You are here:
Publications 
State of the Environment Environment New Zealand 2007 - Summary Online version Section three: State of the environment
Section three: State of the environment
Land
New Zealand is recognised internationally for its stunning landscapes and productive agricultural and horticultural land.
Since human settlement, the way we have used our land has fundamentally shaped our nation. Land is important to many of us in other ways – it can contribute to our sense of belonging to this country, and represent the place we call home.
New Zealand has developed internationally-recognised expertise in the productive use of land resources, exporting high-value agricultural, horticultural, wine, and timber products to the rest of the world. In recent decades, New Zealand has also marketed itself internationally as an attractive destination for scenic and adventure tourism.
A definition of land
Land is considered to include:
-
the aesthetic components of landform and landscape including the vegetation cover
-
the physical components of soil and parent material (the soils and underlying rock types that give rise to soil)
-
the plant and animal communities in the soil, such as, insects, mites, springtails, nematodes, worms, fungi, bacteria, and algae
-
the exotic and native ecosystems resident on the land, such as, exotic forestry, urban settlements, native forests, and tussock grasslands.
Land and our economy
Land plays an integral part in supporting New Zealand’s top two export earners: tourism and primary production. In 2007, agriculture, forestry, horticulture, and viticulture generated $16.1 billion, $3.6 billion, $2.5 billion, and $662 million respectively in export earnings. In other words, about one-sixth, or 17 percent, of New Zealand’s gross domestic product (GDP) depends on the top 15 centimetres of our soil. In 2006, tourism generated $8.3 billion in export earnings.
Land use and environmental impacts
Using land for production and urban development puts pressure on the wider environment: urban and rural run-off pollutes our waterways and coasts; urban expansion leads to the loss of versatile soils; and more intensive agricultural land use increases the risk of detrimental long-term effects on soil quality, and the quality of our waterways.
Intensification of pastoral land use
Recent trends in land use in New Zealand include an increase in intensive pastoral land use (for example, higher stocking rates, increased use of fertilisers and agricultural chemicals, and increases in irrigation use).
For example, Figure 3.4 shows that by 2006, dairy cow and deer numbers had increased to just over 5.2 million and 1.5 million, respectively. Between 1996 and 2006, the national dairy herd grew by 24 per cent. The recent expansion of dairy and deer farming has been particularly notable in the South Island. On the other hand, the number of sheep decreased to just over 40 million, and beef cattle numbers dropped to just under 4.5 million.
See figure at its full size (including text description. Our primary production sectors rely on the land.
Source: Ministry for the Envirnment.
Fertiliser use
Intensification of pastoral land use has led to a noticeable increase in the use of fertilisers in high-producing exotic pastures. Most of the increased fertiliser inputs are removed from the land as production, but there is no doubt that the intensification of pastoral land use has increased the pressure on our surface waterways and groundwater, as discussed in the Freshwater section.
Total fertiliser use significantly increased in New Zealand between 1985 and 2004 (see Figure 3.5). The amount of nitrogen fertiliser used in New Zealand has increased about ten-fold since 1985 and has doubled since the mid-1990s. Nitrogen from livestock manure, which contributes around five times the amount of nitrogen to the land as nitrogenous fertilisers, also steadily increased.
These changes coincide with the trend towards more intensive forms of farming; particularly dairy farming, with its high density of grazing stock. Dairy cows excrete almost seven times the amount of nitrogen and phosphorus in their faeces and urine as breeding ewes, and around three-and-a-half times that of breeding hinds (deer).
See figure at its full size (including text description). Land cover
Reflecting changes in land use, land cover in New Zealand continues to change as our population grows, land prices change, and international commodity prices fluctuate.
In 2002, native forest, native vegetation, and other natural land cover (for example, rivers, lakes, snow, ice, and scrub) made up 50 per cent of New Zealand’s total land cover area. Pasture was our second largest land cover at just over 39 per cent. Exotic forest covered 7.31 per cent of New Zealand’s land area.
Table 3.1 reports satellite measurements between 1997 and 2002, which showed that:
-
pastoral land cover decreased by 125,200 hectares (or just over 1 per cent)
-
human settlements increased by just over 5,300 hectares (or 3 per cent). This represents 96 per cent of the total increase in artificial surfaces of 5,500 hectares
-
native vegetation and native forest decreased by 17,200 hectares (or 0.15 per cent)
-
exotic forest cover increased by 139,500 hectares (or about 8 per cent)
-
horticultural land area increased by 4,500 hectares, with the total area of horticultural land at just under 1.6 per cent of New Zealand’s total land area.
Table 3.1: Changes in land cover between 1997 and 2002
View changes in land cover between 1997 and 2002 (large table).
Land use
In 2004, pastoral land use (for example, sheep, beef, and dairy farming) was New Zealand’s largest human land use at just over 37 per cent of New Zealand’s total land area.
Although the total area of New Zealand land in pasture has been decreasing since 1972, the area of land in dairy pasture has increased. This intensification of agricultural land use has occurred as farmers have responded to economic signals by converting suitable dry-stock pasture, exotic forestry, and existing dairy farms into more intensive dairy farms.
Over the past 10 years, increased diversification of land use has been evident, especially for horticultural land, including vineyards, orchards, and perennial crops. As an example, the area of land in vineyards increased by 28 per cent between 1997 and 2002.
Hill-country erosion
Hill-country erosion is estimated to cost New Zealand between $100 million and $150 million each year through the loss of soil and nutrients; loss of production; damage to houses, fences, roads, phone and power lines; and damage to waterways and aquatic habitats. About 10 per cent of New Zealand is classed as severely erodible.
During the 1990s, hill-country erosion eased in some regions. Satellite measurements between 1997 and 2002 showed that 36,400 hectares of land on erosion-prone hill country was converted from pasture to other land cover during this period. The large majority of this (36,300 hectares) was converted to exotic forestry, or retired and left to revert to scrub.
Soil slip erosion on hill-county pasture.
Source: Ministry for the Environment.
Forestry
In 2006, the total area of planted (exotic) forestry was estimated to be 1.8 million hectares. From 1990 until 2003, a trend of increasing land area in exotic forestry was observed.
Figure 3.6 shows that, from a peak in the mid-1990s, there has been a significant reduction in the amount of new exotic forestry plantings. In 2005, the rate of new exotic forest plantings declined to its lowest level since 1959. Moreover, from 2004, a new trend became apparent of not replanting exotic forestry after harvesting or, in some cases, converting immature forest to pasture.
See figure at its full size (including text description). Land use and soil health
Land use affects soil health. Results from environmental monitoring under the 500 Soils Project and subsequent regional council programmes show changes in New Zealand soils, particularly as intensive land use becomes more widespread.
A large proportion of monitored pasture soils show moderate compaction as a result of stock treading damage, which can lead to reduced pasture growth and increased rates of sediment and nutrient run-off. Some soils under dairy pasture show high phosphate levels and may also be reaching saturation point for organic forms of nitrogen. Saturation increases the risk of excess nitrate being leached to waterways.
Some intensively cropped soils (such as market gardens) also show high phosphate levels and have lower organic matter content and poorer soil structure than pasture soils. Native and exotic (plantation) forest soils generally show similar acidity, and are more acidic than soils associated with other land uses, reflecting the use of lime and phosphate fertilisers to develop agricultural land.
Because pasture lands are so widespread in New Zealand, the condition of pasture soils has a major bearing on soil health nationally. Most declines in soil health are potentially reversible, but the shift toward more intensive farming practices in many regions around New Zealand may make a reversal difficult to achieve for some soils.
Sustainable primary production
Driven by the growing market demand for clean green products, New Zealand’s primary industry associations are increasingly adopting environmental management systems (EMS) to demonstrate the commitment of their sectors to sustainable primary production. Examples of existing initiatives are Sustainable Winegrowing New Zealand (490 members in 2006), Forest Stewardship Council standards (covering 42 per cent of New Zealand’s commercial plantation forests), Market Focused (a dairy farmers’ EMS initiative in 2001), and Official Organic Assurance (as of 2003, 800 farms were either certified or converting to organic status).
Ultimately, New Zealand land owners can benefit by managing, and being seen internationally to be managing, their land in a sustainable way, taking account of the impact of their activities on waterways, erosion, soil health, and also climate change.
Sustainable land management – present and future
Historically, environmental management of land in New Zealand has focused on managing hill-country erosion, minimising flood risk, and improving the health of pasture soils. More recently, attention has turned to protecting riparian stream margins, excluding stock from waterways, minimising nutrient enrichment of our waterways, including through nutrient budgeting and use of nitrification inhibitors, and protecting our land-based primary production sector from pests and diseases from overseas.
Looking ahead, focus is likely to intensify on:
-
how best to minimise the impacts of intensified land use on our soils and waterways
-
identifying and managing land contaminated by historical agricultural and industrial activities (see ‘Contaminated sites’ following)
-
continuing to manage hill-country erosion and biosecurity risks to New Zealand’s primary production sector and native species
-
meeting growing consumer demand for sustainably produced agricultural, horticultural, and forestry products.
Landcare Trust
The New Zealand Landcare Trust was established in 1996. Currently, more than 250 landcare groups operate around New Zealand with the vision of promoting sustainable land management. Each group’s level of activity depends on the community in which they are based and the specific issues they are trying to address. Landcare groups are particularly active where regional councils have programmes for biodiversity protection and offer incentives or assistance to landholders.
Contaminated sites
New Zealand soils generally contain low levels of contaminants, but past industrial, domestic, or agricultural activities (such as the manufacture and use of pesticides, the production of coal and gas, mining, timber treatment, and sheep dipping) have contaminated some sites. Some of these activities – for example, the use of DDT in sheep dips from the 1940s to the 1960s – were not known to be hazardous at the time.
We do not accurately know the extent of contaminated sites in New Zealand. Rough estimates undertaken in the early 1990s put the number of contaminated sites between 7,000 and 8,000. About 1,500 of these were deemed to be a high risk to human health or the environment. However, there are now thought to be over 50,000 contaminated sheep dip sites alone around the country.
Regional councils, central government, and private land owners are gradually making headway in tackling the problem. Seven councils have now screened 4,424 sites across the country. To date, 559 high-risk sites have been identified. Of these, 56 per cent have already been cleaned up, or have a clean-up or management programme in place.
Mapua clean-up
The abandoned Fruitgrowers Chemical Company site at Mapua, near Nelson, was heavily contaminated by a range of toxic pesticides such as DDT, aldrin, lindane, and dieldrin. Central government and the local council, working in partnership, have provided $8 million to clean up the site.
By August 2007, all the known contaminated soil had been treated on site, and de-commissioning of the plant had begun. The project is on target to be completed in late 2007, and the land handed back to the owners, Tasman District Council. About 40 per cent of the land is to be set aside as public space, and the rest designated for residential and commercial land use.
Aerial view of the abandoned fruitgrowers chemical company at Mapua.
Source: Courtesy of John Roosen.
