Quick Tips – Maximising Yield Predictions

What is required to see an accurate yield prediction?

To see a basic APSIM yield prediction requires just one single management operation to be recorded. However, having only a sowing operation will not provide an indicative yield prediction and as a farmer or adviser, you would be senseless to make any future decisions from this information. To maximise the full potential of the APSIM model, the following paddock operations have the greatest effect on the yield predictions.

Presowing Operations

• Soil Characterisation – Select the appropriate soil characterisation for a paddock when setting up your farm
• Previous Crop – Ensure the previous seasons crop was entered including a harvest operation and achieved yield
• Cultivations – Ensure pre-sowing cultivation activities have been recorded as this effects soil moisture loss
• Soil Test – A critical component to provide baseline nutrient levels for each paddock

Sowing Operation

• Ensure an APSIM supported Crop Type (Wht, Bar, Can, Oat) and Variety has been recorded
• To see the following options, Click the Advanced Tab when entering the Sowing operation
  • Ensure Purpose is set to Grain
  • Ensure Row Spacing (mm) is entered
  • Ensure Sowing Depth (mm) is entered
• Sowing Inputs – Inputs applied at sowing such as fertiliser have large effects on yield results

Post Sowing Operations

• Observations – Enables Plant Density (plants/m2) to be recorded
• Fertiliser Applications – Additional nutrient loads should be recorded to see crop and yield response effects

If you have added these details for your paddocks, you will be providing all that is required to generate the most accurate yield predictions.

The example of Baudin Barley in Central Victoria below shows two scenarios of how providing more paddock records generates more accurate yield prediction results.

• The median yield prediction at sowing changed from 0.58 to 6.1
• The current median yield prediction changed from 0.92 to 4.45

 SCENARIO 1: Minimum data required – Poor yield predictions

 SCENARIO 2: Best management practices – More accurate yield predictions

All climatic information that effects the yield model are automatically integrated to assess the climatic variables the crops are exposed to. Yield predictions will automatically update as new climate information is automatically entered to the data.

To view more details on the APSIM yield model, go to APSIM Simulator Help