Agrochemical (or agrichemical), a contraction of agricultural chemical, is a generic term for the various chemical products used in agriculture. In most cases, agrichemical refers to the broad range of pesticides, including insecticides, herbicides, and fungicides. It may also include synthetic fertilizers, hormones and other chemical growth agents, and concentrated stores of raw animal manure.[1][2][3]
Many agrichemicals are toxic, and agrichemicals in bulk storage may pose significant environmental and/or health risks, particularly in the event of accidental spills. In many countries, use of agrichemicals is highly regulated. Government-issued permits for purchase and use of approved agrichemicals may be required. Significant penalties can result from misuse, including improper storage resulting in spillage. On farms, proper storage facilities and labeling, emergency clean-up equipment and procedures, and safety equipment and procedures for handling, application and disposal are often subject to mandatory standards and regulations. Usually, the regulations are carried out through the registration process.
According to Agrow, Bayer CropScience led the agrichemical industry in sales in 2007. Syngenta was second, followed by BASF, Dow Agrosciences, Monsanto, and DuPont.[4]
Fertilizers (or fertilisers) are substances that supply plant nutrients or amend soil fertility. They are the most effective (30 -80 per cent increase in yields)[quantify] means of increasing crop production and of improving the quality of food and fodder. Fertilizers are used in order to supplement nutrient supply in the soil, especially to correct yield-limiting factors.
Fertilizers are applied to promote plant growth; the main nutrients present in fertilizer are nitrogen, phosphorus, and potassium (the 'macronutrients') and other nutrients ('micronutrients') are added in smaller amounts. Fertilizers are usually directly applied to soil, and can also be sprayed on leaves as a foliar feeding.
Organic fertilizers and some mined inorganic fertilizers have been used for many centuries, whereas chemically synthesized inorganic fertilizers were only widely developed during the industrial revolution. Increased understanding and use of fertilizers were important parts of the pre-industrial British Agricultural Revolution and the industrial Green Revolution of the 20th century.
Inorganic fertilizer use has also significantly supported global population growth — it has been estimated that almost half the people on the Earth are currently fed as a result of artificial nitrogen fertilizer use.[1]
Fertilizers typically provide, in varying proportions:
The nitrogen-rich fertilizer ammonium nitrate is also used as an oxidizing agent in improvised explosive devices, sometimes called fertilizer bombs, leading to sale regulations[citation needed].
Fertilizer is described by a three number designator; for example, 20-20-10. These numbers are percentages of three elements: nitrogen, phosphorus, and potassium, respectively. Therefore, 20-20-10 fertilizer contains 20% nitrogen, 20% phosphorus, and 10% potassium by weight.
The fertilizer potash (potassium carbonate) is composed of 1:1 potassium to carbonate by volume (47:53 by wt., owing to differences in molecular weight between potassium and carbonate)[citation needed].
Traditional analysis of 100g of potassium chloride (KCl) would yield 60g of potassium oxide ([[K2O]]). The percentage yield of K2O from the original 100g of fertilizer is the number shown on the label. A potash fertilizer would thus be labeled 0-0-60, and not 0-0-52.
Finally, organic fertilizer is on the rise[citation needed] as people are resorting to environmental friendly (or 'green') products. Although organic fertilizer usually contain less nutrients[citation needed], some people[which?] still prefer organic due to natural ingredients.
Inorganic fertilizer is often synthesized using the Haber-Bosch process, which produces ammonia as the end product. This ammonia is used as a feedstock for other nitrogen fertilizers, such as anhydrous ammonium nitrate and urea. These concentrated products may be diluted with water to form a concentrated liquid fertilizer (e.g. UAN). Ammonia can be combined with rock phosphate and potassium fertilizer in the Odda Process to produce compound fertilizer.
The use of synthetic nitrogen 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.[4] 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 requires 31–50 kg of phosphate fertilizer to be applied, soybean requires 20–25 kg per hectare.[5] Yara International is the world's largest producer of nitrogen based fertilizers.[6]
Nutrients in soil can be thrown out of balance with high concentrations of fertilizers. The interconnectedness and complexity of this soil ‘food web’ means any appraisal of soil function must necessarily take into account interactions with the living communities that exist within the soil. Stability of the system is reduced by the use of nitrogen-containing fertilizers, which cause soil acidification[citation needed].
Applying excessive amounts of fertilizer has environmental impacts, and wastes the growers time and money. To avoid over application, the nutrient status of crops can be assessed. Nutrient deficiency can be detected by visually assessing the physical symptoms of the crop. Nitrogen deficiency, for example has a distinctive presentation in some species. However, quantitative tests are more reliable for detecting nutrient deficiency before it has significantly affected the crop. Both soil tests and and Plant Tissue Tests are used in agriculture to fine-tune nutrient management to the crops needs.
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[citation needed]. Soils in Western Australia are very old, highly weathered and deficient in many of the major nutrients and trace elements[citation needed]. Since this time these trace elements are routinely added to inorganic fertilizers used in agriculture in this state[citation needed].
Fertilizer burnOver-fertilization of a vital nutrient can be as detrimental as underfertilization.[10] "Fertilizer burn" can occur when too much fertilizer is applied, resulting in a drying out of the roots and damage or even death of the plant.[11]
Natural gas is overwhelmingly used for the production of ammonia, but other energy sources, together with a hydrogen source, can be used for the production of nitrogen compounds suitable for fertilizers. The cost of natural gas makes up about 90% of the cost of producing ammonia.[14] 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.[15]
Artificial nitrogen fertilizers are typically synthesized using fossil fuels such as natural gas and coal, which are limited resources. In lieu of converting natural gas to syngas for use in the Haber process, it is also possible to convert renewable biomass to syngas (or wood gas) to supply the necessary energy for the process, though the amount of land and resources (ironically often including fertilizer) necessary for such a project may be prohibitive (see Energy conservation in the United States).
Compost bin for small-scale production of organic fertilizer 
A large commercial compost operationOrganic fertilizers include naturally occurring organic materials, (e.g. manure, worm castings, compost, seaweed, guano), or naturally occurring mineral deposits (e.g. saltpeter).
Organic nutrients increase the abundance of soil organisms by providing organic matter and micronutrients for organisms such as fungal mycorrhiza,[21] (which aid plants in absorbing nutrients), and can drastically reduce external inputs of pesticides, energy and fertilizer, at the cost of decreased yield.[22]
Many agrichemicals are toxic, and agrichemicals in bulk storage may pose significant environmental and/or health risks, particularly in the event of accidental spills. In many countries, use of agrichemicals is highly regulated. Government-issued permits for purchase and use of approved agrichemicals may be required. Significant penalties can result from misuse, including improper storage resulting in spillage. On farms, proper storage facilities and labeling, emergency clean-up equipment and procedures, and safety equipment and procedures for handling, application and disposal are often subject to mandatory standards and regulations. Usually, the regulations are carried out through the registration process.
According to Agrow, Bayer CropScience led the agrichemical industry in sales in 2007. Syngenta was second, followed by BASF, Dow Agrosciences, Monsanto, and DuPont.[4]
Fertilizers (or fertilisers) are substances that supply plant nutrients or amend soil fertility. They are the most effective (30 -80 per cent increase in yields)[quantify] means of increasing crop production and of improving the quality of food and fodder. Fertilizers are used in order to supplement nutrient supply in the soil, especially to correct yield-limiting factors.
Fertilizers are applied to promote plant growth; the main nutrients present in fertilizer are nitrogen, phosphorus, and potassium (the 'macronutrients') and other nutrients ('micronutrients') are added in smaller amounts. Fertilizers are usually directly applied to soil, and can also be sprayed on leaves as a foliar feeding.
Organic fertilizers and some mined inorganic fertilizers have been used for many centuries, whereas chemically synthesized inorganic fertilizers were only widely developed during the industrial revolution. Increased understanding and use of fertilizers were important parts of the pre-industrial British Agricultural Revolution and the industrial Green Revolution of the 20th century.
Inorganic fertilizer use has also significantly supported global population growth — it has been estimated that almost half the people on the Earth are currently fed as a result of artificial nitrogen fertilizer use.[1]
Fertilizers typically provide, in varying proportions:
- the three primary macronutrients: nitrogen (N), phosphorus (P), and potassium (K).
- the three secondary macronutrients: calcium (Ca), sulfur (S), magnesium (Mg).
- and the micronutrients (trace minerals): boron (B), chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), molybdenum (Mo) and selenium (Se).
The nitrogen-rich fertilizer ammonium nitrate is also used as an oxidizing agent in improvised explosive devices, sometimes called fertilizer bombs, leading to sale regulations[citation needed].
Contents[hide] |
[edit] Labeling
Main article: labeling of fertilizers
Labeling of fertilizers take place in some appointed factories. There are some appointed officers who keep a record of the various fertilizers with their advantages as well as disadvantages.[edit] Macronutrient fertilizers
Macronutrient fertilizers are labeled with an NPK analysis (also "N-P-K-S" in Australia).[3]Fertilizer is described by a three number designator; for example, 20-20-10. These numbers are percentages of three elements: nitrogen, phosphorus, and potassium, respectively. Therefore, 20-20-10 fertilizer contains 20% nitrogen, 20% phosphorus, and 10% potassium by weight.
[edit] Example of labeling
 | This article may be confusing or unclear to readers. Please help clarify the article; suggestions may be found on the talk page. (November 2010) |
Traditional analysis of 100g of potassium chloride (KCl) would yield 60g of potassium oxide ([[K2O]]). The percentage yield of K2O from the original 100g of fertilizer is the number shown on the label. A potash fertilizer would thus be labeled 0-0-60, and not 0-0-52.
[edit] History
Main articles: History of organic farming and History of fertilizer
The modern understanding of plant nutrition dates to the 19th century and the work of Justus von Liebig, among others. Management of soil fertility, however, has been the pre-occupation of farmers for thousands of years.[edit] Forms
Fertilizers come in various forms. The most typical[citation needed] form is granular fertilizer (powder form). The next most common form is liquid fertilizer[citation needed]; some advantages of liquid fertilizer are its immediate effect and wide coverage. There are also slow-release fertilizers (various forms including fertilizer spikes, tabs, etc.) which reduce the problem of "burning" the plants due to excess nitrogen.Finally, organic fertilizer is on the rise[citation needed] as people are resorting to environmental friendly (or 'green') products. Although organic fertilizer usually contain less nutrients[citation needed], some people[which?] still prefer organic due to natural ingredients.
[edit] Inorganic fertilizer (synthetic fertilizer)
Fertilizers are broadly divided into organic fertilizers (composed of enriched organic matter—plant or animal), or inorganic fertilizers (composed of synthetic chemicals and/or minerals).Inorganic fertilizer is often synthesized using the Haber-Bosch process, which produces ammonia as the end product. This ammonia is used as a feedstock for other nitrogen fertilizers, such as anhydrous ammonium nitrate and urea. These concentrated products may be diluted with water to form a concentrated liquid fertilizer (e.g. UAN). Ammonia can be combined with rock phosphate and potassium fertilizer in the Odda Process to produce compound fertilizer.
The use of synthetic nitrogen 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.[4] 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 requires 31–50 kg of phosphate fertilizer to be applied, soybean requires 20–25 kg per hectare.[5] Yara International is the world's largest producer of nitrogen based fertilizers.[6]
| Country | Total N use (Mt pa) | Amt. used (feed/pasture) |
|---|---|---|
| China | 18.7 | 3.0 |
| 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 |
| U.K. | 1.3 | 0.9 |
| Mexico | 1.3 | 0.3 |
| Spain | 1.2 | 0.5 |
| Argentina | 0.4 | 0.1 |
[edit] Application
Synthetic fertilizers are commonly used to treat fields used for growing maize, followed by barley, sorghum, rapeseed, soy and sunflower[citation needed]. One study has shown that application of nitrogen fertilizer on off-season cover crops can increase the biomass (and subsequent green manure value) of these crops, while having a beneficial effect on soil nitrogen levels for the main crop planted during the summer season.[8]Nutrients in soil can be thrown out of balance with high concentrations of fertilizers. The interconnectedness and complexity of this soil ‘food web’ means any appraisal of soil function must necessarily take into account interactions with the living communities that exist within the soil. Stability of the system is reduced by the use of nitrogen-containing fertilizers, which cause soil acidification[citation needed].
Applying excessive amounts of fertilizer has environmental impacts, and wastes the growers time and money. To avoid over application, the nutrient status of crops can be assessed. Nutrient deficiency can be detected by visually assessing the physical symptoms of the crop. Nitrogen deficiency, for example has a distinctive presentation in some species. However, quantitative tests are more reliable for detecting nutrient deficiency before it has significantly affected the crop. Both soil tests and and Plant Tissue Tests are used in agriculture to fine-tune nutrient management to the crops needs.
[edit] Problems with inorganic fertilizer
[edit] Trace mineral depletion
Many inorganic fertilizers may not replace trace mineral elements in the soil which become gradually depleted by crops. This depletion has been linked to studies which have shown a marked fall (up to 75%) in the quantities of such minerals present in fruit and vegetables.[9]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[citation needed]. Soils in Western Australia are very old, highly weathered and deficient in many of the major nutrients and trace elements[citation needed]. Since this time these trace elements are routinely added to inorganic fertilizers used in agriculture in this state[citation needed].
[edit] Overfertilization
See also: Fertilizer burn
[edit] High energy consumption
In the USA 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. [12] 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.[13]Natural gas is overwhelmingly used for the production of ammonia, but other energy sources, together with a hydrogen source, can be used for the production of nitrogen compounds suitable for fertilizers. The cost of natural gas makes up about 90% of the cost of producing ammonia.[14] 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.[15]
[edit] Long-Term Sustainability
Inorganic fertilizers are now produced in ways which theoretically cannot be continued indefinitely[citation needed]. Potassium and phosphorus come from mines (or saline lakes such as the Dead Sea) and such resources are limited. More effective fertilizer utilization practices may, however, decrease present usage from mines. Improved knowledge of crop production practices can potentially decrease fertilizer usage of P and K without reducing the critical need to improve and increase crop yields. Atmospheric (unfixed) nitrogen is effectively unlimited (forming over 70% of the atmospheric gases), but this is not in a form useful to plants. To make nitrogen accessible to plants requires nitrogen fixation (conversion of atmospheric nitrogen to a plant-accessible form).Artificial nitrogen fertilizers are typically synthesized using fossil fuels such as natural gas and coal, which are limited resources. In lieu of converting natural gas to syngas for use in the Haber process, it is also possible to convert renewable biomass to syngas (or wood gas) to supply the necessary energy for the process, though the amount of land and resources (ironically often including fertilizer) necessary for such a project may be prohibitive (see Energy conservation in the United States).
[edit] Organic fertilizer
Main article: Organic fertilizer
[edit] Benefits of organic fertilizer
Organic fertilizers have been known to improve the biodiversity (soil life) and long-term productivity of soil,[16][17] and may prove a large depository for excess carbon dioxide.[18][19][20]Organic nutrients increase the abundance of soil organisms by providing organic matter and micronutrients for organisms such as fungal mycorrhiza,[21] (which aid plants in absorbing nutrients), and can drastically reduce external inputs of pesticides, energy and fertilizer, at the cost of decreased yield.[22]
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