Shifts of growing‐season precipitation peaks decrease soil respiration in a semiarid grassland

• Published in: Global change biology 2018-03, Vol.24 (3), p.1001-1011
• Main Authors: Ru, Jingyi, Zhou, Yaqiong, Hui, Dafeng, Zheng, Mengmei, Wan, Shiqiang
• Format: Article
• Language: English
• Subjects: Additives; Annual precipitation; Arid regions; Biosphere; Carbon cycle; carbon cycling; climate change; Ecosystems; Environmental changes; Grasslands; Growing season; Microorganisms; Net Primary Productivity; Plant communities; Plant growth; plants; Plateaus; Precipitation; Primary production; Respiration; Seasonal distribution; Seasons; Semiarid lands; Soil; Soils; temperate steppe; Terrestrial ecosystems; Terrestrial environments; water; Water stress
• ISSN: 1354-1013; 1365-2486
• DOI: 10.1111/gcb.13941

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. This study examining the effects of altered precipitation distributions in the growing season on soil respiration in a temperate steppe in the Mongolian Plateau, and finding that both advanced and delayed precipitation peaks suppressed soil respiration. The observations suggest 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 and highlight the potential role of intra‐annual redistribution of precipitation in regulating ecosystem C cycling in arid and semiarid regions.