Some base assumptions have been set up on the calculator. These are for guidance only and should be adapted for your own situation.
The outcome is in 2 forms, an internal rate of return which reflects the effective annual rate of interest you will receive on the funds invested in the Mouldboard Ploughing/ Spading process. The second measure is the Net present value (in today’s $) of the income stream to you after considering the initial cost.
This calculator, like all on the Soil Quality website has been simplified to provide guidance to the relative benefit of upfront costs of using a Mouldboard Plough or Spader over time. Please note this calculator will only be as good as you assumptions.
Many soils in southern Australia are prone to non-wetting and recent trials have shown the benefits of using a mould board plough or spader every 10 years has lifted yields by burying non-wetting top soils to depths of 20 cm or more. Benefits include alleviating non-wetting soil, burying of weed seeds, loosening of the soil, and incorporating lime to depth.
While these treatments are showing some very positive results, they are very soil type specific. Make sure you know the likely agronomic responses of your soil types before using this calculator. Trial data will provide guidance in this area.
The aim of this tool is to allow you to conduct “what if analysis” of a rate of return and a likely response.