Overseer Limited has created a tool to support users to develop scenario analyses as part of our focus on supporting sustainable farming in New Zealand. We are releasing the Scenario Tool as a Beta test.
Understanding the magnitude of change in a farm system or management approach in relation to a farms nutrient budget and greenhouse gas emissions helps inform farm planning. The Scenario Tool aims to reduce manual data entry in developing scenario analyses and provide useful feedback on the relationship between inputs, energy needs and production to support user decisions in creating an analysis.
As part of our agile development approach, we are releasing a Beta test version of the OverseerFM Scenario Tool to seek feedback from users on how it supports their modelling. As with any Beta version, this is a prototype still in development and so should be regarded in that context. We have created the top six priority scenarios identified by rural professionals in a survey undertaken by the Agribusiness Group at the start of 2020. These all relate to pastoral block modelling. This means that we have not created any scenarios yet that will support arable systems. These will come later.
This guide provides a description of what the Beta test version of the Scenario Tool does, how it works and how to use it.
The Overseer model relies on the entry of a real/balanced farm system where the animal’s energy requirements are balanced with the feed available.
AnimalMERequired = MESupplements + MEcrops + MEpasture
The ME from supplements and crops is based on the yield or dry matter multiplied by ME content of the supplement or crop. If stored or fed out as supplements, this is reduced due to storage and utilisation losses.
The OverseerFM scenario tool (beta) provides a way to analyse the impact of a farm management change while keeping the balance of animal energy requirements to feed available.
This tool assist farmers and their advisors to model different scenarios to inform a plan for the future.
Please note while this tool is designed to assist with setting up plans, advice and experience should still be applied to the analysis to ensure it makes sense and works for the farming business. Analyses should be reviewed and might need some cleaning up after running a scenario, such that they can be included in a Farm Environment Plan (FEP).
Users need to have an understanding of the potential impact of activities on production and the farm business. This can be achieved through both professional judgement and use of feed budgeting and farm viability assessment tools, such as FARMAX.
The scenario tool (beta) provides the following scenarios:
- Adjust amount of nitrogen (N) fertiliser applied
- Remove all imported supplements
- Add an animal structure
- Change the storage condition and/or utilisation of supplements
- Wintering off dairy animals
- Change irrigation system and/or management method
Each scenario may affect where feed is fed to animals and the amount of energy provided by that feed. This can result in an imbalance in energy required versus energy provided. Depending on whether there is too much or too little feed, the user can choose from the following options for each enterprise:
- Import more supplements on to the farm
- Decrease the supplements brought on to the farm
- Adjust animal numbers
- Adjust pasture production
The scenario for adjusting fertiliser can be combined with other scenarios to balance any changes to energy provided to animals. For example, you could improve the storage conditions and utilisation of supplements. This could provide more energy from the same amount and therefore you could reduce fertiliser because you don’t need to grow as much.
How the tool manages feed energy
The scenario tool adjusts pasture production, supplement amounts and energy and animal ME requirements but does not currently adjust crop yields. So, when defoliation is occurring on crop blocks, these will remain unaffected. This may cause some feeding problems as the scenario tool cannot reallocate this feed successfully. Depending on how the analysis is set up, the user may have to manually change the analysis to decide what to do with that feed and how the farm may be configured in the scenario.
In some cases, the scenario may clear out monthly distribution of animals to blocks and monthly distribution of supplements. This is because the changes to how animals are placed on the farm may not be consistent with how the original animal/supplement distribution was configured. By clearing out the existing settings, the model can be allowed to allocate feed more appropriately.
It is recommended that when creating scenarios or plans that they are not too specific as this does not provide the flexibility for making changes. This includes the base analysis that the scenario is generated from.
The steps to complete a scenario are shown below.
- Select a scenario
- Fill in the details
- Select adjustment options
- Click on “Make adjustments” button
The following are more detailed steps for creating a plan, executing a scenario and saving the changes.
Step 1: Make a copy of the base analysis
From the farm home screen, select copy on the analysis that will form the basis for the plan. Save the copy as a predictive analysis with an appropriate name.
Step 2: Select the scenario tool
For very complicated analyses, it may make sense to simplify or reorganise the analysis and its blocks first. It is important that any changes maintain the balance between feed available and animals. This can be done using the Simplify Tool or manually simplifying the analysis.
At the top right of the screen is the scenario tool link. Clicking this link will launch the scenario tool. The tool will make changes to this analysis.
Step 3: Select a scenario
Select the scenario that you wish to run.
Step 4: Fill in the details for the scenario
Each scenario requires different information to run. The following shows the fertiliser scenario. More detail is provided for each scenario further on in this document.
Step 5: Review the changes
The scenario will automatically run once sufficient information has been entered. Any changes to that information will automatically re-run the scenario and update the results.
The results of the scenario are shown on the right. At the top is a summary of the changes made at the farm level. If animal feed is not balanced and warning is shown in orange.
Below this is a section for each animal enterprise.
The table at the top shows the energy requirements and energy from feed of the original analysis versus after running the scenario. The columns in the table are:
- Animals: Energy requirements of the animals
- Imported: Energy provided from imported supplements
- Harvested: Energy provided from harvested supplements
- Crops: Energy provided from defoliation of crops
- Pasture: Energy provided from grazing pasture or crops
- Difference: Difference between energy required and energy provided
The example shown above, shows a reduction in harvested supplements and pasture grown due to a reduction in fertiliser. This means the animals do not have enough feed.
Underneath this table is a list of changes the scenario made to the analysis.
When the after line of the energy table has a difference in energy required to energy provided, the user must make some adjustments to get them to balance. This is shown in the orange message below the table.
Step 6: Make adjustments
If there is not enough feed available to the animals, there are three options for getting it to balance, to bring on more feed, reduce animals or increase pasture production.
To bring on more feed, enter a percentage of the ME required and select the type of supplement. 100% will bring on enough supplements to make up the entire difference in energy.
If there is excess feed and the farm is importing supplements for this enterprise, the amount of feed imported can be reduced. The user would enter a percentage of the excess ME to reduce the imports by and then select the appropriate animal adjustment for the rest. If there is not sufficient energy in the imported supplements to meet the ME required, it will get the remainder from adjusting animals or pasture (depending on what the user selects).
The remaining percentage will need to be made up by selecting on the of following options:
- Change animal numbers – change production: This will change the number of animals on the farm and adjust production (milk, wool, meat etc.) based on the change.
- Change animal numbers – keep production: This will change the number of animals but keep milk, wool, velvet production the same. So, if reducing numbers, it assumes the productivity of the remaining animals increases. Meat production will still adjust based on numbers as the scenario tool does not currently have a way to improve meat productivity. This may be added in the future.
- Change pasture production: This essentially makes no changes to animals because the model will automatically adjust pasture to meet energy requirements. This option assumes the farm will either grow less pasture or is able to grow more pasture in the same conditions.
Step 7: Review adjustments
The adjustments are applied to the analysis and shown as a new line in the energy table.
In the example shown, there is a difference of 404,164 MJ ME or 67 RSU between what the animals need and what is available from feed. The farm is going to import 50% as silage and lower the number of animals on the farm to balance the feed availability.
This is shown as the orange line in the energy table. Animal energy required has gone down, while imported supplement energy has gone up. The energy now balances.
The table at the bottom shows animal numbers before and after making the adjustments. This information is updated as the user makes any changes to the scenario or the way energy is balanced.
At the bottom of the screen, supplements before and after are shown so they can be reviewed by the user.
Once the energy is balanced for all enterprises the “Make adjustments” button under the supplements table is enabled. Pressing this button sends the new analysis to the model to be run. This final step may make changes to the animal ME requirements because of a change in activity or the type of feed being eaten (which may have a different ME content). The results are then adjusted based on these new requirements.
Step 8: Compare changes
After making adjustments, the options change to the following.
You can go back and edit the scenario or, review the changes. In this state no changes can be made to the scenario, unless edit scenario is clicked.
Selecting review changes takes the user to the Farm Impact report to compare before and after the scenario.
This is the same report used in for planning that is available in the overview tab for each analysis. For more information on this report please search the knowledgebase for Farm Impact report.
Step 9: Save changes
Once happy with the scenario, the final step is to save changes.
Selecting accept changes, will update the existing analysis with the changes from the scenario. This cannot be undone and so please ensure that you want to do this before continuing.
1. Adjusting N fertiliser
Decrease/increase the amount of N applied as fertiliser on pasture blocks.
Please note, crop blocks are not affected by this scenario, as it is currently not clear how yield should be adjusted. This may be looked at in future releases of the tool.
The following settings are available for adjusting N fertiliser:
- Percentage: percentage of N to reduce/increase. Enter a negative number to decrease N.
- Response rate: number of kgs or dry matter produced from 1 kg of nitrogen. The default for an entire year is 7, this can be overridden or left as is.
- Adjustment type: How to apply the adjustment to fertilisers. Users can select one of the following:
- Adjust application amounts: Adjusts the amount applied for every fertiliser that contains N. Please note, if fertilisers contain other nutrients, these will also be adjusted because the total amount applied changes.
- Adjust fertilisers with N only: Also adjust amount applied, but only for fertilisers that do not have other nutrients.
- Adjust N concentrations: Makes changes to the concentration of N in fertilisers. For products, this means they are no longer the original product and so these become custom fertilisers and “- N adjusted” is added to their names.
- Select months: By selecting this, you can select which months to apply the change to. Fertilisers in other months remain unchanged.
In reality, response rates vary during the year. Future releases of the scenario tool may look at creating a variable model of response rate, but an average of 7 is currently used. If you wish to make you own adjustments, you can run multiple scenarios by setting a response rate and selecting the months that it applies.
How it works
The following steps are executed to adjust the animal production based on the change in N applied:
- For fertilisers that contain N, adjust the amount of fertiliser or concentration of N by the percentage entered by the user for pasture block applications.
- For each block sum the amount of N applied per hectare.
- Use the response rate to calculate the change in pasture grown per hectare per block.
- Determine the proportion of the change for each block by dividing the change in pasture grown per hectare by the total pasture grown per hectare for that block
- For supplements harvested from blocks:
- Adjust the amount of supplement harvested from each block by the proportional change in pasture grown
- Change the amount of harvested supplement distributed using the same proportional change.
- Where the harvested supplement is distributed to an enterprise, proportion the amount to each enterprise based on the following:
- If fed to an enterprise, the proportion is 1 for that enterprise
- If fed to a structure, the proportion is 1 for the enterprise on the structure
- If fed on blocks, the proportion for each enterprise is the total of the enterprise’s RSU on each block divided by the total RSU for those blocks.
- Calculate the proportional change for each enterprise using the change in amount distributed multiplied by the proportion of the amount assigned to that enterprise divided by the total amount fed before the change.
- For each pastoral block and enterprise:
- Multiply the total pasture RSU by the proportional change in pasture grown to give the change in RSU. Sum these values for each enterprise.
- For each enterprise
- Divide the change in RSU (calculated in 6a) by the total grazed pasture RSU (pasture eaten) to give a proportional change.
- Multiply the proportional change in pasture RSU by the total ME from pasture to give the change in ME.
- Multiply the proportional change in harvested supplements by the total ME from harvested supplements to give the change in ME.
- Add change in harvested supplement ME to change in pasture ME and divide by the total ME to give proportion of total ME.
2. Remove imported supplements
Removes all imported supplements (including purchased and from storage) and so provides a way to change what is being fed to the animals. Once run there will be a lack of feed available to those enterprises and so a different type of feed can be imported to make up the difference.
Any imported supplements fed on a structure is not changed.
3. Add an animal structure
Add a structure for an animal enterprise. Please note effluent management settings are defaulted and is set to exported. This this will need to be configured manually after running the scenario.
The following settings are available:
- Structure: Select from list of structures
- Enterprise: Select from a list of available enterprise. Only those enterprises available for the selected structure type are shown.
- Percentage: The percentage of animals placed on the structure.
- Hours: Number of hours they are on the structure.
- Storage condition: Set the storage condition for supplements fed on structure.
- Utilisation: Set the feed utilisation for supplements fed on the structure.
- Feed option: Select source of feed for the structure:
- Existing supplements and harvest the rest: Find all supplements currently fed to this enterprise and redirect to the structure. If not enough harvest existing blocks where enterprise grazes. This may create unrealistic harvesting and so should be reviewed.
- Existing supplements and import the rest: as with previous but instead of harvesting the rest, import it as supplements. Requires supplement type to be selected.
- Import all: Import all supplements. Requires supplement type to be selected.
How it works
This scenario creates a new structure for the animals and locates supplements that can be fed on the structure.
- ME remaining starts at total ME required by the animals on the structure (total ME * percentage/100 for each month selected)
- If import all feed is selected, a new supplement is created that will provide enough energy for the animals.
- If redirecting existing supplements, for each supplement fed to enterprises or blocks (while there is ME remaining)
- Calculate proportion of supplement fed to this enterprise
- Calculate ME provided by the supplement to this enterprise
- If ME provided is more than remaining ME required by the structure, then move enough supplement to satisfy remaining ME and stop (remaining ME is zero).
- If ME provided is less than remaining ME, move all supplements for this enterprise to the structure and reduce remaining ME by supplement ME.
- If there is ME remaining for each block and harvest remaining is selected:
- Calculate proportion of RSU in this block (compared to total for the enterprise and month)
- Calculate ME required from this block by multiplying proportion by total ME required for each month and adding them together.
- Convert ME to tonnes DM using ME content and storage condition and utilisation.
- Create a harvest event for this amount. Create a supplement for each pasture type.
4. Change storage condition and utilisation
If supplements are fed out to animals on paddocks or structures, there is the option to change the storage conditions or utilisation of those supplements. This will change the amount of energy provided by the supplements.
How it works
All supplement conditions and utilisation are changed to the selected values. The amount of energy provided by the supplements is calculated before and after the change. This change in energy is allocated to each enterprise based on the proportion being fed.
5. Wintering off animals
If the farm has a dairy enterprise, a percentage of the animals can be wintered off for a period of time. This will reduce the energy requirements of the enterprise. This can then be compensated by reducing fertiliser, imported feed and/or adjusting animals.
The following settings are required:
- Percentage: percentage of animals to remove. The number of animals removed is taken as the percentage of animals on the farm in the starting month.
- Starting month: The animals are removed from the farm on the first day of this month
- Returning month: The same number of animals are returned on the first day of this month
How it works
An event is created to remove the animals on the first day of the starting month. The number of animals is calculated using the percentage of animals on the farm in this month. E.g. if 100 animals are on the farm and 80% are removed, then 80 animals are removed from the farm.
All existing events between the start and end months are deleted and so the number of animals on the farm remains consistent between the two months.
An event is created on the first day of the returning month to bring them back on.
The new energy required is calculated by dividing the number of animals that remain on farm for each month by the number of animals that were on farm previously and then multiplying this by the current energy requirements for that month. This is then subtracted from the existing energy requirements.
6. Change irrigation
If a farm has existing irrigation, the type of system and the strategy used to assess soil moisture levels can be changed. The months selected for irrigation that were previously selected remain unchanged.
This has no impact on animal energy requirements or feed.
The following settings are available:
- System: change all irrigators to the selected type
- Soil moisture strategy: Can select a new strategy to use in all applications. This will change how the model manages applications and hence possibility of drainage occurring.
- Trigger point; fixed depth applied: Applications occur when soil moisture hits trigger point (relative to PAW). Fixed amount of water applied.
- Depth applied to achieve target; fixed return period: Applications occur in a fixed frequency. Amount applied varies depending on soil moisture levels against target (based on PAW).
Trigger point and depth applied to achieve target: Applications occur when soil moisture hits trigger point (relative to PAW). Amount applied varies depending on soil moisture levels against target based