Shifts of growing‐season precipitation peaks decrease soil respiration in a semiarid grassland
Shifts of growing‐season precipitation peaks decrease soil respiration in a semiarid grassland
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DOI：
10.1111/gcb.13941
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发表时间：
2018-03
影响因子：
11.6
通讯作者：
Jingyi Ru;Yaqiong Zhou;D. Hui;Mengmei Zheng;S. Wan
中科院分区：
文献类型：
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作者：
Jingyi Ru;Yaqiong Zhou;D. Hui;Mengmei Zheng;S. Wan
变化的降水制度可能对生物圈中的碳(C)循环产生深远的影响。然而，陆地生态系统的土壤C释放如何响应降水季节分布的变化仍不清楚。通过2013-2016年4年的野外试验，研究了蒙古高原温带草原生长季节降水分布变化对土壤呼吸的影响。4 a来，提前和延迟降水高峰均抑制土壤呼吸，且主要发生在8月份。土壤呼吸减少的主要原因可能是水分胁迫导致生长中期植物生长（群落盖度和地下净初级生产力）和土壤微生物活动受到限制，表明生长中期降水量对草地土壤C释放的调节作用比生长早期、晚期和整个生长季更重要。预估未来降水季节再分布下，提前和延迟降水峰值的加性效应表明，半干旱草原通过土壤呼吸过程释放的碳将减少。我们的研究结果强调了在干旱和半干旱地区，降水的年际再分配在调节生态系统C循环中的潜在作用。
Changing precipitation regimes could have profound influences on carbon (C) cycle in the biosphere. However, how soil C release from terrestrial ecosystems responds to changing seasonal distribution of precipitation remains unclear. A field experiment was conducted for 4 years (2013–2016) to examine the effects of altered precipitation distributions in the growing season on soil respiration in a temperate steppe in the Mongolian Plateau. Over the 4 years, both advanced and delayed precipitation peaks suppressed soil respiration, and the reductions mainly occurred in August. The decreased soil respiration could be primarily attributable to water stress and subsequently limited plant growth (community cover and belowground net primary productivity) and soil microbial activities in the middle growing season, suggesting that precipitation amount in the middle growing season is more important than that in the early, late, or whole growing seasons in regulating soil C release in grasslands. The observations of the additive effects of advanced and delayed precipitation peaks indicate semiarid grasslands will release less C through soil respiratory processes under the projected seasonal redistribution of precipitation in the future. Our findings highlight the potential role of intra‐annual redistribution of precipitation in regulating ecosystem C cycling in arid and semiarid regions.