Response of soil respiration to acid rain in forests of different maturity in southern China

PLoS One. 2013 Apr 23;8(4):e62207. doi: 10.1371/journal.pone.0062207. Print 2013.

Abstract

The response of soil respiration to acid rain in forests, especially in forests of different maturity, is poorly understood in southern China despite the fact that acid rain has become a serious environmental threat in this region in recent years. Here, we investigated this issue in three subtropical forests of different maturity [i.e. a young pine forest (PF), a transitional mixed conifer and broadleaf forest (MF) and an old-growth broadleaved forest (BF)] in southern China. Soil respiration was measured over two years under four simulated acid rain (SAR) treatments (CK, the local lake water, pH 4.5; T1, water pH 4.0; T2, water pH 3.5; and T3, water pH 3.0). Results indicated that SAR did not significantly affect soil respiration in the PF, whereas it significantly reduced soil respiration in the MF and the BF. The depressed effects on both forests occurred mostly in the warm-wet seasons and were correlated with a decrease in soil microbial activity and in fine root biomass caused by soil acidification under SAR. The sensitivity of the response of soil respiration to SAR showed an increasing trend with the progressive maturity of the three forests, which may result from their differences in acid buffering ability in soil and in litter layer. These results indicated that the depressed effect of acid rain on soil respiration in southern China may be more pronounced in the future in light of the projected change in forest maturity. However, due to the nature of this field study with chronosequence design and the related pseudoreplication for forest types, this inference should be read with caution. Further studies are needed to draw rigorous conclusions regarding the response differences among forests of different maturity using replicated forest types.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acid Rain*
  • Biomass
  • Carbon / chemistry
  • China
  • Ecosystem
  • Hydrogen-Ion Concentration
  • Plant Roots / microbiology
  • Soil / chemistry*
  • Soil Microbiology
  • Temperature
  • Trees / growth & development*
  • Water

Substances

  • Acid Rain
  • Soil
  • Water
  • Carbon

Grants and funding

This work was financially supported by the Strategic Priority Research Program of Chinese Academy of Sciences (XDA05050205), the National Key Basic Research Development Program (973 Program) (2009CB421101) and the Guangdong Provincial Natural Science Foundation Project (No. 8351065005000001). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.