Why we need to protect soil
Soil underpins New Zealand's agriculture, horticulture and forestry, and contributes to a healthy ecosystem by helping to clean water, cycle nutrients, store carbon and grow plants.
Creating new soil is a slow process and can take hundreds of years, which makes soil effectively a non-renewable resource in our lifetimes. Protecting soil is essential for food security and a sustainable future.
The future of soil management
MPI commissioned a report to help us make decisions about soil and land resources. The 2015 report outlines the state of soil management in New Zealand. A summary and the full report are available to download.
A summary and the full report are available to download.
Future requirements for soil management in New Zealand – a summary
Future requirements for soil management in New Zealand – full report
Major pressures identified
The report identified the major pressures affecting soil resources:
- Intensification: Especially through irrigation and addition of nutrients. Little is known about the long-term effects of irrigation on soil function. Nutrients can encourage rapid plant growth but threaten freshwater quality.
- Land use change: This can result in erosion and sediment run-off to freshwater.
- Legacy effects: Past deforestation and climate change – with more frequent or intense storms – are likely to increase the risk of erosion.
An action plan will be developed based onaround the report's recommendations — whichrecommendations, which includes a national management group and strategy to set direction on soil use, policies and research.
Many of our soils are prone to erosion
Erosion is probably the most critical issue affecting soil and the productivity of the land we use for farming, horticulture and forestry.
When people first arrived in New Zealand and started clearing forest, the amount of land vulnerable to erosion increased dramatically. Planting new trees has helped curb some of the worst cases, but erosion is still an issue particularly in the north and east of the North Island.
Erosion affects productivity by removing topsoil — the most nutrient-rich part of the soil. It also affects thewater quality of surrounding waterways through increasing sediment and nutrient run-off.
See which areas in the North Island are erosion prone – Statistics NZ website
Soil is important for storing carbon
Soil is recognised as important for storing carbon. There is more carbon in Earth's soils than in both terrestrial plants and the atmosphere combined. This means small changes in soil carbon could have big impacts on global greenhouse gas emissions.
Because it's an area of ongoing research, there are not yet any robust practices in New Zealand about how to sustainably increase carbon in soils over the long term. However, some options may include adding nitrogen, having deep-rooted plants, or adding biochar – a form of organic matter charred under controlled high-temperaturehigh temperature conditions.
Find out more
- The New Zealand Agricultural Greenhouse Gas Research Centre website
- Climate change-related documents – Climate Cloud website
Smart management of nutrients
When we put more nutrients on land than grass and other plants can use, the excess nutrients can leach into groundwater and waterways. The excess nutrients can cause unwanted plants to grow and affect freshwater quality.
OVERSEER® is a nutrient management tool that supports farmers and growers to improve their use of fertiliser nutrients to optimise plant growth and minimise nutrient losses to the environment.
Monitoring soil contaminants
The Ministry for the Environment (MfE) and regional councils are responsible for monitoring soil contaminants. MfE's website has more information about the National Environmental Standard for monitoring soil contamination to protect human health.
- MfE website – assessing and managing contaminants
- Learn more about specific responses to cadmium in soils
Digital mapping of soils
S-map is a digital system for storing and managing soil information in New Zealand from soil types that have been mapped in detail.
Explore S-map – Landcare Research website
Soil management programmes funding
Targeted funding is available for some soil management issues, mainly erosion.
- The Sustainable Land Management Hill Country Erosion Programme
- The Erosion Control Funding Programme (for the Gisborne district)
- The Sustainable Farming Fund (SFF)
- The Afforestation Grant Scheme
Explore all of MPI's funds that support and enhance natural resources
Find out more
- Read more about land resources in MfE's 2015 report, Environment Aotearoa
- Explore government statistics on soil health – Statistics NZ website
Who to contact
If you have questions about the information on this page, email info@mpi.govt.nz .