Response of ecosystem respiration to soil water and plant biomass in a semiarid grassland
Response of ecosystem respiration to soil water and plant biomass in a semiarid grassland
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DOI：
10.1111/j.1747-0765.2010.00502.x
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发表时间：
2010-10-01
影响因子：
2
通讯作者：
Shinoda, Masato
中科院分区：
文献类型：
--
作者：
Nakano, Tomoko;Shinoda, Masato
蒙古草原区是东亚草原的重要组成部分。研究了半干旱草地生态系统土壤水分和植物生物量对生态系统呼吸的影响。我们确定R-生态使用不透明，封闭的房间在蒙古草原为主的禾本科多年生禾草在六个时期：2004年7月，2005年5月，2005年7月，2005年9月，2006年6月，2009年8月。利用土壤含水量和地上生物量相对恒定时采集的数据，将R-eco值拟合为指数温度函数，计算了各测区和各测期R-eco在20 ℃时的标准化率（R-20）和温度敏感性（Q（10））。结果表明，地上生物量对R-20的变化有显著影响，其关系符合线性模型。线性生物量模型的R-20残差与土壤含水量呈二次函数关系。Q（10）值与土壤含水量呈弱正相关。利用与地上生物量和土壤含水量相关的R-20和与土壤含水量相关的Q（10）指数温度模型，可以较好地预测R-eco的时空变化。
The Mongolian steppe zone constitutes a major part of East Asian grasslands. The objective of this study was to evaluate the quantitative dependence of ecosystem respiration (R-eco) on the environmental variables of soil water and plant biomass in a semiarid grassland ecosystem. We determined R-eco using opaque, closed chambers in a Mongolian grassland dominated by graminaceous perennial grasses during six periods: July 2004, May 2005, July 2005, September 2005, June 2006, and August 2009. Using the data collected when soil water content and aboveground biomass were relatively constant, values of R-eco were fitted to an exponential temperature function, and the standardized rate of R-eco at 20 degrees C (R-20) and temperature sensitivity (Q(10)) of R-eco were calculated for each measurement plot and period. The results indicate that aboveground biomass significantly affected the variation in R-20, and the relationship was expressed with a linear model. The R-20 residuals of the linear biomass model were highly correlated with soil water content by a quadratic function. The Q(10) values showed a weak positive relationship with soil water content. Temporal and spatial variations in R-eco were well predicted by the exponential temperature model with R-20, which relates to aboveground biomass and soil water content, and with Q(10), which relates to soil water content.