Sustainable Land Management and Climate Change research reports

This project examined how farms may be affected by multiple climate-related shock events occurring more frequently and in succession. Using a conceptual irrigated dairy farm in North Canterbury as a case study, researchers modelled a range of climate and production shock scenarios over a 10-year period to better understand the cumulative exposure risk.

The project developed an efficient modelling approach capable of simulating large numbers of climate, water availability, and farm production scenarios within a practical timeframe. This enabled researchers to assess the effectiveness of a range of adaptation and risk-management options, including changes to water storage, water allocation, and stocking rates, in reducing vulnerability and improving farm resilience.

The findings provide valuable insights into how farmers, regional councils, and the financial sector can better prepare for and manage the impacts of increasing climate variability and extreme events. Practical research briefs were developed for regional councils and financial institutions to support climate-risk assessment and decision-making.

The project has also delivered two open-source modelling tools that are available for researchers and practitioners:
https://github.com/Komanawa/komanawa-simple-farm-model

https://github.com/Komanawa/komanawa-basgra-nz-py

Research outputs from the project are being published in a series of scientific papers. The first paper is: https://link.springer.com/article/10.1007/s10584-025-03946-z

This project investigated the contaminant removal efficiency of two facilitated wetlands with sediment traps, established on a dairy farm (0.06% of catchment area) and a sheep and beef farm (0.2% of area) in South Otago. Water flows were measured continuously over three calendar and analysed for sediment, E. coli, phosphorus and nitrogen. The dairy farm wetland did not significantly reduce contaminants. The pastoral significantly reduced annual loads

Keywords: facilitated wetlands; water quality; sediment; nitrogen; E. coli; phosphorus

This study used a paired catchment experimental design to test the effectiveness of three mitigation strategies targeting the critical source areas (CSAs) that were ephemeral streams in deer grazed pastures. Four small catchments on the same hill slope (2.2 to 3.6 hectares) were monitored for two years. In third year, a grazing mitigation option was applied in three catchments, with the fourth catchment left unchanged as a control. Post-treatment monitoring was conducted for a further two years.

Keywords: CSA; Critical Source Areas; water quality; sediment loss; hill country grazing; deer grazing

Climate change is increasing risks for New Zealand’s primary industries, with more frequent extremes, shifting rainfall patterns, and rising temperatures threatening productivity and rural livelihoods. This report outlines a participatory adaptation pathways approach that engages stakeholders to co-design locally relevant strategies, enabling flexible, long-term planning that combines incremental and transformational options to build resilience under uncertainty.

The participatory approach has been formalised as Farms That Last, a practical toolkit to enable farming communities to effectively manage and proactively respond to climate impacts and other drivers of change. Over a series of workshops, Farms that Last works through a vision for a future that centres farming and benefits farming communities. The aim is for those involved to think about multiple possible futures and the many different ways everyone can achieve their goals.

This research set out to gather data on nitrate leaching in the field, where urine patches were treated separately from the rest of the paddock using Spikey®. Results at the two sites were mixed, with some showing significant improvements in production and leaching losses using a currently available growth hormone. More broadly, the project showed that managing urine patches separately is feasible and that further improvements in both fertilisers and inhibitors can be applied accurately in field situations. The project raises other questions for research around the potential to significantly improve the outcomes from treating urine patches for reducing nitrous oxide and ammonium emissions and reducing nitrate leaching.

The objectives were to create an assessment methodology to identify maladaptation in adaptation strategies and develop a decision-making, education and communication tool for diverse communities to understand and evaluate how effective specific adaptation projects will be. This initial attempt at tackling a complex problem included three case studies and unearthed some significant gaps in the current state of knowledge and practice.

Keywords: climate adaptation; maladaptation; climate resilience; community adaptation;

This research set out to determine whether a theoretical 27% reduction in N-loss from a typical dairy farm on stoney soils in Canterbury could be achieved by radically changing the irrigation management strategy. Due to the highly variable physical structure of stoney soils, tightly managing the level of leachable N to closely match plant needs, while also considering predicted rainfall, is a more important N-leaching strategy than is fine tuning irrigation application efficiency.

This work explored agri-voltaics (combined solar electricity generation and agriculture) as a means of renewable energy production and improved pasture productivity, animal welfare and resilience in a changing climate. The study used pasture modelling tools combined with on-farm measurements to assess the impact of solar arrays on pasture and identify those regions for which agri-voltaics would be most beneficial. Understanding how large-scale solar electricity generation on pasture can deliver improved productivity and livestock welfare in a changing climate.

Research was undertaken at two large field experiments to evaluate the performance of one of two pasture-based wintering system options over three winters – bale grazing in northern Southland and pasture and baleage in South Otago. A general recommendation from the project is that pasture-based wintering of cows can be successfully undertaken, providing some important design and management criteria are incorporated into the chosen system.

The project observed six Otago and Southland sheep, beef and deer farmers use of multi-species, multi-graze cropping options over three winters to help improve animal feeding outcomes while reducing potential environmental damage. Crop yields and nutrient concentration data were collected in July, along with the farmers’ self-collected data and observations. Case studies highlight the range of uses and experiences which occurred at the individual farm level, as well as providing some collective experiences.

Comprehensive monitoring of the flow and water quality at inflows and outflows was undertaken from 2021-2024 at three pre-existing and three new Constructed Wetlands (CWs) in contrasting landscape settings. Sites exhibited considerable variation in inflows and loads of nutrients and sediment during and between years. These data were collected in fine time scales and they add significantly to the performance information supporting the use of CW’s in New Zealand. The sites continue as a ‘demonstration network’, showing how constructed wetlands can improve attenuation of diffuse runoff in pastoral landscapes.

The aim of this project was to provide a summary on the use of salt supplementation of dairy cows to mitigate N leaching and nitrous oxide emissions and to recommend how salt supplementation could be incorporated into OverseerFM. The project confirmed that salt supplementation is most effective in reducing N leaching when used during autumn. It recommends that evaluating changes to the default N loading rate in OverseerFM be the next step.

This SLMACC project followed on from a 25-year study of farm system impacts following land use and management change in the 260-hectare Mangaotama catchment farm (within the former Whatawhata Research Centre). The project has supported an improved understanding of the costs and benefits associated with land use and management change in pastoral hill country, occurring over time scales of multiple decades.

The objective was to compare leaching losses of N and P from diverse pastures, consisting of 5-8 species, with losses from traditional ryegrass-white clover at two sites, near Lincoln, Canterbury and Tihoi, Waikato. Large-scale lysimeters were employed to directly measure leaching for a range of management intensities and across different soil types over four years. The results did not show a consistent difference in leaching between the two pasture types. However, pasture establishment was variable across the sites, with high losses recorded during drainage events that occurred when pasture establishment was incomplete. These results suggest timing of management activities, such as cultivation and irrigation, is likely more important than pasture species composition for reducing leaching losses.

This project sought to provide new information on how catch crops could be established earlier, better managed and shown to reduce the risk of nitrogen leaching and runoff and provide production benefits. The research examined crop choice; sowing method, timing and rate; lysimeter measurements; modelling and farmer uptake of the results. An engaging and collaborative approach was taken throughout the project, from trial establishment on working farms to linking with other researchers and Overseer Ltd as findings emerged.

This project explored management options to maximise the ability of radiata pine to transfer nitrogen from nutrient-rich soils into tree biomass. The project collected data from 12 existing afforestation sites and 3 newly installed pastoral afforestation trials, enabling projections of nutrient movement and storage over the life of a rotation. These predictions demonstrated a substantial opportunity exists to rapidly reduce soil nitrogen loads to manageable levels, but the 3 new afforestation trials need to run another 4 to 5 years to provide sufficient evidence to enable confidence in wider adoption. The trial sites, on Pamu Farms properties, are a unique resource, and could be utilised for silvopastoral systems research on biostimulants, residue management and biofuel generation alongside pastoral farming.