EXPLANATORY NOTES
INTRODUCTION
1 This publication presents estimates of agricultural water use, including pastures and crops irrigated, irrigation water sources, irrigation water management and water related responses to adverse seasonal conditions. Data are available for a range of sub-state geographic levels, including Natural Resource Management (NRM) region, Statistical Division (SD) and Murray-Darling Basin (MDB) in July 2011.
GENERAL
2 In 2007-08, an ARMS was run with a reduced set of commodities compared to the Agricultural Survey/Census of previous years. The ARMS was a combination of a reduced Agricultural Survey and a benchmark survey of land management practices undertaken by agricultural businesses as well as a survey of management responses to adverse seasonal conditions experienced by affected agricultural businesses. In 2008-09, the Australian Bureau of Statistics (ABS) returned to the Agricultural Survey which collected a greater range of agricultural commodities and livestock breakdowns than the 2007-08 ARMS. In 2009-10, a reduced set of commodities was once again collected in the ARMS.
3 Where figures for individual states/territories have been suppressed for reasons of confidentiality, they have been included in relevant totals.
4 Australian Capital Territory data have been combined with New South Wales data.
5 Where figures have been rounded, discrepancies may occur between sums of the component items and totals.
SCOPE AND COVERAGE
6 The scope of the 2009-10 ARMS was all agricultural businesses recorded on the ABS Business Register (ABSBR) above a minimum size cutoff. The ABSBR is based on the Australian Business Register (ABR) which is administered and maintained by the Australian Taxation Office (ATO).
7 A minimum size cut-off of $5,000 was applied to determine whether a business was in-scope for the 2009-10 ARMS. The measure of size was based on the ABS' Estimated Value of Agricultural Operations (EVAO) or a derived value based on Business Activity Statement (BAS) turnover.
8 While the ABSBR does not include all agricultural businesses in Australia, it provides improved coverage from the former ABS-maintained Agricultural Survey frame as most businesses and organisations in Australia need to obtain an Australian Business Number (ABN) from the ATO for their business operations. The ABR-based register is also more up-to-date as it excludes agricultural businesses with cancelled ABNs and incorporates regularly updated information on agricultural businesses from the ATO.
9 For the 2009-10 ARMS, a response rate of approximately 87% was achieved from a sample of approximately 38,000 agricultural businesses selected from an in-scope population of approximately 171,000 agricultural businesses.
AGRICULTURAL BUSINESSES AND AREA UNDER PASTURE OR CROP
10 The number of agricultural businesses and the area under pasture or crop are included for irrigation crop categories where these are available. In some cases, the number of agricultural businesses and the area under pasture or crop are not available or may not be directly comparable with the categories used for irrigated crops. More information is available upon request.
COMPARABILITY WITH AGRICULTURAL COMMODITIES AUSTRALIA
11 The estimates of agricultural establishments and area under pasture or crop for 2004-05 to 2008-09 presented in this publication differ from Agriculture Commodities, Australia (cat. no 7121.0), in that the estimates for grapevines in this publication are derived from the Agricultural Survey and ARMS rather than the Vineyards Collection.
12 Additionally, the number of agricultural businesses in this publication refers to all businesses undertaking agricultural activity within the 2009-10 period, differing from those in Agriculture Commodities, Australia (cat. no 7121.0) which report only on the number of agricultural businesses still active at 30 June 2010. For further clarification, contact the National Information and Referral Service on 1300 135 070.
MURRAY-DARLING BASIN GEOGRAPHY
13 Data for the Murray-Darling Basin (MDB) region were derived from a concordance of NRM regions falling mostly within the MDB region. The MDB data used in Water Use on Australian Farms, 2005-06 (cat. no. 4618.0) were derived from geocoded data. Therefore, there will be small differences when comparing these data to 2006-07, 2007-08, 2008-09 and 2009-10 MDB data.
RELIABILITY OF DATA
14 The estimates in this publication are subject to sampling and non-sampling errors.
SAMPLING ERRORS
15 The estimates in this publication are based on information obtained from respondents to the ARMS for the year ended 30 June 2010 and are subject to sampling variability; that is, estimates may differ from figures that would be produced if all agricultural businesses had been included in the survey. One measure of the likely difference is given by the standard error (SE), which indicates the extent to which an estimate might vary by chance when not all units have responded, i.e. when a 'sample' of responses only is obtained. There are about two chances in three that a 'sample' estimate will differ by less than one SE from the figure that would have been obtained if all units had responded, and about nineteen chances in twenty that the difference will be less than two SEs.
16 In this publication, 'sampling' variability of the estimates is measured by the relative standard error (RSE) which is obtained by expressing the SE as a percentage of the estimate to which it refers.
17 Most published estimates have RSEs less than 5%. For some states/territories with limited irrigation of certain commodities or limited numbers of units reporting a particular source of agricultural water, RSEs are greater than 10%. Where the RSE of an estimate included in this publication falls in the range of 10% to less than 25%, it has been annotated with the symbol '^' indicating that the estimate should be used with caution as it is subject to sampling variability too high for some purposes. Where the RSE of an estimate is 25% to 50%, it has been annotated with the symbol '*', indicating that the estimate should be used with caution as it is subject to sampling variability too high for most practical purposes. Where the RSE of an estimate exceeds 50%, it has been annotated with the symbol '**', indicating that the sampling variability causes the estimate to be considered too unreliable for general use. Separate indication of the RSEs of all estimates is available on request.
18 The following table contains estimates of RSEs for a selection of the statistics presented in this publication:
relative standard errors of selected estimates, by State - 2009-10 |
|
| NSW(a) | Vic. | Qld | SA | WA | Tas. | NT | AUST. |
| % | % | % | % | % | % | % | % |
|
Total area irrigated (ha) | 3.3 | 6.1 | 3.9 | 5.8 | 6.1 | 3.8 | 1.9 | 2.0 |
Total volume applied (ML) | 2.6 | 7.9 | 3.4 | 6.8 | 6.8 | 4.6 | 2.9 | 2.3 |
Pasture for grazing area irrigated (ha) | 7.0 | 9.6 | 19.5 | 14.1 | 12.4 | 5.4 | 8.8 | 5.0 |
Pasture for grazing volume applied (ML) | 9.0 | 13.7 | 14.7 | 14.8 | 15.1 | 6.7 | 11.7 | 7.0 |
Rice area irrigated (ha) | 4.8 | 67.4 | 13.3 | - | - | - | - | 4.8 |
Rice volume applied (ML) | 4.1 | 67.4 | 6.4 | - | - | - | - | 4.0 |
Sugar cane area irrigated (ha) | 95.5 | - | 6.9 | - | - | - | - | 6.9 |
Sugar cane volume applied (ML) | 95.5 | - | 6.5 | - | - | - | - | 6.5 |
Cotton area irrigated (ha) | 3.3 | - | 5.2 | - | - | - | - | 3.1 |
Cotton volume applied (ML) | 3.2 | - | 5.3 | - | - | - | - | 3.1 |
|
- nil or rounded to zero (including null cells) |
(a) Includes ACT. |
NON-SAMPLING ERRORS
19 Errors other than those due to sampling may occur because of deficiencies in the list of units from which the sample was selected, non-response, and errors in reporting by providers. Inaccuracies of this kind are referred to as non-sampling errors, which may occur in any collection, whether it be a census or a sample. Every effort has been made to reduce non-sampling error to a minimum by careful design and testing of questionnaires, operating procedures and systems used to compile the statistics.
ABS DATA AVAILABLE ON REQUEST
20 As well as the statistics included in this and related publications, the ABS may have other relevant data available on request. Inquiries should be made to the National Information and Referral Service on 1300 135 070.
ACKNOWLEDGMENT
21 ABS publications draw extensively on information provided freely by individuals, businesses, governments and other organisations. Their continued cooperation is very much appreciated. Without it, the wide range of statistics published by the ABS would not be available. The Bureau of Meteorology's contribution of the Climate Conditions Appendix in this publication is especially acknowledged. Information received by the ABS is treated in strict confidence, as required by the
Census and Statistics Act 1905.