Frequently Asked Questions

The sections below outline answers to questions users may have about the portal and its responses. They are broken up into category groups based on the portal functionality to help users more easily find what they are looking for. Click one of the options listed below to go to the category group.

What is a Farm Portal?

The Farm Portal is designed to calculate a farm’s Nitrogen losses at Good Management Practice (GMP) as defined by industry. Nitrogen losses at GMP can be calculated by using OVERSEER® or by answering some simple question for permitted activities.

It will also determine if the land use is authorised as a permitted activity or if a resource consent is required from Environment Canterbury.

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Who should use the Farm Portal?

The Farm Portal has been developed for all farmers in Canterbury to help you determine if a consent to farm is required and to calculate your Nitrogen Losses at Good Management Practice.

Some farmers will be required under their consent to use the Farm Portal to submit information regarding their farming activity.

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Will the Farm Portal provide a report of results?

Yes, each analysis provides the user a Nutrient Loss report containing information about the farm’s nitrogen losses, boundaries, soil, and climate.

When used for official purposes, reports must be kept for at least seven years.

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What happens once I’ve calculated my GMP Nitrogen losses on the Portal?

You will be asked some questions to determine whether or not you require a land use consent to farm.

If you already hold a land use consent for your farming activity, you will need to provide a copy of the report to your FEP Auditor.

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Where can I find more information about my land use consent requirements?

You can call customer service on 0800 324 636. Alternatively, you can contact your fertiliser representative, irrigation scheme (if you are part of one) or a farm consultant.

Our website has plenty of zone-specific information relevant to your farm.

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What is a Baseline GMP Loss Rate?

Baseline GMP Loss Rate means the average nitrogen loss rate below the root zone, as estimated by the Farm Portal, for the farming activity carried out during the nitrogen baseline period, if operated at Good Management Practice.

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What is an Equivalent Baseline GMP Loss Rate?

Equivalent Baseline GMP Loss Rate means a nitrogen loss rate, expressed in kg per hectare per annum, for a 48 month consecutive period within the period 01 January 2009 to 31 December 2013, and that has been calculated by applying:

  1. modelling proxies equivalent to those in Schedule 28 of the Canterbury Land and Water Regional Plan to that part of the farming activity where that is practicable and appropriate; and
  2. alternative methods and modelling proxies that are representative of good management practice to the balance of the farming activity.

For the purposes of clarity, in the case where a building consent and effluent discharge consent have been granted for a new or upgraded dairy milking shed in the period 01 January 2009 to 31 December 2013, the calculation will be on the basis that the dairy farming activity is operational.

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What is a GMP Loss Rate?

GMP Loss Rate means the average nitrogen loss rate below the root zone, as estimated by the Farm Portal, for the farming activity carried out over the most recent four year period, if operated at Good Management Practice.

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What is an Equivalent Good Management Practice Loss Rate?

Equivalent Good Management Practice Loss Rate means the average nitrogen loss rate below the root zone, expressed in kg per hectare per annum, for the most recent four year period and that has been calculated by applying:

  1. modelling proxies equivalent to those in Schedule 28 of the Canterbury Land and Water Regional Plan to that part of the farming activity where that is practicable and appropriate; and
  2. alternative methods and modelling proxies that are representative of Good Management Practice to the balance of the farming activity.
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What is a Nitrogen Baseline?

Nitrogen baseline means:

  1. the discharge of nitrogen below the root zone, as modelled with OVERSEER®, (where the required data is inputted into the model in accordance with OVERSEER® Best Practice Data Input Standards), or an equivalent model approved by the Chief Executive of Environment Canterbury, averaged over a 48 month consecutive period within the period 1 January 2009 to 31 December 2013, and expressed in kg per hectare per annum, except in relation to Rules 5.46 and 5.62, where it is expressed as a total kg per annum from the identified area of land; and
  2. in the case where a building consent and effluent discharge consent have been granted for a new or upgraded dairy milking shed in the period 01 January 2009 to 31 December 2013, the calculation under (a) will be on the basis that the dairy farming activity is operational; and
  3. if OVERSEER® is updated, the most recent version is to be used to recalculate the nitrogen baseline using the same input data for the same period as used in (a) above.
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What is Nitrogen Loss Calculation?

Nitrogen loss calculation means the discharge of nitrogen below the root zone, as modelled with OVERSEER®, (where the required data is inputted into the model in accordance with OVERSEER® Best Practice Data Input Standards), or an equivalent model approved by the Chief Executive of Environment Canterbury, averaged over the most recent four year period and expressed in kg per hectare per annum. If OVERSEER® is updated, the most recent version is to be used.

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What is a permitted activity?

A permitted activity is an activity that complies with the requirements, conditions and permissions of a regional plan.

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What is a Principal Water Supplier?

A Principal Water Supplier is a publicly or privately owned supplier of water which is conveyed and distributed to constituent irrigation schemes, community and/or stockwater schemes, hydro-electricity generators and/or other users of the water.

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What is a Property?

Property means any contiguous area of land, including land separated by a road or river, held in one or more than one ownership that is utilised as a single operating unit, and may include one or more certificates of title.

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What is Winter Grazing?

Winter Grazing means the grazing of cattle within the period of 1 May to 30 September, where the cattle are contained for break-feeding of in-situ brassica and root vegetable forage crops or for consuming supplementary feed that has been brought onto the property.

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What is an Irrigation Scheme?

Irrigation Scheme means a trust, company, incorporated society or other legal entity that holds a resource consent to take and supply water to more than one property.

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What is a Resource Consent?

A resource consent is a formal authorisation for an activity that is not permitted by the relevant rule(s) in a regional plan.

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What is a Management Plan?

Any property larger than 10 hectares that does not require resource consent must have a management plan. The management plan will describe:

  • your property details.
  • the key features of your property, such as the main land management units, the location of water bodies.
  • what good practices you have implemented over the last 12 months, and what good practices you intend to do over the next 12 months.

You don’t have to submit a copy of your management plan to Environment Canterbury, but you may be asked to provide a copy to show that you have been implementing good practices.

You can find out more about management plans (including templates for specific activities) here

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Where is Portal data stored and who has access to it?

All data (including farm boundaries, farm status, N-Loss, baseline and GMP for consented activities) will be stored by Environment Canterbury in their internal systems.

All Environment Canterbury data is discoverable unless the data contains personal information or is commercially sensitive. Information relating to OVERSEER® files, Nitrogen Losses and GMP losses for a specific farm are considered commercially sensitive information.

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How accurate is the Farm Portal data?

The Farm Portal uses OVERSEER® to determine estimates of nitrogen loss rates at good management practice.

Click here for more information about the accuracy of OVERSEER®.

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How are the new nutrient management rules likely to affect my farming operation?

The new rules do not take legal effect until they are made operative. Visit your zone page here for full details about your current local nutrient management rules and additional requirements.

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What happens if there is an adverse season that affects my farming operations?

The nitrogen loss calculation and the Good Management Practice Loss Rates, calculated by the Farm Portal, are based on the average nitrogen losses over the last four years. The rolling average is designed to ‘smooth’ out the influence of extreme events, such as a drought, on the calculation of nitrogen losses.

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What do I do if the farming operation changes boundaries?

Land can only be modelled on whole land parcels. Create a new farm in the Farm Portal to reflect your new farm boundaries. You will need to re-create your nitrogen baseline.

The land owner is responsible for creating a nutrient budget and the entry of information into the Farm Portal (even if the land is leased).

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What if I lease part of a land parcel?

In this case where two farming operations are being carried out on a single land parcel (e.g. where the land parcel is being leased to two different parties) the land owner is responsible for entering information into the Farm Portal. They will need to amalgamate the two farming operations and treat them as one farm and when entering information into the Farm Portal.

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How do I get an OVERSEER® File that is compliant?

The Farm Portal has specific requirements for OVERSEER® files that are uploaded into it, primarily related to the soil and climate details for the farm (see below). Before you upload an OVERSEER® file to the portal, you may want to check that it will meet those requirements and work in it. A utility is available on this website for users to upload their OVERSEER files to see if they are valid for use with the Farm Portal. The utility will check if it meets the necessary requirements, and will display any issues or problems that it finds with the file.

Click here to go to the OVERSEER® file checker (or click the Check my OVERSEER® file option in the side panel.

The following are the basic requirements for an OVERSEER® file to be valid for use in the Farm Portal.

  1. Climate Data - you must have the following values:
    • Mean annual rainfall
    • Mean annual temperature - use of default value is not valid
    • Annual PET - "use default PET" is not valid.
  2. Soil Description:
    • Soil moisture values – You must use this method for choosing the soil, and ensure the soil water properties section is filled out.
    • Sibling name – You must have a valid S-map sibling name. Note that at this point in time, only S-map soils for areas that are within the Canterbury Region are supported by the Farm Portal. Using incorrect soil names or soil sibling names for areas outside this region will result in a invalid file error being displayed.
  3. If you have supplements imported (see Figure 1) or exported (see Figure 2) in your OVERSEER® file you will need to ensure that the weight is entered on dry weight basis. If your values are currently provided on a wet weight basis then Figure 3 shows how to modify this.
  4. You will need to have your OVERSEER® files at the current version of OVERSEER®.
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Good Management Practices

You can access information about your industry Good Management Practice at the Canterburywater.farm website.

What is the difference between the Nitrogen Baseline/Baseline GMP Loss Rate and the Nitrogen Loss Calculation/Good Management Practice Loss Rate?

The Canterbury Land & Water Regional Plan requires most Canterbury farmers to calculate a nitrogen baseline and a nitrogen loss calculation for their land (see Canterburywater.farm).

Under the proposed new regional nutrient rules to the Canterbury Land & Water Regional Plan, these two calculations would be modified as follows:

The Farm Portal will use the OVERSEER® file for your property to calculate both the Baseline GMP Loss Rate and the Good Management Practice Loss Rate for consented activities.

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How can I meet my Good Management Practice loss Rate?

There are several things that you can do:

  • Check your OVERSEER® file, e.g. management blocks, inputs, soils and climate, to make sure that it accurately represents your farm system.
  • Look at the nutrient losses from each block. Are there any blocks with particularly high losses? Check to see if there are any practices that might be causing these losses, e.g. applying nitrogen fertiliser in winter months.
  • Seek professional advice from a farm consultant, fertiliser representative or your industry organisation.
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Might there be a difference between my actual nitrogen loss calculation and my GMP loss rate?

There may be a difference between your current nitrogen loss calculation and your GMP Loss Rate if you are not implementing industry-agreed GMPs on your farm, or if you are operating beyond GMP

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How do I know what Good Management Practice has the greatest influence on my GMP loss rate?

You can find this information in the Nutrient Loss Report, if you have used the OVERSEER® method.

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How are GMPs modelled?

The narrative industry-agreed GMPs were ‘translated’ into a set of ‘modelling proxies’. These modelling proxies are applied to a farmer’s uploaded OVERSEER® nutrient budget to provide an estimate of a farming activity’s nitrogen loss rate when the farm is operated at Good Management Practice. For more information on the modelling proxies refer to Schedule 28 of the Canterbury Land and Water Regional Plan

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Does OVERSEER® assume Good Management Practice is being applied?

No. There are some GMPs that are already implicit within the OVERSEER® model, but there are many that aren’t. In addition, OVERSEER® continues to improve to be able to characterise current practice which may be different from GMP.

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My OVERSEER® number keeps changing with different versions. Is my leaching changing?

Given the same management practices and soil/climate conditions, your actual leaching losses won’t be changing even though your modelled loss may increase or decrease. As the modelling and underpinning science improves, the estimates of nutrient loss are likely to be getting more accurate with version updates.

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Will the Farm Portal use the latest version of OVERSEER®?

The catchment matrix and methodology for determining specific farm GMP will update with each version of OVERSEER®.

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What does "Block “x” must have required climate details defined." mean?

When uploading an OVERSEER® file, the file will be rejected if it does not contain climate details, or the details are incorrect, for each "block" specified in the OVERSEER® file. Default PET and Temp are not valid. Please revise climate input in OVERSEER® and use actual instead of default settings.

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What does "Block “x” must have a S-map soil sibling defined." mean?

When uploading an OVERSEER® file, the file will be rejected if it does not contain specific soil information for each "block". It is mandatory to use the “soil moisture values” method for soil description in OVERSEER®. Please revise the soil description in OVERSEER® using the soil moisture values method. The soil description is a key driver of soil nutrient losses, particularly nutrient leaching due to the impact of the Profile Available Water (PAW).

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What does "S-map soil sibling names must be correct."?

When uploading an OVERSEER® file, the file will be rejected if it contains a soil name that is not currently available in Landcare Research's S-map database. Check that you have entered the name correctly in OVERSEER®.

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What does "Original Overseer file: Data Error: ....." mean?

An error message that starts with Original Overseer file: Data Error: when uploading an OVERSEER® file means that there was a problem within the OVERSEER® file itself, most often that:

  • it was incomplete or missing required information; or
  • the information currently contained in the file contravenes an OVERSEER® file requirement; or
  • the file was corrupt; or
  • it is a file that was generated with an older version of OVERSEER®

The message itself will generally give an indication of what the problem is with the file.

If this occurs, load the file into the current version of OVERSEER® and re-run the process, ensuring that all of the required information has been completed. You can then attempt to upload the file to the Farm Portal again.

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