Plants Mediate the Sensitivity of Soil Respiration to Rainfall Variability
Plants Mediate the Sensitivity of Soil Respiration to Rainfall Variability
复制标题
DOI：
10.1007/s10021-010-9401-y
复制
发表时间：
2011-01-01
期刊：
影响因子：
3.7
通讯作者：
Lennon, Jay T.
中科院分区：
文献类型：
--
作者：
Aanderud, Zachary T.;Schoolmaster, Donald R., Jr.;Lennon, Jay T.
草原土壤呼吸在土壤与大气之间的二氧化碳（CO2）反馈中起着关键作用。在这些通常的中温系统中，土壤水分和温度往往共同调节土壤呼吸。降雨模式的变化可能会改变地上-地下的相互作用，并对土壤呼吸对水分和温度波动的敏感性产生重要影响。我们进行了一系列的田间试验，以评估独立和交互作用的影响，降雨变异和植物土壤过程对呼吸动力学。植物去除草地土壤，其中包括改变CO2通量，由于没有根呼吸;增加土壤水分和温度;和减少微生物异养呼吸的溶解有机碳（DOC）的可用性有很强的影响。这些植物介导的影响与我们的降雨变率处理，以确定土壤呼吸的敏感性，水分和温度。利用时间序列多元回归分析，我们发现，植物阻尼呼吸水分的敏感性，在高变率降雨处理，这可能反映了相对稳定的根系对总土壤呼吸的贡献。与此相反，植物增加了呼吸作用的敏感性，温度低变率降雨处理下，这表明土壤CO2动态的环境控制中的梅西奇栖息地可能是上下文相关的。我们的研究结果提供了深入了解地上地下机制控制呼吸在草原上可变的降雨制度，这可能是重要的预测CO2动态下，当前和未来的气候情景。
Soil respiration from grasslands plays a critical role in determining carbon dioxide (CO2) feedbacks between soils and the atmosphere. In these often mesic systems, soil moisture and temperature tend to co-regulate soil respiration. Increasing variance of rainfall patterns may alter aboveground-belowground interactions and have important implications for the sensitivity of soil respiration to fluctuations in moisture and temperature. We conducted a set of field experiments to evaluate the independent and interactive effects of rainfall variability and plant-soil processes on respiration dynamics. Plant removal had strong effects on grassland soils, which included altered CO2 flux owing to absence of root respiration; increased soil moisture and temperature; and reduced availability of dissolved organic carbon (DOC) for heterotrophic respiration by microorganisms. These plant-mediated effects interacted with our rainfall variability treatments to determine the sensitivity of soil respiration to both moisture and temperature. Using time-series multiple regression, we found that plants dampened the sensitivity of respiration to moisture under high variability rainfall treatments, which may reflect the relative stability of root contributions to total soil respiration. In contrast, plants increased the sensitivity of respiration to temperature under low variability rainfall treatment suggesting that the environmental controls on soil CO2 dynamics in mesic habitats may be context dependent. Our results provide insight into the aboveground-belowground mechanisms controlling respiration in grasslands under variable rainfall regimes, which may be important for predicting CO2 dynamics under current and future climate scenarios.