Partitioning of ecosystem respiration of CO 2 released during land-use transition from temperate agricultural grassland to Miscanthus × giganteus
Partitioning of ecosystem respiration of CO 2 released during land-use transition from temperate agricultural grassland to Miscanthus × giganteus
复制标题
温带农业草地向芒草土地利用转变过程中释放的CO 2 生态系统呼吸分配
DOI：
10.1111/gcbb.12380
复制
发表时间：
2016
期刊：
影响因子：
5.6
通讯作者：
McCalmont J
中科院分区：
文献类型：
--
作者：
McCalmont J
如果欧洲和英国国内的生物质生产要在满足需求方面发挥重要作用，那么大面积的农业草地的转换是不可避免的。了解这些土地利用变化对土壤碳循环和碳储量的影响取决于参数化模型的准确预测。关键考虑因素是栽培干扰和自养根输入刺激对新型生物质作物下土壤碳分解的影响。这项研究提出了分区参数从半改良草地转化为米斯维厄斯生物能源生产，并比较了自养和异养呼吸的贡献，整体生态系统呼吸的CO2在第一年和第二年的建立。使用根排除环内和无根排除环的呼吸重复测量值来产生时间序列模型积分，将活根输入与新作物种植时犁入的草残体分解分离。这些参数，然后比较总生态系统呼吸来自涡度协方差传感器。在第二个生长季节，平均土壤表面呼吸增加了13.4%，从2.9增加到3.29 g CO2-C m-2day-1。生态系统总呼吸量也有类似的趋势，从4.07克CO2-C m-2天-1增加到5.4克CO2-C m-2天-1。在第二个生长季节，根隔离环的异养呼吸为1.20 g CO2-C m-2day-1，比前一年的1.77 g CO2-C m-2day-1低32.2%。在两年的总呼吸通量中，地上部分的自养呼吸和凋落物分解对总生态系统呼吸的贡献率为38.46%，而地下部分的自养呼吸和活根输入的刺激对土壤表面呼吸的贡献率为46.44%。这一数字明显高于文献中非森林土壤的平均值，表明了呼吸模型作物特定参数化的重要性。
Conversion of large areas of agricultural grassland is inevitable if European and UK domestic production of biomass is to play a significant role in meeting demand. Understanding the impact of these land‐use changes on soil carbon cycling and stocks depends on accurate predictions from well‐parameterized models. Key considerations are cultivation disturbance and the effect of autotrophic root input stimulation on soil carbon decomposition under novel biomass crops. This study presents partitioned parameters from the conversion of semi‐improved grassland toMiscanthusbioenergy production and compares the contribution of autotrophic and heterotrophic respiration to overall ecosystem respiration of CO2in the first and second years of establishment. Repeated measures of respiration from within and without root exclusion collars were used to produce time‐series model integrations separating live root inputs from decomposition of grass residues ploughed in with cultivation of the new crop. These parameters were then compared to total ecosystem respiration derived from eddy covariance sensors. Average soil surface respiration was 13.4% higher in the second growing season, increasing from 2.9 to 3.29 g CO2‐C m−2day−1. Total ecosystem respiration followed a similar trend, increasing from 4.07 to 5.4 g CO2‐C m−2day−1. Heterotrophic respiration from the root exclusion collars was 32.2% lower in the second growing season at 1.20 g CO2‐C m−2day−1compared to the previous year at 1.77 g CO2‐C m−2day−1. Of the total respiration flux over the two‐year time period, aboveground autotrophic respiration plus litter decomposition contributed 38.46% to total ecosystem respiration while belowground autotrophic respiration and stimulation by live root inputs contributed 46.44% to soil surface respiration. This figure is notably higher than mean figures for nonforest soils derived from the literature and demonstrates the importance of crop‐specific parameterization of respiration models.