Fertilizer

History

Founded in 1812, Mirat, producer of manures and fertilizers, is claimed to be the oldest industrial business in Salamanca (Spain).
Main article: History of fertilizer
Management of soil fertility has been the preoccupation of farmers for thousands of years. Egyptians, Romans, Babylonians, and early Germans are all recorded as using minerals and or manure to enhance the productivity of their farms.[1] The modern science of plant nutrition started in the 19th century and the work of German chemist Justus von Liebig, among others. John Bennet Lawes, an English entrepreneur, began to experiment on the effects of various manures on plants growing in pots in 1837, and a year or two later the experiments were extended to crops in the field. One immediate consequence was that in 1842 he patented a manure formed by treating phosphates with sulfuric acid, and thus was the first to create the artificial manure industry. In the succeeding year he enlisted the services of Joseph Henry Gilbert, with whom he carried on for more than half a century on experiments in raising crops at the Institute of Arable Crops Research.[2]

The Birkeland–Eyde process was one of the competing industrial processes in the beginning of nitrogen based fertilizer production.[3] This process was used to fix atmospheric nitrogen (N2) into nitric acid (HNO3), one of several chemical processes generally referred to as nitrogen fixation. The resultant nitric acid was then used as a source of nitrate (NO3−). A factory based on the process was built in Rjukan and Notodden in Norway, combined with the building of large hydroelectric power facilities.[4]

The 1910s and 1920s witnessed the rise of the Haber process and the Ostwald process. The Haber process produces ammonia (NH3) from methane (CH4) gas and molecular nitrogen (N2). The ammonia from the Haber process is then converted into nitric acid (HNO3) in the Ostwald process.[5] The development of synthetic fertilizer has significantly supported global population growth — it has been estimated that almost half the people on the Earth are currently fed as a result of synthetic nitrogen fertilizer use.[6]

The use of commercial fertilizers has increased steadily in the last 50 years, rising almost 20-fold to the current rate of 100 million tonnes of nitrogen per year.[7] Without commercial fertilizers it is estimated that about one-third of the food produced now could not be produced.[8] The use of phosphate fertilizers has also increased from 9 million tonnes per year in 1960 to 40 million tonnes per year in 2000. A maize crop yielding 6–9 tonnes of grain per hectare (2.5 acres) requires 31–50 kilograms (68–110 lb) of phosphate fertilizer to be applied; soybean crops require about half, as 20–25 kg per hectare.[9] Yara International is the world's largest producer of nitrogen-based fertilizers.[10]

Controlled-nitrogen-release technologies based on polymers derived from combining urea and formaldehyde were first produced in 1936 and commercialized in 1955.[11] The early product had 60 percent of the total nitrogen cold-water-insoluble, and the unreacted (quick-release) less than 15%. Methylene ureas were commercialized in the 1960s and 1970s, having 25% and 60% of the nitrogen as cold-water-insoluble, and unreacted urea nitrogen in the range of 15% to 30%.

In the 1960s, the Tennessee Valley Authority National Fertilizer Development Center began developing sulfur-coated urea; sulfur was used as the principal coating material because of its low cost and its value as a secondary nutrient.[11] Usually there is another wax or polymer which seals the sulfur; the slow-release properties depend on the degradation of the secondary sealant by soil microbes as well as mechanical imperfections (cracks, etc.) in the sulfur. They typically provide 6 to 16 weeks of delayed release in turf applications. When a hard polymer is used as the secondary coating, the properties are a cross between diffusion-controlled particles and traditional sulfur-coated.

Mechanism

Six tomato plants grown with and without nitrate fertilizer on nutrient-poor sand/clay soil. One of the plants in the nutrient-poor soil has died.
Fertilizers enhance the growth of plants. This goal is met in two ways, the traditional one being additives that provide nutrients. The second mode by which some fertilizers act is to enhance the effectiveness of the soil by modifying its water retention and aeration. This article, like many on fertilizers, emphasises the nutritional aspect. Fertilizers typically provide, in varying proportions:[12]

three main macronutrients:
Nitrogen (N): leaf growth
Phosphorus (P): Development of roots, flowers, seeds, fruit;
Potassium (K): Strong stem growth, movement of water in plants, promotion of flowering and fruiting;
three secondary macronutrients: calcium (Ca), magnesium (Mg), and sulfur (S);
micronutrients: copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), boron (B). Of occasional significance are silicon (Si), cobalt (Co), and vanadium (V).
The nutrients required for healthy plant life are classified according to the elements, but the elements are not used as fertilizers. Instead compounds containing these elements are the basis of fertilizers. The macro-nutrients are consumed in larger quantities and are present in plant tissue in quantities from 0.15% to 6.0% on a dry matter (DM) (0% moisture) basis. Plants are made up of four main elements: hydrogen, oxygen, carbon, and nitrogen. Carbon, hydrogen and oxygen are widely available as water and carbon dioxide. Although nitrogen makes up most of the atmosphere, it is in a form that is unavailable to plants. Nitrogen is the most important fertilizer since nitrogen is present in proteins, DNA and other components (e.g., chlorophyll). To be nutritious to plants, nitrogen must be made available in a "fixed" form. Only some bacteria and their host plants (notably legumes) can fix atmospheric nitrogen (N2) by converting it to ammonia. Phosphate is required for the production of DNA and ATP, the main energy carrier in cells, as well as certain lipids.

Micronutrients are consumed in smaller quantities and are present in plant tissue on the order of parts-per-million (ppm), ranging from 0.15 to 400 ppm DM, or less than 0.04% DM.[13][14] These elements are often present at the active sites of enzymes that carry out the plant's metabolism. Because these elements enable catalysts (enzymes) their impact far exceeds their weight percentage.

Classification
Fertilizers are classified in several ways. They are classified according to whether they provide a single nutrient (e.g., K, P, or N), in which case they are classified as "straight fertilizers." "Multinutrient fertilizers" (or "complex fertilizers") provide two or more nutrients, for example N and P. Fertilizers are also sometimes classified as inorganic (the topic of most of this article) versus organic. Inorganic fertilizers exclude carbon-containing materials except ureas. Organic fertilizers are usually (recycled) plant- or animal-derived matter. Inorganic are sometimes called synthetic fertilizers since various chemical treatments are required for their manufacture.[15]

Single nutrient ("straight") fertilizers
The main nitrogen-based straight fertilizer is ammonia or its solutions. Ammonium nitrate (NH4NO3) is also widely used. Urea is another popular source of nitrogen, having the advantage that it is solid and non-explosive, unlike ammonia and ammonium nitrate, respectively. A few percent of the nitrogen fertilizer market (4% in 2007)[16] has been met by calcium ammonium nitrate (Ca(NO3)2 • NH4 • 10H2O).

The main straight phosphate fertilizers are the superphosphates. "Single superphosphate" (SSP) consists of 14–18% P2O5, again in the form of Ca(H2PO4)2, but also phosphogypsum (CaSO4 • 2H2O). Triple superphosphate (TSP) typically consists of 44-48% of P2O5 and no gypsum. A mixture of single superphosphate and triple superphosphate is called double superphosphate. More than 90% of a typical superphosphate fertilizer is water-soluble.

The main potassium-based straight fertilizer is Muriate of Potash (MOP). Muriate of Potash consists of 95-99% KCl, and is typically available as 0-0-60 or 0-0-62 fertilizer.

Multinutrient fertilizers
These fertilizers are common. They consist of two or more nutrient components.

Binary (NP, NK, PK) fertilizers
Major two-component fertilizers provide both nitrogen and phosphorus to the plants. These are called NP fertilizers. The main NP fertilizers are monoammonium phosphate (MAP) and diammonium phosphate (DAP). The active ingredient in MAP is NH4H2PO4. The active ingredient in DAP is (NH4)2HPO4. About 85% of MAP and DAP fertilizers are soluble in water.

NPK fertilizers
Main article: Labeling of fertilizer
NPK fertilizers are three-component fertilizers providing nitrogen, phosphorus, and potassium.

NPK rating is a rating system describing the amount of nitrogen, phosphorus, and potassium in a fertilizer. NPK ratings consist of three numbers separated by dashes (e.g., 10-10-10 or 16-4-8) describing the chemical content of fertilizers.[17][18] The first number represents the percentage of nitrogen in the product; the second number, P2O5; the third, K2O. Fertilizers do not actually contain P2O5 or K2O, but the system is a conventional shorthand for the amount of the phosphorus (P) or potassium (K) in a fertilizer. A 50-pound (23 kg) bag of fertilizer labeled 16-4-8 contains 8 lb (3.6 kg) of nitrogen (16% of the 50 pounds), an amount of phosphorus equivalent to that in 2 pounds of P2O5 (4% of 50 pounds), and 4 pounds of K2O (8% of 50 pounds). Most fertilizers are labeled according to this N-P-K convention, although Australian convention, following an N-P-K-S system, adds a fourth number for sulfur, and uses elemental values for all values including P and K.[19]

Micronutrients
The main micronutrients are molybdenum, zinc, boron, and copper. These elements are provided as water-soluble salts. Iron presents special problems because it converts to insoluble (bio-unavailable) compounds at moderate soil pH and phosphate concentrations. For this reason, iron is often administered as a chelate complex, e.g., the EDTA derivative. The micronutrient needs depend on the plant and the environment. For example, sugar beets appear to require boron, and legumes require cobalt,[1] while environmental conditions such as heat or drought make boron less available for plants.[20]

Production
Nitrogen fertilizers
Top users of nitrogen-based fertilizer[21]
Country Total N use
(Mt pa) Amt. used for
feed/pasture
(Mt pa)
China 18.7 3.0
India 11.9 N/A[22]
U.S. 9.1 4.7
France 2.5 1.3
Germany 2.0 1.2
Brazil 1.7 0.7
Canada 1.6 0.9
Turkey 1.5 0.3
UK 1.3 0.9
Mexico 1.3 0.3
Spain 1.2 0.5
Argentina 0.4 0.1
Nitrogen fertilizers are made from ammonia (NH3), which is sometimes injected into the ground directly. The ammonia is produced by the Haber-Bosch process.[16] In this energy-intensive process, natural gas (CH4) usually supplies the hydrogen, and the nitrogen (N2) is derived from the air. This ammonia is used as a feedstock for all other nitrogen fertilizers, such as anhydrous ammonium nitrate (NH4NO3) and urea (CO(NH2)2).

Deposits of sodium nitrate (NaNO3) (Chilean saltpeter) are also found in the Atacama desert in Chile and was one of the original (1830) nitrogen-rich fertilizers used.[23] It is still mined for fertilizer.[24] Nitrates are also produced from ammonia by the Ostwald process.

Phosphate fertilizers

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An apatite mine in Siilinjärvi, Finland.
All phosphate fertilizers are obtained by extraction from minerals containing the anion PO43−. In rare cases, fields are treated with the crushed mineral, but most often more soluble salts are produced by chemical treatment of phosphate minerals. The most popular phosphate-containing minerals are referred to collectively as phosphate rock. The main minerals are fluorapatite Ca5(PO4)3F (CFA) and hydroxyapatite Ca5(PO4)3OH. These minerals are converted to water-soluble phosphate salts by treatment with sulfuric (H2SO4) or phosphoric acids (H3PO4). The large production of sulfuric acid as an industrial chemical is primarily due to its use as cheap acid in processing phosphate rock into phosphate fertilizer. The global primary uses for both sulfur and phosphorus compounds relate to this basic process.

In the nitrophosphate process or Odda process (invented in 1927), phosphate rock with up to a 20% phosphorus (P) content is dissolved with nitric acid (HNO3) to produce a mixture of phosphoric acid (H3PO4) and calcium nitrate (Ca(NO3)2). This mixture can be combined with a potassium fertilizer to produce a compound fertilizer with the three macronutrients N, P and K in easily dissolved form.[25]

Potassium fertilizers
Potash is a mixture of potassium minerals used to make potassium (chemical symbol: K) fertilizers. Potash is soluble in water, so the main effort in producing this nutrient from the ore involves some purification steps; e.g., to remove sodium chloride (NaCl) (common salt). Sometimes potash is referred to as K2O, as a matter of convenience to those describing the potassium content. In fact, potash fertilizers are usually potassium chloride, potassium sulfate, potassium carbonate, or potassium nitrate.[26]

Compound fertilizers
Compound fertilizers, which contain N, P, and K, can often be produced by mixing straight fertilizers. In some cases, chemical reactions occur between the two or more components. For example, monoammonium and diammonium phosphates, which provide plants with both N and P, are produced by neutralizing phosphoric acid (from phosphate rock) and ammonia :

NH3 + H3PO4 → (NH4)H2PO4
2 NH3 + H3PO4 → (NH4)2HPO4
Organic fertilizers
Main article: Organic fertilizer

Compost bin for small-scale production of organic fertilizer

A large commercial compost operation
“Organic fertilizers” can describe those fertilizers with an organic — biologic — origin—that is, fertilizers derived from living or formerly living materials. Organic fertilizers can also describe commercially available and frequently packaged products that strive to follow the expectations and restrictions adopted by “organic agriculture” and ”environmentally friendly" gardening — related systems of food and plant production that significantly limit or strictly avoid the use of synthetic fertilizers and pesticides. The “organic fertilizer” products typically contain both some organic materials as well as acceptable additives such as nutritive rock powders, ground sea shells (crab, oyster, etc.), other prepared products such as seed meal or kelp, and cultivated microorganisms and derivatives.

Fertilizers of an organic origin (the first definition) include animal wastes, plant wastes from agriculture, compost, and treated sewage sludge (biosolids). Beyond manures, animal sources can include products from the slaughter of animals — bloodmeal, bone meal, feather meal, hides, hoofs, and horns all are typical components.[12] Organically derived materials available to industry such as sewage sludge may not be acceptable components of organic farming and gardening, because of factors ranging from residual contaminants to public perception. On the other hand, marketed “organic fertilizers” may include, and promote, processed organics because the materials have consumer appeal. No matter the definition nor composition, most of these products contain less concentrated nutrients, and the nutrients are not as easily quantified. They can offer soil-building advantages as well as be appealing to those who are trying to farm / garden more “naturally”.[27]

In terms of volume, peat is the most widely used packaged organic soil amendment. It is an immature form of coal and improves the soil by aeration and absorbing water but confers no nutritional value to the plants. It is therefore not a fertilizer as defined in the beginning of the article, but rather an amendment. Coir, (derived from coconut husks), bark, and sawdust when added to soil all act similarly (but not identically) to peat and are also considered organic soil amendments - or texturizers - because of their limited nutritive inputs. Some organic additives can have a reverse effect on nutrients — fresh sawdust can consume soil nutrients as it breaks down, and may lower soil pH — but these same organic texturizers (as well as compost, etc.) may increase the availability of nutrients through improved cation exchange, or through increased growth of microorganisms that in turn increase availability of certain plant nutrients. Organic fertilizers such as composts and manures may be distributed locally without going into industry production, making actual consumption more difficult to quantify.

Application
Fertilizers are commonly used for growing all crops, with application rates depending on the soil fertility, usually as measured by a soil test and according to the particular crop. Legumes, for example, fix nitrogen from the atmosphere and generally do not require nitrogen fertilizer.

Liquid vs solid
Fertilizers are applied to crops both as solids and as liquid. About 90% of fertilizers are applied as solids. The most widely used solid inorganic fertilizers are urea, diammonium phosphate and potassium chloride.[28] Solid fertilizer is typically granulated or powdered. Often solids are available as prills, a solid globule. Liquid fertilizers comprise anhydrous ammonia, aqueous solutions of ammonia, aqueous solutions of ammonium nitrate or urea. These concentrated products may be diluted with water to form a concentrated liquid fertilizer (e.g., UAN). Advantages of liquid fertilizer are its more rapid effect and easier coverage.[12] The addition of fertilizer to irrigation water is called "fertigation".[26]

Slow- and controlled-release fertilizers
Slow- and controlled-release involve only 0.15% (562,000 tons) of the fertilizer market (1995). Their utility stems from the fact that fertilizers are subject to antagonistic processes. In addition to their providing the nutrition to plants, excess fertilizers can be poisonous to the same plant. Competitive with the uptake by plants is the degradation or loss of the fertilizer. Microbes degrade many fertilizers, e.g., by immobilization or oxidation. Furthermore, fertilizers are lost by evaporation or leaching. Most slow-release fertilizers are derivatives of urea, a straight fertilizer providing nitrogen. Isobutylidenediurea ("IBDU") and urea-formaldehyde slowly convert in the soil to free urea, which is rapidly uptaken by plants. IBDU is a single compound with the formula (CH3)2CHCH(NHC(O)NH2)2 whereas the urea-formaldehydes consist of mixtures of the approximate formula (HOCH2NHC(O)NH)nCH2.

Besides being more efficient in the utilization of the applied nutrients, slow-release technologies also reduce the impact on the environment and the contamination of the subsurface water.[11] Slow-release fertilizers (various forms including fertilizer spikes, tabs, etc.) which reduce the problem of "burning" the plants due to excess nitrogen. Polymer coating of fertilizer ingredients gives tablets and spikes a 'true time-release' or 'staged nutrient release' (SNR) of fertilizer nutrients.

Controlled release fertilizers are traditional fertilizers encapsulated in a shell that degrades at a specified rate. Sulfur is a typical encapsulation material. Other coated products use thermoplastics (and sometimes ethylene-vinyl acetate and surfactants, etc.) to produce diffusion-controlled release of urea or other fertilizers. "Reactive Layer Coating" can produce thinner, hence cheaper, membrane coatings by applying reactive monomers simultaneously to the soluble particles. "Multicote" is a process applying layers of low-cost fatty acid salts with a paraffin topcoat.

Foliar application
Foliar fertilizers are applied directly to leaves. The method is almost invariably used to apply water-soluble straight nitrogen fertilizers and used especially for high value crops such as fruits.[12]


Fertilizer burn
Chemicals that affect nitrogen uptake
Various chemicals are used to enhance the efficiency of nitrogen-based fertilizers. In this way farmers can limit the polluting effects of nitrogen run-off. Nitrification inhibitors (also known as nitrogen stabilizers) suppress the conversion of ammonia into nitrate, an anion that is more prone to leaching. 1-Carbamoyl-3-methylpyrazole (CMP), dicyandiamide, nitrapyrin (2-chloro-6-trichloromethylpyridine) and 3,4-Dimethylpyrazole phosphate (DMPP) are popular.[29] Urease inhibitors are used to slow the hydrolytic conversion of urea into ammonia, which is prone to evaporation as well as nitrification. The conversion of urea to ammonia catalyzed by enzymes called ureases. A popular inhibitor of ureases is N-(n-butyl)thiophosphoric triamide (NBPT).

Overfertilization
Careful fertilization technologies are important because excess nutrients can be detrimental.[30] Fertilizer burn can occur when too much fertilizer is applied, resulting in damage or even death of the plant. Fertilizers vary in their tendency to burn roughly in accordance with their salt index.[31][32]

Statistics
Recently nitrogen fertilizers have plateaued in most developed countries. China although has become the largest producer and consumer of nitrogen fertilizers.[33] Africa has little reliance on nitrogen fertilizers.[34] Agricultural and chemical minerals are very important in industrial use of fertilizers, which is valued at approximately $200 billion.[35] Nitrogen has a significant impact in the global mineral use, followed by potash and phosphate. The production of nitrogen has drastically increased since the 1960s. Phosphate and potash have increased in price since the 1960s, which is larger than the consumer price index.[35] Potash is produced in Canada, Russia and Belarus, together making up over half of the world production.[35] Potash production in Canada rose in 2017 and 2018 by 18.6%.[36] Conservative estimates report 30 to 50% of crop yields are attributed to natural or synthetic commercial fertilizer.[26][37] Fertilizer consumption has surpassed the amount of farmland in the United States[35]. Global market value is likely to rise to more than US$185 billion until 2019.[38] The European fertilizer market will grow to earn revenues of approx. €15.3 billion in 2018.[39]

Data on the fertilizer consumption per hectare arable land in 2012 are published by The World Bank.[40] For the diagram below values of the European Union (EU) countries have been extracted and are presented as kilograms per hectare (pounds per acre). The total consumption of fertilizer in the EU is 15.9 million tons for 105 million hectare arable land area[41] (or 107 million hectare arable land according to another estimate[42]). This figure equates to 151 kg of fertilizers consumed per ha arable land on average for the EU countries.

The diagram displays the statistics of fertilizer consumption in western and central European counties from data published by The World Bank for 2012.

Environmental effects

Runoff of soil and fertilizer during a rain storm
Use of fertilizers are beneficial in providing nutrients to plants although they have some negative environmental effects. The large growing consumption of fertilizers can affect soil, surface water, and groundwater due to dispersion of mineral use.[35]

See also: Environmental impact of agriculture, Human impact on the nitrogen cycle, Nitrogen fertilizer § Problems with inorganic fertilizer, and Nitrogen Cycle
Water
Main article: Eutrophication
Phosphorus and nitrogen fertilizers when commonly used have major environmental effects. This is due to high rainfalls causing the fertilizers to be washed into waterways.[43] Agricultural run-off is a major contributor to the eutrophication of fresh water bodies. For example, in the US, about half of all the lakes are eutrophic. The main contributor to eutrophication is phosphate, which is normally a limiting nutrient; high concentrations promote the growth of cyanobacteria and algae, the demise of which consumes oxygen.[44] Cyanobacteria blooms ('algal blooms') can also produce harmful toxins that can accumulate in the food chain, and can be harmful to humans.[45][46]

The nitrogen-rich compounds found in fertilizer runoff are the primary cause of serious oxygen depletion in many parts of oceans, especially in coastal zones, lakes and rivers. The resulting lack of dissolved oxygen greatly reduces the ability of these areas to sustain oceanic fauna.[47] The number of oceanic dead zones near inhabited coastlines are increasing.[48] As of 2006, the application of nitrogen fertilizer is being increasingly controlled in northwestern Europe[49] and the United States.[50][51] If eutrophication can be reversed, it may take decades[citation needed] before the accumulated nitrates in groundwater can be broken down by natural processes.

Nitrate pollution
Only a fraction of the nitrogen-based fertilizers is converted to plant matter. The remainder accumulates in the soil or is lost as run-off.[52] High application rates of nitrogen-containing fertilizers combined with the high water solubility of nitrate leads to increased runoff into surface water as well as leaching into groundwater, thereby causing groundwater pollution.[53][54][55] The excessive use of nitrogen-containing fertilizers (be they synthetic or natural) is particularly damaging, as much of the nitrogen that is not taken up by plants is transformed into nitrate which is easily leached.[56]

Nitrate levels above 10 mg/L (10 ppm) in groundwater can cause 'blue baby syndrome' (acquired methemoglobinemia).[57] The nutrients, especially nitrates, in fertilizers can cause problems for natural habitats and for human health if they are washed off soil into watercourses or leached through soil into groundwater.[citation needed]

Soil
Acidification
See also: Soil pH and Soil acidification
Nitrogen-containing fertilizers can cause soil acidification when added.[58][59] This may lead to decrease in nutrient availability which may be offset by liming.

Accumulation of toxic elements
Cadmium
The concentration of cadmium in phosphorus-containing fertilizers varies considerably and can be problematic.[60] For example, mono-ammonium phosphate fertilizer may have a cadmium content of as low as 0.14 mg/kg or as high as 50.9 mg/kg.[61] The phosphate rock used in their manufacture can contain as much as 188 mg/kg cadmium[62] (examples are deposits on Nauru[63] and the Christmas islands[64]). Continuous use of high-cadmium fertilizer can contaminate soil (as shown in New Zealand)[65] and plants.[66] Limits to the cadmium content of phosphate fertilizers has been considered by the European Commission.[67][68][69] Producers of phosphorus-containing fertilizers now select phosphate rock based on the cadmium content.[44]

Fluoride
Phosphate rocks contain high levels of fluoride. Consequently, the widespread use of phosphate fertilizers has increased soil fluoride concentrations.[66] It has been found that food contamination from fertilizer is of little concern as plants accumulate little fluoride from the soil; of greater concern is the possibility of fluoride toxicity to livestock that ingest contaminated soils.[70][71] Also of possible concern are the effects of fluoride on soil microorganisms.[70][71][72]

Radioactive elements
The radioactive content of the fertilizers varies considerably and depends both on their concentrations in the parent mineral and on the fertilizer production process.[66][73] Uranium-238 concentrations can range from 7 to 100 pCi/g in phosphate rock[74] and from 1 to 67 pCi/g in phosphate fertilizers.[75][76][77] Where high annual rates of phosphorus fertilizer are used, this can result in uranium-238 concentrations in soils and drainage waters that are several times greater than are normally present.[76][78] However, the impact of these increases on the risk to human health from radinuclide contamination of foods is very small (less than 0.05 mSv/y).[76][79][80]

Other metals
Steel industry wastes, recycled into fertilizers for their high levels of zinc (essential to plant growth), wastes can include the following toxic metals: lead[81] arsenic, cadmium,[81] chromium, and nickel. The most common toxic elements in this type of fertilizer are mercury, lead, and arsenic.[82][83][84] These potentially harmful impurities can be removed; however, this significantly increases cost. Highly pure fertilizers are widely available and perhaps best known as the highly water-soluble fertilizers containing blue dyes used around households, such as Miracle-Gro. These highly water-soluble fertilizers are used in the plant nursery business and are available in larger packages at significantly less cost than retail quantities. Some inexpensive retail granular garden fertilizers are made with high purity ingredients.

Trace mineral depletion
Attention has been addressed to the decreasing concentrations of elements such as iron, zinc, copper and magnesium in many foods over the last 50–60 years.[85][86] Intensive farming practices, including the use of synthetic fertilizers are frequently suggested as reasons for these declines and organic farming is often suggested as a solution.[86] Although improved crop yields resulting from NPK fertilizers are known to dilute the concentrations of other nutrients in plants,[85][87] much of the measured decline can be attributed to the use of progressively higher-yielding crop varieties which produce foods with lower mineral concentrations than their less productive ancestors.[85][88][89] It is, therefore, unlikely that organic farming or reduced use of fertilizers will solve the problem; foods with high nutrient density are posited to be achieved using older, lower-yielding varieties or the development of new high-yield, nutrient-dense varieties.[85][90]

Fertilizers are, in fact, more likely to solve trace mineral deficiency problems than cause them: In Western Australia deficiencies of zinc, copper, manganese, iron and molybdenum were identified as limiting the growth of broad-acre crops and pastures in the 1940s and 1950s.[91] Soils in Western Australia are very old, highly weathered and deficient in many of the major nutrients and trace elements.[91] Since this time these trace elements are routinely added to fertilizers used in agriculture in this state.[91] Many other soils around the world are deficient in zinc, leading to deficiency in both plants and humans, and zinc fertilizers are widely used to solve this problem.[92]

Changes in soil biology
Further information: soil biology
High levels of fertilizer may cause the breakdown of the symbiotic relationships between plant roots and mycorrhizal fungi.[93]

Energy consumption and sustainability
In the US in 2004, 317 billion cubic feet of natural gas were consumed in the industrial production of ammonia, less than 1.5% of total U.S. annual consumption of natural gas.[94] A 2002 report suggested that the production of ammonia consumes about 5% of global natural gas consumption, which is somewhat under 2% of world energy production.[95]

Ammonia is produced from natural gas and air.[96] The cost of natural gas makes up about 90% of the cost of producing ammonia.[97] The increase in price of natural gases over the past decade, along with other factors such as increasing demand, have contributed to an increase in fertilizer price.[98]

Contribution to climate change
The greenhouse gases carbon dioxide, methane and nitrous oxide are produced during the manufacture of nitrogen fertilizer. The effects can be combined into an equivalent amount of carbon dioxide. The amount varies according to the efficiency of the process. The figure for the United Kingdom is over 2 kilograms of carbon dioxide equivalent for each kilogram of ammonium nitrate.[99] Nitrogen fertilizer can be converted by soil bacteria to nitrous oxide, a greenhouse gas.

Atmosphere

Global methane concentrations (surface and atmospheric) for 2005; note distinct plumes
Through the increasing use of nitrogen fertilizer, which was used at a rate of about 110 million tons (of N) per year in 2012,[100][101] adding to the already existing amount of reactive nitrogen, nitrous oxide (N2O) has become the third most important greenhouse gas after carbon dioxide and methane. It has a global warming potential 296 times larger than an equal mass of carbon dioxide and it also contributes to stratospheric ozone depletion.[102] By changing processes and procedures, it is possible to mitigate some, but not all, of these effects on anthropogenic climate change.[103]

Methane emissions from crop fields (notably rice paddy fields) are increased by the application of ammonium-based fertilizers. These emissions contribute to global climate change as methane is a potent greenhouse gas.[104][105]

Regulation
In Europe problems with high nitrate concentrations in run-off are being addressed by the European Union's Nitrates Directive.[106] Within Britain, farmers are encouraged to manage their land more sustainably in 'catchment-sensitive farming'.[107] In the US, high concentrations of nitrate and phosphorus in runoff and drainage water are classified as non-point source pollutants due to their diffuse origin; this pollution is regulated at state level.[108] Oregon and Washington, both in the United States, have fertilizer registration programs with on-line databases listing chemical analyses of fertilizers.[109][110]

In China, regulations have been implemented to control the use of N fertilizers in farming. In 2008, Chinese governments began to partially withdraw fertilizer subsidies, including subsidies to fertilizer transportation and to electricity and natural gas use in the industry. In consequence, the price of fertilizer has gone up and large-scale farms have begun to use less fertilizer. If large-scale farms keep reducing their use of fertilizer subsidies, they have no choice but to optimize the fertilizer they have which would therefore gain an increase in both grain yield and profit.[111]

Two types of agricultural management practices include organic agriculture and conventional agriculture. The former encourages soil fertility using local resources to maximize efficiency. Organic agriculture avoids synthetic agrochemicals. Conventional agriculture uses all the components that organic agriculture does not use.[112]

The Different Types of Fertilizers

A good gardener knows the importance of a good fertilizer. Recognizing which fertilizer best fits the needs of your specific plants will help you to maximize your gardens’ growth. Become a fertilizing expert as you learn about the different options and nutrients that can impact your plants. 

Organic and Inorganic Fertilizers

Organic fertilizers are made from natural and organic materials—mainly manure, compost, or other animal and plant products. These fertilizers are a great source of nutrients, though there isn’t a measurable amount of any specific nutrients—some bags will print estimates. Organic fertilizers tend to work slowly and over the long-term. It can help to build up your soil over time. One of the best benefits of organic fertilizers is that is can be made at home. Using your own compost can help grow your garden!

Inorganic fertilizers are made of up chemical components that contain necessary nutrients. If you’re looking to give your garden a quick boost, this is likely the best option for you. For successful short-term growth, determine what nutrient your plant needs and use an inorganic fertilizer with nutrient.  

Nitrogen Fertilizers

Nitrogen is a plan nutrient responsible for growth. This ingredient is useful in fertilizers, particularly during the middle stages of a plant’s lifespan, when it needs encouragement to continue to grow large and stem new leaves. Both organic and inorganic fertilizers have sources of nitrogen in them. 

Phosphate Fertilizers

Phosphorous is a nutrient that plants need continuously. Throughout their lifecycle, phosphorous help to strengthen the root system and stems of a plant. Flowering, seeding, and fruiting can all be improved with phosphorous.

Plants with a phosphorous deficiency will experience stunted growth. Phosphorous is long-lasting and slow acting. Using fertilizer in your soil before planting is generally a good idea. 

Potassium Fertilizers

Potassium will help your plants to grow deeper and stronger roots. It can also help protect your plants from harm when they are deprived of other nutrients. This nutrient is vital for photosynthesis and has the ability to slow down any diseases that may infect your garden. Potassium fertilizer has a lot of benefits. The when and how of planting this fertilizer will depend on what you’re are planting. When you are using this fertilizer, place it as close to the roots as possible.

If there is a potassium deficiency in your plant, you may see yellowing or browning on the edges of leaves. Leaves will eventually die off if the deficiency continues. 

Fertilizer Forms

Fertilizer comes in a few different forms. There is liquid, powder, and granular. Liquid fertilizers are often diluted with water. Spreading them is similar to watering your garden, usually done with a hose attachment. Powdered fertilizers also need water to be productive. Usually they are spread by hand and watered to complete absorption. Granular lawn fertilizers can easily be spread on top of soil. These nutrient pack granules will be soaked into your garden over time as you water it. 

Fertilizers can provide the nutrients essential for plant growth. They are generally applied on the soil or leaves of the plants to promote their rapid growth and development. They generally come in three basic forms - dry, soluble, and time release fertilizers. Soluble fertilizers can be dissolved in water. On the other hand, the time release fertilizers can come in both dry and soluble form, and they are released slowly over a period of time.

Whether organic or synthetic, the key ingredients of a fertilizer are, nitrogen, phosphorus, and potassium, which are usually referred to as NPK. These are the primary macro nutrients found in any fertilizer. However, their concentration can vary considerably from one fertilizer to another. The concentration of these three main components are expressed as three numbers printed on the label of a particular fertilizer. For example, if a fertilizer is labeled as 10-5-5, it contains 10% nitrogen, 5% phosphorus, and 5% potassium.

Nitrogen (N)

Nitrogen is one of the vital nutrients required for the rapid growth of plants, and their foliage and fruits. Plants synthesize proteins from nitrogen, and they also need this nutrient to develop seeds. Plants usually assimilate nitrogen in the form of nitrate, ammonium, organic nitrogen, or molecular nitrogen. Though nitrogen is vital for the healthy growth of plants, an excess of it can result in an overgrowth, which can make the plants weak and vulnerable to diseases and insects. Therefore, nitrogen-rich fertilizers are usually applied, when a plant has established itself firmly on the ground.

Phosphorus (P)

Plants require sufficient amounts of phosphorus for flower and fruit production. Phosphorus is also required for growing strong roots that are resistant to rot diseases. This nutrient helps plants store energy in the form of adenosine diphosphate (ADP) and adenosine triphosphate (ATP). Fertilizers containing phosphate are usually applied on the soil before planting, and then continued until the plant establishes itself on the ground.

Potassium (K)

Potassium is mainly required for strengthening the plants. A deficiency of this macronutrient can result in stunted growth and reduced yields. Phosphorus can stimulate early growth in plants by increasing protein synthesis, and it can increase their resistance to diseases and insects. Potassium-rich fertilizers are typically used before or during winter. However, it should be kept in mind that an overuse of potassium fertilizers can kill the plants.

Along with nitrogen, phosphorus, and potassium, some fertilizers can contain a small amount of calcium, magnesium, and sulfur, which are termed as secondary macronutrients. They are as essential for plant growth as the primary macronutrients, but their requirement is usually managed with the help of manuring and liming practices. In addition to all the primary and secondary macronutrients, plants also require traces of iron, copper, manganese, boron, molybdenum, chlorine, zinc, and nickel, which are called micronutrients. Many fertilizers contain these nutrients in small amounts.

Apart from macro and micronutrients, a small amount of sand, sawdust, or granulated limestone can also be found in fertilizers. These are known as fillers, and they help prevent the fertilizer from hardening. They can also ensure that the basic ingredients, i.e., nitrogen, potassium, and phosphorus do not become too concentrated. Without fillers, a high concentration of these nutrients can burn or kill the plants instead of benefiting them.

Phosphatic fertilisers:

The nutrient phosphorus present in phosphate fertilizers are usually expressed in terms of phosphoric anhydride or simply as phosphorus pentaoxide, P2O5. The availability of phosphorus in which it is present. The amount of phosphorus available to the plants depends upon the extent to which the fertilizer supplies HPO4----or H2PO4 –ions. According to the solubilities, the phosphatic fertilizers are divided in following groups.

1. Water soluble phosphatic fertilizers: These fertilizers contain phosphorus in available form in neutral soils, which can be readily absorbed by young plants. In acid, soils and free iron, aluminium hydroxy phosphates but in alkaline and calcareous soils, water soluble phosphorous is converted into insoluble calcium phosphate. The common examples of these fertilizers are:

Sr. No.	Fertiliser	% P2O5
i	Single Superphosphate (CaH2PO4)16	18% P2O5
ii	Double superphosphate CaH4(PO4) 2	32% P2O5
iii	Triple superphosphate Ca(H2 PO4) 2	46 to 48% P2O5
iv	Ammonium phosphate	20% P2O5



2. Citric acid soluble Phosphatic Fertilizers: The citric soluble fertilizers are suitable for acidic soils because at low pH citrate soluble phosphorus is converted to monocalcium phosphate not as water soluble phosphate and therefore, phosphorus is not fixed as iron and aluminium phosphate.

Sr. No.	Fertiliser	% P2O5
i	Dicalcium phosphate, CaHPO4	14% P2O5 extract soluble
ii	Basic slag (CaO) 5P2 O5. SiO2 17	20% P2 O5 extract soluble
iii	Calcium metaphosphate Ca (PO3) 2	60 to 64%P2 O5 extract soluble



1. Water and citrate insoluble phosphatic fertilizers: These mineral fertilizers contain phosphorus, which is insoluble in water as well as in citric acid. They are suitable in strongly acid soils or organic soils. These fertilizers are given in green manured fields. The phosphorus is very slowly released by microbes at action and remains in soil for long time.

Sr. No.	Fertiliser	% P2O5
i	Rock Phosphate Ca3 (PO4)2CaF2	20 to 30% P2O5extract soluble
ii	Bone meal (Ca(PO4) 2) 3 CaF2	21 to 25% P2O5 extract soluble

(d) Other phosphatic fertilizers: Following are the other phosphatic fertilisers.

. No.	Fertiliser	% P2O5
i	Kotka phosphate	26% P2O5
ii	Rhenmia phosphate	26 to 28% P2O5
iii	Thermophos	18.3% P2O5
iv	Pelophos	18% P2O5
v	Coronat phosphate	21% P2O5

The two types of fertilizers - inorganic and organic

In the broadest sense all types of fertilizers include any substance, living or inorganic which aids in plant growth and health. We exclude water, CO2, and sunlight.

Types of Fertilizers - Commercial
During the 1800's Justus von Liebig, considered by many to be the father of the fertilizer industry, made substantial contributions toward the organization and development of organic chemistry laboratory methods. He discovered that plants need nitrogen to survive. A basic assumption developed - to maintain plant health simply return to the soil what the plant removes.

With commercial types of fertilizers the following are identified as necessary for plant growth:

1. Primary nutrients - nitrogen (N), phosphorus (P), and potassium (K)
2. Secondary nutrients - calcium (Ca), magnesium (Mg), sulfur (S)
3. Trace minerals) - boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), zinc (Zn), and selenium (Se)

Types of Fertilizers - Organic
Generally the term “organic fertilizer” is used to refer to fertilizer that has gone through minimal processing, where nutrients are still found in their natural forms. This includes manure and compost, which you can prepare yourself, along with items which can be purchased. Inorganic fertilizers generally refer to fertilizers that are synthetic or artificial, and generally are manufactured from petroleum products (yes, fertilizer that is made from crude oil).

In the last 60 to 70 years, a phenomenon has happened in farming in the USA. Farmers started using Inorganic Fertilizer instead of Organic Fertilizer.From that point we have seen a gradual worsening of soils, resulting in increased insect, disease and weed problems.

Inorganic Fertilizers are “water soluble”. They are minerals in concentrated form that are readily available to the plant. Unlike most organic fertilizers, they don’t need the help of the soil to break them down so the plant can utilize them. They only need the soil to hold them until the plant takes them in. Water soluble inorganic fertilizers do nothing to contribute to the health of the soil. So over time, soils become run down and diseased, and become ever more limited in the types of crops they will grow.

Types of Fertilizers - Why Farmers Choose Inorganic Fertilizers
Soils and plants need so many more nutrients than Nitrogen, Phosphorus and Potassium (also called NPK). But research has shown that it is these three that are the primary nutrients needed to produce bigger yields. To the farmer, with all the expenses involved in farming, coupled together with low crop prices, if he doesn’t produce larger yields, he very well won’t be able to make enough money to stay in business.

The issue of Organic vs. Inorganic Fertilizer is the same issue faced by human beings. Do we live a healthy lifestyle and eat nutritious foods, or do we indulge ourselves with empty calories and then count on drugs to save us from the consequences? Because inorganic fertilizers do not supply most of the micro-nutrients needed by the soil and plants, soils become out of balance, and disease, insect problems and weed problems multiply. To counter these, the inorganic farmer utilizes poisons (insecticides, pesticides, herbicides) to treat these symptoms. Of course, these are highly detrimental to the soil. Along with killing the bad, they also kill the many beneficial insects, algae, nematodes, flagellates, amoebae, ciliates, fungi and bacteria in the soil.

Types of Fertilizers - Nutritious Foods
Inorganic fertilizers may grow a greater volume of food, but organic fertilizers grow more nutritious food. Both plants and people need a host of micro-nutrients. Inorganic fertilizers only supply a handful of these nutrients, while organic fertilizers provide many more.

It has been said that blood plasma and plant sap have almost the identical proportion of minerals as are found in the ocean. In fact, one of the best sources for micro-nutrients is ocean water, where all 76 naturally occurring minerals are present in perfect balance. This is organic fertilizer at it’s best. When you give plants and soil the nutrients they need, it means healthier plants, and greater nutrition for you.

Organic and Inorganic Fertilizer - Your Choice
If you choose to use only inorganic fertilizers, you are asking for trouble. Why not add in some organic fertilizers as well. Better yet, forget the inorganic fertilizers, and educate yourself in the use of organic fertilizers. Our research has shown that when used properly, they will result in less insect damage, fewer pet injuries, fewer diseases, and less weed problems, while giving you a bountiful harvest of highly nutritious foods that have a great shelf life. 

Organic Vs. Biological

I often call myself an organic gardener, but I would more accurately be called a biological gardener, which is not a legally defined term, but I’ll explain it here:

• In organic gardening and farming the focus is on avoiding the use of all synthetic products.
• In biological gardening and farming the focus is on growing the most nutrient-dense food possible, using whichever products would help with that, as long as those products aren’t harming the environment.

Now that’s not to say that there aren’t people in the organic group who are trying to grow nutrient-dense food.

It’s just that the legal regulations around organic farming and gardening are usually about what you can’t use rather than what the outcome should be – nutritious, non-toxic food.

Some have started using this word ‘biological’ to focus more on that outcome. They may use some synthetics to get the job done.

It’s not as though they’re spraying 20-20-20 all over the place or something like that, but there are a few specialty synthetic fertilizers that are very helpful for plant health, and not harmful to soil and environmental health, and so have been deemed worthwhile using in small amounts.

This product would fit into that group.

The Ingredients

The analysis is N-P-K of 5-16-4 – plus 5% calcium.

Those seem like high numbers when compared to organic fertilizers, but we only use 3 Tbsp per 1000 square feet!

So it actually ends up being much less overall fertilizer than a liquid fish fertilizer, but it’s in a form that more easily gets into the leaf and gets immediately used by the plant. It contains:

• Urea. Urea is the one ingredient I’ve traditionally not been a huge fan of because it’s often in the form of urea formaldehyde, and formaldehyde is not good for any living thing. But a tiny bit of just straight urea is actually a big help in a foliar feed. It has the nitrate form of nitrogen, and it also has carbon to balance it out. It’s probably about 1 of the 5% nitrogen content here.
• Phosphoric acid. I’ve been a fan of phosphoric acid for a long time, not for human consumption, but for use in the garden in small amounts. That’s one reason why I like using organic liquid fish fertilizer, because it often contains about 2% phosphoric acid. The reason there’s so much phosphate in this mix is because it’s what pulls many other nutrients into the leaf.
• Potassium phosphate. Potassium phosphate is another quality fertilizer. I think it’s main use here is to allow the phosphoric acid and calcium nitrate to coexist in the same formula. It supplies a bit of potassium, too, which is no doubt useful at this small of a dose.
• Calcium nitrate. Another excellent fertilizer – a great source of calcium and nitrogen. It’s probably about 4 of the 5% nitrogen content here.

At the incredibly low application rates, I believe this product is one of the few synthetics that should be used in a garden where the goal is optimal health.

Chemical free and perfect for an organic kitchen garden, Jeff Holman rounds up the organic fertilisers that will leave your plants blooming gorgeous

For years, gardeners have been told to use chemical fertilisers with their high nitrogen, potash, and phosphorous content; the three main elements that plants need in order to grow. But according to Ben Raskin of the Soil Association, many chemical fertilisers contain more than triple the amount of minerals that your fruit and veg actually need. ‘This is problematic,’ says Raskin, ‘because the excess minerals are then washed away by rain and irrigation and find their way into water sources used by both humans and animals, creating a major pollution risk.’ Unlike farmers, most of us aren’t growing food for sale; so don’t need turbo-charged chemical fertilisers; particularly when the large number of eco-friendly alternatives is taken into account. Here are five of the best.

Kelp
Kelp-based fertilisers contain potassium and a little nitrogen but the true benefits are the long-term effect they can have on your plants. Kelp has been shown to stimulate soil development, which in turn enables plants to thrive and increases overall yield. It also enables plants and crops to develop a higher tolerance for extremes of temperature such as ice and prolonged periods of sunshine. While you can buy kelp in garden centres, the cheapest way to get your hands on some is to gather and compost it yourself.

Cow manure
The most commonly used type of muck; cow manure is rich in nutrients that feed plants and soil alike. As with chicken manure, applying fresh directly to plants can burn them, so you have to properly compost it before use. If you’re using it on fruit and vegetables, it’s worth searching for manure produced by organically farmed cows, otherwise you risk putting chemical antibiotic residues, among others, on your plants.

Alfalfa meal
Alfalfa meal is another plant-based fertiliser that benefits the garden in subtle ways, although it does contain a decent amount of nitrogen as well as some potassium and phosphorous. Alfalfa’s real benefit is that it helps improve soil quality and enables production more nutrients for plants to feed from, which increases plant growth over time. It works particularly well on roses and can be bought from most garden centres.

Limestone
Limestone fertiliser is usually a healthy addition to soil but benefits differ depending on the source of the stone. Used to balance PH levels in soils with high acidity, limestone also contains calcium, which helps with overall plant growth, and magnesium, which encourages stronger, healthier plants. With limestone fertilisers, it’s important to test levels of acidity in your soil to determine how much, if any is needed before application.

Chicken manure
Chicken poo contains more nitrogen, potassium and phosphorous than any other type of manure and it’s a great source of other nutrients such as calcium and magnesium to boot. The manure can be bought in pellet form or you can ask a friendly farmer for leftover chicken muck and compost it yourself. However, you must make sure that the manure is properly composted before use as the high nitrogen content can burn plants if the manure is raw. Also, as Raskin points out, make sure that your fertiliser comes from a free-range chicken farm in order to maintain the organic and nutritional value.

Qualities of Organic Soil The Boston Gardener Recommends

Whether you use an indoor garden or conventional outdoor plots, having organic soil is key to a thriving crop. Good organic garden soil offers three vital qualities, including:

Nutrients

Your plants require food to grow, and organic soil nutrients deliver. For gardeners that prefer to mix their own organic soil Boston, including a phosphate fertilizer is a good plan. Bat guano is a longtime favorite of growers around the world. Seafood fertilizer is another ingredient that provides a good source of nutrients. Be sure your soil is PH balanced from the start, and monitor that balance throughout plant development.

Timing

Opt for slow-release fertilizers or institute a regular schedule of additives. Some products come with minerals that release over time to enhance the soil, while others need to be topped up with compost tea or your preferred method of fertilization.

Moisture Retention

Although some indoor gardeners avoid water retention additives, organic soils must include this feature. Mix in some sand to lighten the soil, and add perlite or other absorbent organic materials, such as coco fiber and worm castings.
With these three essential qualities you can create an organic soil the we Boston gardeners, and their plants, will love

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Manure" – news · newspapers · books · scholar · JSTOR (May 2017) (Learn how and when to remove this template message)

Animal manure is often a mixture of animal feces and bedding straw, as in this example from a stable

Manure is organic matter, mostly derived from animal feces except in the case of green manure, which can be used as organic fertilizer in agriculture. Manures contribute to the fertility of the soil by adding organic matter and nutrients, such as nitrogen, that are utilised by bacteria, fungi and other organisms in the soil. Higher organisms then feed on the fungi and bacteria in a chain of life that comprises the soil food web.

In the past, the term "manure" included inorganic fertilizers, but this usage is now very rare.

Contents

• 1Types
  • 1.1Animal manure
    • 1.1.1Human manure
  • 1.2Compost
  • 1.3Green manure
• 2Uses of manure
  • 2.1Animal manure
• 3Issues
  • 3.1Livestock antibiotics
• 4See also
• 5References
• 6External links

Types

There are in the 21st century three main classes of manures used in soil management:

Animal manure

Concrete reservoirs, one new, and one containing cow manure mixed with water. This is common in rural HainanProvince, China.

Most animal manure consists of feces. Common forms of animal manure include farmyard manure (FYM) or farm slurry (liquid manure). FYM also contains plant material (often straw), which has been used as bedding for animals and has absorbed the feces and urine. Agricultural manure in liquid form, known as slurry, is produced by more intensive livestock rearing systems where concrete or slats are used, instead of straw bedding. Manure from different animals has different qualities and requires different application rates when used as fertilizer. For example horses, cattle, pigs, sheep, chickens, turkeys, rabbits, and guano from seabirds and bats all have different properties.^[1] For instance, sheep manure is high in nitrogen and potash, while pig manure is relatively low in both. Horses mainly eat grass and a few weeds so horse manure can contain grass and weed seeds, as horses do not digest seeds the way that cattle do. Cattle manure is a good source of nitrogen as well as organic carbon.^[2]Chicken litter, coming from a bird, is very concentrated in nitrogen and phosphate and is prized for both properties.^[2][3]

Animal manures may be adulterated or contaminated with other animal products, such as wool (shoddy and other hair), feathers, blood, and bone. Livestock feed can be mixed with the manure due to spillage. For example, chickens are often fed meat and bone meal, an animal product, which can end up becoming mixed with chicken litter.

Human manure

Some people refer to human excreta as human manure, and the word "humanure" has also been used. Just like animal manure, it can be applied as a soil conditioner (reuse of excreta in agriculture). Sewage sludge is a material that contains human excreta, as it is generated after mixing excreta with water and treatment of the wastewater in a sewage treatment plant.

Compost

Main article: Compost

Compost containing turkey manure and wood chips from bedding material is dried and then applied to pastures for fertilizer.

Compost is the decomposed remnants of organic materials. It is usually of plant origin, but often includes some animal dung or bedding.

Green manure

Green manures are crops grown for the express purpose of plowing them in, thus increasing fertility through the incorporation of nutrients and organic matter into the soil. Leguminous plants such as clover are often used for this, as they fix nitrogen using Rhizobia bacteria in specialized nodes in the root structure.

Other types of plant matter used as manure include the contents of the rumens of slaughtered ruminants, spent grain (left over from brewingbeer) and seaweed.

Uses of manure

Further information: Reuse of excreta

Animal manure

Manure on a wall.

Animal manure, such as chicken manure and cow dung, has been used for centuries as a fertilizer for farming. It can improve the soil structure (aggregation) so that the soil holds more nutrients and water, and therefore becomes more fertile. Animal manure also encourages soil microbial activity which promotes the soil's trace mineral supply, improving plant nutrition. It also contains some nitrogen and other nutrients that assist the growth of plants.^[4]

Manures with a particularly unpleasant odor (such as slurries from intensive pig farming) are usually knifed (injected) directly into the soil to reduce release of the odor. Manure from pigs and cattle is usually spread on fields using a manure spreader. Due to the relatively lower level of proteins in vegetable matter, herbivore manure has a milder smell than the dung of carnivores or omnivores. However, herbivore slurry that has undergone anaerobic fermentation may develop more unpleasant odors, and this can be a problem in some agricultural regions. Poultry droppings are harmful to plants when fresh, but after a period of composting are valuable fertilizers.^[5]

Manure is also commercially composted and bagged and sold as a soil amendment.^[6][7]

In 2018, Austrian scientists offered a method of paper production from elephant and cow manure.^[8]

Issues

The women of a neighborhood ward with manure on their way to the field of one of them, Tireli, Mali 1990

Any quantity of manure may be a source of pathogens or food spoilage organisms which may be carried by flies, rodents or a range of other vector organisms and cause disease or put food safety at risk.

Livestock antibiotics

In 2007, a University of Minnesota study^[9] indicated that foods such as corn, lettuce, and potatoes have been found to accumulate antibioticsfrom soils spread with animal manure that contains these drugs.

Organic foods may be much more or much less likely to contain antibiotics, depending on their sources and treatment of manure. For instance, by Soil Association Standard 4.7.38, most organic arable farmers either have their own supply of manure (which would, therefore, not normally contain drug residues) or else rely on green manure crops for the extra fertility (if any nonorganic manure is used by organic farmers, then it usually has to be rotted or composted to degrade any residues of drugs and eliminate any pathogenic bacteria—Standard 4.7.38, Soil Association organic farming standards). On the other hand, as found in the University of Minnesota study, the non-usage of artificial fertilizers, and resulting exclusive use of manure as fertilizer, by organic farmers can result in significantly greater accumulations of antibiotics in organic foods.^[9]

WHY DO FARMERS USE FERTILIZERS?

March 18, 2015 · by soilsmatter2011 · in Environment/Ecology, Farming/Gardening. ·

Question: I’ve heard that fertilizers can have negative effects. Why do farmers use fertilizers?

Answer: All the nutrients in our food originally come from the soil. In order to create healthy crops full of nutrients, farmers need to work with healthy soil.

A large sprayer applies nitrogen fertilizer to a field. The equipment is assisted by technology that optimizes the application of fertilizer—using it only where needed on the field. This reduces cost to the grower. Photo credit: Bill Raun

Soils naturally contain many nutrients like nitrogen, phosphorous, calcium, and potassium. These nutrients allow plants to grow. When soil nutrients are missing or in short supply, plants suffer from nutrient deficiency and stop growing. When the nutrient level is too low, the plant cannot function properly and produce the food necessary to feed the worlds’ population.

Once crops are harvested for human consumption, the natural supply of nutrients in the soil must be “re-filled”. This is why farmers add nutrients to their soils. Nutrients can be added from a variety of sources—organic matter, chemical fertilizers, and even by some plants. This maintains the soil fertility, so the farmer can continue to grow nutritious crops and healthy crops.

Farmers turn to fertilizers because these substances contain plant nutrients such as nitrogen, phosphorus, and potassium. Fertilizers are simply plant nutrients applied to agricultural fields to supplement required elements found naturally in the soil. Fertilizers have been used since the start of agriculture. Native American people used crude fertilizers, such as burying a fish in their corn plots, and organic farmers use fertilizer from natural source, such as compost. Most farmers today use fertilizers that are either mined or manufactured.

Regardless of the source of the fertilizer, all plants use the same inorganic forms of fertilizer in the soil. Sometimes the source of nitrogen can be plants called “nitrogen fixers.” Many farmers use crops, such as soybeans and alfalfa (called legumes), that can remove naturally occurring nitrogen in the atmosphere, and place (“fix”) it in the soil for future crops to use.

Fertilizer use is very expensive and can harm the environment if not used correctly. Therefore, before adding fertilizer, farmers send a soil sample to a laboratory for baseline testing. By testing their soil, farmers know which nutrients—and how much—to apply to the soil. If too little is added, crops will not produce as much as they should. If too much is added, or at the wrong time, excess nutrients will run off the fields and pollute streams and groundwater. So, while fertilizers serve an important purpose, farmers must be careful to use the right amount, at the right time, to avoid potential negative effects to the environment.

To stay healthy, humans need to acquire essential nutrients from many different food sources. The demand for food and other products from agricultural systems will increase over the next few decades. This means that we need to keep our soils healthy and full of nutrients in order to feed the growing population.

According to the Environmental Protection Agency, most fertilizers contain about the same basic materials: nitrogen, potassium, phosphorus and sometimes other nutrients, like zinc, needed for healthy plant growth. Many people use fertilizers to give extra life to their lawn and garden, but few people consider the potential drawbacks of these fertilizers. In an effort to be as environmentally conscious as possible, it is important to consider the potentially harmful effects of fertilizers as well as the benefits.

Human Carcinogens

The most significant harmful effects come from fertilizer that is designed to kill or prevent weeds. According to the EPA's Office of Pesticide Programs, 12 of the most popular pesticides in the United States have ingredients known to cause cancer. Organic fertilizers are guaranteed to be safe for the environment, the body and free of pesticides.

Water Pollution

While fertilizers may be beneficial to the plants, they are not always as healthy for the rest of the environment. Many of the "quick-release" fertilizers have been known to lead to oxygen loss in waterways due to runoff into the street and, as a result, into the water. High amounts of nitrogen can find their way into waterways in this way, causing an excess of algae and a resulting loss of oxygen in the water. This can have a negative effect on fish and other wildlife in the water.

Toxic Waste Potential

Many people do not realize that some fertilizers are made from the residuals of waste water treatment facilities or recycled from other areas that cause them to test positive for toxic waste. According to the federation of Public Interest Research Groups (PIRG), 29 popular fertilizers tested positive for 22 toxic heavy metals, including silver, nickel, selenium, thallium and vanadium. All of the metals found are linked directly to human health hazards.

Fertilizer Types

Soil amendments are made by adding fertilizer to the soil but there are different types of fertilizers. There is bulky organic fertilizer, such as cow manure, bat guano, bone meal, organic compost and green manure crops. And then there is also chemical fertilizer which is also referred to as inorganic fertilizer and is made up with different formulations to suit a variety of specified uses. Though many governments and agricultural departments go to great lengths to increase the supply of organic fertilizers, such as bulky organic manures and composting materials, there is just not enough of these fertilizers available to meet the existing and future fertilizer needs. Compared to organic compost, chemical or inorganic fertilizers also have the added advantage of being less bulky. Being less bulky makes chemical fertilizer easier to transport, both overland and from the soil into the plants itself, because they get to be available to the plant relatively quickly when incorporated as part of the plant-food constituents. Chemical fertilizer usually comes in either granular or powder form in bags and boxes, or in liquid formulations in bottles. The different types of chemical fertilizers are usually classified according to the three principal elements, namely Nitrogen (N), Phosphorous (P) and Potassium (K), and may, therefore, be included in more than one group.

Organic and Inorganic Chemical Nitrogenous Fertilizer types

This type of fertilizer is divided into different groups according to the manner in which the Nitrogen combines with other elements. These groups are:

• Sodium Nitrates,
• Ammonium Sulphate and ammonium salts,
• Chemical compounds that contains Nitrogen in amide form, and
• Animal and plant by products.

Sodium Nitrates

Sodium Nitrates are also known as Chilates or Chilean nitrate. The Nitrogen contained in Sodium Nitrate is refined and amounts to 16%. This means that the Nitrogen is immediately available to plants and as such is a valuable source of Nitrogen in a type of fertilizer. When one makes a soil amendment using Sodium Nitrates as a type of fertilizer in the garden, it is usually as a top- and side-dressing. Particularly when nursing young plants and garden vegetables. In soil that is acidic Sodium Nitrate is quite useful as a type of fertilizer. However, the excess use of Sodium Nitrate may cause deflocculation.

Ammonium Sulphate

This fertilizer type comes in a white crystalline salt form, containing 20 to 21% ammonia cal nitrogen. It is easy to handle and it stores well under dry conditions. However, during the rainy season, it sometimes, forms lumps. (TIP: When these lumps do occur you should grind them down to a powered form before use.) Though this fertilizer type is soluble in water, its nitrogen is not readily lost in drainage, because the ammonium ion is retained by the soil particles. A note of caution: Ammonium sulphate may have an acid effect on garden soil. Over time, the long-continued use of this type of fertilizer will increase soil acidity and thus lower the yield. (TIP: It is advisable to use this fertilizer type together with bulky organic manures to safeguard against the ill effects of continued application of ammonium sulphate.)

The application of Ammonium sulphate fertilizer can be done before sowing, at sowing time, or even as a top-dressing to the growing crop. Do however take care NOT to apply it along with, or too close to, the seed, because in concentrated form, it affects seed germination very adversely.

Ammonium Nitrate

This fertilizer type also comes in white crystalline salts. Ammonium Nitrate salts contains 33 to 35% nitrogen, of which half is nitrate nitrogen and the other half in the ammonium form. As part of the ammonium form, this type of fertilizer cannot be easily leached from the soil. This fertilizer is quick-acting, but highly hygroscopic thus making it unfit for storage. (TIP: Coagulation and Granulation of this fertilizer can be combated with a light coating of the granules with oil.) On a note of caution: Ammonium Nitrate also has an acid effect on the soil, in addition this type of fertilizer can be explosive under certain conditions, and, should thus be handled with care.

'Nitro Chalk' is the trade name of a product formed by mixing ammonium nitrate with about 40% lime-stone or dolomite. This fertilizer is granulated, non-hazardous and less hygroscopic. The lime content of this fertilizer type makes it useful for application to acidic garden soils.

Ammonium Sulphate Nitrate

This fertilizer type is available as a mixture of ammonium nitrate and ammonium sulphate and is recognizable as a white crystal or as dirty-white granules. This fertilizer contains 26% nitrogen, three-fourths of it in the ammoniac form and the remainder (i.e. 6.5%) as nitrate nitrogen. Ammonium Sulphate Nitrate is non-explosive, readily soluble in water and is very quick-acting. Because this type of fertilizer keeps well, it is very useful for all crops. Though it can also render garden soil acidic, the acidifying effects is only one-half of that of ammonium sulphate on garden soil. Application of this fertilizer type can be done before sowing, at sowing time or as a top-dressing, but it should not be applied along the seed.

Ammonium Chloride

This fertilizer type comes in a white crystalline compound, which contains a good physical condition and 26%ammoniac nitrogen. In general, Ammonium Chloride is similar to ammonium sulphate in action. (TIP: Do not use this type of fertilizer on crops such as tomatoes because the chorine may harm your crop.)

Urea

This type of fertilizer usually is available to the public in a white, crystalline, organic form. It is a highly concentrated nitrogenous fertilizer and fairly hygroscopic. This also means that this fertilizer can be quite difficult to apply. Urea is also produced in granular or pellet forms and is coated with a non-hygroscopic inert material. It is highly soluble in water and therefore, subject to rapid leaching. It is, however, quick-acting and produces quick results. When applied to the soil, its nitrogen is rapidly changed into ammonia. Similar to ammonium nitrate, urea supplies nothing but nitrogen and the application of Urea as fertilizer can be done at sowing time or as a top-dressing, but should not be allowed to come into contact with the seed.

Ammonia

This fertilizer type is a gas that is made up of about 80% of nitrogen and comes in a liquid form as well because under the right conditions regarding temperature and pressure, Ammonia becomes liquid (anhydrous ammonia). Another form, 'aqueous ammonia', results from the absorption of Ammonia gas into water, in which it is soluble. Ammonia is used as a fertilizer in both these forms. The anhydrous liquid form of Ammonia can be applied by introducing it into irrigation water, or directly into the soil from special containers. Not really suitable for the home gardener as this renders the use of ammonia as a fertilizer very expensive.

Organic Nitrogenous Fertilizers

Organic Nitrogenous fertilizer is the type of fertilizer that includes plant and animal by-products. These by-products can be anything from oil cakes, to fish manure and even to dried blood. The Nitrogen available in organic nitrogenous fertilizer types first has to be converted before the plants can use it. This conversion occurs through bacterial action and is thus a slow process. The upside of this situation is that the supply of available nitrogen lasts so much longer AND the amounts of this type of fertilizer may contain small amounts of organic stimulants that contain other minor elements that might also be needed by the plants that are being fertilized. Furthermore, they may also small amounts of organic stimulants that they may contain, or of some of the minor elements needed by plant. Oil-cakes contain not only nitrogen but also some phosphoric and potash, besides a large quantity of organic matter. This type of fertilizer is used in conjunction with quicker-acting chemical fertilizers.

Then there is also blood meal which contains 10 to 12% highly available Nitrogen as well as 1 to 2% Phosphoric acid. Blood meal, used in much the same way as oilcakes, makes for a quick remedy and can effectively be used on all types of soil as a type of fertilizer.

Fish meal which can be dried fish, fish-meal or even powder is extracted in areas where fish oil is extracted. The resulting residue is used as a fertilizer type. Obviously depending on the type of fish used, the available Nitrogen can be between 5 and 8% and the Phosphoric content can be from 4 to 6%. Fish meal also constitutes a fast-acting fertilizer type which is suitable for most soil types and crops. (TIP: In powder form it is at its best.)

Organic and Inorganic Chemical Phosphate Fertilizer Types

The Phosphate fertilizers are categorized as natural phosphates, either treated or processed, and also by products of phosphates and chemical phosphates.

Rock Phosphate

As a type of fertilizer, rock phosphate occurs as natural deposits in some countries. This fertilizer type has its advantages and disadvantages. The advantage is that with adequate rainfall this fertilizer results in a long growing period which can enhance crops. Powdered phosphate fertilizer is an excellent remedy for soils that are acidic and has a phosphorous deficiency and requires soil amendments.

However, the disadvantage is that although phosphate fertilizer such as rock phosphate contains 25 to 35%phosphoric acid, the phosphorous is insoluble in water. It has to be pulverized to be used as a type of fertilizer before rendering satisfactory results in garden soil. Thus it is not surprising that Rock Phosphate is used to manufacture superphosphate which makes the Phosphoric acid water soluble.

Superphosphate

Superphosphate is a fertilizer type that most gardeners are familiar with. As a fertilizer type one can get superphosphate in three different grades, depending on the manufacturing process. The following is a short description of the different superphosphate fertilizer grades:

• Single superphosphate containing 16 to 20% phosphoric acid;
• Dicalcium phosphate containing 35 to 38% phosphoric acid; and
• Triple superphosphate containing 44 to 49% phosphoric acid.

Triple superphosphate is used mostly in the manufacture of concentrated mixed fertilizer types.

The greatest advantage to be had of using Superphosphate as a fertilizer is that the phosphoric acid is fully water soluble, but when Superphosphate is applied to the soil, it is converted into soluble phosphate. This is due to precipitation as calcium, iron or aluminum phosphate, which is dependent on the soil type to which the fertilizer is added, be it alkaline or acidic garden soil. All garden soil types can benefit from the application of Superphosphate as a fertilizer. Used in conjunction with an organic fertilizer, it should be applied at sowing or transplant time.

Slag

Basic slag is a by-product of steel mills and is used as a fertilizer to a lesser extent than Superphosphate. Slag is an excellent fertilizer that can be used to amend soils that are acidic because of its alkaline reaction. For slag application to be an effective fertilizer it has to be pulverized first.

Bonemeal

Bonemeal as a fertilizer type needs no introduction. Bone-meal is used as a phosphate fertilizer type and is available in two types: raw and steamed. The raw bone-meal contains 4% organic Nitrogen that is slow acting, and 20 to 25% phosphoric acid that is not soluble in water. The steamed bone-meal on the other hand has all the fats, greases, nitrogen and glue-making substances removed as a result of high pressure steaming. But it is more brittle and can be ground into a powder form. In powder form this fertilizer is of great advantage to the gardener in that the rate of availability of the phosphoric acid depends on its pulverization. This fertilizer is particularly suitable as a soil amendment for acid soil and should be applied either at sowing time or even a few days prior to sowing. (TIP: As a fertilizer type, bone-meal is slow acting and should be incorporated into the soil and not as a top-dressing.)

Organic and Inorganic Chemical Potassium Fertilizer types

Chemical Potassium fertilizer should only be added when there is absolute certainty that there is a Potassium deficiency in your garden soil. Potassium fertilizers also work well in sandy garden soil that responds to their application. Crops such as chilies, potato and fruit trees all benefit from this type of fertilizer since it improves the quality and appearance of the produce. There are basically two different types of potassium fertilizers:

• Muriate of potash (Potassium chloride) and
• Sulphate of potash (Potassium sulphate).

Both muriate of potash and sulphate of potash are salts that make up part of the waters of the oceans and inland seas as well as inland saline deposits.

Muriate Of Potash

Muriate of potash is a gray crystal type of fertilizer that consists of 50 to 60% potash. All the potash in this fertilizer type is readily available to plants because it is highly soluble in water. Even so, it does not leach away deep into the soil since the potash is absorbed on the colloidal surfaces. (TIP: Apply muriate of potash at sowing time or prior to sowing.)

Sulphate Of Potash

Sulphate of potash is a fertilizer type manufactured when potassium chloride is treated with magnesium sulphate. It dissolves readily in water and can be applied to the garden soil at any time up to sowing. Some gardeners prefer using sulphate of potash over muriate of potash.

Different Types of Fertilizers

The different types of fertilizers with all its specifications and cautions that should be kept in mind should not detract us from the joys of gardening. Thus to make it easier on most gardeners and since this website is dedicated to the home gardener and growing our own gardens the following section is geared towards the home gardener.

The different types of chemical and organic fertilizers that are usually commercially available in most countries can be categorized further into:

• Complete inorganic fertilizers: – these types of inorganic fertilizers contain all three major macronutrients, Nitrogen (N), Phosphorous (P) and Potassium (K). On the containers you will find that these macronutrients are depicted as a ratio, e.g. 2:3:2 (22). Complete inorganic fertilizers are usually applied at a rate of 60g/m² or roughly 4 tablespoons per square meter.
• Special purpose fertilizer: – these types of fertilizer are formulated especially to target certain plants' requirements or certain soil deficiencies. Of the examples that come to mind here are the Blue Hydrangea Food, and straight fertilizer that is made up of one particular plant nutrient for example lawn fertilizer.
• Liquid fertilizers: – these types of fertilizer come in a variety of formulations and even include organic fertilizer, complete fertilizer as well as special purpose fertilizer. Some examples of liquid fertilizer are Nitrosol and African Violet Food.
• Slow-release fertilizer: – these types of fertilizer are formulated to release their nitrogen at a steady pace. On the packs of this fertilizer that are available commercially it will usually be depicted as 3:1:5 (SR) where the SR indicates slow-release.
• Fertilizer with insecticide: – these types of fertilizer that are prepared and combined with an insecticide. One such example is Wonder 4:1:1 (21) + Karbaspray.

The reason why there are so many different types of chemical fertilizers in different formulations is because different plants require different nutrients and different pH levels in the soil. However, organic fertilizers have more diversity, and these types of fertilizers do not burn plant roots, get into ground water, or affect surrounding growth as is the case when using the different types of chemical fertilizer and NPK amendments.

How to Apply Fertilizer

In our previous section we discussed the different types of fertilizers. We now turn our attention to applying the different types of fertilize, but first there is the issue of when is the best time to apply the specific type of fertilizer that you require. In the case of bulky organic manures and other organic fertilizer, you would serve your garden well if you apply the fertilizer well ahead of sowing time. The reason would be that the preliminary decomposition can then take place prior to the seeds germinating. However, if you neglected to fertilize prior to sowing or time is against you, then you may apply bulky organic fertilizer any time after the seedlings have established themselves. (TIP: In such a case it is best to use fertilizer in the powder form.) Further good gardening practice would be to make sure there is a sufficient supply of moisture in the soil.

When you want to make use of inorganic fertilizer and fertilizer types that include the Potassic and Phosphaticfertilizers, then it is best to apply the fertilizer before sowing or transplanting the seedlings. In the case of Nitrogenous fertilizers, you can feel free to apply the fertilizer at planting and even slightly after planting time. In many cases split application of nitrogenous fertilizers is advantageous in heavy rainfall areas.

Despite all the different types of fertilizers that are available from local nurseries and garden centers it is easy to work out which fertilizer is best for which types of plants by simply reading the container. If you are in doubt regarding the suitability of the fertilizer for your garden then make use of the NPK ratio rhyme.

• Leaves and shoots
• Stems and roots
• Flowers and fruit

The NPK ratio is then read as follows: – leaves and shoots : stems and roots : flowers and fruits. Make use of this ratio rhyme and make your own assessment.

Fertilizers bags and containers also provide ample instructions on the best ways in which to apply the particular fertilizer. Nonetheless, the following is a general guide on the application of different types of chemical or inorganic fertilizer.

Applying Liquid Fertilizer

Liquid fertilizer is usually concentrated. They need to be mixed or dissolved in water before application to the intended plants. When properly diluted you also negate the chances of fertilizer burn. Properly diluted liquid fertilizer is ideal for use of soft, sensitive and young plants. Fertilizer for indoor plants, specialized food for seedlings, bonsai fertilizer, and orchid fertilizer are all water soluble.

Mixing and application of liquid fertilizer

Liquid fertilizer is easy to apply – simply mix the required amount into a watering can or bucket filled with water. (TIP: Add the fertilizer concentrate to the water.) Water the plant with the mixture and do remember that the fertilizer will be more easily absorbed if the soil is moist. You can also use some of the liquid fertilizer as foliar spray. This liquid fertilizer is then sprayed on the leaves since the fertilizer will be absorbed through the leaves. In this case you pour the fertilizer and water mixture into a spray bottle and apply to the leaves. (TIP: Only foliar feed if the instructions on the container indicate so and use the recommended rate.)

Applying Granular Fertilizer

Granular fertilizer can be used in its dry form sprinkled on the soil around the intended plants. After application these types of fertilizer should be watered in immediately to avoid the plants burning. Using granular fertilizer is a trifle more complicated than using liquid fertilizer. In many cases gardeners would just scatter a handful or so around each plant and hope that it will suffice. This brings on problems like burnt plants and even overfed plants, or alternatively not applying enough fertilizer for the size of the plant.

Mixing and application of granular fertilizer

The instruction that you will find on the fertilizer container or bag will indicate the amount (in grams or ounce) that should be applied to a square meter. It sounds easy enough, but it can be difficult to apply this dosage in a garden. Say for instance the recommended dosage is 60g per m². First you need a 60g measuring cup. No problem. Take a cap, say the plastic cap of an empty aerosol spray (a deodorant cap will do fine) and place it on a kitchen scale. Fill it with fertilizer until it weighs 60g. Shake the cap to level the fertilizer in the cap. Then take a marker and mark the level. Empty the fertilizer back into the fertilizer container. Now take a strong pair of scissors and cut along the line that you marked. Voila – now you have your 60g measuring cup. (TIP: Write on the cup the name of the type of fertilizer and the gram measurement for next time.) You will also find that each type of fertilizer has its own dose rate and weight. You will thus need a measuring cup for each of the different types of fertilizer.

When actually applying the granular fertilizer you need to gauge an approximate square meter either by pacing or by cutting a thin stick or bamboo stake to 1 meter in length. Then sprinkle the full measuring cup evenly over the whole area that you gauged as 1 square meter. When fertilizing trees or large shrubs you need to sprinkle the fertilizer over the whole drip area even if it happens to be over the grass. The roots of plants grow away from the trunk; and the fine hair root are usually those furthest away from the base of the tree or shrub. These fine hair roots are the ones responsible for feeding the tree or shrub. Heavy handfuls of fertilizer near the base of the tree or shrub can damage the root system by burning it. (TIP: Use the measuring cup and stake method to apply lawn fertilizer as well.)

General tips for applying fertilizer

1. All fertilizers should preferably be applied before sowing.
2. Fertilizer should preferably be broadcast uniformly and harrowed in.
3. All fertilizers that contain soluble phosphates should preferably be applied in wide bands of between 2.5 and 5 cm on each side of thee rows of seeds at a depth of 10 to 15 cm.
4. The superphosphate fertilizer should preferably be mixed with farmyard manure (in particular organic manure from dairy farms works excellent.)
5. Fertilizer types that include sulphate of ammonia can be used as a top dressing, but do not apply this type of fertilizer when the leaves of the plants are wet.
6. The application of fertilizer should preferably be followed by watering when applied to irrigated crops.
7. When fertilizing fruit trees, the fertilizer should preferably be applied to the soil under the crown. The crown is the area about a few meters away from the trunk. As the tree grows this crown area expands and then fertilizer should also be applied as per the crown of the fruit tree.

Compost is decomposed organic matter and bacteria.

Fertilizer is plant nutrients.

Plants need a variety of nutrients, mainly nitrogen (N), phosphorus (P) and potassium (K). This is the NPK that are listed as a ratio on almost every bag of processed fertilizer. Nitrogen fertilizers can be natural, such as animal manures from cows, horses, chicken, bats etc which have a low to high urea content and low phosphorous/ potassium contents, and when added to soil can be absorbed directly into plant roots. Fertilizers, such as urea, can also be chemically manufactured by industrial processes, or be the by-product of such, and are pure plant nutrient. These invariably take the form of various ionic salts, that easily dissolve in water and are completely and immediately available for plants to absorb through the roots, so much so that one must be careful about the doseage, since high concentrations of salt can quickly “burn” a plant.

Compost is produced by the decomposition of organic matter by bacteria. The original organic matter, consisting of cut-up pieces of dead plants and sometimes animals, had in it all the nutrients that a plant needs. However those nutrients are still locked up in the dead plant cells. Bacteria quickly begin to break open those dead cells to eat the contents and reproduce. This natural process can be assisted and increased by careful design and management of a human-made compost pile. A compost pile therefore is basically a way of growing bacteria. After a few weeks to several months, when the dead organic matter in the pile has been completely decomposed, there is no more food for the bacteria, because they turned it all into more bacteria. This means that all the nutrients have been transferred from the dead plant cells to live bacterial cells, but when their food source is used up, the bacteria begin to die. When the bacteria die, they break open and leak out all those nutrients, which are then directly absorbable by plant roots. These nutrients however are in the form of complex polar molecules, not salts, and therefore can never “burn” a plant regardless of the concentration.

The remaining decomposed organic matter in compost has no nutrient value, but does still benefit plants by adding structure to soil. It increases volume, aeration, water holding capacity, nutrient exchange capacity, and habitat for microorganisms, and it can help to decrease erosion and nutrient leaching from soil.

chemicall salt fertilizers don't do any of that, and they additionally kill microorganisms on contact, which can increase erosion, and decreases plant immune system functions, and the natural nutrient uptake by plants, which sort of like an addictive drug, creates a dependency on the artificially manufactured nutrients.

Composting is natural process to form the compost through agriculture waste is called Compost. They rich in nutrients and contain all kinds of required for agriculture in very little proportionate. With the time span they losses their nutrients

Fertilizers are the synthetic manufacture which gives nutrient like Nitrogen, Phosphorus and Potash. It may contain maximum 1–4 nutrients at a time. We may store for longer time

You have many options when it comes to providing a healthy environment for plants. While numerous types of fertilizers can be an effective way to quickly amend soil to grow healthy plants, they contain synthetic chemicals. Compost, on the other hand, is an organic alternative to fertilizers, and you can make your own or buy it. There are pros and cons to both methods of providing plants with nutrition.

Benefits of Compost

Compost, sometimes called "black gold," consists of decomposed organic matter that enhances the soil with nutrients and microbes. Typically it includes recycled material including decayed vegetables, fruit, grass clippings and plant foliage. Compost also has microscopic fungi, bacteria, earthworms and dung beetles. This mixture creates a symbiotic food web within the soil. The decomposing material feeds the organisms and helps to aerate the soil while also keeping it moist. Compost also helps plants fight disease, helps to prevent erosion, controls weeds and can be mixed with store-bought potting soil. Tightly packed soil, such as clay, becomes easier to work with when you add compost. If you create your own compost, you also decrease the volume of trash that goes into landfills.

Disadvantages of Compost

The drawbacks of compost are few. If you make your own compost, it is important to make sure that any plant remnants you add to the mix do not have soil-borne pathogens that might infest healthy plants. Destroy diseased or damaged plant parts instead of adding them to a compost pile. You need patience to make your own compost. It takes time for the decayed matter to break down and you might have to wait a few months until you see significant results from your composting efforts.

Benefits of Fertilizer

Fertilizer applications target the needs of plants to help them grow faster. If a plant is lacking micro- and macronutrients, such as calcium, magnesium, potassium or phosphorus, adding fertilizer provides a quick and easy solution to alleviate deficiencies. You can purchase fertilizer for specific types of plants. If your plant needs immediate nutrition, fast-release fertilizers provide instant nutrition. On the other hand, slow-release fertilizers, like pellets, provide nutrition over an extended period.

Disadvantages of Fertilizer

The biggest difference between fertilizer and compost is that while compost enhances the soil to create a beneficial environment for plants, fertilizer feeds plants. Fertilizers may overload the soil with nutrients. Chemicals in fertilizer can upset the symbiotic relationship of microbes in soil while compost is a naturally balanced mixed of microorganisms that provide a healthy medium for plant growth. The chemicals in fertilizer can also harm the environment if they are overused and seep into underground water reserves or runoff into nearby bodies of water. The excess nitrogen from fertilizers can spur algae growth that depletes the oxygen supply for fish. From an economic standpoint, compost, especially if you make your own, is less expensive than fertilizer. Poor plant health is often due to poor soil conditions. Improving the soil with compost instead of using fertilizer is a more environmentally friendly and sustainable way of maintaining healthy plants.