Definition
Soil regeneration restores and enhances soil health, biodiversity, and ecosystem function through physical, chemical and biological interventions. Key considerations include rebuilding of soil organic matter, structure, invertebrate populations, microbiomes, and nutrient cycling. Healthy soils are characterised by structure that allows drainage and gas exchange and organic matter that stores and releases nutrients and water and provides microbial habitat. Critically, biodiverse vegetation provides surface protection while living roots and plant litter ‘feed’ the soil. Soils vary naturally across the landscape, so the target outcome for soil regeneration should be guided by the intended use, and local reference conditions where relevant.
What this strategy does
Improves soil function using plants (preferably native), organic amendments (e.g. compost, biochar), soil microbiota management, and where relevant considers additional measures to accelerate ecological recovery (e.g. acoustic attraction). Avoids reliance on synthetic inputs or short-term soil conditioning that undermines long-term resilience.
Context
Urban soils in Aotearoa New Zealand are frequently compacted, contaminated, or biologically depleted due to development disturbance and legacy land uses, limiting vegetation performance and ecosystem services.
Technical considerations
Design considerations
Soil testing
Soil physico-chemical testing will provide guidance whether soil chemistry and physical conditions (e.g. pH, key nutrients, carbon, etc) are within a suitable range for target plant species.
Consider foundational interventions
In the case of highly degraded soils, strategic one-off foundational interventions may be warranted to help reset the physical, chemical and/or biological soil environment. For example, compacted soils may benefit from ripping, weed seed-infested topsoils might be scraped, acidic soils could be limed, and excess high nutrient content in soils could be removed using temporary crop plants (phyto-mining). Organic amendments are also a common way to enhance soil condition.
Composting
Use closed, predator-proof compost systems placed directly on soil. Maintain aerobic conditions with approximately 40% food waste and 60% carbon-rich material (e.g. bark, sticks and leaves) to support soil organisms.
Biochar
Biochar is a stable, carbon-rich material made by heating organic biomass in low oxygen conditions, used to improve soil structure, enhance microbial habitat, and increase water and nutrient retention. Specify biochar appropriate to soil conditions. Biochar qualities can vary, so seek out local examples of products in use where possible.
Soil microbiota management
Soil microbiota interventions are strategies to restore and support the entire soil microbial community. Fungi inoculation is a targeted method that introduces specific fungi, often mycorrhizal species that form symbiotic relationships with plant roots. Apply soil microbiota interventions selectively. Where soil properties remain close to reference conditions, vegetation restoration alone may be sufficient for microbial recovery.
Acoustic attraction (where relevant)
Use species-specific acoustic cues to accelerate recolonisation of target fauna that support soil and ecosystem processes.
Implementation considerations
Design priority
Match intervention type and intensity to the degree of soil disturbance and contamination.
Key constraint
Imported organic materials may introduce weed seeds or contaminants such as herbicides, microplastics, or PFAS, posing risks to soil and food systems.
Issues and barriers
Material contamination
Contaminants in compost feedstocks and biochar can compromise soil health and downstream ecosystems.
Ecological uncertainty
Soil responses vary widely by site. Microbial inoculants may fail where competition, stressors, or unsuitable soil conditions limit establishment.
Synergies and opportunities
- Climate change – Composting reduces methane emissions from landfills, and biochar provides long-term carbon sequestration.
- Human wellbeing – Improved soil and biodiversity enhance restorative urban environments and food-growing opportunities.
- Disaster risk reduction – Healthy soil microbiomes support plant resilience to drought and climate stress.
- Food security – Regenerative soils improve productivity and long-term soil fertility.
- Waste and pollution management – Organic waste diversion supports circular material flows and reduces landfill reliance.
Financial case
Ecosystem services and/or performance value
Value type
Reduced fertiliser inputs, normal nutrient cycling, extended landfill life, improved vegetation performance, and long-term carbon storage.
Cost-effectiveness
Investment logic
Community composting and soil regeneration systems provide long-term economic returns through waste diversion, soil productivity gains, and avoided emissions costs.
Monitoring and evaluation metrics
Core metric
Soil organic carbon, structure, moisture retention, and basic biological presence and activity indicators.
Advanced or long-term metric
Invertebrate and microbial diversity and functional indicators where soil microbiota interventions are applied.
Case studies
- Te Kauwhata Community Compost Hub
- Fungal inoculation in native plantings
Related design strategies
Additional resources or tools
Contaminated Site Risk Management (Manaaki Whenua – Landcare Research)
https://contamsites.landcareresearch.co.nz
National Environmental Standard for Assessing and Managing Contaminants in Soil
https://environment.govt.nz/acts-and-regulations/regulations/national-environmental-standard-for-assessing-and-managing-contaminants-in-soil-to-protect-human-health/
Compost Collective
https://compostcollective.org.nz/
Korukai Biochar Guide
https://blog.korukai.co.nz/2020/08/24/make-your-own-biochar/