SOI phase and Economic analysis

Exercise 7: SOI phase and Economic analysis

In this exercise, you will examine the effect of SOI phase on yield probability, and gross margin outcomes. Exercises will also be conducted using manual generation of a probability distribution and the application of economic principles.

1. Create a new simulation using Continuous Sorghum Simulation.
2. Rename simulation to A (we are choosing this short name to save space on the graph later on)
3. Choose Goondiwindi weather (long term 1940 to 1989)
4. Starting date 01/01/1940 Ending date 31/12/1989
5. Choose "Black Vertosol-Anchorfield (Brookstead No006)" soil. (Soils->Australia->Queensland->Darling Downs) (remember to rename)
6. Set the starting soil water to 33% full – filled from the top
7. Use default initial soil nitrogen
8. Set initial surface organic matter to sorghum and is 1500 kg/ha. (rename the pool name, but leave everything else)
9. Modify sowing rule to:
   

   Force sowing to 10-Dec
   Enter sowing density at 5 pl/m2
   Cultivar as early
   Skip row as soild
   (leave everything else as is)

10. Set fertiliser at sowing to 100 kg/ha of urea_no3. (move this rule up so that it comes before harvesting rule)
11. From the Standard toolbox drag in a "Yield moisture correction" and a "Simple gross margin (put before harvesting rule)" rule. (make sure the "Yield moisture correction" rule comes before the "Simple gross margin" which obviously comes before the harvest rule)
12. Report year, yield and Bank in the output file. (Just type "Bank" in manually into the variable list)
13. Create a linked copy of this simulation via drag and drop and rename this new one to B (to find out how to do this see: How To: Use linking to reduce simulation duplication)
14. Unlink the sowing rule and change change the "Skip row" property to "double".
15. Graph Yield of both simulations using an SOI Box Plot from the Graph toolbox.

    Fully expand the graph component. For the "SOI" component, given we used a sowing date of December, use the SOI from November to split the years.

    You may want to resize your ApsimUI window to make the graph more visibile.





16. Give your graph a different label perhaps SOI Solid and Skip Yields To find out how see: How To: Modify a Graph component)







The output demonstrates the differing probability distributions of solid vs double skip configuration in negative and positive SOI phases





17. Compare with "SOI CDF" and "SOI Probability Exceedence" graphs.

Economic analysis

This simulation has two rules from the Standard toolbox that we dragged in. A "Yield moisture correction" and a "Simple gross margin" rule.

You also remember how you manually typed in Bank into the output variable list. To see where it comes from click on the "post" tab of the "Simple gross margin" rule.

You can create your own economic calculations by using these kind of manager rules.

Keep in mind though when using these rules, that yield in APSIM is calculated as dry yield. So this assumes no water content. Much economic analysis requires a wet yield which is what a farmer will actually harvest from his paddock. This is why in our simulations we used a "Yield moisture correction" to do a simple calculation to work out this wet yield. (see its "start_of_day" tab)

1. Graph gross margin using the SOI graph you have already created. (In "Plot" window delete "Yield", and add "Bank")



2. Change the label to SOI Solid and Skip Profits.

   

   
   
   Note: Similar output can be obtained via the WhopperCropper program that allows selection of the required input variables from a pre-determined set (usually 3 to 6 options for each variable).

Further economic analysis in Excel

1. Select the top component Simulations then click the Excel button on the top toolbar.
2. You will notice that the output files have been exported to 2 separate Excel windows.



3. *** At this point you can manipulate the data however you like in the EXCEL program ***