Fertiliser is a solid or liquid material that is applied to a soil to make it more fertile, and therefore boost plant growth.
Promoting faster growth
Most soils contain some nutrients and can support plant growth even if it is very slow. But when faster growth is important, as in farm crops and pasture, then so long as soil moisture levels are satisfactory, fertiliser will be needed.
Early farmers added compost, animal manure, or dried and ground animal blood and bone to the soil. Other sources were nutrient-rich rocks, which were finely ground and applied directly as a fertiliser, or mixed with chemicals to make a form more easily used by plants.
Natural fertilisers consist of decomposing organic matter (plant and animal tissue). This contains carbon, hydrogen and oxygen, and a number of other mineral elements or nutrients. The major elements are nitrogen, phosphorus, potassium, sulfur, calcium, magnesium and sodium. Trace elements (needed in only very small amounts) are boron, iron, manganese, copper, zinc, molybdenum, chlorine, cobalt, iodine and selenium.
Some elements may not be needed for plant growth, but may be important for the nutrition of grazing animals.
Industry history: 1860s onwards
The fertiliser industry began in New Zealand in 1867 when the first importation of guano (accumulated seabird droppings) arrived in the country for use on farms. This was at a time when nutrients from the ash of forests burnt during land clearance had run out, and crops and pastures started to fail.
A lack of phosphorus was soon identified as the main deficiency on most soils. In 1880 the first shipment of superphosphate, a phosphorus-rich fertiliser, was imported by W. E. Ivey (director of Lincoln School of Agriculture, now Lincoln University).
Local production of superphosphate followed in 1882, at the Kempthorne, Prosser & Company plant near Dunedin. In 1884 the New Zealand Manure and Chemical Company began production at Mt Maunganui in the Bay of Plenty.
Downwind of the docks
From the 1870s, sulfur was mined on Whakaari (White Island) in the Bay of Plenty. It was processed at a factory near the Mt Maunganui docks, and the smell (likened to rotten eggs) was such that the place was named Sulphur Point. It is near the current site of the Ballance Agri-Nutrients superphosphate plant.
From humble beginnings of less than 50,000 tonnes in 1885, manufacture and use of superphosphate grew to around 2 million tonnes in the mid-1960s, and reached a peak of 3.1 million tonnes in 2001–2. There was a brief setback when government subsidies on fertiliser were removed in 1984–85. Use dropped from 2.2 million tonnes that year to 1.2 million tonnes in 1985–86.
The industry expanded to five major companies with manufacturing works in such diverse places as Whāngārei, Morrinsville, New Plymouth, Mt Maunganui, Napier, Nelson, Christchurch, Timaru, Dunedin and Invercargill.
Production efficiencies, takeovers and cyclical downturns in the rural economy have transformed the industry. In 2007 it consisted of:
- two 100% farmer-owned manufacturing and importing cooperatives – Ballance Agri-Nutrients (making superphosphate at Whāngārei, Mt Maunganui and Invercargill), and Ravensdown Fertiliser (operating in Napier, Christchurch and Dunedin). They have about 94% of market share.
- a smaller importer, Summit Quinphos (with headquarters in Auckland and nationwide distribution points), with about 6% of market share.