Sugarcane, experimental regional estimates using new data sources and methods methodology

This publication contains experimental estimates of Australia’s sugarcane production, area harvested, and number of sugarcane businesses in 2020-21. These experimental estimates are produced using industry and government data sources.

The experimental sugarcane estimates are presented on the following Australian Statistical Geography Standard (ASGS) (2016 edition) regions:

• Australia
• State
• Statistical Area Level 4 (SA4)
• Statistical Area Level 2 (SA2)
   

All experimental sugarcane estimates are available as a data cube (Excel xlsx) file attached to this publication.

This data is collected on behalf of Sugar Research Australia (SRA) by the Department of Agriculture, Water and the Environment (DAWE). This register contains data of the quantity of sugarcane delivered to a processing establishment and business address information for all sugarcane levy payers during the 2020-21 harvest period. It is supplied, along with other primary industries data, by DAWE to the ABS as authorised under the Primary Industries Levies and Charges Collection Act 1991 for the purpose of the ABS administering the Census and Statistics Act 1905. Any discussion of limitations or weaknesses in the data is in the context of its use by the ABS for statistical purposes and not the adequacy of the data for DAWE purposes.

Legislative requirements to ensure privacy and secrecy of this data have been adhered to. In accordance with the Census and Statistics Act 1905, results have been confidentialised to ensure that they are not likely to enable identification of a particular person or organisation. The ABS complies with the Privacy Act 1988 (Cth), and the Australian Privacy Principles contained within.

Australian Sugar Milling Council (ASMC) releases aggregate sugarcane data from information provided by sugar mills on its website: https://asmc.com.au/policy-advocacy/sugar-industry-overview/statistics/. This information includes statistics on Area Harvested for Milling and Tonnes of Cane Crushed for Australia and the 5 sugarcane producing regions: Northern, Herbert-Burdekin, Mackay-Proserpine, Southern (all in Queensland) and New South Wales.

The Queensland Department of Environment and Science produce cropping maps derived from satellite data. These maps identify broad groups of crops grown in Queensland's Strategic Cropping Land, for annual summer and winter growing seasons (see: https://www.qld.gov.au/environment/land/management/mapping/statewide-monitoring/crops).

Cropping areas for sugarcane for the 2020 growing season were used to identify the SA2s where sugarcane is likely to be grown in Queensland, and provide an estimate of the sugarcane area grown in those SA2s. (State of Queensland Department of Environment and Science). Updated data available at http://qldspatial.information.qld.gov.au/catalogue).

The Australian Bureau of Agricultural and Resource Economics and Sciences (ABARES), within the DAWE produce land use maps derived from satellite data for Australia. The Catchment scale land use of Australia - Commodities - Update December 2018 was used to identify the SA2s where sugarcane is likely to be grown within New South Wales, and provide and estimate of the sugarcane area grown in those SA2s. (ABARES 2019, Catchment Scale Land Use of Australia – Commodities – Update December 2018 version 2, ABARES, Canberra, November CC BY 4.0. https://doi.org/10.25814/5c887edfb0bbb).

The following steps provide a summary of the method that was used to create the experimental sugarcane production estimates for 2020-21:

1. All records in the Sugar Cane Levy Payer Register data were assigned an SA2. The SA2 assigned to the record was first extracted from existing information held on the Rural Environment and Agricultural Commodities Survey database. Where an SA2 was not recorded in this source then the address provided with the Levy Payer Register data was used to geocode and assign an SA2 to the record.
All records in the Sugar Cane Levy Payer Register data were then assigned to an Australian Sugar Milling Council (ASMC) Region.

2. The satellite derived sugarcane maps for Queensland and New South Wales were used to measure the area of sugarcane within each SA2. This area of sugarcane was then rescaled against the ASMC regions’ area harvested data to create an adjusted area of sugarcane harvested within each SA2.

3. For a small proportion of Sugar Cane Levy Payer Register records, the SA2 that was assigned to it did not have any sugarcane area grown. The levy production data in these SA2s were summed and redistributed across all SA2s within a broader region where sugarcane was grown. This redistribution was based on the adjusted area of sugarcane within each SA2. For example, if an SA2 contained 1% of the total sugarcane growing area in the broader region, it would receive 1% of the unallocated Levy Payer tonnes of sugarcane. The same process was used to redistribute the business counts associated with those levy records.

4. The broad regions that production and business counts were redistributed across depended on the level of confidence given to the original SA2 assigned.  If the assigned SA2s were included in an ASMC sugarcane growing region, then these items were redistributed across all sugarcane growing SA2s within the ASMC growing region. If the assigned SA2s were not within an ASMC growing region, but were within New South Wales or Queensland, then they were redistributed across all sugarcane growing SA2s within their State.  Finally, any assigned SA2s in a State other than New South Wales or Queensland were redistributed across all sugarcane growing SA2s.

5. A small number of Sugar Cane Levy Payer Register records produced very large volumes of sugarcane that related to an area broader than just the SA2 they were assigned to. These records were identified by comparing tonnes of sugarcane produced with the adjusted area of sugarcane growing within the SA2. The production and business counts from these records were redistributed across all SA2s within the ASMC region based on the adjusted area of sugarcane growing within each SA2 in the ASMC region. For example, if an SA2 contained 5% of the total sugarcane growing area within an ASMC region it would receive 5% of the redistributed Levy Payer tonnes of sugarcane.

6. SA2 production estimates were rescaled to ensure alignment with the ASMC regional totals. Similarly, SA2 business count estimates were rescaled to ensure alignment with ASMC state totals. This rescaling is done because the ASMC statistics are derived directly from the sugar mills which ensures accuracy within the sugar milling regions. Prior to this rescaling, the production total from the Sugar Cane Levy Payer Register data was within 0.01% of the ASMC total for Australia, while the business count total was within 4.2% of the ASMC total for Australia. One approach to assessing the accuracy of the ABS method is to compare the total production value for all SA2s within each ASMC region with the ASMC statistics prior to the rescaling. These difference were:  

• Northern 0.25%
• Herbert-Burdekin 2.04%
• Mackay-Proserpine 1.23%
• Southern 1.15%
• New South Wales 7.65%
   

The scope of these experimental estimates was to create estimates for Australia’s sugarcane production, area harvested and number of sugarcane businesses in 2020-21.

The information reported through the Sugar Cane Levy Payer Register represents all growers who delivered sugarcane to a processing establishment during the harvest period. For a small number of levy payers, the production amounts reported for a record on the register may represent more than one grower. For more information see https://www.agriculture.gov.au/ag-farm-food/levies/rates/sugar-cane.

The satellite imagery derived crop maps provide an estimate of the sugarcane area grown, and so may differ slightly from the area that is eventually harvested. This difference is accounted for at a broad level by rescaling the estimates of area grown to align with ASMC region totals for area harvested.

SA2 production totals were rounded to the nearest 100 tonnes to reflect the level of accuracy provided by this method and the experimental nature of this work.

Business counts were rounded to the nearest whole number. Any SA2s with counts of less than 5 then had their data substituted with 'less than 5' to provide privacy protection and reflect the uncertainty in accurately estimating small counts of businesses within an SA2.

A small number of SA2s contained very low estimates for sugar cane crop area, or sugar cane production with no associated Sugar Cane Levy Payer Register data.  These were excluded from the compilation process to form SA2 statistics.

The statistical methods used to produce the experimental sugarcane estimates ensure that no individual Sugar Cane Levy Payer Register records are identifiable using a spatial perturbation method. This identified any situations where it was possible to closely estimate an individual levy payer production amount and redistributed these records across all SA2s within that ASMC region. 

These are experimental estimates and although this data is consistent with other published data from ASMC at the national and regional level it should be used with caution, particularly when using the SA2 level statistics. SA2s with less than 10 thousand tonnes of sugarcane should be used with extreme caution as these smaller totals are likely to be disproportionately dependent on the data redistribution process described above.

ABS agricultural commodity (including sugarcane) area, production and value statistics, sourced from the Rural Environment and Agricultural Commodities Survey and Value of Agricultural Commodities Produced collections for 2019-20, are available in:

Agricultural Commodities, Australia, 2019-20.

Value of Agricultural Commodities Produced, Australia, 2019-20.

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