Microtopographic variation in soil respiration and its controlling factors vary with plant phenophases in a desert–shrub ecosystem
Microtopographic variation in soil respiration and its controlling factors vary with plant phenophases in a desert–shrub ecosystem
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DOI：
10.5194/bg-12-5705-2015
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发表时间：
2015-10
期刊：
影响因子：
4.9
通讯作者：
Ben Wang;T. Zha;Xin Jia;Jinnan Gong;Bin Wu;C. Bourque;Yuqing Zhang;Shu-gao Qin;G. P. Chen
中科院分区：
文献类型：
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作者：
Ben Wang;T. Zha;Xin Jia;Jinnan Gong;Bin Wu;C. Bourque;Yuqing Zhang;Shu-gao Qin;G. P. Chen
抽象的。 2012年，在中国西北荒漠灌丛生态系统的固定沙丘上测量了土壤呼吸（Rs）及其生物物理控制，以探讨土壤呼吸（Rs）空间异质性的控制机制，并了解植物对不同物候期Rs空间变化的影响。测量是在优势灌木物种（油蒿）物候期的四个坡向（即迎风、背风、朝北和朝南）和每个坡度的三个高度位置（即下、上和顶部）上进行的。在我们的测量期间，11 个微型站点的 Rs 变异系数（即标准差/平均值）为 23.5%。背风坡土壤呼吸强度最高，迎风坡土壤呼吸强度最低。在测量期间，与植物相关的因素，而不是微水文气象因素，影响了卢比的微地形变化。在开花阶段，根生物量对 Rs 的影响最大，解释了总变异的 72%。在叶片着色-落叶阶段，土壤氮含量对 Rs 的影响最大，解释了总变化的 56%。我们的研究结果强调，Rs 的空间格局取决于沙漠沙丘上的植物分布，而植物相关因素在很大程度上调节了 Rs 的地形变化，并且这种调节随植物物候的变化而变化。
Abstract. Soil respiration (Rs) and its biophysical controls were measured over a fixed sand dune in a desert–shrub ecosystem in northwest China in 2012 to explore the mechanisms controlling the spatial heterogeneity in Rs and to understand the plant effects on the spatial variation in Rs in different phenophases. The measurements were carried out on four slope orientations (i.e., windward, leeward, north- and south-facing) and three height positions on each slope (i.e., lower, upper, and top) across the phenophases of the dominant shrub species (Artemisia ordosica). Coefficient of variation (i.e., standard deviation/mean) of Rs across the 11 microsites over our measurement period was 23.5 %. Soil respiration was highest on the leeward slope, and lowest on the windward slope. Over the measurement period, plant-related factors, rather than microhydrometeorological factors, affected the microtopographic variation in Rs. During the flower-bearing phase, root biomass affected Rs most, explaining 72 % of the total variation. During the leaf coloration–defoliation phase, soil nitrogen content affected Rs the most, explaining 56 % of the total variation. Our findings highlight that spatial pattern in Rs was dependent on plant distribution over a desert sand dune, and plant-related factors largely regulated topographic variation in Rs, and such regulations varied with plant phenology.