A Study Of Fertilizers In Chemistry Environmental Sciences Essay

Fertilizers are soil amendments applied to advance works growing ; the chief foods present in fertiliser are nitrogen, P, and K ( the ‘macronutrients ‘ ) and other foods ( ‘micronutrients ‘ ) are added in smaller sums. Fertilizers are normally straight applied to dirty, and besides sprayed on foliages ( ‘foliar feeding ‘ ) .

Fertilizers are approximately broken up between organic and inorganic fertiliser, with the chief difference between the two being sourcing, and non needfully differences in alimentary content

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Organic fertilisers and some mined inorganic fertilisers have been used for many centuries, whereas chemically-synthesized inorganic fertilisers were merely widely developed during the industrial revolution. Increased apprehension and usage of fertilisers were of import parts of the pre-industrial British Agricultural Revolution and the industrial green revolution of the twentieth century.

Plant nutrition and the soil-plant system. The key-role of fertilisers and their wise usage in harvest farming is good understood, when 1 is familiar with the general facts about works nutrition. It is now known that at least 16 plant-food elements are necessary for the growing of green workss. These plant-nutrients are called indispensable elements. In the absence of any one of these indispensable elements, a works fails to finish its life rhythm, though the upset caused can, nevertheless, be corrected by the add-on of that component. These 16 elements are: Carbon ( C ) , H ( H ) , O ( O ) , nitrogen ( N ) , phosphoric ( P ) , sulphur ( S ) , K ( K ) , Ca ( Ca ) , Mg ( Mg ) , Fe ( Fe ) , manganese ( Mn ) , zinc ( Zn ) , Cu ( Cu ) , molybdenum ( Mb ) , B ( B ) and Cl ( Cl ) . Green workss obtain C from carbon-di-oxide from the air ; O and H from H2O, whereas the staying elements are taken from the dirt. Based on their comparative sums, usually found in workss, the works foods are termed as macronutrients, if big sums are involved, and micronutrients, if lone hints are involved. The micronutrients indispensable for works growing are Fe, manganese, Cu, Zn, B, Mo, and Cl. All other indispensable elements listed above are macronutrients.

As mentioned above, most of the works foods, besides C, H and O, originate from the dirt. The dirt system is viewed by the dirt scientists as a triple-phased system of solid, liquid and a gaseous stages. These stages are physically dissociable. The works foods are based in the solid stage and their usual tract to the works system is through the environing liquid stage, the dirt solution and so to the works root and works cells. This tract may be written in the signifier of an equation as: M ( Solid ) – & gt ; M ( Solution ) – & gt ; N ( Plant root ) – & gt ; ( Plant top ) where ‘M ‘ is the works alimentary component in continual motion through the soil-plant system. The operation of the above system is dependent on the solar energy through photosynthesis and metabolic activities. This is nevertheless, an oversimplified statement for deriving a physical construct of the natural phenomenon, but one should bear in head that there are many physico and physico-chemical procedures act uponing the reactions in the tract. The existent transportation in nature takes topographic point through the charged ions, the usual signifier in which plant-food elements occur in solutions ( liquid stage of the system ) . Plant roots take up plant-food elements elements from the dirt in these ionic signifiers. The positively charged ions are called ‘cations ‘ which include K ( K+ ) , Calcium ( Ca++ ) , Mg ( Mg++ ) , Fe ( Fe+++ ) , zinc ( Zn++ ) , and so on. The negatively charged ions are called anions and the of import works foods taken in this signifier include N ( NO-3 ) , phosphoric ( H2PO-4 ) , sulphur ( SO-4 ) , Chlorine ( Cl ) , etc.

The procedure of alimentary uptake by workss refers to the transportation of the alimentary ions across the dirt root interfaces into the works cell. The energy for the procedure is provided by the metabolic activity of the works and in its absence no soaking up of foods take topographic point. Alimentary soaking up involves the phenomenon of ion exchange. The root surface, like dirt, carries a negative charge and exhibits cation-exchange belongings. The most efficient soaking up of the works foods takes topographic point on the younger tissues of the roots, capable of growing and elongation.

In this regard, root-systems are known to change from harvest to harvest. Hence their eating power differs. The extent and the spread of the effectual root-system determine the dirt volume trapped in the feeding-zone of the harvest works. This is so an of import information in a given soil-plant system which helps us to take fertilisers and fertilizer-use patterns. The soaking up mechanisms of the harvest workss are reasonably known now. There are three mechanisms in operation in the soil-water-plant systems. They are: ( I ) the contact exchange and root interception, ( two ) the mass flow or convection, and ( three ) diffusion. In the instance of contact exchange and root interception, the exchangeable foods ions from the clay-humus colloids migrates straight to the root surface through contact exchange when works roots come into contact with the dirt solids. Alimentary soaking up through this mechanism is, nevertheless, undistinguished as most of the works foods occur in the dirt solutions. Scientists have found that works roots really grow to come into contact with merely 3 per centum of the dirt volume exploited by the root mass, and the alimentary consumption through root interception is even still less. The 2nd mechanism is aggregate flow or convection, which is considered to be the of import manner of alimentary consumption. This mechanism relates to alimentary mobility with the motion of dirt H2O towards the root surface where soaking up through the roots takes topographic point along with H2O. Some are called nomadic foods. Others which move merely a few millimeters are called immobile foods. Alimentary ions such as nitrate, chloride and sulfate, are non absorbed by the dirt colloids and are chiefly in solution. Such alimentary ions are absorbed by the roots along with dirt H2O. The alimentary consumption through this mechanism is straight related to the sum of H2O used by the workss ( transpiration ) . It may, nevertheless, be mentioned that the exchangeable alimentary cations and anions other than nitrate, chloride and sulfate, which are absorbed on dirt colloids are in equilibrium with the dirt solution do non travel freely with H2O when it is absorbed by the works roots. These considerations, hence, conveying out that there are big differences in the conveyance and root soaking up of assorted ion through the mechanism of mass flow. Mass flow is, nevertheless, responsible for providing the root with much of the works needs for N, Ca and Mg, when nowadays in high concentrations in the dirt solution, but does non make so in the instance of phosphoric or K. The alimentary consumption through mass flow is mostly dependent on the wet position of the dirt and is extremely influenced by the dirt physical belongingss commanding the motion of dirt H2O.

The 3rd mechanism is diffusion. It is an of import phenomenon by which ions in the dirt medium move from a point of higher concentration to a point of lower concentration. in other words, the mechanism enables the motion of the foods ion without the motion of H2O. The sum of nutrient-ion motion in this instance is dependent on the ion-concentration gradient and conveyance tracts which, in bend, are extremely influenced by the content of dirt H2O. This mechanism is prevailing in providing most of the phosphoric and K to works roots. It is of import to observe that the rhizophere volume of dirt in the immediate vicinity of the effectual works root receives works foods continuously to be delivered to the roots by diffusion. However, when the alimentary concentration builds up far surplus of the works in the rearward way. These are some of the pick of fertilisers and fertiliser patterns for rehearsing scientific agribusiness.

The relationship in the soil-plant system stated in the simple equation spring in the earlier paragraph reflects the extremely dynamic nature of the dirt solution. One knows that the roots of the turning workss continuously take alimentary ions from the dirt solutions. At the same clip, the dislocation of the dirt minerals and the generating of more exchangeable cations, the biological activity and the add-ons made to the anions, e.g. nitrates, continuously change the composing of the dirt solution. At a given point of clip, hence, the available works foods in the dirt solution may run from a bantam sum to larger measures. Under favorable conditions, harvest workss, in general, require larger sums of works foods than the quality found in dirt solution at any given clip. Hence, the state of affairs of foods supply to workss becomes a confining factor, specially, at the critical phases of works growing and low harvest outputs result in acknowledgment, hence, fertilisers application and the usage of suited fertilisers are recommended for higher harvest outputs in productive agriculture. The cognition of the specific function of each indispensable component in the growing of harvest workss and their sums required for efficient harvest production is considered necessary in following scientific fertilisers use.

Inorganic fertiliser ( man-made fertiliser )

Fertilizers are loosely divided into organic fertilisers ( composed of enriched organic matter-plant or animate being ) , or inorganic fertilisers ( composed of man-made chemicals and/or minerals ) .

Inorganic fertiliser is frequently synthesized utilizing the Haber-Bosch procedure, which produces ammonium hydroxide as the terminal merchandise. This ammonium hydroxide is used as a feedstock for other N fertilisers, such as anhydrous ammonium nitrate and urea. These concentrated merchandises may be diluted with H2O to organize a concentrated liquid fertiliser ( e.g. UAN ) . Ammonia can be combined with stone phosphate and K fertiliser in the Odda Process to bring forth compound fertiliser.

The usage of man-made N fertilisers has increased steadily in the last 50 old ages, lifting about 20-fold to the current rate of 1 billion dozenss of N per twelvemonth. The usage of phosphate fertilisers has besides increased from 9 million dozenss per twelvemonth in 1960 to 40 million dozenss per twelvemonth in 2000. A maize harvest giving 6-9 dozenss of grain per hectare requires 30-50A kilogram of phosphate fertiliser to be applied ; soybean requires 20-25A kilograms per hectare. Yara International is the universe ‘s largest manufacturer of N based fertilisers.

Top users of nitrogen-based fertiliser


Entire N usage

( Mt dad )

Amt. used

( feed/pasture )


































Man-made fertilisers are normally used to handle Fieldss used for turning corn, followed by barley, sorghum, rapeseed, soy and helianthus. One survey has shown that application of nitrogen fertiliser on off-season screen harvests can increase the biomass ( and subsequent green manure value ) of these harvests, while holding a good consequence on dirt N degrees for the chief harvest planted during the summer season.

Problems of inorganic fertiliser

Trace mineral depletion

Many inorganic fertilisers do non replace trace mineral elements in the dirt which become bit by bit depleted by harvests. This depletion has been linked to surveies which have shown a pronounced autumn ( up to 75 % ) in the measures of such minerals present in fruit and veggies.

However, a recent reappraisal of 55 scientific surveies concluded “ there is no grounds of a difference in alimentary quality between organically and conventionally produced groceries ” . Conversely, a major long-run survey funded by the European Union found that organically-produced milk and green goods were significantly higher in antioxidants ( such as carotenoids and alpha-linoleic acids ) than their conventionally grown opposite numbers.

In Western Australia lacks of Zn, Cu, manganese, Fe and Mo were identified as restricting the growing of broad-acre harvests and grazing lands in the 1940s and 1950s. Dirts in Western Australia are really old, extremely weathered and deficient in many of the major foods and hint elements. Since this clip these hint elements are routinely added to inorganic fertilisers used in agribusiness in this province.

Over fertilisation

Fertilizer burn

Over-fertilization of a critical food can be every bit damaging as under fertilisation. “ Fertilizer burn ” can happen when excessively much fertiliser is applied, ensuing in a drying out of the roots and harm or even decease of the works.

High energy ingestion

The production of man-made ammonium hydroxide presently consumes about 5 % of planetary natural gas ingestion, which is slightly under 2 % of universe energy production.

Natural gas is overpoweringly used for the production of ammonium hydroxide, but other energy beginnings, together with a H beginning, can be used for the production of nitrogen compounds suited for fertilisers. The cost of natural gas makes up approximately 90 % of the cost of bring forthing ammonium hydroxide. The addition in monetary value of natural gases over the past decennary, along with other factors such as increasing demand, has contributed to an addition in fertilizer monetary value.

Long-run Sustainability

Inorganic fertilisers are now produced in ways which can non be continued indefinitely. Potassium and P come from mines ( or saline lakes such as the Dead Sea ) and such resources are limited. Atmospheric ( unfixed ) N is efficaciously limitless ( organizing over 70 % of the atmospheric gases ) , but this is non in a signifier utile to workss. To do N accessible to workss requires nitrogen arrested development ( transition of atmospheric N to a plant-accessible signifier ) .

Artificial N fertilisers are typically synthesized utilizing fossil fuels such as natural gas and coal, which are limited resources. In stead of change overing natural gas to syngas for usage in the Haber procedure, it is besides possible to change over renewable biomass to syngas ( or wood gas ) to provide the necessary energy for the procedure, though the sum of land and resources ( ironically frequently including fertiliser ) necessary for such a undertaking may be prohibitory ( see Energy preservation in the United States ) .

Organic fertiliser

Compost bin for small-scale production of organic fertiliser

A big commercial compost operation

Organic fertilisers include naturally-occurring organic stuffs, ( e.g. manure, worm castings, compost, seaweed ) , or of course occurring mineral sedimentations ( e.g. potassium nitrate, guano ) .

Benefits of organic fertiliser

In add-on to increasing output and fertilizing workss straight, organic fertilisers can better the biodiversity ( soil life ) and long-run productiveness of dirt, and may turn out a big depositary for extra C dioxide.

Organic foods increase the copiousness of dirt beings by supplying organic affair and micronutrients for beings such as fungous mycorrhiza, ( which assistance workss in absorbing foods ) , and can drastically cut down external inputs of pesticides, energy and fertiliser, at the cost of reduced output.

Comparison with inorganic fertiliser

Organic fertiliser food content, solubility, and alimentary release rates are typically all lower than inorganic fertilisers. One survey found that over a 140-day period, after 7 leachings:

Organic fertilisers had released between 25 % and 60 % of their N content

Controlled release fertilisers ( CRFs ) had a comparatively changeless rate of release

Soluble fertiliser released most of its N content at the first leaching

In general, the foods in organic fertiliser are both more dilute and besides much less readily available to workss. Harmonizing to UC IPM, all organic fertilisers are classified as ‘slow-release ‘ fertilisers, and hence can non do nitrogen burn.

Organic fertilisers from composts and other beginnings can be rather variable from one batch to the following { hypertext transfer protocol: //www.msuorganicfarm.com/Compost.pdf } , without batch proving sums of applied food can non be exactly known. Nevertheless they are at least every bit effectual as chemical fertilisers over longer periods of usage.

Organic fertiliser beginnings


Decomposing carnal manure, an organic fertiliser beginning

Animal-sourced Urea, are suited for application organic agribusiness, while pure man-made signifiers of carbamide are non. The common yarn that can be seen through these illustrations is that organic agribusiness efforts to specify itself through minimum processing ( in contrast to the semisynthetic Haber procedure ) , every bit good as being naturally-occurring or via natural biological procedures such as composting.

Sewage sludge usage in organic agricultural operations in the U.S. has been highly limited and rare due to USDA prohibition of the pattern ( due to toxic metal accretion, among other factors ) . The USDA now requires 3rd-party enfranchisement of high-nitrogen liquid organic fertilisers sold in the U.S.


Cover harvests are besides grown to enrich dirt as a green manure through nitrogen arrested development from the ambiance ; every bit good as P ( through food mobilisation ) content of dirts.


Naturally mined powdery limestone, mined stone phosphate and Na nitrate, are inorganic ( in a chemical sense ) , are energetically-intensive to reap, yet are approved for use in organic agribusiness in minimum sums.

Environmental effects of fertiliser usage

Runoff of dirt and fertiliser during a rain storm

An algal bloom doing eutrophication



The nitrogen-rich compound found in fertilizer run-off is the primary cause of a serious depletion of O in many parts of the ocean, particularly in coastal zones ; the ensuing deficiency of dissolved O is greatly cut downing the ability of these countries to prolong pelagic zoology. Visually, H2O may go cloudy and discolored ( green, xanthous, brown, or ruddy ) .

About half of all the lakes in the United States are now eutrophic, while the figure of pelagic dead zones near inhabited coastlines are increasing. As of 2006, the application of nitrogen fertiliser is being progressively controlled in Britain and the United States. If eutrophication can be reversed, it may take decennaries before the accrued nitrates in groundwater can be broken down by natural procedures.

High application rates of inorganic N fertilisers in order to maximise harvest outputs, combined with the high solubility ‘s of these fertilisers leads to increased overflow into surface H2O every bit good as leaching into groundwater. The usage of ammonium nitrate in inorganic fertilisers is peculiarly detrimental, as workss absorb ammonium ions preferentially over nitrate ions, while extra nitrate ions which are non absorbed dissolve ( by rain or irrigation ) into overflow or groundwater.

Blue Baby Syndrome

Nitrate degrees above 10A mg/L ( 10 ppm ) in groundwater can do ‘blue babe syndrome ‘ ( acquired methemoglobinemia ) , taking to hypoxia ( which can take to coma and decease if non treated ) .


Soil acidification

Nitrogen-containing inorganic and organic fertilisers can do dirt acidification when added. This may take to lessenings in alimentary handiness which may be offset by liming.

Persistent organic pollutants

Chief article: Persistent organic pollutants

Toxic persistent organic pollutants ( “ POPs ” ) , such as Dioxins, polychlorinated dibenzo-p-dioxins ( PCDDs ) , and polychlorinated dibenzofurans ( PCDFs ) have been detected in agricultural fertilisers and dirt amendments.

Heavy metal accretion

The concentration of up to 100A mg/kg of Cd in phosphate minerals ( for illustration, minerals from Nauru [ 48 ] and the Christmas islands ) increases the taint of dirt with Cd, for illustration in New Zealand.

Uranium is another illustration of a contamination frequently found in phosphate fertilisers ( at degrees from 7 to 100 pCi/g ) . Finally these heavy metals can construct up to unacceptable degrees and construct up in vegetable green goods. [ 50 ] ( See cadmium poisoning ) Average one-year consumption of U by grownups is estimated to be about 0.5A milligrams ( 500 I?g ) from consumption of nutrient and H2O and 0.6 I?g from take a breathing air [ 52 ] .

Steel industry wastes, recycled into fertilisers for their high degrees of Zn ( indispensable to works growing ) , wastes can include the undermentioned toxic metals: lead, arsenic, Cd, Cr, and nickel. The most common toxic elements in this type of fertiliser are quicksilver, lead, and arsenic. Concerns have been raised refering fish meal quicksilver content by at least one beginning in Spain.

Besides, highly-radioactive Polonium-210 contained in phosphate fertilisers is absorbed by the roots of workss and stored in its tissues ; baccy derived from workss fertilized by stone phosphates contains Polonium-210 which emits alpha radiation estimated to do about 11,700 lung malignant neoplastic disease deceases each twelvemonth worldwide.

For these grounds, it is recommended that food budgeting, through careful observation and monitoring of harvests, take topographic point to extenuate the effects of extra fertilizer application.

Other jobs

Atmospheric effects

Global methane concentrations ( surface and atmospheric ) for 2005 ; note distinguishable plumes

Methane emanations from harvest Fieldss ( notably rice paddy Fieldss ) are increased by the application of ammonium-based fertilisers ; these emanations contribute greatly to planetary clime alteration as methane is a potent nursery gas.

Through the increasing usage of N fertiliser, which is added at a rate of 1 billion dozenss per twelvemonth soon to the already bing sum of reactive N, azotic oxide ( N2O ) has become the 3rd most of import nursery gas after C dioxide and methane. It has a planetary heating possible 296 times larger than an equal mass of C dioxide and it besides contributes to stratospheric ozone depletion.

Storage and application of some N fertilisers in some conditions or dirt conditions can do emanations of the potent nursery gas-nitrous oxide. Ammonia gas ( NH3 ) may be emitted following application of ‘inorganic ‘ fertilisers and/or manures and slurries.

The usage of fertilisers on a planetary graduated table emits important measures of nursery gas into the ambiance. Emissions come about through the usage of:

carnal manures and carbamide, which release methane, azotic oxide, ammonium hydroxide, and C dioxide in changing measures depending on their signifier ( solid or liquid ) and direction ( aggregation, storage, distributing )

fertilisers that use azotic acid or ammonium hydrogen carbonate, the production and application of which consequences in emanations of N oxides, azotic oxide, ammonium hydroxide and C dioxide into the ambiance.

By altering procedures and processs, it is possible to extenuate some, but non all, of these effects on anthropogenetic clime alteration.

Increased pest wellness

Excessive N fertiliser applications can besides take to pest jobs by increasing the birth rate, length of service and overall fittingness of certain agricultural plagues

The chemical compound ammonium nitrate, the nitrate of ammonium hydroxide with the chemical expression NH4NO3, is a white crystalline solid at room temperature and standard force per unit area. It is normally used in agribusiness as a high-nitrogen fertiliser, and it has besides been used as an oxidising agent in explosives, including jury-rigged explosive devices. It is the chief constituent of ANFO, a really popular explosive.

Ammonium nitrate is used in cold battalions, as hydrating the salt is an endothermal procedure.


Public Sector:

National Fertilizers Limited

Fertilizers and Chemicals Travancore Ltd.

Rashtriya Chemicals & A ; Fertilizers Limited

Madras Fertilizers Limited

Concerted Sector:

Indian Farmers Fertilizer Cooperative Ltd.

Krishak Bharati Cooperative Limited

Private Sector:

Gujarat State Fertilizer Company Limited

Coromondel Fertilisers Limited

Shriram fertilisers & A ; Chemicals Limited

Zuari Industries Limited

Mentions AND LINKS

hypertext transfer protocol: //www.krishiworld.com/html/soil_ferti1.html

www.landscape-and-garden.com/ … /fertilizer-types.aspx – United States ( TYPES OF FERTILIZERS )


business.mapsofindia.com/national-fertilizers/ ( FERTILIZER PRODUCERS IN INDIA )



hypertext transfer protocol: //fert.nic.in/fertcompanies/webcomp.asp


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