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Introduction

The way we have used our land has fundamentally shaped our nation. From earliest times, settlers in New Zealand have worked the land to produce food and fibre (for example, wool and flax), to raise animals, and to build dwellings. Today, New Zealanders value land for its scenic, recreational, historical, and cultural significance.

Māori relate to land as the tangata whenua (people of the land). This term expresses an understanding that land and people are inseparable through whakapapa (kinship) (Durie, 1998). Iwi (tribes) relate to specific places within New Zealand over which they have mana whenua (customary authority).

While many people equate New Zealand’s landscape with its natural areas, most of our landscapes have been modified by human use. Many of our urban and pastoral landscapes have changed significantly from the landscapes that existed in the first 100 years of European settlement.

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.

(Williams and Mulcock, 1996).

Landform and landscape

Landforms are the result of geological processes and chemical and physical weathering. Landforms interact constantly with living and non-living features such as plants and waterways to make up a landscape.

New Zealand’s geological history has resulted in significant variations in landscape from dry plains, to steep hill country, snow-capped mountains, and coastal dunes. Even within a few kilometres, neighbouring landscapes can differ greatly. Except for the occasional large earthquake, volcanic eruption, forest fire, or extreme storm event, the natural factors that created and continue to change New Zealand’s landforms tend to operate slowly over hundreds, thousands, or millions of years.

Today, New Zealand’s landscapes include both cultural landscapes (those modified by people) and natural landscapes. While both landscapes are subject to constant change, the speed of this change depends on whether the change is due to natural or human influence.

Land use defines New Zealand’s identity

Reliance on land resources is a defining feature of New Zealand’s national identity. The expertise we have developed in using our land resources has put New Zealand on the international stage. Land underpins New Zealand’s top two export earners: tourism and primary production.

Our high-value agricultural, horticultural, wine, and forestry products are exported around the world. And, in recent years, New Zealand has marketed itself internationally as a premier destination for scenic and adventure tourism.

Export earnings

In the year ended 31 March 2007, primary production generated export earnings that equated to:

  • agriculture – $16.1 billion

  • forestry – $3.6 billion

  • horticulture – $2.5 billion

  • viticulture – $662 million.

(Ministry of Agriculture and Forestry, 2007b; New Zealand Wine, 2007).

In the year ended 31 March 2006, tourism generated export earnings of $8.3 billion (Statistics New Zealand, 2007b).

Primary production

Dairy products were New Zealand’s single largest export earner in the year to December 2006, making up 18.1 per cent of total exports. Meat and timber were our next largest export products, accounting for 13.5 and 6.2 per cent of total exports respectively (Statistics New Zealand, 2007a).

Primary production also provides direct and indirect employment for a significant proportion of the New Zealand workforce, particularly in rural areas.

Tourism

In terms of both export earnings and onshore economic value, international tourism contributed $12.3 billion to New Zealand’s economy in the year ending 31 March 2005 (Ministry of Tourism, 2007).

New Zealand’s changing land cover and land use

‘Land cover’ describes the types of features present on the surface of the earth (Lillesand and Kiefer, 1994). Pastures, snow and ice, forests, human settlements, and lakes are all examples of land cover types.

The term ‘land use’ relates to the human activity or economic function associated with a piece of land, such as built-up areas, commercially planted forestry, and different types of farming or horticulture (for example, dairy, sheep and beef, grapes, berryfruit) (Lillesand and Kiefer, 1994).

Human activity modifies many aspects of the environment, particularly land cover and land use. Before human settlement, forests were New Zealand’s predominant land cover (see chapter 12, ‘Biodiversity’). Since then, New Zealand’s land cover has undergone significant human-influenced change.

New forms of cultural landscapes (those modified by people) were created from natural landscapes. Settlements grew around the river mouths that provided harbours as settlers made use of New Zealand’s most suitable land for economic, social, and cultural development. About 24 per cent of New Zealand’s original native-forest land cover remains today; however, nearly all lowland areas have been cleared of forest for human uses, including agriculture, horticulture, and urban development.

Topography and geology influenced the choice of land use. Thirty per cent of our country is hilly with a slope of more than 25 degrees (Sparling, 2007). Our preference for animal production over crop production reflects the lack of flat land available for cultivation in many areas (Ministry for the Environment, 1997). Climatic variations and soil types also affect land productivity, and have resulted in different patterns of primary production and land use around the country.

New Zealand’s soils

New Zealand has a diverse range of soils and parent materials. This range has been further increased by human activity to enhance soil fertility.

New Zealand soils are naturally acidic with low levels of nitrogen, phosphorus, and sulphur. Consequently, soils used to grow crops and pasture derived from European agriculture need to be developed and maintained with nitrogen-fixing plants (such as clover), fertilisers and, often, lime to sustain high-yield plant growth. As a result, farmed soils today are not the same as the soils farmed by early settlers (they have different biological, chemical, and physical properties than earlier soils) (During, 1984).

In general, North Island soils are strongly influenced by volcanic ash, with many areas naturally low in minerals such as magnesium, copper, iron, cobalt, and boron. In the South Island, most arable soils come from parent material carried down from mountains and foothills by rivers and wind, aided by glacial action. Mineral deficiencies in South Island soils follow rainfall patterns – the wetter the area, the greater the potential for minerals to be leached out (Hewitt, pers comm).

Figures 9.1 and 9.2 show the location of New Zealand’s 15 soil orders – the highest and most generalised level of soil groups in a soil classification (see box ‘More about soil classification in New Zealand’).

Nitrification inhibitors: tackling nitrous oxide emissions from soils

The agricultural sector produces close to 50 per cent of New Zealand’s greenhouse gas emissions (see chapter 8, ‘Atmosphere’).

Around one third of New Zealand’s agricultural emissions are in the form of nitrous oxide. Nitrous oxide is emitted from soil processes. Increased emissions can result from the addition of nitrogen to soils (for example, urine and dung from grazing sheep and cattle, the application of nitrogen fertilisers, and from the absorption (fixation) by clover of nitrogen from the atmosphere).

What are nitrification inhibitors?

Nitrification inhibitors are chemical compounds which stop the conversion of nitrogen into nitrous oxide in soils. These inhibitors can be applied to soil to reduce emissions of nitrous oxide to the atmosphere.

What is the impact of nitrification inhibitors?

Research conducted at a number of sites in New Zealand indicates that the application of nitrification inhibitors to soil results in an average 70 per cent reduction in nitrous oxide emissions when urine is applied to pasture (Di et al, 2007). Similar, although variable, reductions in nitrate leaching have been recorded. Actual reductions in both nitrate leaching and nitrous oxide emissions may be lower in an on-farm environment.

An added benefit is the potential for increased pasture production associated with the reduction in loss of nitrogen. In addition, reductions in nitrogen losses from soils help keep our waterways clean: leaching of nitrates from agricultural soils affects water quality in many areas (see chapter 8, 'Atmosphere and chapter 10, ‘Freshwater').

Research is continuing to evaluate this innovative technology in New Zealand.

Figure 9.1: New Zealand’s soil orders (North Island)

 See figure at its full size (including text description).

Figure 9.2: New Zealand’s soil orders (South Island)

 See figure at its full size (including text description).

Table 9.1 notes the predominant land uses and locations for the 15 soil orders shown in Figures 9.1 and 9.2.

Table 9.1: New Zealand’s 15 soil orders and their predominant land uses

View New Zealand’s 15 soil orders and their predominant land uses (large table).

Soil classification and its use in New Zealand are explained in the box ‘More about soil classification in New Zealand’.

More about soil classification in New Zealand

What is a soil classification used for?

A soil classification can be used to trace the formation, or evolution, of soils through time. The need for soil classification has been part of human activity in New Zealand. Soil classification has been used in New Zealand since the arrival of the first Polynesian canoe. Māori horticulturalists recognised and named soil classes that were relevant to the establishment and management of their gardens, in particular, kūmara gardens. They recognised classes such as oneharuru (a light but good sandy loam) and onetea (white soil from sandy volcanic material).

Who developed New Zealand’s classification?

The New Zealand soil scientist, Norman Taylor, developed the New Zealand Genetic Classification in 1948, which recognised ‘soil groups’ and related them to the environmental factors that most influenced their character. Knowledge of these relationships helped the prediction of soil classes from observations of geology, landscape, climate, and vegetation. Such predictions enabled rapid progress in the broad-scale mapping of New Zealand soils.

By the late 1970s, Taylor’s classification was becoming outdated. With new information, the New Zealand Soil Classification was developed (see Figures 9.1 and 9.2). Under this classification there are 73 major soil groups that can be aggregated into 15 different soil orders. Soil orders are the highest and most generalised level of the classification. The soil groups can be divided into 272 subgroups with a further subdivision into soilforms. The top three levels of the classification (orders, groups, and subgroups) were described by Hewitt (1993) and the fourth level (soilforms) by Clayden and Webb (1994).

Source: Molloy, 1998.

Factors that affect land

New Zealand’s land is constantly changing. The speed of this change depends on natural or human influences. Land use, a change due to human activity, directly influences land cover. Urban land uses generally go hand-in-hand with artificial land cover such as roadways, pavements, and buildings. Rural land uses generally go hand-in-hand with land cover such as pastures, forests, vineyards, croplands, and orchards. Changing land use and land cover can create pressures on the environment, which in turn affect land-based ecosystems, soils, plants and animals, waterways, and our atmosphere (see chapter 8, ‘Atmosphere’;chapter 10, ‘Freshwater’; chapter 11, ‘Oceans’; and chapter 12, ‘Biodiversity’).

Some environmental pressures on land include:

  • changes in land cover that affect land-based ecosystems and native or exotic (introduced) biodiversity

  • changes in land use that affect soil health (that is, soil quality) or soil intactness (that is, the ability of soils to stay in place), and have flow-on effects for water quality in rivers, lakes, estuaries, and the coastal marine environment, and increase the risk of erosion and flooding

  • pesticide, herbicide, and other chemical contamination of soils that result in contaminated land

  • introduced animal pests, diseases, and weeds that affect land-based ecosystems and threaten biosecurity, animal health, productivity, or human health.

Historic land use

Nearly all New Zealand’s cultural landscapes have been modified by agriculture, horticulture or forestry at some time in the past. As in other countries, historic land-use practices have had serious impacts on New Zealand’s environment, including soil erosion (which causes siltation of streams, rivers, and estuaries) and increased flooding risk (see box ‘More about flooding in New Zealand’).

In many areas, the effect of historic land use is only now being felt – it often takes decades for nutrients from farm run-off to reach our lakes and groundwaters, where they cause algal blooms and dense growth of aquatic weeds (Ministry for the Environment, 1996).

More about flooding in New Zealand

About 100 of our towns and cities are located on floodplains. As a result, flooding remains the most common cause of civil defence emergencies in New Zealand.

Although flooding occurred in New Zealand before human settlement, the nature of flooding was changed significantly by the European settlers’ intensive land clearing. The capacity of the land to retain rainfall was reduced by converting forests to pasture. This change caused greater flood peaks, more intensive erosion, and changes in river systems, leading to more frequent and severe flooding.

Early flood protection measures

The importance of protecting our valuable topsoils was recognised in New Zealand in the mid-1900s. The Soil Conservation and Rivers Control Act 1941 was introduced to limit soil erosion and the effects of flooding. Most of New Zealand’s large-scale river-control schemes were built under this regime. About 3,000 kilometres of stopbanks were constructed in the 1950s and 1960s alone.

Stopbanks protected communities from regular flooding, but they also allowed more intensive development on floodplains. In some cases, stopbanks actually increased the consequences of flooding, because more people and assets were affected when large floods breached stopbanks. Over time, the traditional approach of building structures to protect people and property from flooding shifted to focusing on planning measures to control development in flood zones.

Integrated catchment management schemes

Integrated catchment management schemes were introduced in the 1970s and 1980s. These schemes put in place soil conservation measures in upper catchments, and river control and erosion protection in the lower reaches of rivers and floodplains. An integrated approach is particularly relevant to dealing with flood risk.

The ‘4Rs’ approach (risk, readiness, response, recovery)

Since 2002, New Zealand has followed a risk management approach to natural hazards, including floods. This approach relies on reducing risk, being ready (risk-preparedness), response, and recovery.

Severe consequences

Widespread flooding in the lower North Island in February 2004 reminded New Zealanders how disastrous floods can be. Heavy rainfall (up to 300 millimetres in 2 days) saw rivers and streams flood in Hutt Valley, Kapiti Coast, Wairarapa, South Taranaki, Wanganui, and Manawatū. Manawatū was worst affected, with 1,800 people evacuated from their homes and farms, and economic losses estimated at $400 million (McSaveney, no date).

Lesser floods can also have significant consequences. In July 2004, flooding in the Eastern Bay of Plenty led to the evacuation of 3,200 people. About 450 farms were affected, and 200 houses were left uninhabitable. Mangawhero River flooding in July 2006 caused a bridge to collapse, isolated the settlement of Mangawai and caused damage estimated at $10 million. (National Institute of Water and Atmospheric Research, and Institute of Geological and Nuclear Sciences, 2006).

Future management of flooding

Climate change is expected to increase the frequency and severity of flood events in some areas of New Zealand, particularly those already prone to flooding. Integrated catchment management and the 4Rs approach to hazard management are particularly relevant to managing future flood risk. Central and local government are working together to meet this challenge.

Changing and intensifying land use

Today, although many land management practices have improved, there remain some significant pressures on the environment from changing and/or intensifying land use.

Over the past 10 years, a change to more intensive farming in some regions has resulted in:

Effects of commodity prices

Changes in land use in our primary production sectors are driven by export prices (Ministry for the Environment, 1997). High market prices for particular commodities (such as milk and dairy products, timber and forestry products, and more recently grapes and wine products) can cause farmers to convert from one land use to another.

Versatile soils

In recent years, the spread of urban and rural lifestyle subdivision in some regions has put pressure on soils known as ‘versatile soils’ (Molloy, 1998). Versatile soils cover about 10 per cent of New Zealand’s total land area. These soils are fertile, generally well-drained, and found on slopes of less than 12 degrees (Molloy, 1998).

Because versatile soils are of high value for food production, they are traditionally used for horticulture or arable cropping. While changing the use of these soils from large scale food production to human settlement may result in a loss of fertile productive land, it also changes the pressures on the immediate land environment.

Horticulture is estimated to cover 1.6 per cent of New Zealand's total land area compared to 24 per cent in Europe.

Source: Ministry for the Environment.

Tourism infrastructure needs

Scenic and adventure tourism, a growth industry in New Zealand, relies on natural and pastoral landscapes and native biodiversity.

Land use for tourism purposes has different impacts on the environment than other land uses. Revenue from tourism can help protect valuable native land cover and biodiversity. The infrastructure needs associated with tourism (such as roads, accommodation, and waste management) place different pressures on our land than other land uses (for example, primary production). However, tourism can have a wider positive environmental impact when the tourism demand is for a ‘clean and green’ environment.

Vulnerability to introduced pests

As an island nation, New Zealand has unique biological characteristics that have developed in isolation over millions of years. This isolated development has meant New Zealand’s primary production has benefited from a high health status; that is, being relatively free from pests and diseases compared with other countries.

Over the past few decades, increased trade and travel and changing climatic conditions have increased New Zealand’s vulnerability to introduced pests that can affect our land-based economy. An example is the varroa mite, which affects bees and, therefore, pollination activity.

An increasing number of vessels, cargo shipments, and people are arriving from other regions which have organisms with the potential to become high-risk pests for New Zealand’s primary production sectors.

Land management legislation

Resource Management Act 1991

The Resource Management Act 1991 is the primary piece of legislation that governs the use, development, and protection of land in New Zealand. The Resource Management Act promotes the sustainable management of natural and physical resources, including land.

District council functions under the Resource Management Act include the integrated management and control of the effects of the use, development, or protection of land.

Territorial authority functions include controlling the effects of land use relating to natural hazards, hazardous substances, and biodiversity.

Regional council functions include the control of the use of land for purposes of soil conservation, natural hazards, water quality, and hazardous substances.

Both territorial and regional councils have functions relating to identifying, monitoring, and managing the effects of contaminated land.

A number of other Acts impact on land management. These include:

  • Biosecurity Act 1993

  • Building Act 2004

  • Crown Minerals Act 1991

  • Hazardous Substances and New Organisms Act 1996

  • Historic Places Act 1993

  • Local Government Act 1974

  • Local Government Act 2002

  • Soil Conservation and Rivers Control Act 1941.

Legislation relating to land tenure includes:

  • Land Act 1948

  • Land Transfer Act 1952

  • Property Law Act 1952

  • Te Ture Whenua Māori Act 1993.