Shen Xuanxuan, Wang Qitong, Wang Yilin, Zhang Feng, Yu Haiqun, Jia Xin. Effects of rainfall reduction on litter leaf decomposition of Pinus tabuliformis plantation[J]. Journal of Beijing Forestry University, 2020, 42(7): 68-76. DOI: 10.12171/j.1000-1522.20190211
    Citation: Du Linyao, Liu Qianhui, Shen Xuanxuan, Wang Qitong, Wang Yilin, Zhang Feng, Yu Haiqun, Jia Xin. Effects of rainfall reduction on litter leaf decomposition of Pinus tabuliformis plantation[J]. Journal of Beijing Forestry University, 2020, 42(7): 68-76. DOI: 10.12171/j.1000-1522.20190211

    降雨减少对油松人工林凋落叶分解的影响

    Effects of rainfall reduction on litter leaf decomposition of Pinus tabuliformis plantation

    • 摘要:
        目的  凋落物分解是森林生态系统物质循环和能量流动的重要环节。探究降雨减少对油松人工林凋落叶分解的影响,有助于理解油松人工林碳(C)氮(N)循环对降雨减少的响应,可为气候变化情景下人工林生态系统功能预测与评估提供科学支撑。
        方法  以北京八达岭林场油松人工林为研究对象,采用野外控制实验,通过设置3个减雨水平(100%减雨、50%减雨和对照),对比分析不同处理下油松人工林凋落叶分解过程中的质量损失和C、N动态。
        结果  布设分解袋5个月后(2018年5—10月),100%减雨处理下的油松凋落叶未见质量损失,甚至出现微弱的物质积累;50%减雨处理下的凋落叶质量残留率、C残留率和N残留率分别为75.75%、49.31%和71.00%;对照下分别为73.18%、51.92%和75.50%。凋落叶质量和C、N残留率在50%减雨处理和对照间差异不显著。50%减雨处理和对照下的年分解速率k分别为0.64和0.92。油松凋落叶月分解速率与土壤含水量之间呈显著正相关。50%减雨处理和对照下的油松凋落叶N元素呈现出先富集(6月)后释放(7—10月)的动态。
        结论  在北京油松人工林中,降雨减少对油松凋落叶分解的影响依赖于降雨减少的程度,在轻度和中度干旱下其分解速率仅略微下降,且C、N动态基本维持不变;而严重干旱下其分解速率和C、N周转均受到强烈制约。

       

      Abstract:
        Objective  Litter decomposition plays an important role in carbon and nutrient cycles of forest ecosystems. The effects of rainfall reduction on leaf litter decomposition of Pinus tabuliformis were examined to understand the response of carbon (C) and nitrogen (N) turnover dynamics of P. tabuliformis plantations to future changes in precipitation, and to improve the prediction and assessment of ecosystem functions of plantations under climate change.
        Method  A field rainfall reduction experiment was performed in a plantation at Badaling Forest Farm, about 50 km north of Beijing from May to October, 2018. Losses of mass, C and N dynamics of P. tabuliformis leaf litter were measured and compared among three growing-season rainfall levels, i.e. 100% rainfall reduction, 50% rainfall reduction and control.
        Result  After five months of decomposition, no litter mass loss was detected for the 100% rainfall reduction treatment and slight increase in litter mass was actually observed. The percentages of remaining litter mass, C and N for the 50% rainfall reduction treatment were 75.75%, 49.31% and 71.00%, respectively, while those for the control were 73.18%, 51.92% and 75.50%, respectively. There were no significant differences in remaining litter mass, C and N between the 50% rainfall reduction treatment and control. The annual decomposition coefficients (k) for the 50% rainfall reduction treatment and control were 0.64 and 0.92, respectively. There was a significant positive correlation between the monthly decomposition rate and soil water content. For the 50% rainfall reduction treatment and control, N immobilization was observed in June and N release was observed from July to October.
        Conclusion  In the P. tabuliformis plantation, the effects of rainfall reduction on leaf litter decomposition depend on the magnitude of rainfall reduction. The decomposition dynamics of P. tabuliformis leaf litter may be relatively insensitive to mild and moderate droughts, but severe droughts can strongly restrict the decomposition rate and the turnover of C and N.

       

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