Land Use Tools

This webinar discusses the potential impacts of climate change on pastoral, arable and horticultural farm systems, and appropriate adaptation measures.

This report identifies the potential impacts of climate change on pastoral, arable and horticultural farm systems, and appropriate adaptation measures. This research used and compared several biophysical models to project future changes in production and impacts on nutrient loss and water demand under different climate scenarios over the next 80 years.

Advice for New Zealand and Australian farmers on the application of fertiliser to mitigate phosphorus loss on sensitive areas, showing how farmers can halve the amount of phosphorus leaving their farm with minimal impact on farm profitability.

A new way to measure denitrification in groundwater has been proved, and could make analysing groundwater’s denitrification capacity more accessible for regional councils and farmers. The new method for measuring excess nitrogen could be used to locate and characterise groundwater denitrification sites, so spatial variability of sites and rates can be mapped. Identifying the location and efficiency of groundwater denitrification sites can result in more effective nutrient
loss regulations, more strategic nitrogen loss mitigation measures and improved land management

This research summary describes how effective on-farm mitigations have been so far, by comparing losses of nitrogen (N), phosphorus (P) and sediment in 1995 and 2015. It also models what would be possible for future water quality in 2035 if every farm in New Zealand adopted every known mitigation. This information is crucial to helping farmers in degraded catchments decide whether to continue investing in mitigation actions or consider making changes to land use or land-use intensity.

At least 43% of New Zealand’s agricultural land (31% of New Zealand’s total land area) is in catchments that are under pressure – ‘pressure' meaning the ratio of the current load of total nitrogen to the maximum allowable load of nitrogen that can be emitted and still meet current regulatory criteria. The nitrogen load reductions required to meet water quality objectives in some regions are large relative to existing loads. The current load is twice the maximum allowable load in parts of the Waikato, Manawatu-Wanganui, Marlborough, Canterbury, Otago and Southland.

An interactive map shows the total nitrogen (TN) in excess of current national rules and the potential for mitigation strategies to reduce TN losses from land to water by 2035. The map allows users to zoom in to any of New Zealand’s catchments or regions, and swipe between two views. Swiping to the left reveals the total nitrogen load in excess of current regulatory objectives. Swiping to the right reveals the potential for on-farm actions to reduce nitrogen loss from land to water. This allows New Zealanders to see which rivers, lakes and estuaries are under the most pressure from agriculture, and whether all farmers adopting all on-farm mitigation actions will ease this pressure by 2035.

We've summarised research on how Aotearoa’s fresh water responds to stressors into a short Research Findings Brief. Using Lake Hayes near Queenstown as a scenario example, the research brief describes how this research can be used to prioritise actions to take on land to prevent and reverse degradation. This research can help us manage and restore fresh water, and encourages deeper understanding of complex ecosystems.

To make farm plans an effective tool for improving waterways, we propose a four-step approach based on collective action delivered by catchment groups. Planning together is more efficient for everyone. Linking farm plans to sub-catchment priorities, and to each other, enables landowners to exchange knowledge and identify solutions unique to their soils, land use practices and waterways.

We have prepared a guidance document for people who need to design effective FEPs, FEP templates and processes. It proses a four-step approach and makes 7 key recommendations. The focus of this guidance is freshwater, in line with Our Land and Water’s objective.

We developed the first national-scale map of surface erosion for New Zealand that can also be used at farm scale. The map is also the first in the world to include the impact of stock grazing, so provides a more accurate picture of surface erosion susceptibility.

The LandscapeDNA information hub gives you access to the Physiographic Environment Classification developed with funding from Our Land and Water. Interactive maps allow you to explore right down to property scale. Videos for each environment show what contaminants are most susceptible to loss, how they travel, and where they end up. These insights will allow farmers to consider what actions they can take to minimise water contamination risks from their property.

This interactive infographic compiles actions to decrease the loss of contaminants from agricultural land. Actions can be filtered by farm system, and by any of five critical issues (nitrogen, phosphorus, E.coli, sediment and GHGs). Applying both a farm type and issue filter enables a pop-up for each action containing a short description and data on co-benefits, factors that may limit application, and potential standard measurements.

Fate Factors (FFs) for use in life-cycle analysis (PCA) were developed for both dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP), distinguishing emissions from soil and emissions to freshwater. The use of these FFs, in conjunction with a spatially explicit inventory of DIN and DIP emissions, improves the environmental relevance and discriminatory power of the assessment of freshwater eutrophication impacts for LCA applications internationally.

This grid‐based sediment tracing technique improves the precision of source contribution estimates and enhances the granularity of sediment source maps. This technique provides a greater spatial resolution of the sediment sources by assigning sediment contributions into grid sources rather than area‐specific source types.

Maps of the potential groundwater recharge zones across New Zealand (500m x 500m resolution), which can be used to identify areas of high nutrient leaching in zones where high groundwater recharge potential exists.

A land-use decision support tool developed by Te Tumu Paeroa that combines datasets to gain insight into how Māori land can operate at highest and best use. Our Land Use Suitability researchers are augmenting this with land-use suitability data.

Built on a detailed farm map, MitAgator’s software gives a spatial view of where contaminant losses are occurring and identifies critical source areas (CSAs). Targeting mitigation actions to CSAs is six to seven times more cost-effective than an untargeted approach. MitAgator allows mitigation scenarios to be validated and targeted more precisely, improving their cost-effectiveness.

Soil conservation over large areas is expensive and needs to be targeted to obtain maximum benefit for the least cost. Cascade of Soil Erosion research has outlined an event-based model of soil erosion and sediment transport at the catchment scale.

This land-use assessment framework has been developed by Next Generation Systems to explore opportunities for adopting more suitable land use and to identify gaps in knowledge. It uses multi-criteria decision-making to simultaneously consider multiple domains, where selection of best alternatives is highly complex, context-specific and deeply personal. Please email Alan Renwick to discuss using the tool.

A model of soil erosion developed for the Manawatū-Wanganui by Cascade of Soil Erosion researchers can be parameterised with local data, then used in spreadsheet form to evaluate the impact of changes to land use and management on the sediment yield of catchments, and help regional councils plan cost-effective soil conservation work projects of varying size and complexity.

Cascade of Soil Erosion research developed a method for estimating the improvement in water clarity when soil conservation is practiced.

Land Use Suitability research has developed a method to identify the most appropriate management actions for aquatic ecosystems. This method provides a valuable decision support strategy to optimise catchment management actions toward a water quality objective.

Sources and Flows research modelled drought duration-severity distribution and frequency to generate SDF curves for six locations in different climatic regions. Modelling of soil drainage at these sites indicated 35% to 80% more drainage peaks than expected, suggesting better monitoring of soil moisture and scheduling of irrigation is required. The SDF curves provide a comprehensive understanding of occurrence and duration of dry conditions, and can be a useful tool for developing strategies for water management.

Measuring Groundwater Denitrification research has developed and proven a methodology for measuring dissolved neon which, in combination with argon and nitrogen measurements, can be to quantify excess nitrogen in groundwater. Measurement of ‘excess N2’ is the most promising method for directly measuring denitrification that has occurred in an aquifer.

Sources and Flows research identified 5 potential groundwater recharge zones across New Zealand. Knowledge of groundwater recharge potential is required for sustainable groundwater management, including the assessment of vulnerability to contamination. The maps can be used to identify areas of high nutrient leaching in zones where high groundwater recharge potential exists (regions with large lakes and in the lower elevation plains).

Physiographic Environments of New Zealand research is developing a cost-effective technique to measure and map (as an integrated physiographic layer) how features of the natural landscape lead to variation in water composition, and hence quality. A web-based map is being co-developed with a wide range of collaborators. So far 7 regional and district councils are sharing data and collaborating to develop and apply the physiographic approach to their regions. This document contains information for interested regional councils.

Phosphorus Best Practice research found that current practice and regional rules for the application of farm dairy effluent (FDE) to stony free-draining soil under irrigation were not sufficient to prevent phosphorus losses. Regional government and industry bodies can use these results to strengthen guidelines and regulations, particularly regarding the use of FDE on stony free-draining soils with low capacity to absorb P, such as those common in the Canterbury region, in order to meet community and government expectations.

Assessing Contaminants with Stream Order research discovered that fencing only large streams to exclude stock has less effect on freshwater quality than expected. Small, steeply sloping streams contribute, on average, 77% of the load of freshwater contaminants. To substantially reduce contaminant losses, stock should be excluded from small, steeply sloping streams. This research can be used by local government to determine policy to improve the quality of fresh water.