Question On Notice No. 2880 asked in the Legislative Council on 19 March 2020 by Hon Dr Steve Thomas
Question Directed to the: Minister for Agriculture and Food
Parliament: 40 Session: 1
Question
I refer to the University of Western Australia lime calculator endorsed by the Department of Agriculture and Food, and I ask:
(a) will the Minister please provide the algorithms used in the WA lime calculator;
(b) will the Minister please provide the Efficiency Factors used in the WA lime calculator;
(c) do any links on the website of the Department of Primary Industries and Regional Development (DPIRD), send users to any old or outdated calculators;
(d) do staff of the DIRP carry out audit testing of lime samples; and
(e) if yes to (d), is this service available to all lime suppliers, or only to members of Lime WA Inc?
Answered on 19 May 2020
- The WA lime calculator on the soilquality.org.au website compares the costs ($/t) between two lime sources based on efficiency factors (% of sample x Neutralising Value x particle size efficiency) and summed costs of application (lime + transport + spreading). Equivalent lime cost $/t = Cost of application x (100/EF)
- The efficiency factors used in the WA lime calculator are based on particle size ranges where:
Particle size Efficiency
0 – 0.5mm = 1
0.5 – 1 mm = 0.5
> 1mm = 0.2
3. The particle size ranges and corresponding efficiencies provided on the DPIRD website, used in the WA Lime Calculator and the WA Lime Industry calculator, are based on values developed by Cregan et al. 1989. The NSW Lime calculator uses efficiency values based on work by Scott et al. 1992, developed around the same time period. The Scott method discounts coarser particles more than the Cregan method. The relative advantages of each method are contested but not resolved. As a consequence, the recently developed iLime app, developed in conjunction with DPIRD, allows the user to input their preferred efficiency values.
4. Yes. An independent lime sample has been collected annually by DPIRD from Lime WA Inc. member lime quarries. The sample is submitted to a commercial laboratory for analysis at the cost of Lime WA Inc.
5. This arrangement has been in place for Lime WA Inc. members.