Housing buries our fertile fields
The best soils for growing fruit and vegetables are being eaten by housing and lifestyle blocks, a trend that could increase people’s food bills – and raise climatewarming gases.
The Our Land report from Statistics NZ and the Ministry for the Environment – the most up-todate estimate of land cover – says the area of highly productive land that is unavailable for growing food because it’s covered by housing increased by 54 per cent between 2002 and 2019.
As of 2019, the area of prime soil for growing potatoes, onions, leafy vegetables and other produce that was buried under housing totalled more than 107,000 hectares.
New Zealand’s best foodgrowing soil comprises just 15 per cent of the country. Much of it is concentrated around cities, leaving it vulnerable to urban sprawl.
Without action, fresh fruit and vegetables could get even more expensive, says Secretary for the Environment Vicky Robertson.
‘‘Highly productive land is at risk of becoming unavailable for agriculture due to housing developments,’’ says the Our Land report.
‘‘Our exports and domestic food production currently rely on the small amount of highly productive land we have.’’
‘‘Once land is in housing it is gone for good,’’ says Lincoln University Associate Professor Amanda Black, who advised on the report.
The problem of soil loss dates back to the 1950s, when urban development of market-gardening land around Auckland became a concern.
Now, climate change is adding new complications and urgency to the problem.
Food grown remotely needs to be trucked further, potentially raising transport emissions. Pushing horticulture onto poorer soil also means farmers need more fertiliser, with potential environmental impacts, including increasing output of a potent greenhouse gas, nitrous oxide.
As the planet warms, the report says, rising sea levels will encourage people to move away from coastal residential areas, increasing already-intense pressure on city-fringe soil. Flat, fertile land on city fringes is
cheaper to develop than hilly, less productive soil.
The Government has consulted on a National Policy Statement that would direct councils to better protect topnotch soil when considering zoning and development. The Environment Ministry says an NPS is expected by the end of the year.
The country’s land use has changed drastically before. Higher global milk prices drove widespread conversion of farmland from sheep to dairying from the 1990s.
Droughts, floods, and changing growing conditions mean the pattern of land use in decades to come could be as different from today’s as today’s is from the predairy boom years.