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New Zealand’s reputation as a quality food producer is growing.

Optimising food production

Over the next 50 years farmers around the world will need to produce more food than has been grown over the past 10,000 years.

Best use from a limited resource

Fertiliser helps farmers produce food efficiently by replenishing the soil. But fertiliser needs to be used responsibly.

Responsible and sustainable nutrient management

The Fertiliser Association invests in research and tools to ensure farm profitability while minimising nutrient losses to the environment.

The Fertiliser Association of New Zealand promotes and encourages responsible and scientifically-based nutrient management.

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New Zealand soil Olsen P levels

The majority of soil data is from pastoral farms, with much smaller numbers of samples from arable or horticulture land use. This is simply a reflection of the relative land areas in these land-use activities.

As a single data set, the national median value of Olsen P showed some fluctuations over time, but little change, with a small increase across the overall time period.

The graphs are reporting median levels of Olsen P, and (in grey) the 25th to 75th percentile range.


Figure 1: Time series of the national median value of Olsen P across all farm and soil types and regions.


Olsen P levels by farm type

We have analysed the data for individual land uses.

Land use categories such as horticulture or orchard cover a wide range of crops with differing nutrient needs. This means that the results from orchard and horticulture land uses show a very wide range of Olsen P results (Figures 2 and 3).



Figure 2: Time series of the national median value of Olsen P across all soil types for horticultural properties.


Figure 3: Time series of the national median value of Olsen P across all soil types for orchards.


Figure 4: Time series of the national median value of Olsen P across all soil types for arable and fodder crop farms.


The bulk of the data reflects tests from pastoral soils (dairy and dry stock farming). The national median values across all soil types are at the high end of target soil Olsen P values for dairy farms on Ash or Sedimentary soils, (20-40, with 30-40 for high producing farms) shown in Figure 5.

The median value for drystock farms across all soil types, is trending toward the middle of target soil Olsen P values for Ash or Sedimentary soils, (20-30), shown in Figure 6. There is some variability attributable to differences in soil type and production intensity.


Figure 5: Time series of the national median value of Olsen P across all soil types for dairy farms.


Figure 6: Time series of the national median value of Olsen P across all soil types for dry stock farms.


Olsen P levels by soil type

When broken down to specific soil types, the higher Olsen P target ranges for Pumice and Organic soils are reflected in the results for those soils (Figures 7 to 10 respectively).


Figure 7: Time series of the national median value of Olsen P across all farm types for Ash soil.


Figure 8: Time series of the national median value of Olsen P across all farm types for Sedimentary soil.


Figure 9: Time series of the national median value of Olsen P across all farm types for Pumice soil.


Figure 10: Time series of the national median value of Olsen P across all farm types for Peat soil.


Variations to the target range

Figures 11 to 18 include the target range for the optimum pasture response.

The target ranges apply to representative farm systems across a combination of farm and soil types. While the vast majority of soil sample results fall within the target range, there remains a considerable 'scatter' of results above and below this range.

Where Olsen P values exceed the target range for the particular farm production system, steps should be taken to understand the circumstances and best ways to ensure any excessive phosphorus use is reduced.

Dairy

Where milksolids production is near the average for the supply area, best economic return is provided by maintenance of soil Olsen P levels in the target range for near maximum pasture production (20-30 for Ash and Sedimentary soils, 35-45 for Pumice and Peat soils).

If milksolids production is in the top 25% for the supply area, or it is intended to increase to this level, increasing soil Olsen P to 30-40 for Ash and Sedimentary soils and to 45-55 for Pumice and Peat soils, may be justified where a response in pasture production is obtained.

Figure 11: Yearly time series of the median level of Olsen P across Ash soils for Dairy farms nationally.

Figure 12: Yearly time series of the median level of Olsen P across Sedimentary soils for Dairy Farms nationally.

Figure 13: Yearly time series of the median level of Olsen P across Pumice soils for Dairy farms nationally.

Figure 14: Yearly time series of the median level of Olsen P across Peat soils for Dairy Farms nationally.


Drystock

On most sheep and beef farms economically optimal soil fertility will be achieved at soil test results below the target soil test range, which provides for near-maximum pasture production (20-30 for Ash and Sedimentary soils, 35-45 for Pumice and Peat soils).


Figure 15: Yearly time series of the median level of Olsen P across Ash soils for Drystock farms, nationally.

Figure 16: Yearly time series of the median level of Olsen P across Sediment soils for Drystock farms, nationally.

Figure 17: Yearly time series of the median level of Olsen P across Pumice soils for Drystock farms, nationally.

Figure 18: Yearly time series of the median level of Olsen P across Peat soils for Drystock farms, nationally.


Arable and Fodder Crops

Figure 19: Yearly time series of the median level of Olsen P across Ash soils for Arable and Fodder Crop farms, nationally.

Figure 20: Yearly time series of the median level of Olsen P across Sedimentary soils for Arable and Fodder Crop farms, nationally.

Figure 21: Yearly time series of the median level of Olsen P across Pumice soils for Arable and Fodder Crop farms, nationally.

Figure 22: Yearly time series of the median level of Olsen P across Peat soils for Arable and Fodder Crop farms, nationally.


Horticulture

Figure 23: Yearly time series of the median level of Olsen P across Ash soils for Horticulture properties, nationally.

Figure 24: Yearly time series of the median level of Olsen P across Sedimentary soils for Horticulture properties, nationally.

Figure 25: Yearly time series of the median level of Olsen P across Pumice soils for Horticulture properties, nationally.

Figure 26: Yearly time series of the median level of Olsen P across Peat soils for Horticulture properties, nationally.


Orchard

Figure 26: Yearly time series of the median level of Olsen P across Ash soils for Orchards, nationally.

Figure 28: Yearly time series of the median level of Olsen P across Sediment soils for Orchards, nationally.

Figure 29: Yearly time series of the median level of Olsen P across Pumice soils for Orchards, nationally.

Figure 30: Yearly time series of the median level of Olsen P across Peat soils for Orchards, nationally.

The Fertiliser Association of New Zealand and Dairy NZ funded development of the Nutrient Management Adviser Certification Programme (NMACP). This industry-wide certification aims to ensure that advisers have the learning, experience and capability to give sound nutrient advice.

Find out more

14 May 2023

 

The New Zealand Journal of Agricultural Research has published a paper titled Nitrogen fertiliser use in grazed pasture-based systems in New Zealand. The research paper was commissioned by the Fertiliser Association of New Zealand and written by AgReserch senior scientist Colin Gray.

The paper can be found here.


30 April 2023

Commercial fertilisers have long been critical to viable economic production in Aotearoa New Zealand’s agriculture and horticulture sectors – starting in 1867 with the import of 459 tonnes of phosphorus-rich Pacific Island bird and bat dung. The Fertiliser Association of New Zealand marks its 75th anniversary in 2023. This article looks back at some of the history of fertiliser use in New Zealand.

In 1880 the first shipment of superphosphate was imported into New Zealand likely by William Ivey, Director of Canterbury Agricultural College based at Lincoln. Ivey demonstrated the power of superphosphate to enhance production in New Zealand pastoral soils that are naturally low in phosphorus and sulphur. The shipment probably came from Adelaide, Australia, which had the first superphosphate manufacturing plant in the Southern Hemisphere.

To encourage domestic production, the government announced grants for firms that could produce large amounts of sulphuric acid for use in superphosphate manufacture. In 1881 the first NZ production was underway, by Kempthorne Prosser & Co of Burnside, Dunedin, using livestock bones from a nearby abattoir. Kempthorne Prosser went on to construct further superphosphate plants in Auckland, Christchurch and Whanganui and to become New Zealand’s major superphosphate supplier, until the 1970s.

A major game changer came in the late 1890s when Henry Denson, a cargo officer for the Pacific Islands Company, picked up a strange-looking rock on Nauru, and went on to use it as a door stop in the company’s Sydney office.

Albert Ellis from the company’s phosphate division spotted it and tested it - rather against Denson’s wishes as he was convinced it was petrified wood. It turned out to be the highest quality phosphate ore. Further investigation identified rich sources on both Nauru and neighbouring Banaba. Rock was also mined on Christmas Island.

The British Phosphate Commission was established by the British, Australian and New Zealand governments in 1920 to manage the phosphate resources in Nauru and Banaba, largely for the benefit of Australian and New Zealand farmers. Management of the Christmas Island rock was taken over by the Commission from 1949.

The reliable supply of rich deposits of phosphate rock from the Pacific saw superphosphate use become standard practice. The importance of phosphate to New Zealand and Australian agriculture became obvious when Japanese occupation of the islands resulted in the need for government rationing of phosphate fertiliser in New Zealand.

Over time, the Commission was seen as a product of the colonial era and became controversial. Although a percentage of revenue was returned to the Nauruan people, an Australian Commission of Inquiry in 1980 noted the Commission and its shareholders did not adapt quickly enough to the passing of the colonial era. Nauru became a sovereign independent nation in 1968 and in 1970 its newly formed government purchased the phosphate rights, bringing an economic boost to the new nation. Mining on Banaba ended in 1979 but in Nauru continues at a small scale.

In the wake of WWII, the first fertiliser co-operatives – the Southland Co-operative Phosphate Company and the Bay of Plenty Fertiliser Co-operative – were founded. The New Zealand Fertiliser Manufacturers’ Research Association, focused on research for industry good purposes, was established in 1947 – the name was changed to the Fertiliser Association in 2012.

Government and fertiliser companies supported the Association’s work. In 1950 a research site was established in South Auckland with laboratory facilities and library. The site housed a working scaled-down model of a superphosphate manufacturing plant.

Former Association chair Arthur Duncan worked for Dunedin-based Dominion Fertilisers from the 1960s and ultimately became group marketing manager for Ravensdown.

“The early focus of the association was on methods for assessing phosphate rock from different sources for the manufacture of superphosphate fertiliser, and also for research on manufacturing processes,” recalls Mr Duncan.

“It consisted of a mix of representatives from industry, government departments, the Department of Scientific and Industrial Research (DSIR) and universities, working together. Initially there was one very large committee, but this evolved to be two. One addressed the manufacturing processes, and the second addressed use and application.”

The manufacturing research papers with detailed technical findings were presented at the New Zealand Fertiliser Manufacturers’ Research Association Technical Conferences from 1957 through until the mid-1970s. Addressing wider nutrient management issues the Association continued with its conferences and symposiums into the early 2000s. The Association still holds these technical papers in its library.

Behind the scenes, throughout this period there were many changes taking place across the industry. In 1977 Kempthorne Prosser announced plans to buy Dominion Fertilisers. Fearing a monopoly, South Canterbury, Otago and North Otago farmers led a ‘gumboot revolution’, resulting in the formation of Ravensdown which mounted a successful takeover of Kempthorne Prosser.

In 1984, under Rogernomics, removal of price controls and government subsidies on fertiliser was initiated, resulting in further alliances between fertiliser companies and support operations. The Fertiliser Association’s research centre was closed, with focus moving to commissioning rather than conducting research.

Industry acquisitions and mergers continued through the 1980s and 1990s, culminating in the Bay of Plenty Fertiliser company evolving into a second large co-operative – becoming Ballance Agri-Nutrients in 2001.

Peter Macdougall chaired the board of Southland Co-operative Phosphate Company and represented the South Island on the board of the BoP Fertiliser Company after the two companies merged. He remembers the 80s and 90s as “challenging times” but says decisions made by the sector then shaped the industry we have today.

“There was an awful lot of politics behind the scenes. But what emerged was a very efficient industry. New Zealand fertiliser companies looked at what was happening in Europe and said, ‘We have to be ahead of the game’. An example was seeing The Code of Practice for Fertiliser Use developed by the Fertiliser Association, around targeted, efficient use of fertiliser.

“The sector also built very strong relationships with overseas suppliers of phosphate rock, sulphur and potash that still serve it very well today. We ended up with two farmer-owned co-operatives of similar size, both doing a really good job for the New Zealand farmers who own them. If we had just one major fertiliser company, I don’t think we’d have the good choice of products we have today.”

Another impact of the removal of subsidies was a spike in fertiliser prices, resulting in many farmers reducing phosphate applications.

“By all accounts, those were fraught times,” says Fertiliser Association executive manager Greg Sneath “The impact on farms that withdrew application was significant, reducing livestock capacity. Once they began using fertiliser again, it took several years to build up production.

“People are mindful of not doing that again. During the 2007-2008 global monetary crisis it was again very difficult but farmers focused on keeping their fertiliser budgets and maintaining soil fertility as much as they could. We are seeing some of this challenge today with high prices in response to geo-political pressures. Today farmers and growers face high costs for fertilisers, but also increased regulatory controls to address environmental risk.”

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