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Farming and the environment

by  Julia Haggerty and Hugh Campbell

Farmland is now an ordinary part of the rural landscape, and has become a core aspect of New Zealand’s national identity. But the pastures of New Zealand’s countryside were created through massive human effort, with significant cost to the environment. Balancing agricultural land use with care of the environment is a growing challenge.

A modified landscape

Changing the landscape

Farming has been the most significant human influence on the land in New Zealand. There are about 70,000 farms, which cover about half of the country’s land area.

Despite New Zealand’s relatively gentle climate, farming has not come altogether ‘naturally’. From the kūmara plots of early Māori to today’s intensive farms, orchards and vineyards, farming has demanded determination, technological innovation and significant changes to the environment.


Farming has long been the backbone of New Zealand’s economy, and is a significant part of its cultural and aesthetic landscape. But it also causes some of the nation’s most vexing environmental problems.

Farming practices can lead to erosion and loss of nutrients from the soil, which affect farmers themselves. Other environmental consequences affect the wider community, for example the depletion of aquifers (underground layers of water-soaked rock) or contamination of fresh water. Some effects are immediately noticeable, but others, such as ground water contamination, can take years, or even decades, to appear.

Changing expectations

Over the past few decades, public opinion has changed significantly about the appropriate balance between human land use and care for the environment. Because New Zealand’s agricultural produce is mostly exported, farmers are highly sensitive to the demands of overseas consumers. A growing preference for ‘safe’ and ‘green’ foods has resulted in changes in farming practices. The emphasis has changed from harvesting as much of a product as is possible, to meeting new standards, mainly related to protecting the environment.

Reducing chemical use

New Zealand’s horticultural exporters – particularly of kiwifruit and apples – used to rely heavily on pesticides. They have now responded to market demands by becoming some of the world’s most environmentally friendly fruit producers. Wine producers have also been proactive in adopting practices to protect the environment.

Changes are being forced on other farming sectors because the old methods are no longer working as well. For example the effectiveness of anthelmintic drenches for internal parasite control in sheep and cattle has declined dramatically. Alternatives involving better grazing management and different feed types are being examined.

Production practices have changed considerably in almost every New Zealand food-export industry. Dairying is now the only significant exporter still facing serious environmental problems, which have resulted from expansion and intensification.

Early changes

Polynesian practices

Before Europeans arrived, Māori grew crops they had brought from Polynesia. However, due to New Zealand’s cooler climate, and different vegetation and soils, many could not flourish and some only survived in the warmer north. Māori also changed the landscape by burning large areas of forest, probably to make hunting easier.

Māori agriculture expanded rapidly after initial contact with Europeans, who provided new technologies, trading opportunities and crops. Māori rapidly incorporated the potato into their range of crops, as it was easier to grow and more productive than kūmara.

Transforming the landscape

In 1840 rainforests covered about half of New Zealand’s land area, and native tussock grassland covered most of the eastern hill and high country of the South Island. By 1930 about half of the forest area, and a large part of the tussocklands – totalling 39% of New Zealand’s land area – had been transformed into pastures. European settlers carried out this extraordinary conversion by:

  • clearing forest, mainly through burning
  • draining swamps and wetlands, removing most of the lowland forest in the process
  • burning hill and high country tussock grasslands.

Forest clearing

Clearing forest, whether by burning or felling trees, was expensive and time-consuming, and didn’t gain momentum until the 1850s. It was also slowed by Māori resistance, but accelerated in the 1870s after military intervention.

The first successful shipment of frozen meat and butter to London in 1882 made dairying and fat-lamb farming viable, adding economic incentives to clear land and grow pasture. By the early 1900s English ryegrass, white and red clover, and cocksfoot began to dominate the countryside.

Draining wetlands

Lowland swamps soon attracted settler attention. Assisted by the state, a remarkable 85% of wetlands were drained by the Second World War. This figure is high compared with countries such as the Netherlands or Great Britain, where about 60% have been drained.

Burning tussock

Fire was used to clear the tussock lands of the South Island for pasture, and farmers continued to burn regrowth, which also added nutrients to the soil. Pioneer botanists such as John Buchanan showed that the intricate ecosystems of high country areas had been radically changed by farming as early as the 1870s.

Soil fertility

The new pastures, and increased numbers of grazing animals, soon exhausted New Zealand’s limited soil fertility, so farmland required constant addition of fertilisers. Of these, superphosphate, which helped correct phosphate and sulfur deficiencies, was the most important. On hill country, it was not possible to add fertiliser to the soil until the advent of topdressing from 1949.


To stop the spread of stock diseases, such as sheep scab (a small mite which ruined the fleece) and footrot, and to keep animals penned in, farmers criss-crossed the landscape with fences.

Expansion in the 20th century

The move to pasture

From the 1890s to 1914, large grain-growing and sheep-raising estates were bought and subdivided by the government into smaller, family-run farms. New Zealand farming became more industrialised, modern and simplified during this period of increasing intensification. For example, mixed farming, which involved rotations of wheat or oats with pasture, was largely replaced by grassland farming.

Experiments continued with fruit growing and horticulture, but sheep and dairy farming became more dominant.

The grasslands revolution

Before the late 1920s there was much experimentation with pasture grass combinations. Agricultural scientists decided to base New Zealand pasture on perennial ryegrasses they helped develop, and white and red clover. Since then, New Zealand's grasslands have been based on a small number of pasture plants.


From the 1920s key agricultural bureaucrats and scientists, such as A. H. Cockayne and Bruce Levy, portrayed the England-like pastures of New Zealand as normal and natural, even though they had been quite deliberately created by massive human effort.

There were a few challenges to this interpretation, by writers such as William Pember Reeves, poet Blanche Baughan and novelist Jane Mander, who lamented the passing of the forest. There were also conservationist groups formed to preserve the remnants of native forest in national parks and reserves.

However, most people celebrated the country’s extraordinary transformation from forests, swamps and tussocklands to farms – especially once New Zealand, as the farm for the British Empire, gained one of the highest standards of living in the world.

Chemical boosts

Farmers have been eager adopters of technologies that promised to improve production. After the Second World War, millions of tonnes of fertilisers, especially superphosphate, and some 245 chemicals – including the later-banned pesticides DDT and 2,4,5-T – were eagerly purchased by farmers to increase productivity on relatively poor soils.

An unnatural farm

In just over 100 years, New Zealand was reinvented as a stock farm. Its emerging national identity was closely linked to pioneering and transforming the land, although its population increasingly lived in cities. Few seemed concerned that the previously diverse range of environments was being reduced to a simplified and highly regulated farm.

Environmental impacts in the 2000s

Ecological borrowing

Increases in productivity gained by agricultural intensification often have an ecological cost, but this is typically paid for in a different time or location. For example, depleting underground freshwater aquifers or exhausting energy reserves means ‘borrowing’ these resources from future generations. Another example is erosion of hill country, which adds sediment to rivers and contributes to flooding of lowlands.


The expansionist phase of agricultural production in New Zealand came to an end in the mid-20th century. Since then, there has been a drive towards agricultural intensification – to produce more milk, lambs, wool, meat or crops from the same land area. This has accelerated since the 1970s, due to increasingly competitive overseas markets. Farmers have increased productivity by using new technologies and using more water and fertiliser.


In 2004, after an extensive inquiry, the Parliamentary Commissioner for the Environment issued a report, Growing for good. It found that intensified farming was causing many pressing environmental problems, including declining water quality in many areas. According to the report, the growth in demand for irrigation water appeared to be unsustainable in some regions.

Effects on soil and water

Soil-related effects

Soil is the essential ingredient in any farming enterprise. When it is in poor health, plants cannot grow to their full potential. Contaminated soil is a risk to public health and unstable soil can lead to landslips and dust storms.

Farming contributes to problems such as soil erosion, fertility loss (unless corrected by fertiliser) and compaction.

Soil fertility

Farming places a significant demand on the organic and mineral components of soil. Because many New Zealand soils developed under forests, they do not have large stores of vital nutrients. In farming, the minerals needed for plant growth, such as nitrogen and phosphorus, are typically removed more quickly than they can be replaced by natural processes, so farmers add fertilisers. While organic fertilisers are used by some farmers, synthetic fertilisers have been in use in New Zealand since the late 19th century.

Soil erosion

Soil erosion is an ongoing concern in New Zealand. Between 200 and 300 million tonnes of soil are carried out to sea every year – a rate well above the global average for soil loss. New Zealand’s hilly topography and active geology amplifies the problem, but farming continues to be a leading cause of erosion. Land clearance and grazing on unstable lands contribute to this problem.

Water-related effects

Farmers in drier parts of the world envy the relatively abundant and gentle rains that New Zealand’s farmlands receive. However, local variations in rainfall and topography mean that some farmers in New Zealand are plagued with too much water, while others worry about having too little.

Wetland drainage

In wetter regions, farmers often drain land to make it dry enough for stock and cropping. However, too much land drainage can lead to the loss of ecologically important wetlands. Important native fauna, like eels and whitebait, depend on wetlands for their survival. Land drainage can also contribute to making floods worse.


In parts of New Zealand, such as Central Otago and the east coasts of both islands, the problem is too little water. Irrigation has increased significantly in these areas in recent years, especially in Canterbury where dairying has expanded. Where farm irrigation is particularly intensive, the depletion of some underground aquifers is an increasing concern.


Farming can lead to the run-off and leaching of nutrients into rivers, streams, estuaries and underground water. The four pollutants of greatest concern are nitrogen, phosphorus, sediment and animal faecal matter. These typically enter waterways as run-off and leaching from farm paddocks. When livestock have direct access to waterways, they can pollute more directly, and can add sediment by breaking down stream banks.

Water quality

Nitrogen and phosphorus, which can end up in waterways from farms, make some aquatic plants and algae thrive. They then multiply and can damage native eel and whitebait habitats, restrict swimming, boating and fishing, clog drains and hydro dam intakes, and spoil the aesthetic appeal of waterways.

Often, the most immediate water-quality problems can be easily remedied, for example building fences to keep cattle out of waterways. But other problems are more complicated to solve, such as the lag effect in nutrient leaching from soils. For example, the deterioration in Lake Taupō’s water quality is thought to be partly caused by farming activities dating back as far as 50 years.

Biodiversity and greenhouse gas changes

Loss of biodiversity

Many of New Zealand’s tens of thousands of native species are not found anywhere else in the world. More than 50 species of bird are known to have become extinct since the arrival of humans, and an unknown number of invertebrate animals and plants have also been lost and continue to decline. In 2007 there were 2,788 species (including birds, bats, fish and plants) listed as threatened.

The establishment and expansion of farms, orchards, and vineyards – with their exotic plants and animals – have been key drivers of the land clearance and changing patterns of habitat that have led to diminishing biodiversity. Agricultural activities destroy the habitats of some species and create habitats for other, usually introduced, species.

Building biodiversity

Proponents of organic farming believe that a holistic approach to production, and not using synthetic fertilisers and pesticides, will benefit not only consumers of organic produce, but also the farm environment. Biodiversity is important from the farmers’ perspective – many farmers and researchers believe that the more diverse the ‘agro-ecosystem’, the better its chances against disease and pests. Ongoing research is investigating this.

Greenhouse gases

The contribution of agriculture to New Zealand’s total greenhouse gas emissions is significant – over 50%, compared to the global average of 14%. In 2004 livestock contributed 90% of methane emissions and over 95% of nitrous oxide. Since 1990 New Zealand’s agricultural emissions have grown by about 1% each year.

As agriculture changed from sheep-dominated to mixed farming – with intensive dairy farming increasing since the 1980s – its role in New Zealand’s greenhouse gas emissions has become significant. In 2004, carbon dioxide comprised nearly half of New Zealand’s total greenhouse gas emissions, but subtracting the carbon dioxide removed from the atmosphere through activities such as forestry, reduces it to a net 19%. The major net contributors were methane (54%), and nitrous oxide (26%). Nitrous oxide emissions have grown with the increasing use of nitrogen fertilisers in farming.

Methane, a by-product of animal rumination (released in sheep and cow burps), is still of concern, with outputs increasing by 10% between 1990 and 2006. In 2003 the New Zealand Parliament considered an emissions tax (commonly called the ‘fart tax’) to control the amount of methane produced on farms. There was so much opposition from farmers that the idea was rejected.

Given the dairy industry’s commitment to continued growth, it will be difficult to reduce agricultural greenhouse gas emissions. Solutions may lie in regulatory approaches (such as amendments to the Resource Management Act 1991 to control nitrogen fertiliser use), market-based initiatives (such as tradeable pollution permits), and incentives to encourage practices to reduce nitrous oxide emissions (such as applying nitrification inhibitors to pasture).

Clean green solutions

Few regulations

Because of its high economic and cultural status in New Zealand, the farming sector has historically been relatively free of national regulations, especially when compared with European countries. Early interventions from central government, such as the Soil and Water Conservation Act 1941, tended to focus on managing environmental problems through engineering. Prevention of erosion and the promotion of soil conservation were encouraged, but environmental problems were seen mainly in economic terms as loss of farm productivity.

A general political reluctance to impose controls on farming has remained, even since the passing of the Resource Management Act 1991 (RMA).

Resource Management Act 1991

The RMA replaced a large number of sometimes conflicting environmental protection and land-use statutes with a single act. Its main purpose is to ensure sustainable environmental management by promoting the careful use of resources.

The RMA does not specifically target farming practices, but it affects farmers through the resource consent process. Farmers typically need approvals in the form of water permits for irrigation and stream withdrawals, and discharge permits. They may also be subject to land-use permits for track or road building.

Regional responsibility

The RMA devolved most resource management responsibilities to local government. Activities like soil conservation, flood control, water quality monitoring and pest management must be initiated and funded by local councils.

In general, local governments have been reluctant to strongly regulate farming practices. However, the responsibility to monitor the state of the environment has led many councils – and the public – to a greater awareness of the cumulative effects of intensive farming. This process of monitoring, education, research and outreach helps councils tackle the complex problems related to agriculture’s impact on the environment.

Other regulations

The need to make difficult decisions about the impact of rural land use on the environment has brought about new approaches to environmental regulation. For example, Environment Waikato has recently adopted a strategy to address the high nitrate level in Lake Taupō – it is thought this will require reducing the amount of nitrogen leaching into ground water by 20%. The strategy requires farmers to limit their nitrogen output, but allows the trading of nitrogen output quotas. This kind of pollution trading is possible because the plan sets a cap on total nitrogen output – a regulatory commitment that few councils have made to date.

Voluntary environmental management

Biodiversity on farms

Traditionally, conservation efforts have focused on the remnants of indigenous habitats (often protected in reserves and national parks), rather than viewing farms as potential allies in stemming the loss of native flora and fauna. Farms often have patches of native bush in gullies, and some native birds make their homes on farms. The Queen Elizabeth II National Trust helps landowners protect remnant habitats on farms and other private property. There is also a push to preserve or create small wetland areas on farms.

Farmers have often been leaders in efforts to control problematic invasive species, such as possums, rabbits and weeds, and can have a significant role in preserving and restoring biodiversity.

Raising whitebait on dairy dung?

Fisheries consultant Charles Mitchell is experimenting with ways to ‘farm’ New Zealand’s native whitebait, which have never been successfully reared in captivity to date. Among his innovative ideas is to grow the larvae, and other life forms that it needs to survive, in recycled dairy farm effluent.

Environmental management agencies

Many national and regional environmental agencies promote voluntary and collaborative approaches to environmental protection and restoration. However, studies have shown that, regardless of how much information and knowledge most farmers had about environmental management, any decision to adopt specific practices was largely based on financial factors.

Organic management

In 1941 New Zealand was the first country in the world to establish an organic agriculture organisation. In 1983 a growing world market for organic food led to the formation of the New Zealand Biological Producers Council, which wrote Bio-Gro standards to certify organic production.

Organic farming took off in 1991 when two important food exporters – Wattie’s and the New Zealand Kiwifruit Marketing Board – both established a group of growers to produce Bio-Gro certified organic products. Organic exports expanded in the 1990s, with over 1,000 certified organic growers, several professional certification organisations, and over 100 export companies carrying organic products.

Landcare Trust

The New Zealand Landcare Trust is a non-governmental organisation that works directly with rural communities and private landowners. It provides support and information to encourage them to manage their land more sustainably and maintain biodiversity.

Clean Streams Accord

The 2005 Clean Streams Accord is an agreement between New Zealand’s largest dairy cooperative, Fonterra, and representatives of national and regional government. It compels Fonterra’s farmers to follow practices designed to stem the damage from intensive dairying to water quality of waterways and estuaries. These practices include fencing waterways to keep stock out, complying with local government regulations regarding farm effluent, and limiting fertiliser use. The target is for full compliance with the accord by 2012.

Hononga, rauemi nō waho

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How to cite this page: Julia Haggerty and Hugh Campbell, 'Farming and the environment', Te Ara - the Encyclopedia of New Zealand, (accessed 27 July 2021)

He kōrero nā Julia Haggerty and Hugh Campbell, i tāngia i te 24 Nov 2008