Which crops should be included in a carbon accounting system for Australian agriculture?
Murray Unkovich A C , Jeff Baldock B and Steve Marvanek BA Soil and Land Systems Group, Earth and Environmental Sciences, The University of Adelaide, Waite Campus, Private Bag 1, Glen Osmond, SA 5064, Australia.
B CSIRO Land and Water, Private Bag 2, Glen Osmond, SA 5064, Australia.
C Corresponding author. Email: murray.unkovich@adelaide.edu.au
Crop and Pasture Science 60(7) 617-626 https://doi.org/10.1071/CP08428
Submitted: 2 December 2008 Accepted: 20 April 2009 Published: 14 July 2009
Abstract
Dryland agriculture is both a potential source and potential sink for CO2 and other greenhouse gases. Many carbon accounting systems apply simple emissions factors to production units to estimate greenhouse gas (GHG) fluxes. However, in Australia, substantial variation in climate, soils, and management across >20 Mha of field crop sowings and >30 Mha of sown pastures in the intensive land use zone, provides substantial challenges for a national carbon accounting system, and simple emission factors are unlikely to apply across the region. In Australia a model framework has been developed that requires estimates of crop dry matter production and harvested yield as the first step to obtain carbon (residue) inputs. We use Australian Bureau of Statistics data to identify which crops would need to be included in such a carbon accounting system. Wheat, barley, lupin, and canola accounted for >80% of field crop sowings in Australia in 2006, and a total of 22 crops account for >99% of the sowing area in all States. In some States, only four or six crops can account for 99% of the cropping area. We provide a ranking of these crops for Australia and for each Australian State as a focus for the establishment of a comprehensive carbon accounting framework. Horticultural crops, although diverse, are less important in terms of total area and thus C balances for generic viticulture, vegetables, and orchard fruit crops should suffice. The dataset of crop areas presented here is the most comprehensive account of crop sowings presented in the literature and provides a useful resource for those interested in Australian agriculture. The field crop rankings presented represent only the area of crop sowings and should not be taken as rankings of importance in terms of the magnitude of all GHG fluxes. This awaits a more detailed analysis of climate, soils, and management practices across each of the regions where the crops are grown and their relationships to CO2, nitrous oxide and methane fluxes. For pastures, there is a need for more detailed, up to date, spatially explicit information on the predominant sown pasture types across the Australian cropping belt before C balances for these can be more reliably modelled at the desired spatial scale.
Acknowledgments
This work was supported by funding from NCAS (the National Carbon Accounting System) within the Department of Climate Change. We thank Bill Slattery and two anonymous reviewers for constructive comments.
Adger WN, Subak S
(1996) Estimating above-ground carbon fluxes from UK agricultural land. The Geographical Journal 162, 191–204.
| Crossref | GoogleScholarGoogle Scholar |
Bolinder MA,
Janzen HH,
Gregorich EG,
Angers DA, VandenBygaart AJ
(2007) An approach for estimating net primary productivity and annual carbon inputs to soil for common agricultural crops in Canada. Agriculture, Ecosystems & Environment 118, 29–42.
| Crossref | GoogleScholarGoogle Scholar |
Houghton RA, Hackler JL
(2000) Changes in terrestrial carbon storage in the United States. 1: The roles of agriculture and forestry. Global Ecology and Biogeography 9, 125–144.
| Crossref | GoogleScholarGoogle Scholar |
Johnson JMF,
Allmaras RR, Reicosky DC
(2006) Estimating source carbon from crop residues, roots and rhizodeposits using the national grain-yield database. Agronomy Journal 98, 622–636.
| Crossref | GoogleScholarGoogle Scholar |
CAS |
Keating BA,
Carberry PS,
Hammer GL,
Probert ME, Robertson MJ ,
et al
.
(2003) An overview of APSIM, a model designed for farming systems simulation. European Journal of Agronomy 18, 267–288.
| Crossref | GoogleScholarGoogle Scholar |
Loi A,
Howieson JG,
Nutt BJ, Carr SJ
(2005) A second generation of annual pasture legumes and their potential for inclusion in Mediterranean-type farming systems. Australian Journal of Experimental Agriculture 45, 289–299.
| Crossref | GoogleScholarGoogle Scholar |
Nicholls N,
Drosdowsky W, Lavery B
(1997) Australian rainfall variability and change. Weather 52, 66–71.
Pearson CJ,
Brown R,
Collins WJ,
Archer KA,
Wood MS,
Petersen C, Bootle B
(1997) An Australian temperate pastures database. Australian Journal of Agricultural Research 48, 453–465.
| Crossref | GoogleScholarGoogle Scholar |
Prince S,
Haskett J,
Steininger M,
Strand H, Wright R
(2001) Net primary production of the US mid-West croplands from agricultural harvest yield data. Ecological Applications 11, 1194–1205.
| Crossref | GoogleScholarGoogle Scholar |
Richards G, Evans D
(2004) Development of a carbon accounting model (FullCAM v1.0) for the Australian continent. Australian Forestry 67, 277–283.
Rounsevell MDA,
Ewert F,
Reginster I,
Leemans R, Carter TR
(2005) Future scenarios of European agricultural land use: II. Projecting changes in cropland and grassland. Agriculture, Ecosystems & Environment 107, 117–135.
| Crossref | GoogleScholarGoogle Scholar |
Smith P,
Powlson D,
Smith J,
Falloon P, Coleman K
(2000) Meeting the UK’s climate change commitments: options for carbon mitigation on agricultural land. Soil Use and Management 16, 1–11.
Vleeshouwers LM, Verhagen A
(2002) Carbon emission and sequestration by agricultural land use: a model study for Europe. Global Change Biology 8, 519–530.
| Crossref | GoogleScholarGoogle Scholar |
