my chemical romance black parade
Organic fertilizers
A compost binNaturally occurring organic fertilizers include manure, slurry, worm castings, peat, seaweed, sewage ,
and guano. Green manure crops are also grown to add nutrients to the soil. Naturally occurring minerals such as mine
rock phosphate, sulfate of potash and limestone are also considered Organic Fertilizers.
Manufactured organic fertilizers include compost, bloodmeal, bone meal and seaweed extracts. Other examples are
natural enzyme digested proteins, fish meal, and feather meal.
The decomposing crop residue from prior years is another source of fertility. Though not strictly considered
"fertilizer", the distinction seems more a matter of words than reality.
Some ambiguity in the usage of the term 'organic' exists because some of synthetic fertilizers, such as urea and
urea formaldehyde, are fully organic in the sense of organic chemistry. In fact, it would be difficult to chemically
distinguish between urea of biological origin and that produced synthetically. On the other hand, some fertilizer
materials commonly approved for organic agriculture, such as powdered limestone, mined "rock phosphate" and Chilean
saltpeter, are inorganic in the use of the term by chemistry.
Although the density of nutrients in organic material is comparatively modest, they have some advantages. For one
thing organic growers typically produce some or all of their fertilizer on-site, thus lowering operating costs
considerably. Then there is the matter of how effective they are at promoting plant growth, chemical soil test
results aside. The answers are encouraging. Since the majority of nitrogen supplying organic fertilizers contain
insoluble nitrogen and are slow release fertilizers their effectiveness can be greater than conventional nitrogen
fertilzers.
Implicit in modern theories of organic agriculture is the idea that the pendulum has swung the other way to some
extent in thinking about plant nutrition. While admitting the obvious success of Leibig's theory, they stress that
there are serious limitations to the current methods of implementing it via chemical fertilization. They
re-emphasize the role of humus and other organic components of soil, which are believed to play several important
roles:
Mobilizing existing soil nutrients, so that good growth is achieved with lower nutrient densities while wasting
less
Releasing nutrients at a slower, more consistent rate, helping to avoid a boom-and-bust pattern
Helping to retain soil moisture, reducing the stress due to temporary moisture stress
Organics also have the advantage of avoiding certain long-term problems associated with the regular heavy use of
artificial fertilizers:
the possibility of "burning" plants with the concentrated chemicals (i.e. an over supply of some nutrients)
the progressive decrease of real or perceived "soil health", apparent in loss of structure, reduced ability to
absorb precipitation, lightening of soil color, etc.
the necessity of reapplying artificial fertilizers regularly (and perhaps in increasing quantities) to maintain
fertility
the cost (substantial and rising in recent years) and resulting lack of independence
Organic fertilizers also have their disadvantages:
As acknowledged above, they are typically a dilute source of nutrients compared to inorganic fertilizers, and
where significant amounts of nutrients are required for profitable yields, very large amounts of organic fertilizers
must be applied. This results in prohibitive transportation and application costs, especially where the agriculture
is practiced a long distance from the source of the organic fertilizer.
The composition of organic fertilizers tends to be highly variable, so that accurate application of nutrients to
match plant production is difficult. Hence, large-scale agriculture tends to rely on inorganic fertilizers while
organic fertilizers are cost-effective on small-scale horticultural or domestic gardens.
Improperly-processed organic fertilizers may contain pathogens harmful to humans or plants. Organic fertilizers
are derived from natural sources, which may include animal feces or plant/animal matter contaminated with pathogens.
However, proper composting of raw materials used in organic fertilizers will kill pathogens.
In practice a compromise between the use of artificial and organic fertilizers is common, typically by using
inorganic fertilizers supplemented with the application of organics that are readily available such as the return of
crop residues or the application of manure.
There is an important difference between fertilizers that are 'organic' in origin and those fertilizers approved for
use by organic certification bodies for use in organic farming and organic gardening. Some of their approved
fertilizers may be inorganic, naturally occurring chemical compounds, e.g. minerals.
Fertilizers (also spelled fertilisers) are compounds given to plants to promote growth; they are usually applied
either via the soil, for uptake by plant roots, or by foliar feeding, for uptake through leaves. Fertilizers can be
organic (composed of organic matter), or inorganic (made of simple, inorganic chemicals or minerals). They can be
naturally occurring compounds such as peat or mineral deposits, or manufactured through natural processes (such as
composting) or chemical processes (such as the Haber process).
Fertilizers typically provide, in varying proportions, the three major plant nutrients (nitrogen, phosphorus, and
potassium), the secondary plant nutrients (calcium, sulfur, magnesium), and sometimes trace elements (or
micronutrients) with a role in plant nutrition: boron, chlorine, manganese, iron, zinc, copper, and
molybdenum.
In the past, both organic and inorganic fertilizers were called "manures" derived from the French expression for
manual tillage, but this term is now mostly 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 biologically useful form). Most plants thus require nitrogen compounds to
be present in the soil in which they grow.
History
While manure, cinder and ironmaking slag have been used to improve crops for centuries, the fertilizers were
arguably one of the great innovations of the Agricultural Revolution of the 19th Century.
Key people
In the 1730s Viscount Charles Townshend 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.
Chemist Justus von Liebig 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
the importance of inorganic minerals. Primarily his work succeeded in setting out questions for agricultural science
to address over the next 50 years. In England he attempted to implement his theories commercially through a
fertilizer created by treating phosphate of lime in bone meal with sulphuric acid. 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.
At that time in England Sir John Bennet Lawes 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.
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 that they founded still investigates the
impact of inorganic and organic fertilizers on crop yields.
In France, Jean Baptiste Boussingault pointed out that the amount of nitrogen in various kinds of fertilizers
is important.
Metallurgists Percy Gilchrist and Sidney Gilchrist Thomas invented the Thomas-Gilchrist
converter, which enabled the use of high phosphorus acidic Continental ores on steelmaking. The dolomite lime
lining of the converter turned in time into calcium phosphate, which could be used as fertilizer known as
Thomas-phosphate.
In the early decades of the 20th Century the Nobel prize-winning chemists Carl Bosch of IG Farben and Fritz
Haber developed the process that enabled nitrogen to be cheaply synthesised into ammonia, for subsequent oxidisation
into nitrates and nitrites.
In 1927 Erling Johnson developed an industrial method for producing nitrophosphate, also known as the Odda
process after his Odda Smelteverk of Norway. The process involved acidifying phosphate rock (from Nauru and Banaba
Islands in the South Pacific) with nitric acid to produce phosphoric acid and calcium nitrate which, once
neutralized, could be used as a nitrogen fertilizer.
Industry
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. 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. By 1870 there were about 80 factories
making superphosphate. After World War I these businesses came under financial pressure through new competition from
guano, primarily found on the Pacific islands, as their extraction and distribution had become economically
attractive.
The interwar period 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. 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. Together they were producing 80,000
tonnes of superphosphate per annum by 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, and two years later the large Anglo-Continental
Guano Works, founded in 1917.
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 and AstraZeneca companies.
Inorganic fertilizers (mineral fertilizer)
Naturally occurring inorganic fertilizers include Chilean sodium nitrate, mined "rock phosphate," and limestone (a
calcium source).
Macronutrients and micronutrients
Fertilizers can be divided into macronutrients or 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. 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). There
are many micronutrients, required in concentrations ranging from 5 to 100 parts per million (ppm) by mass. Plant
micronutrients include iron (Fe), manganese (Mn), boron (B), copper (Cu), molybdenum (Mo), nickel (Ni), chlorine
(Cl), and zinc (Zn).
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), which are known as N-P-K
fertilizers or compound fertilizers when elements are mixed intentionally. They are named or labeled according to
the content of these three elements, which are macronutrients. The mass fraction (percent) nitrogen is reported
directly. However, phosphorus is reported as phosphorus pentoxide (P2O5), the anhydride of phosphoric acid, and
potassium is reported as potash or potassium oxide (K2O), which is the anhydride of potassium hydroxide. Fertilizer
composition is expressed in this fashion for historical reasons in the way it was analyzed (conversion to ash for P
and K); this practice dates back to Justus von Liebig (see more below). Consequently, an 18-51-20 fertilizer would
have 18% nitrogen as N, 51% phosphorus as P2O5, and 20% potassium as K2O, The other 11% is known as ballast 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 often described as
nitrogen fertilizers.
In general, the mass fraction (percentage) of elemental phosphorus, [P] = 0.436 x [P2O5]
and the mass fraction (percentage) of elemental potassium, [K] = 0.83 x [K2O]
(These conversion factors are mandatory under the UK fertilizer-labelling regulations if elemental values are
declared in addition to the N-P-K declaration.)
An 18−51−20 fertilizer therefore contains, by weight, 18% elemental nitrogen (N), 22% elemental phosphorus (P) and
16% elemental potassium (K).
Agricultural versus horticultural
In general, agricultural fertilizers contain only one or two macronutrients. Agricultural fertilizers are intended
to be applied infrequently and normally prior to or along side seeding. Examples of agricultural fertilizers are
granular triple superphosphate, potassium chloride, urea, and anhydrous ammonia. The commodity nature of fertilizer,
combined with the high cost of shipping, leads to use of locally available materials or those from the
closest/cheapest source, which may vary with factors affecting transportation by rail, ship, or truck. In other
words, a particular nitrogen source may be very popular in one part of the country while another is very popular in
another geographic region only due to factors unrelated to agronomic concerns.
Horticultural or specialty fertilizers, on the other hand, are formulated from many of the same compounds and some
others to produce well-balanced fertilizers that also contain micronutrients. Some materials, such as ammonium
nitrate, are used minimally in large scale production farming. The 18-51-20 example above is a horticultural
fertilizer formulated with high phosphorus to promote bloom development in ornamental flowers. Horticultural
fertilizers may be water-soluble (instant release) or relatively insoluble (controlled release). Controlled release
fertilizers are also referred to as sustained release or timed release. Many controlled release fertilizers are
intended to be applied approximately every 3-6 months, depending on watering, growth rates, and other conditions,
whereas water-soluble fertilizers must be applied at least every 1-2 weeks and can be applied as often as every
watering if sufficiently dilute. Unlike agricultural fertilizers, horticultural fertilizers are marketed directly to
consumers and become part of retail product distribution lines.
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