Simulation of Salinity Effects on Past, Present, and Future Soil Organic Carbon Stocks

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

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Soil organic carbon (SOC) models are used to predict changes in SOC stocks and carbon dioxide (CO2) emissions from soils, and have been successfully validated for non-saline soils. However, SOC models have not been developed to simulate SOC turnover in saline soils. Due to the large extent of salt-affected areas in the world, it is important to correctly predict SOC dynamics in salt-affected soils. To close this knowledge gap, we modified the Rothamsted Carbon Model (RothC) to simulate SOC turnover in salt-affected soils, using data from non-salt-affected and salt-affected soils in two agricultural regions in India (120 soils) and in Australia (160 soils). Recently we developed a decomposition rate modifier based on an incubation study of a subset of these soils. In the present study, we introduce a new method to estimate the past losses of SOC due to salinity and show how salinity affects future SOC stocks on a regional scale. Because salinity decreases decomposition rates, simulations using the decomposition rate modifier for salinity suggest an accumulation of SOC. However, if the plant inputs are also adjusted to reflect reduced plant growth under saline conditions, the simulations show a significant loss of soil carbon in the past due to salinization, with a higher average loss of SOC in Australian soils (55 t C ha(-1)) than in Indian soils (31 t C ha(-1)). There was a significant negative correlation (p < 0.05) between SOC loss and osmotic potential. Simulations of future SOC stocks with the decomposition rate modifier and the plant input modifier indicate a greater decrease in SOC in saline than in non-saline soils under future climate. The simulations of past losses of SOC due to salinity were repeated using either measured charcoal-C or the inert organic matter predicted by the Falloon et al. equation to determine how much deviation from the Falloon et al. equation affects the amount of plant inputs generated by the model for the soils used in this study. Both sets of results suggest that saline soils have lost carbon and will continue to lose carbon under future climate. This demonstrates the importance of both reduced decomposition and reduced plant input in simulations of future changes in SOC stocks in saline soils.

Original languageEnglish
Pages (from-to)1624-1631
Number of pages8
JournalEnvironmental Science & Technology
Volume46
Issue number3
Early online date20 Dec 2011
DOIs
Publication statusPublished - 7 Feb 2012

Keywords

  • long-term experiments
  • osmotic adjustment
  • projected changes
  • salt stress
  • model
  • yield
  • irrigation
  • decomposition
  • turnover
  • proline

Cite this

Simulation of Salinity Effects on Past, Present, and Future Soil Organic Carbon Stocks. / Setia, Raj; Smith, Pete; Marschner, Petra; Gottschalk, Pia; Baldock, Jeff; Verma, Vipan; Setia, Deepika; Smith, Jo.

In: Environmental Science & Technology, Vol. 46, No. 3, 07.02.2012, p. 1624-1631.

Research output: Contribution to journalArticle

Setia, Raj ; Smith, Pete ; Marschner, Petra ; Gottschalk, Pia ; Baldock, Jeff ; Verma, Vipan ; Setia, Deepika ; Smith, Jo. / Simulation of Salinity Effects on Past, Present, and Future Soil Organic Carbon Stocks. In: Environmental Science & Technology. 2012 ; Vol. 46, No. 3. pp. 1624-1631.
@article{83fdc4af356b4c91a9c0de13db00be2d,
title = "Simulation of Salinity Effects on Past, Present, and Future Soil Organic Carbon Stocks",
abstract = "Soil organic carbon (SOC) models are used to predict changes in SOC stocks and carbon dioxide (CO2) emissions from soils, and have been successfully validated for non-saline soils. However, SOC models have not been developed to simulate SOC turnover in saline soils. Due to the large extent of salt-affected areas in the world, it is important to correctly predict SOC dynamics in salt-affected soils. To close this knowledge gap, we modified the Rothamsted Carbon Model (RothC) to simulate SOC turnover in salt-affected soils, using data from non-salt-affected and salt-affected soils in two agricultural regions in India (120 soils) and in Australia (160 soils). Recently we developed a decomposition rate modifier based on an incubation study of a subset of these soils. In the present study, we introduce a new method to estimate the past losses of SOC due to salinity and show how salinity affects future SOC stocks on a regional scale. Because salinity decreases decomposition rates, simulations using the decomposition rate modifier for salinity suggest an accumulation of SOC. However, if the plant inputs are also adjusted to reflect reduced plant growth under saline conditions, the simulations show a significant loss of soil carbon in the past due to salinization, with a higher average loss of SOC in Australian soils (55 t C ha(-1)) than in Indian soils (31 t C ha(-1)). There was a significant negative correlation (p < 0.05) between SOC loss and osmotic potential. Simulations of future SOC stocks with the decomposition rate modifier and the plant input modifier indicate a greater decrease in SOC in saline than in non-saline soils under future climate. The simulations of past losses of SOC due to salinity were repeated using either measured charcoal-C or the inert organic matter predicted by the Falloon et al. equation to determine how much deviation from the Falloon et al. equation affects the amount of plant inputs generated by the model for the soils used in this study. Both sets of results suggest that saline soils have lost carbon and will continue to lose carbon under future climate. This demonstrates the importance of both reduced decomposition and reduced plant input in simulations of future changes in SOC stocks in saline soils.",
keywords = "long-term experiments, osmotic adjustment, projected changes, salt stress, model, yield, irrigation, decomposition, turnover, proline",
author = "Raj Setia and Pete Smith and Petra Marschner and Pia Gottschalk and Jeff Baldock and Vipan Verma and Deepika Setia and Jo Smith",
year = "2012",
month = "2",
day = "7",
doi = "10.1021/es2027345",
language = "English",
volume = "46",
pages = "1624--1631",
journal = "Environmental Science & Technology",
issn = "0013-936X",
publisher = "American Chemical Society",
number = "3",

}

TY - JOUR

T1 - Simulation of Salinity Effects on Past, Present, and Future Soil Organic Carbon Stocks

AU - Setia, Raj

AU - Smith, Pete

AU - Marschner, Petra

AU - Gottschalk, Pia

AU - Baldock, Jeff

AU - Verma, Vipan

AU - Setia, Deepika

AU - Smith, Jo

PY - 2012/2/7

Y1 - 2012/2/7

N2 - Soil organic carbon (SOC) models are used to predict changes in SOC stocks and carbon dioxide (CO2) emissions from soils, and have been successfully validated for non-saline soils. However, SOC models have not been developed to simulate SOC turnover in saline soils. Due to the large extent of salt-affected areas in the world, it is important to correctly predict SOC dynamics in salt-affected soils. To close this knowledge gap, we modified the Rothamsted Carbon Model (RothC) to simulate SOC turnover in salt-affected soils, using data from non-salt-affected and salt-affected soils in two agricultural regions in India (120 soils) and in Australia (160 soils). Recently we developed a decomposition rate modifier based on an incubation study of a subset of these soils. In the present study, we introduce a new method to estimate the past losses of SOC due to salinity and show how salinity affects future SOC stocks on a regional scale. Because salinity decreases decomposition rates, simulations using the decomposition rate modifier for salinity suggest an accumulation of SOC. However, if the plant inputs are also adjusted to reflect reduced plant growth under saline conditions, the simulations show a significant loss of soil carbon in the past due to salinization, with a higher average loss of SOC in Australian soils (55 t C ha(-1)) than in Indian soils (31 t C ha(-1)). There was a significant negative correlation (p < 0.05) between SOC loss and osmotic potential. Simulations of future SOC stocks with the decomposition rate modifier and the plant input modifier indicate a greater decrease in SOC in saline than in non-saline soils under future climate. The simulations of past losses of SOC due to salinity were repeated using either measured charcoal-C or the inert organic matter predicted by the Falloon et al. equation to determine how much deviation from the Falloon et al. equation affects the amount of plant inputs generated by the model for the soils used in this study. Both sets of results suggest that saline soils have lost carbon and will continue to lose carbon under future climate. This demonstrates the importance of both reduced decomposition and reduced plant input in simulations of future changes in SOC stocks in saline soils.

AB - Soil organic carbon (SOC) models are used to predict changes in SOC stocks and carbon dioxide (CO2) emissions from soils, and have been successfully validated for non-saline soils. However, SOC models have not been developed to simulate SOC turnover in saline soils. Due to the large extent of salt-affected areas in the world, it is important to correctly predict SOC dynamics in salt-affected soils. To close this knowledge gap, we modified the Rothamsted Carbon Model (RothC) to simulate SOC turnover in salt-affected soils, using data from non-salt-affected and salt-affected soils in two agricultural regions in India (120 soils) and in Australia (160 soils). Recently we developed a decomposition rate modifier based on an incubation study of a subset of these soils. In the present study, we introduce a new method to estimate the past losses of SOC due to salinity and show how salinity affects future SOC stocks on a regional scale. Because salinity decreases decomposition rates, simulations using the decomposition rate modifier for salinity suggest an accumulation of SOC. However, if the plant inputs are also adjusted to reflect reduced plant growth under saline conditions, the simulations show a significant loss of soil carbon in the past due to salinization, with a higher average loss of SOC in Australian soils (55 t C ha(-1)) than in Indian soils (31 t C ha(-1)). There was a significant negative correlation (p < 0.05) between SOC loss and osmotic potential. Simulations of future SOC stocks with the decomposition rate modifier and the plant input modifier indicate a greater decrease in SOC in saline than in non-saline soils under future climate. The simulations of past losses of SOC due to salinity were repeated using either measured charcoal-C or the inert organic matter predicted by the Falloon et al. equation to determine how much deviation from the Falloon et al. equation affects the amount of plant inputs generated by the model for the soils used in this study. Both sets of results suggest that saline soils have lost carbon and will continue to lose carbon under future climate. This demonstrates the importance of both reduced decomposition and reduced plant input in simulations of future changes in SOC stocks in saline soils.

KW - long-term experiments

KW - osmotic adjustment

KW - projected changes

KW - salt stress

KW - model

KW - yield

KW - irrigation

KW - decomposition

KW - turnover

KW - proline

U2 - 10.1021/es2027345

DO - 10.1021/es2027345

M3 - Article

VL - 46

SP - 1624

EP - 1631

JO - Environmental Science & Technology

JF - Environmental Science & Technology

SN - 0013-936X

IS - 3

ER -