New report shows impact of demands on land in New Zealand

The land cover data in an environmental report published today, Our land 2021, provides the most up-to-date estimates of New Zealand’s land cover and associated land use and changes.

Released by the Ministry for the Environment and Stats NZ, the report presents new data on the country’s land cover, soil quality and land fragmentation.

Our land 2021 continues the second cycle of environmental reporting by Stats NZ and the Ministry for the Environment.

It updates Our land 2018 and the second theme ‘How we use our land’ from Environment Aotearoa 2019, which was the most recent report on the state of the environment as a whole.

Overseas markets are a significant driver of land use, and with global populations projected to reach 10.9 billion by 2100, market-based pressures on land are set to increase.

Most of our agriculture and forestry products are exported and these activities currently cover about half our land area, the report says.

While urban land cover continues to make up 1% of total land area in New Zealand, urban and residential expansion is outwards onto productive land, which creates tension between the use of land for housing and land for agriculture.

This results in a complex trade-off, because using land that is not highly productive for food growing results in lower yields unless more intensive land management approaches are used. Intensive land management brings with it the risks of degrading the quality and health of the soil and the wider environment.

The Secretary for the Environment, Vicky Robertson, says the report shows how the health of our land impacts on the health of our rivers, lakes, oceans, air, indigenous biodiversity, climate – and our own wellbeing.

“Land is central to our identity as people of Aotearoa New Zealand. It is our tūrangawaewae, our place to stand.

“The choices we make for where we build, what we grow for ourselves, and what we export are creating tensions for the best use of available land. Climate change and a growing population are only going to make future choices more difficult,” she says.

The partnership between the Ministry for the Environment and Stats NZ to deliver the environmental reporting programme aims to ensure the best available information is bought into the reports.

“For Our land 2021, we have made great strides in bringing together data from a range of other agencies, and adding value through our analysis, interpretation, and presentation,” Government Statistician Mark Sowden says.

“In particular, we have developed new and updated indicators that provide invaluable information on changes to New Zealand’s land and soil.

“Nevertheless, there are still gaps. We have an incomplete picture of the impact on the environment and our wellbeing of what we do on the land.

“We need better and more targeted data to understand the impact of intensive land use, particularly on native ecosystems.”

Key facts from the report

  • The number of consumers in New Zealand is projected to reach 6.8 million by 2073 having passed 5 million in June 2020. This will continue to drive the demand on land to supply food, housing, and opportunities for recreation.
  • About half of the total land area in New Zealand is used for agriculture, forestry, and housing: land cover exotic grassland 40%, exotic forestry 8%, cropping & horticulture 2%, urban 1%, native land cover 49%. (Note: These percentages exclude lakes and rivers.)
  • 87% of the population live in towns and cities. About 80% of our population growth for 2018–43 is expected to be in the main urban centres.
  • 15% of land is particularly good for food production. This highly productive land has a good climate, suitable soil, and is flat or gently sloping. Here, less irrigation and fertiliser is needed to grow food than in other areas. Highly productive land is often on the fringes of our cities.
  • Highly productive land became more fragmented between 2002 and 2019, especially through residential development of land sized 2–8 hectares (lifestyle blocks are about 5 hectares on average). The area of highly productive land that was unavailable for agriculture (because it had a house on it) increased by 54% during this period, from 69,920 hectares in 2002 to 107, 444 hectares in 2019.
  • The total area of land used for agriculture and horticulture has been decreasing since 2002 with an overall reduction of 1,878,409 hectares (14%) between 2002 and 2019, and a reduction of 207,747 hectares (2%) between 2017 and 2019, and the number and size of farms has decreased during the same period, with a reduction of 19,980 farms (29%) and 2,028,710 hectares (13%) between 2002 and 2019. However, the export income from farming products has increased, from $23 billion in 2010 to $44 billion in 2019 (primary industries export revenue excluding seafood)
  • Dairy cattle numbers have more than doubled since the 1980s, rising from 3 million to almost 7 million in 2015, with more than 6 million in 2019.
  • The use of irrigation, especially on land used for dairy farming, has nearly doubled since 2002. In 2019, 5%  (735,073 hectares) of agricultural land in New Zealand was irrigated, with dairy farming making up 58% of irrigated agricultural land 2019.
  • The sale of phosphorus fertiliser peaked in 2005 at 219,000 tonnes per year. It has reduced since then, with 154,000 tonnes sold in 2019. The sale of nitrogen fertiliser increased sharply from 62,000 to 452,000 tonnes per year between 1991 and 2019.
  • Nationwide, 80% of monitoring sites failed to meet the targets for at least one soil quality indicator. No declining or improving trend in soil quality was observed for 1994–2018.
  • Macroporosity – a measure of pore spaces in soil and a potential indicator of soil compaction – was below the target range in 65% of dairy farming sites, 48% of drystock farming sites and 46% of orchard/vineyard sites sampled between 2014 and 2018. No decreasing trend or improvement in macroporosity was found in drystock farming or in dairy farming from 1995 to 2018.
  • Levels of Olsen phosphorus, an indication of soil fertility, were above the recommended target range for 61% of the dairy farming and cropping sites, and 46% of orchard/vineyard sites sampled between 2014 and 2018. High levels of Olsen phosphorus in the soil indicate that too much fertiliser has been applied.

Source:  StatsNZ and Ministry for the Environment


Author: Bob Edlin

Editor of AgScience Magazine and Editor of the AgScience Blog