Abstract
Soil respiration, a major component of the global carbon cycle, is significantly influenced by land management practices. Grasslands are potentially a major sink for carbon, but can also be a source. Here, we investigated the potential effect of land management (grazing, clipping, and ungrazed enclosures) on soil respiration in the semiarid grassland of northern China. Our results showed the mean soil respiration was significantly higher under enclosures (2.17μmol.m−2.s−1) and clipping (2.06μmol.m−2.s−1) than under grazing (1.65μmol.m−2.s−1) over the three growing seasons. The high rates of soil respiration under enclosure and clipping were associated with the higher belowground net primary productivity (BNPP). Our analyses indicated that soil respiration was primarily related to BNPP under grazing, to soil water content under clipping. Using structural equation models, we found that soil water content, aboveground net primary productivity (ANPP) and BNPP regulated soil respiration, with soil water content as the predominant factor. Our findings highlight that management-induced changes in abiotic (soil temperature and soil water content) and biotic (ANPP and BNPP) factors regulate soil respiration in the semiarid temperate grassland of northern China.
Highlights
Soil respiration is the second largest carbon (C) flux between terrestrial ecosystems and the atmosphere in the global C cycle [1,2], and plays an important role in regulating the soil carbon pool and ecosystem C-cycling [3,4]
Soil temperature was the highest under enclosure comparing to grazing or clipping treatments (P
Soil respiration is lower in the temperate steppe of northern China than that reported for alpine meadows [30], but similar to that in other semiarid ecosystems [8, 31, 32]
Summary
Soil respiration is the second largest carbon (C) flux between terrestrial ecosystems and the atmosphere in the global C cycle [1,2], and plays an important role in regulating the soil carbon pool and ecosystem C-cycling [3,4]. Many studies were conducted to examine the effect of climate change factors on soil respiration, such as increasing temperature [6] and atmospheric CO2 concentration [7], and changes in precipitation patterns [8]. Land management changes are the most dominant component of global climate change in terms of their impacts on terrestrial ecosystems [9,10], as they profoundly alter land cover [11, 12] and biogeochemical cycles [13,14,15]. PLOS ONE | DOI:10.1371/journal.pone.0147987 January 25, 2016
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