Effect of soil temperature and soil water content on fine root turnover rate in a California mixed conifer ecosystem
Effect of soil temperature and soil water content on fine root turnover rate in a California mixed conifer ecosystem
复制标题
DOI：
10.1029/2009jg001210
复制
发表时间：
2010-12-04
影响因子：
3.7
通讯作者：
Allen, Michael F.
中科院分区：
文献类型：
--
作者：
Kitajima, Kuni;Anderson, Kurt E.;Allen, Michael F.
细根产量和周转率（根系种群平均寿命的倒数）的测量对于理解生态系统的碳循环至关重要，因为细根占全球陆地净初级产量的30%。我们的目标是描述地中海气候下细根产量、死亡率、立地作物和周转率。通过仿真，我们确定我们的采样间隔必须小于一个月，以保持流动率误差小于10%。在此区间内，我们通过标记-再捕获建模方法测量细根周转率，并将预测的周转率与观测的周转率进行比较。最佳选择模型表明，这些速率是直径、长度、土壤温度和土壤含水量的函数。周转率随直径和长度的减小以及土壤温度和含水量的增加而增加。我们发现细根产量、死亡率和周转率与土壤温度之间存在逐年滞后的规律。这可以用我们选择的最佳模型来解释土壤温度-水分滞后。春至初夏土壤温度和湿度均较高，产量和周转率较大，造成地下净初级产量的季节变化。我们认为这种行为可能是细根应对半干旱地中海气候有限生长季节的策略的结果。
Measurement of fine root production and turnover rate, the reciprocal of mean life span of a root population, is crucial to the understanding of the carbon cycle of an ecosystem as fine roots account for up to 30% of global terrestrial net primary production. Our goal was to characterize fine root production, mortality, standing crop, and turnover rate in a Mediterranean climate. Using simulations, we established that our sampling interval must be less than monthly to keep the turnover rate error to less than 10%. Adhering to this interval, we measured fine root turnover rate by mark-recapture modeling methods and compared predicted with observed turnover rates. The best selected model indicated that these rates were a function of diameter, length, soil temperature, and soil water content. Turnover rate increased with decreasing diameter and length and increasing soil temperature and soil water content. We found a yearly pattern of hysteresis between fine root production, mortality, and turnover rate relative to soil temperature. This was explained by soil temperature-moisture hysteresis using our best selected model. Production and turnover rate were greater in spring to early summer when both soil temperature and soil moisture were high, resulting in a seasonal variation of belowground net primary production. We suggest that this behavior could be a result of fine roots' strategy to cope with a limited growing season of a semiarid Mediterranean climate.