Fertilizer: Difference between revisions

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[[File:Manure spreading Hlokozi 2007 11 29.jpg|thumb|upright=1.35|A [[farmer]] spreading [[manure]] to improve [[soil fertility]]]]

A '''fertilizer''' or '''fertiliser''' is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply [[plant nutrition|plant nutrients]]. Fertilizers may be distinct from [[Liming (soil)|liming materials]] or other non-nutrient [[soil amendments]]. Many sources of fertilizer exist, both natural and [[Agrochemical|industrially]] produced.~~<ref name=Ullmann1/>~~ For most modern agricultural practices, fertilization focuses on three main macro nutrients: [[nitrogen]] (N), [[phosphorus]] (P), and [[potassium]] (K) with occasional addition of supplements like [[rock flour]] for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment, or hand-tool methods.

A '''fertilizer''' or '''fertiliser''' is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply [[plant nutrition|plant nutrients]]. Fertilizers may be distinct from [[Liming (soil)|liming materials]] or other non-nutrient [[soil amendments]]. Many sources of fertilizer exist, both natural and [[Agrochemical|industrially]] produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: [[nitrogen]] (N), [[phosphorus]] (P), and [[potassium]] (K) with occasional addition of supplements like [[rock flour]] for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment, or hand-tool methods.

Historically, fertilization came from natural or organic sources: [[compost]], [[Manure|animal manure]], [[Human waste|human manure]], harvested minerals, [[crop rotation]]s, and byproducts of human-nature industries (e.g. [[Fish meal|fish processing waste]], or [[Blood meal|bloodmeal]] from [[animal slaughter]]). However, starting in the 19th century, after innovations in [[plant nutrition]], an [[Industrial agriculture|agricultural industry]] developed around synthetically created [[Agrochemical|agrochemical fertilizers]]. This transition was important in transforming the [[Food system|global food system]], allowing for larger-scale [[Intensive farming|industrial agriculture]] with large crop yields.

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Management of [[soil fertility]] has preoccupied farmers since the beginning of agriculture. Middle Eastern, Chinese, Mesoamerican, and Cultures of the Central Andes were all early adopters of agriculture. This is thought to have led to their cultures growing faster in population which allowed an exportation of culture to neighboring hunter-gatherer groups. Fertilizer use along with agriculture allowed some of these early societies a critical advantage over their neighbors, leading them to become dominant cultures in their respective regions (P Bellwood - 2023''''''. Egyptians, Romans, Babylonians, and early Germans are all recorded as using minerals or manure to enhance the productivity of their farms. The scientific research of plant nutrition started well before the work of German chemist [[Justus von Liebig]] although his name is most mentioned as the "father of the fertilizer industry". [[Nicolas Théodore de Saussure]] and scientific colleagues at the time were quick to disprove the simplifications of von Liebig. Prominent scientists whom von Liebig drew were [[Carl Ludwig Sprenger]] and [[Hermann Hellriegel]]. In this field, a 'knowledge erosion' took place, partly driven by an intermingling of economics and research. [[John Bennet Lawes]], an English [[entrepreneur]], began experimenting 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]]; together they performed crop experiments at the [[Rothamsted Research|Institute of Arable Crops Research]].

The [[Birkeland–Eyde process]] was one of the competing industrial processes at the beginning of nitrogen-based fertilizer production.~~<ref>{{cite book~~

The [[Birkeland–Eyde process]] was one of the competing industrial processes at the beginning of nitrogen-based fertilizer production. This process was used to fix atmospheric [[nitrogen]] (N2) into [[nitric acid]] (HNO3), one of several chemical processes called [[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 and large [[hydroelectric power]] facilities were built.

~~| title = The development of modern chemistry~~

~~| author = Aaron John Ihde~~

~~| publisher = Courier Dover Publications~~

~~| year = 1984~~

~~| isbn = 978-0-486-64235-2~~

~~| page = 678~~

~~}}</ref>~~ This process was used to fix atmospheric [[nitrogen]] (N2) into [[nitric acid]] (HNO3), one of several chemical processes called [[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 and large [[hydroelectric power]] facilities were built.

The 1910s and 1920s witnessed the rise of the [[Haber process]] and the [[Ostwald process]]. The Haber process produces ammonia (NH3) from [[methane]] (CH4) ([[natural gas]]) gas and molecular nitrogen (N2) from the air. The ammonia from the Haber process is then partially converted into [[nitric acid]] (HNO3) in the [[Ostwald process]]. It is estimated that a third of annual global food production uses ammonia from the Haber–Bosch process and that this supports nearly half the world's population. After World War II, nitrogen production plants that had ramped up for wartime bomb manufacturing were pivoted towards agricultural uses. The use of synthetic nitrogen fertilizers has increased steadily over the last 50 years, rising almost 20-fold to the current rate of 100 million [[tonnes]] of nitrogen per year.

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===Phosphate fertilizers===

[[File:Siilinjärvi Särkijärvi pit.jpg|thumb|left|An apatite mine for phosphates in [[Siilinjärvi carbonatite|Siilinjärvi]], Finland]]

Phosphate fertilizers are obtained by extraction from [[phosphate rock]], which contains two principal phosphorus-containing minerals, [[fluorapatite]] Ca5(PO4)3F (CFA) and [[hydroxyapatite]] Ca5(PO4)3OH. Billions of kg of phosphate rock are mined annually, but the size and quality of the remaining ore is decreasing. These minerals are converted into water-soluble phosphate salts by treatment with [[acid]]s. The large production of [[sulfuric acid]] is primarily motivated by this application.~~<ref>{{Greenwood&Earnshaw2nd}}</ref>~~ 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.

Phosphate fertilizers are obtained by extraction from [[phosphate rock]], which contains two principal phosphorus-containing minerals, [[fluorapatite]] Ca5(PO4)3F (CFA) and [[hydroxyapatite]] Ca5(PO4)3OH. Billions of kg of phosphate rock are mined annually, but the size and quality of the remaining ore is decreasing. These minerals are converted into water-soluble phosphate salts by treatment with [[acid]]s. The large production of [[sulfuric acid]] is primarily motivated by this application. 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.

===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]]).~~<ref>{{Cite web |title=Potassium chloride (PIM 430) |url=https://www.inchem.org/documents/pims/pharm/potasscl.htm |access-date=2025-02-09 |website=www.inchem.org}}</ref>~~ 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]].

[[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]].

===NPK fertilizers===

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===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. Solid fertilizer is typically granulated or powdered. Often solids are available as [[prill]]s, 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.~~<ref name=Ull/>~~ The addition of fertilizer to irrigation water is called "[[fertigation]]".

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. Solid fertilizer is typically granulated or powdered. Often solids are available as [[prill]]s, 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. The addition of fertilizer to irrigation water is called "[[fertigation]]".

====Urea====

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====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. [[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.~~<ref name=Thomas2007 />~~ Although improved crop yields resulting from NPK fertilizers are known to dilute the concentrations of other nutrients in plants, much of the measured decline can be attributed to the use of progressively higher-yielding crop varieties that produce foods with lower mineral concentrations than their less-productive ancestors. 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.

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. [[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. Although improved crop yields resulting from NPK fertilizers are known to dilute the concentrations of other nutrients in plants, much of the measured decline can be attributed to the use of progressively higher-yielding crop varieties that produce foods with lower mineral concentrations than their less-productive ancestors. 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.

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. Soils in Western Australia are very old, highly weathered and deficient in many of the major nutrients and trace elements. Since this time these trace elements are routinely added to fertilizers used in agriculture in this state. 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.

@@ Line 2: / Line 2: @@
 [[File:Manure spreading Hlokozi 2007 11 29.jpg|thumb|upright=1.35|A [[farmer]] spreading [[manure]] to improve [[soil fertility]]]]
-A '''fertilizer''' or '''fertiliser''' is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply [[plant nutrition|plant nutrients]]. Fertilizers may be distinct from [[Liming (soil)|liming materials]] or other non-nutrient [[soil amendments]]. Many sources of fertilizer exist, both natural and [[Agrochemical|industrially]] produced.<ref name=Ullmann1/> For most modern agricultural practices, fertilization focuses on three main macro nutrients: [[nitrogen]] (N), [[phosphorus]] (P), and [[potassium]] (K) with occasional addition of supplements like [[rock flour]] for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment, or hand-tool methods.
+A '''fertilizer''' or '''fertiliser''' is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply [[plant nutrition|plant nutrients]]. Fertilizers may be distinct from [[Liming (soil)|liming materials]] or other non-nutrient [[soil amendments]]. Many sources of fertilizer exist, both natural and [[Agrochemical|industrially]] produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: [[nitrogen]] (N), [[phosphorus]] (P), and [[potassium]] (K) with occasional addition of supplements like [[rock flour]] for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment, or hand-tool methods.
 Historically, fertilization came from natural or organic sources: [[compost]], [[Manure|animal manure]], [[Human waste|human manure]], harvested minerals, [[crop rotation]]s, and byproducts of human-nature industries (e.g. [[Fish meal|fish processing waste]], or [[Blood meal|bloodmeal]] from [[animal slaughter]]). However, starting in the 19th century, after innovations in [[plant nutrition]], an [[Industrial agriculture|agricultural industry]] developed around synthetically created [[Agrochemical|agrochemical fertilizers]]. This transition was important in transforming the [[Food system|global food system]], allowing for larger-scale [[Intensive farming|industrial agriculture]] with large crop yields.
@@ Line 20: / Line 20: @@
 Management of [[soil fertility]] has preoccupied farmers since the beginning of agriculture. Middle Eastern, Chinese, Mesoamerican, and Cultures of the Central Andes were all early adopters of agriculture. This is thought to have led to their cultures growing faster in population which allowed an exportation of culture to neighboring hunter-gatherer groups. Fertilizer use along with agriculture allowed some of these early societies a critical advantage over their neighbors, leading them to become dominant cultures in their respective regions (P Bellwood - 2023''''''. Egyptians, Romans, Babylonians, and early Germans are all recorded as using minerals or manure to enhance the productivity of their farms. The scientific research of plant nutrition started well before the work of German chemist [[Justus von Liebig]] although his name is most mentioned as the "father of the fertilizer industry". [[Nicolas Théodore de Saussure]] and scientific colleagues at the time were quick to disprove the simplifications of von Liebig. Prominent scientists whom von Liebig drew were [[Carl Ludwig Sprenger]] and [[Hermann Hellriegel]]. In this field, a 'knowledge erosion' took place, partly driven by an intermingling of economics and research. [[John Bennet Lawes]], an English [[entrepreneur]], began experimenting 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]]; together they performed crop experiments at the [[Rothamsted Research|Institute of Arable Crops Research]].
-The [[Birkeland–Eyde process]] was one of the competing industrial processes at the beginning of nitrogen-based fertilizer production.<ref>{{cite book
+The [[Birkeland–Eyde process]] was one of the competing industrial processes at the beginning of nitrogen-based fertilizer production. This process was used to fix atmospheric [[nitrogen]] (N<sub>2</sub>) into [[nitric acid]] (HNO<sub>3</sub>), one of several chemical processes called [[nitrogen fixation]]. The resultant nitric acid was then used as a source of [[nitrate]] (NO<sub>3</sub><sup>−</sup>). A factory based on the process was built in [[Rjukan]] and [[Notodden]] in Norway and large [[hydroelectric power]] facilities were built.
-| title = The development of modern chemistry
-| author = Aaron John Ihde
-| publisher = Courier Dover Publications
-| year = 1984
-| isbn = 978-0-486-64235-2
-| page = 678
-}}</ref> This process was used to fix atmospheric [[nitrogen]] (N<sub>2</sub>) into [[nitric acid]] (HNO<sub>3</sub>), one of several chemical processes called [[nitrogen fixation]]. The resultant nitric acid was then used as a source of [[nitrate]] (NO<sub>3</sub><sup>−</sup>). A factory based on the process was built in [[Rjukan]] and [[Notodden]] in Norway and large [[hydroelectric power]] facilities were built.
 The 1910s and 1920s witnessed the rise of the [[Haber process]] and the [[Ostwald process]]. The Haber process produces ammonia (NH<sub>3</sub>) from [[methane]] (CH<sub>4</sub>) ([[natural gas]]) gas and molecular nitrogen (N<sub>2</sub>) from the air. The ammonia from the Haber process is then partially converted into [[nitric acid]] (HNO<sub>3</sub>) in the [[Ostwald process]]. It is estimated that a third of annual global food production uses ammonia from the Haber–Bosch process and that this supports nearly half the world's population. After World War II, nitrogen production plants that had ramped up for wartime bomb manufacturing were pivoted towards agricultural uses. The use of synthetic nitrogen fertilizers has increased steadily over the last 50 years, rising almost 20-fold to the current rate of 100 million [[tonnes]] of nitrogen per year.
@@ Line 116: / Line 109: @@
 ===Phosphate fertilizers===
 [[File:Siilinjärvi Särkijärvi pit.jpg|thumb|left|An apatite mine for phosphates in [[Siilinjärvi carbonatite|Siilinjärvi]], Finland]]
-Phosphate fertilizers are obtained by extraction from [[phosphate rock]], which contains two principal phosphorus-containing minerals, [[fluorapatite]] Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>F (CFA) and [[hydroxyapatite]] Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>OH. Billions of kg of phosphate rock are mined annually, but the size and quality of the remaining ore is decreasing. These minerals are converted into water-soluble phosphate salts by treatment with [[acid]]s. The large production of [[sulfuric acid]] is primarily motivated by this application.<ref>{{Greenwood&Earnshaw2nd}}</ref> 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]] (HNO<sub>3</sub>) to produce a mixture of phosphoric acid (H<sub>3</sub>PO<sub>4</sub>) and [[calcium nitrate]] (Ca(NO<sub>3</sub>)<sub>2</sub>). 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.
+Phosphate fertilizers are obtained by extraction from [[phosphate rock]], which contains two principal phosphorus-containing minerals, [[fluorapatite]] Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>F (CFA) and [[hydroxyapatite]] Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>OH. Billions of kg of phosphate rock are mined annually, but the size and quality of the remaining ore is decreasing. These minerals are converted into water-soluble phosphate salts by treatment with [[acid]]s. The large production of [[sulfuric acid]] is primarily motivated by this application. 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]] (HNO<sub>3</sub>) to produce a mixture of phosphoric acid (H<sub>3</sub>PO<sub>4</sub>) and [[calcium nitrate]] (Ca(NO<sub>3</sub>)<sub>2</sub>). 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.
 ===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]]).<ref>{{Cite web |title=Potassium chloride (PIM 430) |url=https://www.inchem.org/documents/pims/pharm/potasscl.htm |access-date=2025-02-09 |website=www.inchem.org}}</ref> Sometimes potash is referred to as K<sub>2</sub>O, 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]].
+[[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 K<sub>2</sub>O, 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]].
 ===NPK fertilizers===
@@ Line 235: / Line 228: @@
 ===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. Solid fertilizer is typically granulated or powdered. Often solids are available as [[prill]]s, 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.<ref name=Ull/> The addition of fertilizer to irrigation water is called "[[fertigation]]".
+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. Solid fertilizer is typically granulated or powdered. Often solids are available as [[prill]]s, 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. The addition of fertilizer to irrigation water is called "[[fertigation]]".
 ====Urea====
@@ Line 314: / Line 307: @@
 ====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. [[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.<ref name=Thomas2007 /> Although improved crop yields resulting from NPK fertilizers are known to dilute the concentrations of other nutrients in plants, much of the measured decline can be attributed to the use of progressively higher-yielding crop varieties that produce foods with lower mineral concentrations than their less-productive ancestors. 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.
+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. [[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. Although improved crop yields resulting from NPK fertilizers are known to dilute the concentrations of other nutrients in plants, much of the measured decline can be attributed to the use of progressively higher-yielding crop varieties that produce foods with lower mineral concentrations than their less-productive ancestors. 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.
 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. Soils in Western Australia are very old, highly weathered and deficient in many of the major nutrients and trace elements. Since this time these trace elements are routinely added to fertilizers used in agriculture in this state. 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.