Soil salinity decreases global soil organic carbon stocks

Raj Setia*, Pia Gottschalk, Pete Smith, Petra Marschner, Jeff Baldock, Deepika Setia, Jo Smith

*Corresponding author for this work

Research output: Contribution to journalArticle

74 Citations (Scopus)

Abstract

Saline soils cover 3.1% (397 million hectare) of the total land area of the world. The stock of soil organic carbon (SOC) reflects the balance between carbon (C) inputs from plants, and losses through decomposition, leaching and erosion. Soil salinity decreases plant productivity and hence C inputs to the soil, but also microbial activity and therefore SOC decomposition rates. Using a modified Rothamsted Carbon model (RothC) with a newly introduced salinity decomposition rate modifier and a plant input modifier we estimate that, historically, world soils that are currently saline have lost an average of 3.47 t SOC ha(-1) since they became saline. With the extent of saline soils predicted to increase in the future, our modelling suggests that world soils may lose 6.8 Pg SOC due to salinity by the year 2100. Our findings suggest that current models overestimate future global SOC stocks and underestimate net CO2 emissions from the soil-plant system by not taking salinity effects into account. From the perspective of enhancing soil C stocks, however, given the lower SOC decomposition rate in saline soils, salt tolerant plants could be used to sequester C in salt-affected areas. (C) 2012 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)267-272
Number of pages6
JournalScience of the Total Environment
Volume465
Early online date5 Sep 2012
DOIs
Publication statusPublished - 1 Nov 2013

Keywords

  • decomposition rate modifier
  • global
  • past
  • present
  • RothC
  • Salinity
  • long-term experiments
  • model
  • irrigation
  • croplands
  • turnover
  • yield

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