Nitrogen loss reductions in Selwyn Waihora

Farmers in Selwyn Waihora have faced challenging times over the past decade with tightening environmental regulations. Good progress is being made toward achieving better environmental outcomes, and we recognise the work and contributions of our rural communities.

This is an overview of current requirements for farming in the Selwyn Waihora zone. Support is available, please contact us if you have any questions.

About the zone

Download the brochure about nitrogen loss reductions in Selwyn Waihora

Download the brochure (PDF File, 60.4 KB)

The social and economic wellbeing of the Selwyn Waihora community is largely reliant on its agricultural industry. Over the years, flows in lowland streams and the Waikirikiri/Selwyn River have decreased, while nitrate concentrations have increased, and the health of Te Waihora/Lake Ellesmere has deteriorated.

As part of Plan Change 1, the Selwyn Waihora Water Zone Committee, with input from the community, developed a package of actions including restricting the agricultural nitrogen load losses from the catchment. This requires all farming activities to operate at good management practice and make further improvements over time for managing nitrogen on farm and reducing its impact on the environment.

Nitrogen loss reductions

Farms in the Selwyn Waihora catchment with consent conditions to reduce their nitrogen losses from 1 January 2022 will have their reductions audited from mid-2023 (when the 2022-23 season ends and the nutrient budget is available).

About 200 farms in the area with nitrogen losses greater than 15kg of nitrogen per hectare per year have farming land use consent conditions that require specific percentage reductions in nitrogen loss from 1 January 2022. Consent holders will have these checked as part of their scheduled Farm Environment Plan (FEP) audits.

Farm Environment Plan (FEP) audits in Selwyn Waihora had been on hold while we addressed how these reductions would be evaluated under the Overseer interim solution. This has now been resolved and audits have resumed.

How much will I need to reduce?

Farms in Selwyn Waihora leaching more than 15kg nitrogen per hectare per year are subject to percentage reductions in nitrogen losses below their nitrogen baseline. Your specific reduction requirements may be stated or pre-calculated in your consent conditions – if this is the case, the reduction target specified must be used.

The reductions under the Canterbury Land and Water Regional Plan (LWRP) are:

  • 30% for dairy
  • 22% for dairy support
  • 20% for pigs
  • 5% for irrigated sheep, beef or deer
  • 2% for dryland sheep, beef or deer
  • 7% for arable
  • 5% for fruit, viticulture or vegetables
  • 0% for any other land uses.

How were these numbers determined?

The 15kgN/ha/yr number was recommended to the Selwyn Waihora Water Zone Committee during the limit-setting process by a working group of Environment Canterbury, industry, and Ngāi Tahu. The limit provides flexibility for low-leaching land uses, while also ensuring that the additional reductions that would need to be made by properties with higher losses could be achieved.

The reduction rates were developed in collaboration with industry partners and Environment Canterbury to give a balanced impact on farm profit across all sectors and reduce agricultural nitrogen losses by an average of 14%. This was to meet the catchment nitrogen load limit set in the Selwyn Waihora section of the LWRP , and for that target to be met by no later than 2037.

What you need to do

How do I prepare for my audit?

The evidence required for your audit is dependent on how large your reduction requirement is and what changes have been made to the farming system since the baseline period (2009-2013).

Your FEP auditor will be able to advise on the specific information they'll need on the day, but some examples of important evidence are:

  • an updated Farm Environment Plan
  • Overseer nutrient budgets
  • a clear description of the farming system
  • management practices and mitigations.

Do I need to provide an Overseer nutrient budget?

Depending on how large your reduction requirement is, and what changes have been made to your farming system in the last several years, you may need to provide an Overseer nutrient budget for your audit.

In some situations, other sources of evidence may be able to demonstrate that the farm system changes and mitigations are overwhelmingly capable of delivering the reduction, and an Overseer nutrient budget may not be required.

We no longer rely solely on Overseer modelling, due to the ongoing government review. Other forms of robust evidence are required to make assessments that a property is meeting its nitrogen loss limit.

Talk to your FEP Auditor to find out whether you will need to provide an Overseer nutrient budget.

Actions to lower nitrogen losses

There are various actions you can take to achieve lower nitrogen loss and improve farming efficiency, beyond GMP. Mitigation techniques such as planting catch crops, irrigation scheduling, plantain and soil nitrogen testing have been identified as effective and practical options for farmers, offering the best value for money, industry support and availability. Learn more about these options for reducing nitrogen loss.

Talk to a nutrient management advisor or farm consultant to discuss what may work best for your farm system. Our Farming Land Use team and your local Land Management Advisors are also happy to help.

Key Contacts

Zone Manager

Andrew Arps  027 554 4007

Talk to your zone

Gillian Jenkins — Zone Delivery Lead 027 706 7254

Talk to your scheme

Central Plains Water Limited — Fiona Crombie 027 207 6499

Fereday Irrigation — Rowan McMath 021 655 547

Lynton Irrigation — Brian Gallagher 027 450 2470

Northbank Irrigation — Gary McGregor 027 434 6558