Canty farmers notified on run off

The application of nutrient discharge allowances in Canterbury has the potential to radically affect land use.

The Canterbury Land and Water Regional Plan (LWRP) contains a set of nutrient management rules designed to limit the diffuse discharge of nutrients from farming. These nutrient discharge provisions apply to all farmers and will radically constrain intensive farming within the region.

In red zones covering much of the Canterbury Plains, where water quality outcomes are deemed not to be met, or sensitive lake zones, where there are particularly sensitive receiving environments, the LWRP effectively imposes a moratorium on intensification of land use until catchment-based limits are set in sub-regional plans.

To assist with the management of nitrogen (N) discharge, the Matrix of Good Management (MGM) project is currently under way.

This project will establish a matrix of N discharge values to be achieved by adopting good management practice (GMP) under particular combinations of land-use, soil type, climate and topography.

Typically the MGM values will be based on the adoption of practices which minimise N discharge, while being reasonable and cost-effective. The expectation is that all land users will perform at the level of good management practice defined by the MGM project.

In addition, water quality and water quantity limit-setting processes are under way throughout Canterbury to set catchment-based limits in collaboration with local communities.

Nitrogen discharge loads are set for catchments which satisfy the environmental objectives established in consultation with local communities.

Where these loads are the same as or greater than the discharge loads under current land use, then it will be sufficient for land users to operate at GMP. Where the N discharge load under current land use exceeds the load limit, then reductions in N discharge, below GMP, will be required.

Where the ability to discharge N is nearing full allocation, fully allocated or over-allocated, a number of discussions must take place. Firstly, it must be decided how the right to discharge N will be allocated. Options range from grandparenting (based on GMP) at one extreme to equal allocation (per hectare) at the other. (Grandparenting would allow the continuation of current land use and discharge, at GMP for the particular land use.)

If clawbacks of N discharge are required, it must be decided how these will be applied to different land uses and to high versus low dischargers. There are substantial equity issues around all of this.

Grandparenting favours current high dischargers. It may prevent land-use change by low dischargers and decrease the value of their land. In contrast, equal allocation favours low dischargers by giving them a windfall allocation that they currently don't need and penalises high dischargers by leaving them without sufficient discharge capacity and failing to recognise their previous investment.

Where clawbacks are required, the tendency to date has been to require greater percentage reductions from high compared with low dischargers. So far, clawbacks have been applied on a land-use basis, with greater percentage reductions required from dairy farmers than other land users.

Where there is potential for further intensification of land use in fully or over-allocated areas, headroom must be created to enable this to happen. This can be done by reducing the discharge of existing users or by alternative approaches to address environmental issues.

Alternative options may include augmentation of water bodies with fresh water to dilute nutrients. Proposed examples of this are the augmentation of Wainono Lagoon in South Canterbury with Waitaki River water, and managed aquifer recharge to reduce nitrate concentrations in shallow groundwater in the Hinds catchment in Mid Canterbury.

The application of nutrient discharge allowances in Canterbury has the potential to radically affect existing land use and greatly constrain intensification of land use.

In the Selwyn-Waihora zone (Central Canterbury), it is proposed that dairy farmers will be required to reduce N discharge 30 per cent by 2022 (from a baseline of GMP) in order to address environmental issues in Te Waihora/Lake Ellesmere and to create headroom for the Central Plains irrigation scheme.

The situation is far from simple because the Central Plains scheme also assists with addressing some of the environmental issues.

In the Hinds catchment (Mid Canterbury), it is proposed that dairy farmers will be required to reduce N discharge 50 per cent by 2035, while farmers in the upper catchment will be locked into their current N discharge, even though they have not contributed to the elevated nitrate concentrations in lower plains groundwater.

In other catchments, such as some in South Canterbury, with deep, fine textured soils, operation at GMP will be sufficient to achieve environmental objectives. For Waihao/Wainono in South Canterbury, operation at GMP will be sufficient as long as Wainono Lagoon is augmented with Waitaki River water.

To assist with nutrient management, the Land and Water Partnership (convened by Federated Farmers) is working toward a common primary sector position on the allocation of nutrient discharge. It is crucial that the primary industry reaches an agreed position which is as fair as possible, so that land users are not pitted against one another during limit-setting processes as these occur both across Canterbury and around the rest of the country.