TY - JOUR
T1 - Soil carbon market-based instrument pilot
T2 - The sequestration of soil organic carbon for the purpose of obtaining carbon credits
AU - Badgery, Warwick
AU - Murphy, Brian
AU - Cowie, Annette
AU - Orgill, Susan
AU - Rawson, Andrew
AU - Simmons, Aaron
AU - Crean, Jason
N1 - Includes bibliographical references
PY - 2021
Y1 - 2021
N2 - Increasing soil organic carbon (SOC) in Australian farming systems has the potential to offset greenhouse gas emissions. Even though methods for soil carbon (C) sequestration have been developed under the Australian Government's Emissions Reduction Fund, the scope for farm-scale soil C sequestration is poorly understood. A pilot scheme was developed in Central West New South Wales to trial the use of a market-based instrument to encourage farmers to change farm management to increase SOC. This paper reports changes to SOC stocks measured on farms that were successfully contracted in the pilot. The 10 contracted farms were those that submitted the lowest bid per Mg CO2-e. Four land uses were contracted in the pilot: (1) reduced tillage cropping (reference); (2) reduced tillage cropping with organic amendments (e.g. biosolids or compost); (3) conversion from cropping land to permanent pasture; and (4) conversion from cropping land to permanent pasture with organic amendments. At each site a minimum of 10 locations (sampling points) were sampled and analysed for total carbon (LECO elemental analyser) and bulk density calculated. The SOC stocks (0-0.3 m) were assessed before (2012) and after the pilot (2017; calculated on equivalent soil mass of 2012), with 60% of sites showing a significant increase. Pasture had a higher rate of SOC sequestration than reduced tillage cropping (1.2 vs 0.28 Mg C ha-1 year-1, 0-0.3 m); and organic amendments had higher rates of SOC sequestration than without (1.14 vs 0.78 Mg C ha-1 year-1, 0-0.3 m). The results of the pilot demonstrated increases in SOC, using quantification methods consistent with the current Measurement Method of the Australian Government's Emissions Reduction Fund policy used to generate Australian Carbon Credit Units. The results require careful interpretation as rates of sequestration are likely to be lower in the longer term than initial rates of change seen in this pilot (five years), and the pilot intentionally selected sites with initially low SOC, which ensured a greater opportunity to sequester SOC.
AB - Increasing soil organic carbon (SOC) in Australian farming systems has the potential to offset greenhouse gas emissions. Even though methods for soil carbon (C) sequestration have been developed under the Australian Government's Emissions Reduction Fund, the scope for farm-scale soil C sequestration is poorly understood. A pilot scheme was developed in Central West New South Wales to trial the use of a market-based instrument to encourage farmers to change farm management to increase SOC. This paper reports changes to SOC stocks measured on farms that were successfully contracted in the pilot. The 10 contracted farms were those that submitted the lowest bid per Mg CO2-e. Four land uses were contracted in the pilot: (1) reduced tillage cropping (reference); (2) reduced tillage cropping with organic amendments (e.g. biosolids or compost); (3) conversion from cropping land to permanent pasture; and (4) conversion from cropping land to permanent pasture with organic amendments. At each site a minimum of 10 locations (sampling points) were sampled and analysed for total carbon (LECO elemental analyser) and bulk density calculated. The SOC stocks (0-0.3 m) were assessed before (2012) and after the pilot (2017; calculated on equivalent soil mass of 2012), with 60% of sites showing a significant increase. Pasture had a higher rate of SOC sequestration than reduced tillage cropping (1.2 vs 0.28 Mg C ha-1 year-1, 0-0.3 m); and organic amendments had higher rates of SOC sequestration than without (1.14 vs 0.78 Mg C ha-1 year-1, 0-0.3 m). The results of the pilot demonstrated increases in SOC, using quantification methods consistent with the current Measurement Method of the Australian Government's Emissions Reduction Fund policy used to generate Australian Carbon Credit Units. The results require careful interpretation as rates of sequestration are likely to be lower in the longer term than initial rates of change seen in this pilot (five years), and the pilot intentionally selected sites with initially low SOC, which ensured a greater opportunity to sequester SOC.
KW - land management change
KW - organic amendments
KW - permanent pasture
KW - soil carbon sequestration
KW - soil carbon trading
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U2 - 10.1071/SR19331
DO - 10.1071/SR19331
M3 - Article
AN - SCOPUS:85086835000
SN - 0004-9573
VL - 59
SP - 12
EP - 23
JO - Australian Journal of Soil Research
JF - Australian Journal of Soil Research
IS - 1
ER -