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August 22, 2024
Optimal Changes for Water Quality May Not be Financially Feasible
A new farmer-driven, catchment-level model raises questions about how farmers can achieve mandated water quality changes.
In three catchments where agriculture has led to poor water quality, new research has identified optimal land-use changes and preferred practices to improve freshwater.
Yet for these changes to be feasible, so existing farmers and their families can continue to farm the same land differently, they must be able to be achieved within 20 years (or one generation).
“What we found is that while the modelling showed that the conversion of sheep and beef farms to forestry is viable as a mechanism to improve water quality and nominally maintain farm profitability, it is not financially feasible for those who are currently farming that land,” says Lee Matheson, managing director at Perrin Ag and lead researcher on the project.
“The only financially feasible option would be for these families to sell their farms.”
“What we found is that while the modelling showed that the conversion of sheep and beef farms to forestry is viable as a mechanism to improve water quality and nominally maintain farm profitability, it is not financially feasible for those who are currently farming that land”
Lee Matheson, managing director at Perrin Ag
Testing land-use aspirations
The research looked closely at Tukituki in Hawke’s Bay, with two further case studies in Te Hoiere (Rai Valley) in Marlborough and Waihou in Canterbury.
To better understand land-use management change and how farmers might modify their practices to improve freshwater, surveys were conducted with 71 farmers across three catchments.
Alongside these surveys, researchers utilised the Land Use Management Support System (LUMASS) to create specific geospatial catchment models. Based on water quality mitigations and farmer surveys, catchment-specific mitigation cost curves were then developed and adapted for use within the catchment models to highlight outcomes of both land-use management and land-use change to meet national water quality targets.
“It is important to remember that the potential amount of change that is required, and how a catchment might respond, will be different for different catchments,” says Lee. “What this research gives us is a framework to evaluate the practicality and feasibility of freshwater management policies.”
The modelling from this project shows that 78% of the catchment area requires land-use change to meet water quality targets.
Understanding the rate of change for Tukituki
Findings show that for nitrogen-heavy catchments, such as Tukituki, even conversion of the majority of the catchment to forestry will not fully achieve the water quality targets, as set by the National Policy Statement for Freshwater Management (NPS-FM) (2020).
The Tukituki catchment is one of the largest in the Hawke’s Bay, covering 221,000 hectares. The modelling from this project shows that 78% of the catchment area requires land-use change to meet water quality targets. The predominant land-use change suggested by the model was the conversion of sheep, beef and deer farmland to exotic forest.
“In Tukituki, the main element is nitrogen and so pine trees become a proxy for a higher impact, lower-cost land-use change,” says Lee. “But the model is limited in its ability to accomodate variable market dynamics and regulatory settings – that’s why we keep getting pine trees as the answer.”
| Why pines? A white paper associated with this research provides context for research results that appear to support land conversion into pine forestry. >>Read more |
Meanwhile a further financial feasibility study was carried out on five farms in the Tukituki catchment to understand how a transition from current to future land use to reduce containment loads would affect their profit.
The research shows that even with a mosaic of existing land uses, which was the farmer preference, this would not enable water quality targets to be met, despite achieving a 49% reduction in total N load and accepting a profit erosion of 17% from current levels.
“While there are potential pathways to profitable water quality outcomes, when interrogated through even a single perspective, such as financial capacity, the feasibility of the change required is potentially uncertain. This means that, even if change is desired, it might not always be possible to achieve,” says Lee.
“This should not be interpreted as grounds to dismiss action or targets as meaningless or misguided, but rather as an opportunity to continue to explore the pathways towards the better future our farming communities both desire and require.”
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