Horticulture New Zealand natural resources and environment manager Michelle Sands is reasonably optimistic about what the final version of the statement will look like and the protection it is likely to offer soils of high-productive value.
The statement was first raised by Environment Minister David Parker last year as a result of concern over the amount of quality soils lost to urban development in the past generation. The statement is intended to target the high-value classes 1 and 2 soils that account for 5% of NZ’s soil profile but almost 85% of its high-value crop production.
Between 2002 and 2016 NZ has been losing just over 100,000ha a year of growing land to urban development or lifestyle blocks that have been growing at a rate of 5800 a year.
Auckland has swallowed 10,500ha of high-quality soils in the past 35 years as it supports an average annual population growth rate of 3%. That lost area alone is sufficient to supply most of the North Island with vegetables.
“Indications are the NPS is looking to have quite a broad definition of soils, enabling regional councils to identify themselves what soils in their region are classed as highly productive, based on land use capability. It will also enable them to identify special soils, such as gravels that may be suitable for wine growing,” she said.
It is hoped the statement will bring greater security to Auckland’s highly valuable volcanic soils used for over 100 years to grow crops supplying the city and much of the North Island. Only 3000ha of this soil is protected by the Unitary Plan, less than half what many want to see protected.
Sands is also encouraged by the statement possibly containing a provision that councils avoid inappropriate development on certain soils.
There is a strong likelihood that could help put the brakes on land-sucking lifestyle block developments that have locked up 10% of the land lost nationally from 1990 to 2008 with 170,000 blocks occupying almost 900,000ha by 2011.
More than 40% of them came after 1998 at the average of 5800 a year and account for 35% of Auckland’s high-value land.
But Sands cautions a statement is unlikely to take account of the need for a domestic food supply policy.
“While we have a lot of good quality soil, that is only one factor in growing things like vegetables. They also require certain climate conditions to be productive.”
HortNZ chief executive Mike Chapman said food security requires a plan unlikely to be covered in the statement.
“The soils protection is really only one leg in the trifecta.
“The concept of food security is quite foreign in NZ. It has tended to be left to commercial forces in the past.”
Sands said continued conversion of land to higher-value vegetable growing is challenging in most parts of the country, given regional plans prevent changes in land use on grounds of nutrient losses.
Both Chapman and Sands maintain it is not too late to stop the slide in NZ’s productive soil loss. They look to Melbourne as an example of leaving it too late.
With a population similar to NZ’s Melbourne provides 85% of its own fruit and greens but based on continuing land loss that is expected to fall to only 20% by 2050, entirely because of urban development.
A report commissioned by Auckland City in 2017 predicted Auckland, too, risks losing a similar amount of soils should growth continue unimpeded for the next 50 years.
