Elsevier

Quaternary International

Volume 306, 3 September 2013, Pages 114-120
Quaternary International

Carbon stocks and storage potential as affected by vegetation in the Songnen grassland of northeast China

https://doi.org/10.1016/j.quaint.2013.05.053Get rights and content

Abstract

Soil organic carbon storage in grasslands reflects a balance between carbon inputs and the rate of its mineralization. The ability of different plant communities to capture, store and release carbon could lead to different carbon storage in grassland soil. In this study, the plant biomass and soil organic carbon (SOC) stocks of seven communities were investigated. SOC concentration differed significantly among the seven communities, varying from 4.08 g C kg−1 for Suaeda glauca community to 9.18 g C kg−1 for Echinochloa phyllopogon community. Over the entire profile to 100 cm, the SOC storage of E. phyllopogon community was highest with the value of 10.09 kg C m−2, while the storage of S. glauca community was lowest with the value of 5.63 kg C m−2. Over 30% of organic carbon was found in the top soils (0–20 cm). Compared to the Leymus chinensis community, halophytic communities have a great potential to store carbon in the Songnen grassland, with a mean value of 2.95 kg C m−2 in the 0–100 cm soil layer. Vegetation has a great effect on the carbon storage of grassland.

Introduction

As the largest carbon pool in terrestrial ecosystem, soils store more than twice as much carbon than does vegetation or the atmosphere, and even a slight change in soil carbon stock could have a major impact on global carbon cycling (Johnson et al., 2007, Yang et al., 2010). The concentration of carbon dioxide in the atmosphere continues to increase rapidly (Rawlins et al., 2011). One factor that could contribute to mitigating atmospheric CO2 concentrations would be to replace carbon lost from terrestrial ecosystems through appropriate ecosystem management practices that enhance uptake CO2 or decrease CO2 release from soils and vegetation (Conant, 2011).

Grasslands are an important part of the global C cycle, as they cover approximately one quarter of Earth's land surface (Paz-Ferreiro et al., 2012) and store more than one third of the total terrestrial carbon (White et al., 2000). The dynamics of soil organic carbon in grassland ecosystems have received considerable attention, but remain an important area of research (He et al., 2008, Meersmans et al., 2009, Yang et al., 2010). He et al. (2008) suggested that the storage potential of C and N in the Leymus chinensis grasslands are approximately 15.8 kg C m−2 and 1.5 kg N m−2, respectively. Therefore, there is tremendous potential for increasing C storage in the temperate grasslands of northern China by improving grassland use or management. Yang et al. (2010) observed that the carbon stocks in the top 100 cm depth was 8.49 kg C m−2, which is lower than the result of Ni (2002) and Xie et al. (2007). The different results among these studies require additional work.

Carbon dynamics in grassland ecosystems are controlled by various ecosystem processes, which can be affected by land-use change, grazing, enclosure, and restoration of degraded grassland (Ganjegunte et al., 2005, Ruiz-Peinado et al., 2013, Twongyirwe et al., 2013). These management practices could easily cause changes of plant species or communities. The different plant species and communities differ in their ability to capture, store and release carbon, the collective functional characteristics of plant communities should be a major driver of carbon sequestration in terrestrial ecosystems (Thompson et al., 2009). Plant tissue quality, such as plant nutrient concentration, can influence the residence time of both living tissues and litter, and therefore indirectly influence the soil carbon storage in grassland (Aerts and Chapin, 2000, Wardle et al., 2004, Conti and Diza, 2013). Conti and Diza (2013) suggested that the tall plants usually store more carbon than the short plants in an ecosystem. Six-year Elymus nutans artificial grassland establishment significantly increased soil organic carbon and soil total nitrogen compared with black-soil-type degraded grassland in the eastern Qinghai Tibetan Plateau (Wu et al., 2010). Yang et al. (2010) found that the SOC storage in the top 100 cm was lower than others estimated, and suggested that the difference could be induced by different vegetation types. Study of the effect of vegetation on the dynamics of SOC storage in grassland is still rare.

The Songnen grassland is located in northeast China. Due to the impact of human activity, the Songnen grassland has suffered substantial land degradation during recent decades. The salt content of surface soil increased, making it unsuitable for L. chinensis survival. As salinization progresses, the L. chinensis community is gradually replaced by halophytic communities (Zhou et al., 2011). Understanding the effect of plant community change on SOC stocks and dynamics will facilitate better understanding of the terrestrial C cycle in this grassland region. The purpose of this work was to characterize soil organic carbon (SOC) stocks in seven different communities and investigate the relationship between vegetation type and SOC stocks. The objectives were to study the effect of vegetation on the SOC stocks; and to estimate the storage potential of SOC after restoration of the degraded grassland.

Section snippets

Study area

The study area was located in the Changling Station of Grassland and Agroecology, Chinese Academy of Sciences, Songnen grassland, northeast China (44°33′ N, 123°31′ E), with an area of 300 ha. The study area was relatively flat and its elevation is about 145 m above sea level. The area is characterized by a temperate, semi-arid continental monsoon climate. The annual average air temperature was between 4.9 °C and 6.4 °C. Precipitation varied from 300 mm to 450 mm, greatly differing between

Above- and belowground biomass and litter

The standing biomass values differed significantly among the seven communities (P < 0.01), varying from 244.77 g m−2 for H. intersita community to 726.95 g m−2 for P. australis community (Fig. 2). The root biomass of the seven communities ranged between a minimum of 106.13 g m−2 for S. glauca community and a maximum of 1047.97 g m−2 for P. australis community (Fig. 2). The root biomass of P. australis community and L. chinensis community was significantly higher that other communities (P

Discussion

As the main source of SOC in grassland, the aboveground and underground biomass analysis is an important element in the carbon cycle, especially carbon sequestration (Devagiri et al., 2013). The average height of community is a good predictor of total biomass for plants (Chave et al., 2005), which directly influences the amount of C contained in vegetation and incorporated into the soil as litter (Lavorel and Grigulis, 2012, Devagiri et al., 2013). In the seven communities, the difference of

Conclusions

Soil organic carbon is one of the most important parameters affecting the characteristics of natural soils. Community type has significant effect on the carbon concentration and storage in the Songnen grassland, northeast China. The E. phyllopogon community has the largest SOC concentration and storage among the seven communities, followed by the L. chinensis community. The growing site may be the main reason that led to the largest SOC concentration and storage in the E. phyllopogon community.

Acknowledgments

This work was supported by the Strategic Science and Technology Guide Project of CAS (XDA05050401), the National Basic Research Program of China (2011CB403203) and National Natural Science Foundation of China (4101534). Special thanks are due to Professor Richard T. Conant and Dr. Shiwei Liu for invaluable advice and English revision for this paper.

References (34)

  • R.T. Conant

    Sequestration through forestry and agriculture

    Climate Change

    (2011)
  • G. Conti et al.

    Plant functional diversity and carbon storage – an empirical test in semi-arid forest ecosystems

    Journal of Ecology

    (2013)
  • G.M. Devagiri et al.

    Assessment of above ground biomass and carbon pool in different vegetation types of south western part of Karnataka, India using spectral modeling

    Tropical Ecology

    (2013)
  • G.K. Ganjegunte et al.

    Soil organic carbon composition in a northern mixed-grass prairie: effects of grazing

    Soil Science Society of America Journal

    (2005)
  • E. Garnier et al.

    Plant functional markers capture ecosystem properties during secondary succession

    Ecology

    (2004)
  • R.A. Gill et al.

    Global patterns of root turnover for terrestrial ecosystems

    New Phytologist

    (2000)
  • B. Han et al.

    Grassland biomass of communities along gradients of the inner Mongolia grassland transect

    Journal of Plant Ecology

    (2006)
  • Cited by (0)

    View full text