Fertilizer

Fertilizers are chemical compounds applied to promote plant and fruit growth. Fertilizers are usually applied either through the soil (for uptake by plant roots) or, by foliar feeding (for uptake through leaves).

Fertilizers can be placed into the categories of organic fertilizers (composed of plant or animal matter), or inorganic fertilizers (made of simple, non-carbonaceous chemicals or minerals).

'Organic' fertilizers are composed of 'naturally' occurring compounds such as peat manufactured through natural processes (such as composting) or naturally occurring mineral deposits; or in the case of 'inorganic' fertilizers, manufactured through chemical processes (such as the Haber process) or from naturally occurring deposits that have been chemically altered (e.g. concentrated triple superphosphate^[1]).

Properly applied, organic fertilizers can improve the health, and productivity of soil and plants as they provide different essential nutrients intended to encourage plant growth. Organic nutrients increase the abundance of soil organisms such as mycorrhiza, which aid plants in absorbing nutrients . Chemical fertilizers have long-term adverse impact on the organisms living in soil^{[citation needed]} and a detrimental long term effect on soil productivity of the soil^{[citation needed]}.

Contents of fertilizer

Fertilizers typically provide, in varying proportions, the three major plant nutrients: nitrogen, phosphorus, potassium known shorthand as N-P-K); the secondary plant nutrients (calcium, sulfur, magnesium) and sometimes trace elements (or micronutrients) with a role in plant or animal nutrition: boron, chlorine, manganese, iron, zinc, copper, molybdenum and (in some countries) selenium.

Organic vs. Non-organic (MANURE)

Both organic and inorganic fertilizers were called "manure" derived from the French expression for manual (of or belonging to the hand^[2]) tillage, however, this term is currently restricted to organic manure. Though nitrogen is plentiful in the Earth's atmosphere, relatively few plants engage in nitrogen fixation (conversion of atmospheric nitrogen to a plant-accessible form).

It is believed by some that 'organic' agricultural methods are more environmentally friendly and better maintain soil organic matter (SOM) levels. There are some scientific studies that support this position.^[3]

History of fertilizers

While manure, cinder and ironmaking slag have been used to improve crops for centuries, the use of fertilizers is arguably one of the great innovations of the Agricultural Revolution of the 19th Century.

Key figures(Europe)

In the 1730s, Viscount Charles Townshend (1674–1738) first studied the improving effects of the four crop rotation system that he had observed in use in Flanders. For this he gained the nickname of Turnip Townshend.

Justus von Liebig

Chemist Justus von Liebig (1803–1883) contributed greatly to the advancement in the understanding of plant nutrition. His influential works first denounced the vitalist theory of humus, arguing first the importance of ammonia, and later promoting the importance of inorganic minerals to plant nutrition. Primarily Liebig's work succeeded in exposition of questions for agricultural science to address over the next 50 years^{[citation needed]}.

In England, he attempted to implement his theories commercially through a fertilizer created by treating phosphate of lime in bone meal with sulfuric acid^{[citation needed]}. Although it was much less expensive than the guano that was used at the time, it failed because it was not able to be properly absorbed by crops^{[citation needed]}.

Sir John Bennet Lawes

At that time in England, Sir John Bennet Lawes (1814–1900) was experimenting with crops and manures at his farm at Harpenden and was able to produce a practical superphosphate in 1842 from the phosphates in rock and coprolites^{[citation needed]}. Encouraged, he employed Sir Joseph Henry Gilbert, who had studied under Liebig at the University of Giessen, as director of research. To this day, the Rothamsted research station the pair founded still investigates the impact of inorganic and organic fertilizers on crop yields^{[citation needed]}.

Jean Baptiste Boussingault

In France, Jean Baptiste Boussingault (1802–1887) pointed out that the amount of nitrogen in various kinds of fertilizers is important.

Metallurgists Percy Gilchrist (1851–1935) and Sidney Gilchrist Thomas (1850–1885) invented the Thomas-Gilchrist converter, which enabled the use of high phosphorus acidic Continental ores for steelmaking. The dolomite lime lining of the converter turned in time into calcium phosphate, which could be used as fertilizer known as Thomas-phosphate.

Bosch Farben and Haber

In the early decades of the 20th Century, the Nobel prize-winning chemists Carl Bosch of IG Farben and Fritz Haber developed the process^[4] that enabled nitrogen to be cheaply synthesised into ammonia, for subsequent oxidation into nitrates and nitrites.

Erling Johnson

In 1927 Erling Johnson developed an industrial method for producing nitrophosphate, also known as the Odda process after his Odda Smelteverk of Norway^{[citation needed]}. The process involved acidifying phosphate rock (from Nauru and Banaba Islands in the southern Pacific Ocean) with nitric acid to produce phosphoric acid and calcium nitrate which, once neutralized, could be used as a nitrogen fertilizer[^[5]].

Industry

British

The Englishmen James Fison, Edward Packard, Thomas Hadfield and the Prentice brothers each founded companies in the early 19th century to create fertilizers from bonemeal^{[citation needed]}.

The developing sciences of chemistry and Paleontology, combined with the discovery of coprolites in commercial quantities in East Anglia, led Fisons and Packard to develop sulfuric acid and fertilizer plants at Bramford, and Snape, Suffolk in the 1850s to create superphosphates, which were shipped around the world from the port at Ipswich^{[citation needed]}. By 1871 there were about 80 factories making superphosphateTemplate:Where?.^[6]

After World War I these businesses came under competitive pressure from naturally-produced guano, primarily found on the Pacific islands, as their extraction and distribution had become economically attractive^{[citation needed]}.

The interwar period^[7] saw innovative competition from Imperial Chemical Industries who developed synthetic ammonium sulfate in 1923, Nitro-chalk in 1927, and a more concentrated and economical fertilizer called CCF based on ammonium phosphate in 1931. Competition was limited as ICI ensured it controlled most of the world's ammonium sulfate supplies.

North America and other European Countries

Other European and North American fertilizer companies developed their market share, forcing the English pioneer companies to merge, becoming Fisons, Packard, and Prentice Ltd. in 1929^{[citation needed]}. Together they produced 85,000 tons of superphosphate/year in 1934 from their new factory and deep-water docks in Ipswich. By World War II they had acquired about 40 companies, including Hadfields in 1935^{[citation needed]}, and two years later the large Anglo-Continental Guano Works, founded in 1917^{[citation needed]}.

The post-war environment was characterized by much higher production levels as a result of the "Green Revolution" and new types of seed with increased nitrogen-absorbing potential, notably the high-response varieties of maize, wheat, and rice. This has accompanied the development of strong national competition, accusations of cartels and supply monopolies, and ultimately another wave of mergers and acquisitions. The original names no longer exist other than as holding companies or brand names: Fisons and ICI agrochemicals are part of today's Yara International^[8] and AstraZeneca companies.

Major players in this market now include the Russian Uralkali fertilizer company Uralkali (listed on the London Stock Exchange), whose majority owner is Dmitry Rybolovlev, ranked by Forbes as 60th in the list of wealthiest people in 2008.

Inorganic fertilizers (mineral fertilizer)

Naturally occurring inorganic fertilizers include Chilean sodium nitrate, mined rock phosphate, and limestone (a calcium source).

Macronutrients and micronutrients fertilizers

Fertilizers can be divided into macronutrients and micronutrients based on their concentrations in plant dry matter. There are six macronutrients: nitrogen, phosphorus, and potassium, often termed "primary macronutrients" because their availability is usually managed with NPK fertilizers, and the "secondary macronutrients" — calcium, magnesium, and sulfur — which are required in roughly similar quantities but whose availability is often managed as part of liming and manuring practices rather than fertilizers^{[citation needed]}.

The macronutrients are consumed in larger quantities and normally present as a whole number or tenths of percentages in plant tissues (on a dry matter weight basis)^{[citation needed]}. There are many micronutrients, required in concentrations ranging from 5 to 100 parts per million (ppm) by mass^{[citation needed]}. Plant micronutrients include iron (Fe), manganese (Mn), boron (B), copper (Cu), molybdenum (Mo), nickel (Ni), chlorine (Cl), and zinc (Zn).

Tennessee Valley Authority: "Results of Fertilizer" demonstration 1942.

Further information: Plant nutrition

Macronutrient fertilizers

Synthesized materials are also called artificial, and may be described as straight, where the product predominantly contains the three primary ingredients of nitrogen (N), phosphorus (P), and potassium (K), (known as N-P-K fertilizers or compound fertilizers when elements are mixed intentionally).

Reporting of N-P-K

Such fertilizers are named or labeled according to the content of these three elements. The percent (mass fraction) of nitrogen is reported directly. However, phosphorus is reported as phosphorus pentoxide (P₂O₅), the anhydride of phosphoric acid, and potassium is reported as potassium oxide (K₂O), which is the anhydride of potassium hydroxide mass fraction.

Fertilizer composition is expressed in this fashion for historical reasons in the way it was analyzed (conversion to ash for P and K) mass fraction; this practice dates back to Justus von Liebig.

The remaining 11% is known as ballast^{[citation needed]} and may or may not be valuable to the plants, depending on what is used as ballast. Although analyses are no longer carried out by ashing first, the naming convention remains. If nitrogen is the main element, they are the fertilizer is often described as nitrogen fertilizers.