What is Yield Prophet?You may scroll down the page to read about Yield Prophet, or use the links below to jump straight to a particular heading:
Yield Prophet® is an on-line crop production model designed to provide grain growers with real-time information about the crop, providing integrated production risk and monitoring decision support relevant to farm management. Operated as a web interface for the Agricultural Production Simulator (APSIM), Yield Prophet generates crop simulations and reports to assist in decision making.
The simulations provide a framework for growers and advisors to forecast yield, manage climate and soil water risk, target specific grain quality and make informed decisions about nitrogen and irrigation applications and allow users to match the inputs with the yield potential of their crop. By matching crop inputs with potential yield in a given season, Yield Prophet subscribers may avoid over and under investing in their crop.
Subscriptions for 2009 are now open. For details on how to subscribe to Yield Prophet in 2009 click here.
Yield Prophet services
Yield Prophet is a sophisticated tool with a significant number of applications and services that can support your farm business in the production and marketing of grain.
Paddock subscriptions
Yield Prophet should be incorporated into every farm as it provides in-crop decisions support and generates information that contributes to producers matching crop inputs with production potential.
By registering a number of paddocks across the farm with different soil types, climatic conditions and crop types, a representative sample of crop conditions should be generated.
In 2008, over 471 paddock subscriptions were received across Australia. Figure 1 shows the 2008 Yield Prophet paddock subscriptions by Australian meteorological district.
Figure 1. 2008 Yield Prophet paddock subscriptions by Australian meterological district.
Yield Prophet workshops and help line
Individuals and businesses who subscribe to Yield Prophet are entitled to the necessary assistance to ensure easy operation of the web interface and interpretation of Yield Prophet reports.
A help line is available to assist subscribers with any problems or queries that arise in the day-to-day operation or interpretation of Yield Prophet.
Groups of subscribers are also entitled to request a workshop throughout the growing season where a member of the Yield Prophet team will provide training in the operation of the web interface and an introductory session on the interpretation of Yield Prophet reports and outputs.
Yield Prophet reports
A number of report types are available to users of Yield Prophet to assist with management decisions. The reports are:
- Sowing by Variety Report: The Sowing by Variety Report allows subscribers to simulate different scenarios and compare yield probability distributions of crop cultivars or sowing dates. By comparing the effects on yield, growers can assess the impacts on likely crop yield of different sowing dates and cultivars prior to the growing season.
Yield Prophet produces a probability curve for each scenario allowing subscribers to compare the yield effects. This report is generally used by subscribers prior to the growing season as a basis for planting decisions by assessing the impacts of different sowing dates and cultivars on likely crop yield.
- Crop Report: The Crop Report is the principal report used by Yield Prophet subscribers. It contains sixteen separate outputs relating to the individual crop and produces a snap shot in time with:
— a potential yield range for grain and hay production;
— the quantity of available nitrogen and water resources;
— the incidence of nitrogen and water stress;
— estimated and forecast phenological progress of the crop;
— the probability of frost and heat shock; and
— the effect of forecast climatic conditions on yield.
This report is used throughout the growing season as an in-crop decision support tool for decisions related to nitrogen management, irrigation management, hay cutting, frost risk assessment, marketing, insurance etc.
- Nitrogen Comparison Report: The Nitrogen Comparison Report allows subscribers to compare the effects on yield of changes in the quantity or timing of applied nitrogen in different scenarios.
- Nitrogen Profit Report: The Nitrogen Profit Report, using basic gross margin inputs, allows subscribers to compare the profitability of the management decisions applied in the Nitrogen Comparison Report.
- Irrigation Comparison Report: The Irrigation Comparison Report allows subscribers to compare the effects on yield of changes in the quantity or timing of water and nitrogen applied by simulating different scenarios.
- Irrigation Profit Report: The Irrigation Profit Report, using basic gross margin inputs, allows subscribers to compare the profitability of the management decisions applied in the Irrigation Comparison Report.
- Fallow Monitoring Report: The Fallow Monitoring Report allows subscribers to determine the soil moisture and nitrogen levels at the time of the report. This report is generally used after crops have been harvested and feeds into the Stubble Management Report.
- Stubble Management Report: The Stubble Management Report allows subscribers to compare the effect of different tillage and grazing decisions on soil nitrogen and moisture content. This report is usually used out of the growing season, between harvest and sowing, as a basis for tillage and grazing decisions.
- Climate Change Report: The Climate Change Report allows subscribers to observe the potential effects of climate change on crop yields in the year 2030. Yield Prophet produces a yield probability curve for historic climatic conditions and two climate change scenarios developed by the CSIRO for comparison.
Yield Prophet subscription and pricing
For Yield Prophet subscription types and prices click here. Prices do not include sampling and analysis for initial soil conditions. For information on the requirements and costs of initial soil data click here.
To subscribe to Yield Prophet in 2009, register online. Please register before 1 April to ensure access prior to sowing.
How does it work?
Simulation inputs
The crop simulations are created by combining the essential components of growing a crop including:
- A soil test sampled prior to planting;
- A soil classification selected from the Yield Prophet library of 500 soils selected to be representative of the production area;
- Historical and active climate data taken from the nearest Bureau of Meteorology (BOM) weather station;
- Paddock specific rainfall data recorded by the user (optional);
- Individual crop details; and
- Fertiliser and irrigation applications during the growing season.
Soil Test Sampling
In autumn, subscribers sample the soil in their Yield Prophet paddocks down to the maximum rooting depth of their crop at different intervals (e.g. 0-10, 10-40, 40-70, 70-100cm). These samples are analysed for water content, organic carbon, nitrate and chloride concentration, electrical conductivity, and pH. This information is entered by growers into the Yield Prophet web interface and is then used by the grower and the Yield Prophet team to select a suitable soil characterisation. For more information on soil sampling and analysis please click here.
Soil Characterisation
An appropriately measured soil characterisation is an essential input for Yield Prophet to accurately simulate crop growth and yield.
The plant available water capacity (PAWC) and bulk density of a specific soil type are used to determine how much of the measured water and nitrogen is available to the crop for growth during the season. PAWC is determined by a soil’s ‘drained upper limit’ (DUL, or field capacity) and its ‘crop lower limit’ (CLL, similar to permanent wilting point).
The Yield Prophet team has a catalogue of soil characterisations (APSoil) for many of the major cropping soil types found throughout Australia. For more information on APSoil and a Google Earth map of the soil characterisation locations please click here. Many subscribers have soil types for which there is no available measured characterisation data. In these circumstances, a soil characterisation is estimated based on soil type and previous rainfall and crop yields, and any information available from existing soil surveys. An estimated characterisation is less likely to produce accurate results in comparison to a measured characterisation, and it is recommended that potential subscribers to Yield Prophet consider characterising their soil if no appropriate data exists. Figure 2 shows the number of soil characterisations by Australian meteorological district.
If you would be interested in having your soils characterised it may be possible to submit a funding application to cover the costs associated with carrying out the characterisation. If you would like more information please feel free to contact Tim McClelland. Alternatively, if you would like to understand more about the soil characterisation process please click here for a methodology.
Figure 2. APsoil characterisations by Australian meterological district.
Climate Data
Yield Prophet uses the last 100 years of climate data (maximum and minimum temperature, radiation, evaporation and vapour pressure) taken from the subscriber-nominated BOM weather station to simulate crop growth and make predictions about crop yield. The climate information is sourced directly over the web from the SILO patched point dataset. This is a catalogue of climate information for 4600 weather stations across Australia.
Rainfall Data
During the season, Yield Prophet subscribers may enter rainfall for each paddock into the web interface. Alternatively, they can opt to utilise the seasonal rainfall data recorded at their nominated BOM station.
Crop Details
Yield Prophet requires subscribers to enter individual crop details into the website for inclusion in the simulations. Specific details required are the type and amount of starting stubble, sowing date, crop type, cultivar, and sowing density.
Fertiliser and Irrigation Applications
During the season, subscribers need to update paddock management details (cultivations and nitrogen fertiliser and irrigation applications) as they occur.
Crop growth simulation
When a report is requested, the paddock-specific information is emailed from the Yield Prophet database to a computer cluster where the simulation is processed. Using climate data for the current season, Yield Prophet simulates the soil water and nitrogen processes in the paddock from the soil sampling date, and crop growth from the user-nominated sowing date, up to the present. Yield Prophet calculates the amount of water and nitrogen available to the crop and the water and nitrogen demand of the crop. This is used to determine if the crop is suffering stress from lack of either of these resources and any subsequent reduction in growth and yield potential.
Figure 3. Output from Yield Prophet® indicating the amounts of water and nitrogen available to the crop during the season. The stress graphs indicate loss of potential growth and carbon fixation from insufficient water and nitrogen, i.e. on a day when the graph is at 0.5, the crop is growing and photosynthesising at half its potential rate.
Then, using historic climate data, Yield Prophet simulates crop growth and resource availability from the day on which the report was generated to the end of the season.
This process is repeated 100 times (once for each year of climate data) providing 100 separate yield outcomes (Figure 4). These yields are then plotted as a probability curve (Figure 5), providing growers with an estimate of the probabilities of obtaining different yields. This output is then adapted to the requested report type and emailed to the database where it can be viewed by the subscriber. Report generation takes from five to fifteen minutes.
Figure 4. Visual representation of the Yield Prophet simulation process.
Figure 5. A yield probability curve, the principal output of Yield Prophet.
Figure 5 is the main output of Yield Prophet, and its value is increased by incorporating seasonal forecasts, such as the Southern Oscillation Index (SOI) phase system. In this case, instead of using season finishes for the last 100 years, Yield Prophet selects the years in which the SOI phase was the same as in the current year, and runs the future part of the simulation using only the finishes from those years. This creates another probability curve which growers can use if the SOI phase is strongly indicating wet or dry conditions (Figure 6).
Figure 6. Yield probablitlity curve generated using season finishes for the last 100 years of climate data (solid blue line), and only those years in which the SOI phase was the same as the current phase at the time the report was generated. In the above eaxmple, this includes the years with a negative SOI pahse in May. The report was generated for a paddock near Birchip on 6 June 2008.
Scenario predictions
The likely impact of different sowing dates, varieties and irrigation and nitrogen applications can then be determined by simulating different ‘scenarios’. Yield Prophet calculates a probability curve for each scenario, and subscribers use this to determine the probability of achieving a yield or protein response from the addition of water or nitrogen (Figures 7 and 8), or from different sowing dates and varieties (Figure 9). Yield Prophet can also calculate a nitrogen gross margin based on likely grain quality and price (Figure 10).
Figure 7. Yield probability curves for three different nitrogen top-dressing scenarios generated for a dryland wheat crop on 18 July 2008. Scenario 1 (pink line) is the yield probability adding no further nitrogen, Scenario 2 (blue line) is the yield probability with 20 kg/ha of nitrogen top-dressed on 24 July, Scenario 3 is the yield probability with 40 kg/ha of nitrogen top-dressed on 24 July 2008. There is an 80% chance of achieving a yield response with top-dressing, and about a 30% chance of achieving a 1 t/ha yield response from 40 kg/ha of nitrogen.
Figure 8. Yield probability curves for three different nitrogen and irrigation scenarios generated for an irrigated wheat crop on 3 October 2005. Scenario 1 (pink line) is the yield probability adding no further water or nitrogen, Scenario 2 (blue line) is the yield probability with an additional 50 kg/ha of nitrogen top-dressed on 3 October, Scenario 3 is the yield probability with 50 kg/ha of nitrogen top-dressed on 3 October and two additional 25 mm irrigations on 3 and 17 October.
Figure 9. Yield probability curves for three different sowing date scenarios (sowing dates are shown above the graph) generated for a wheat crop at Birchip on 17 November 2008.
Figure 10. Nitrogen profit curves for the same nitrogen application scenarios shown in Figure 5. Each line is calculated as the return from grain (determined by yield and protein minus cost of fertiliser and spreading) for Scenario 1 (solid pink line 0kg/ha of nitrogen) Scenario 2 (solid blue line, 20 kg/ha of nitrogen) and 3 (solid red line, 40 kg/ha of nitrogen). This shows the difference in return between applying nitrogen of specified amounts, and not applying nitrogen. In this case, the cost of fertiliser is assumed to be $2.00 per kg of nitrogen, cost of spreading $10 per ha and the wheat price (AH) $350/t, with a $2.50 per 0.5% protein bonus.
See it for yourself
You can visit the Yield Prophet website to view previously generated reports for the BCG trial site and access help files which will tell you more about operating Yield Prophet and how to interpret reports. Simply respond to Username and Password by typing in Visitor.
For further information
Please contact:
Tim McClelland
Yield Prophet Coordinator
Phone: 03 9882 2670
Fax: 03 9882 0996
Mobile: 0400 090 659
Email: yieldprophet@bcg.org.au
A one-page flyer for Yield Prophet is available.
The Yield Prophet Project is supported by the Australian Government through the Information Technology Online (ITOL) Program of DCITA (Department of Communications, Information Technology and the Arts).
Yield Prophet is also partially funded by the GRDC supported Land and Water Australia MCVP (Managing Climate Variability R&D Program) project: 'Prophetable' Cropping Using Seasonal Forecasting Tools.
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