Precipitation regime shift enhanced the rain pulse effect on soil respiration in a semi-arid steppe

PLoS One. 2014 Aug 5;9(8):e104217. doi: 10.1371/journal.pone.0104217. eCollection 2014.

Abstract

The effect of resource pulses, such as rainfall events, on soil respiration plays an important role in controlling grassland carbon balance, but how shifts in long-term precipitation regime regulate rain pulse effect on soil respiration is still unclear. We first quantified the influence of rainfall event on soil respiration based on a two-year (2006 and 2009) continuously measured soil respiration data set in a temperate steppe in northern China. In 2006 and 2009, soil carbon release induced by rainfall events contributed about 44.5% (83.3 g C m(-2)) and 39.6% (61.7 g C m(-2)) to the growing-season total soil respiration, respectively. The pulse effect of rainfall event on soil respiration can be accurately predicted by a water status index (WSI), which is the product of rainfall event size and the ratio between antecedent soil temperature to moisture at the depth of 10 cm (r2 = 0.92, P<0.001) through the growing season. It indicates the pulse effect can be enhanced by not only larger individual rainfall event, but also higher soil temperature/moisture ratio which is usually associated with longer dry spells. We then analyzed a long-term (1953-2009) precipitation record in the experimental area. We found both the extreme heavy rainfall events (>40 mm per event) and the long dry-spells (>5 days) during the growing seasons increased from 1953-2009. It suggests the shift in precipitation regime has increased the contribution of rain pulse effect to growing-season total soil respiration in this region. These findings highlight the importance of incorporating precipitation regime shift and its impacts on the rain pulse effect into the future predictions of grassland carbon cycle under climate change.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • China
  • Environment
  • Rain*
  • Seasons
  • Soil*
  • Time Factors

Substances

  • Soil

Associated data

  • figshare/10.6084/M9.FIGSHARE.1092629

Grants and funding

This study was supported partly by the “Strategic Priority Research Program” of the Chinese Academy of Sciences, Climate Change: Carbon Budget and Relevant Issues (XDA05050402), the National Natural Science Foundation of China (31170453), the National Basic Research Program of China (973 program, 2010CB833501), and a Selected Young Scientist Program of the State Key Laboratory of Vegetation and Environment Change to SC. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.