The Farm Portal is set to become the online tool farmers use to find out their nitrate leaching limit in Canterbury, and potentially further afield, but industry groups, farmers, scientists and fertiliser companies have all raised serious doubts about some of the calculations used to determine the leaching limit.
Accuracy of the Farm Portal output is critical because, under a proposed regional plan change, farms in red zones (and not part of an irrigation company) that exceed their individualised nitrogen loss limit after July 2020 will be deemed a prohibited activity.
Farms in other zones – green, light blue, lake or orange – that don’t meet their requirements, will be non-complying activities.
Plan Change Five is the latest change to Canterbury’s Land and Water Regional Plan and brings changes to what’s permissible in terms of increase in nitrate leaching in some zones, denoted by their colour – red, orange, green and light blue – as well as changes to thresholds for consent requirements and the introduction of individualised, farm-by-farm nitrate leaching limits.
Based on the plan change any farm with more than 20ha of winter grazing or 50ha of irrigation will require a consent. All farms 10ha or more will have to register their farm details in the Farm Portal.
Dairy farms that require a consent will also have to upload their Overseer budget files to it.
The Farm Portal applies proxy calculations to simulate good management practices and create a new, modified Overseer budget to produce a new nitrogen loss rate.
That will tell ECan and the farmer what their nitrogen loss should be if the farm is run using the industry-agreed good management practices.
Farmers will be required to upload a number of Overseer files – first their Overseer files from 2009 to 2013, which will be used to determine what’s called their baseline good management practice (GMP) loss rate.
The Farm Portal will use the proxy calculations over the historic files to calculate the baseline GMP loss rate.
Farmers will then have to upload their Overseer files each year so the proxy calculations can again be applied and a rolling four-year average calculated to give the GMP loss rate number.
From 2020, depending on the zone they’re in, most farms will be in a situation where they won’t be allowed to exceed the Baseline GMP loss rate number.
Farms that belong to irrigation schemes that have been granted global nutrient loss limits won’t have to apply for their own consents – they will be managed by the irrigation companies.
Hearings are under way to work through more than 120 submissions on Plan Change Five, which will set the policies and rules for farms not covered by irrigation company consents and farms across Canterbury in all areas that are yet to develop their own chapter through the Canterbury Water Management Strategy process.
Nitrate leaching limits are under submission in Canterbury.
Dairy industry groups, farming bodies, irrigation representatives and individual farmers have been working collaboratively with ECan and other groups for several years to develop policies aimed at maintaining or improving water quality in the region.
Developing industry-agreed good management practices has been a key component of the work. Dairy farms are now going through, or have completed, the process of having farm environment plans aimed at ensuring all are farming to those standards.
Modelling has estimated moving all farms to the industry-agreed good management practice could reduce nutrient losses by 20% across the region.
While this process has been successful and supported by industry, the move to develop specific, individualised nitrogen loss limit numbers for each farm has not been so straight forward.
The Farm Portal has been a major focus of submissions with the main concerns centring on the proxy calculations related to irrigation and nitrogen fertiliser.
DairyNZ’s submission called the proxies underpinning the portal “inconsistent, technically flawed and not validated”.
It brought in experts – DairyNZ scientist and strategy and investment leader Dr Bruce Thorrold and AgResearch principal scientist Dr Stewart Ledgard – to give evidence about why the proxies were flawed and offer alternative approaches.
Irrigation New Zealand also provided evidence relating to the irrigation proxies. Following that evidence, hearing commissioners asked ECan staff to investigate the proxies proffered by the industry group experts and do a comparative analysis of the different approaches.
Results of that analysis must be presented back to the hearing by the end of November.
The DairyNZ submission called for a robust validation process for each of the proxies to ascertain the extent of errors and variances.
Both DairyNZ and Fonterra criticised ECan for not allowing access to the tools behind the portal workings so the details of how the proxies adjust particular files could be assessed.
When and where numerical limits are set, these need to be well-justified so that the result does not become ‘farming to a number’ without a sound basis.
DairyNZ
The Farm Portal was developed in parallel to the Matrix of Good Management (MGM) project, which set out to define agreed good management practices onfarm and then come up with a matrix or table that could give estimated nitrate leaching losses based on soil type, location, climate, farm type and level of farm system intensity.
The good management practices were incorporated into proxy calculations used to develop the Farm Portal.
DairyNZ was a key member of the MGM project team, leading several work streams, and while it backs the Farm Portal as a tool for ECan’s nutrient management accounting obligations, it’s critical of both the nitrogen fertiliser and irrigation proxies.
In its submission DairyNZ noted, “However, as the MGM project was nearing completion, the MGM project team and Environment Canterbury made decisions regarding the development of modelling proxies for nutrient management that DairyNZ does not support”.
Testing the accuracy of the proxies had been severely hampered by not having access to specific tools used within the Farm Portal, but what was done found wide variations in nitrogen loss number outputs.
Numerous submitters, including DairyNZ and Fonterra, have called for an alternative consenting pathway other than committing to the portal loss rates ascribed to individual farms.
Even if sensible proxies are developed there’s concern that variability inherently associated with the Overseer model and issues with running some Overseer files through the Farm Portal mean nitrogen loss numbers for some farms could be highly inaccurate.
“DairyNZ expects significant differences between modelled nitrogen baseline and baseline GMP loss rates for many farming operations, without certainty that those differences are due to the farm not operating at GMP.
“While the proxies may well provide a basis for estimating a baseline GMP loss rate, DairyNZ does not believe that this is a sufficiently accurate process for estimating baseline GMP loss rates for the purpose of deciding whether to grant or decline a consent”, the levy funded organisation noted in its submission.
“In the first instance we consider requiring farmers to implement good management practice is the primary focus. When and where numerical limits are set, these need to be well-justified so that the result does not become ‘farming to a number’ without a sound basis.
“This is a particular concern given the potential for inaccuracies as a result of the use of proxies within the portal.”
Fonterra noted concerns about the reliability of the Farm Portal proxies too but also said regardless of those concerns there would always be “outlier” farms and farming systems that, for any number of reasons, might not be able to be reliably modelled by Overseer.
Fonterra was critical of ECan’s Section 32 report that accompanied the plan change. Its submission argued the risks associated with enabling a tool that could generate inaccurate baseline GMP values had not been adequately assessed.
“The Section 32 report should have included a sensitivity analysis, weighing the suggested benefits of the Farm Portal, as against the various potential costs that may arise, depending on how inaccurate the portal’s modelling proxies might prove to be.
“That this critical analysis has not been undertaken is another reason why a ‘safety valve’ for the Farm Portal, in the form of the proposed alternative consent pathway, must be provided for in the plan change.”
Given the concerns raised, hearing commissioners have asked ECan staff to develop rules for an alternative consenting pathway and report back to the hearing by late November.
Portal option – risk or incentive?
Even though Canterbury’s Plan Change Five is working its way through the hearing and submissions process it’s relevant to farmers now.
That’s because using the Farm Portal is already being offered as an option in the consents farmers are applying for.
Under the existing Canterbury Land and Water Regional Plan there’s a timeline for farmers to apply for consents to farm.
Those in the Orange Zone requiring a consent should have begun their consent application process earlier this year. Those in the Red Zone needing a consent must do so by January 2017.
Consent application forms give farmers the choice of ticking an option that binds them to the nitrogen loss numbers from Farm Portal from 2020.
If they take that option now they are eligible for a 15-year consent. Those who don’t take up the option will only receive a five-year consent.
Consultants and dairy industry commentators are divided over which action to take, given the problems with the portal and the potential for farmers to be committing now to nitrogen loss levels they might not yet know.
The Farm Portal is available in test mode so farmers can get an indication of what their nitrogen loss limits might be.
But with submissions still being heard, changes to the workings of the Farm Portal calculations could be possible.
• Click here for more information about Plan Change Five, the submissions and evidence. For more on Farm Portal go to farmportal.ecan.govt.nz
