Fertilizer

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A farmer spreading manure to improve soil fertility Manure spreading Hlokozi 2007 11 29.jpg
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 nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Many sources of fertilizer exist, both natural and industrially produced. [1] 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.

Contents

Historically, fertilization came from natural or organic sources: compost, animal manure, human manure, harvested minerals, crop rotations, and byproducts of human-nature industries (e.g. fish processing waste, or bloodmeal from animal slaughter). [2] However, starting in the 19th century, after innovations in plant nutrition following Justus von Liebig's discoveries, an agricultural industry developed around synthetically created agrochemical fertilizers. [3] This transition was important in transforming the global food system towards larger-scale industrial agriculture with large crop yields in monocultures. [4]

A farmer throws solid fertilizer into his field in Janakkala, Finland in 1960 Fertilization (JOKAMT2Pe14-1).tif
A farmer throws solid fertilizer into his field in Janakkala, Finland in 1960

The invention of Haber process for producing ammonia for nitrogen in the 20th century combined with amplified chemical production capacity created during World War II led to a boom in using nitrogen fertilizers. [5] In the latter half of the 20th century, increased use of nitrogen fertilizers (800% increase between 1961 and 2019) has been a crucial component of the increased productivity of conventional food systems as part of the so-called "Green Revolution". [6]

Fertilizers, especially when applied excessively, can have environmental consequences such as water pollution [7] and eutrophication [8] due to nutrient runoff. [9] Additionally, the chemical process for creating the fertilizers results in byproducts, including carbon and other emissions. [10] In some cases contamination and pollution of soil result by accumulation of heavy metals contained in some fertilizers collected through mining. [11] Sustainable agricultural practices, such as reduced tillage and planting buffer strips, can minimize these adverse environmental effects. [12]

History

Total fertilizer production by type. Total fertilizer production by nutrient, OWID.svg
Total fertilizer production by type.
World population supported with and without synthetic nitrogen fertilizers. World population supported by synthetic nitrogen fertilizers, OWID.svg
World population supported with and without synthetic nitrogen fertilizers.
Founded in 1812, Mirat, producer of manures and fertilizers, is claimed to be the oldest industrial business in Salamanca (Spain). Instalaciones MIRAT S.A. Salamanca.JPG
Founded in 1812, Mirat, producer of manures and fertilizers, is claimed to be the oldest industrial business in Salamanca (Spain).
Cropland nitrogen balance by component and region Cropland nitrogen balance by component and region.svg
Cropland nitrogen balance by component and region

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. [16] [17] Egyptians, Romans, Babylonians, and early Germans are all recorded as using minerals or manure to enhance the productivity of their farms. [1] 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". [18] 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, [19] partly driven by an intermingling of economics and research. [20] 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 Institute of Arable Crops Research. [21]

The Birkeland–Eyde process was one of the competing industrial processes at the beginning of nitrogen-based fertilizer production. [22] 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. [23]

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) 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. [24] 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. [25] [26] After World War II, nitrogen production plants that had ramped up for wartime bomb manufacturing were pivoted towards agricultural uses. [27] The use of synthetic nitrogen fertilizers has increased steadily over the last 50 years of the 20th century, rising almost 20-fold to the current rate of 100 million tonnes of nitrogen per year in 2003. [28]

The development of synthetic nitrogen fertilizers has significantly supported global population growth. It has been estimated that almost half the people on the Earth are currently fed due to synthetic nitrogen fertilizer use. [29] The use of phosphate fertilizers has also increased from 9 million tonnes per year in 1960 to 40 million tonnes per year in 2000, but future phosphorus fertilizer availability is now a critical issue. [30]

Agricultural use of inorganic fertilizers in 2021 was 195 million tonnes of nutrients, of which 56% was nitrogen. [31] Asia represented 53% of the world's total agricultural use of inorganic fertilizers in 2021, followed by the Americas (29%), Europe (12%), Africa (4%) and Oceania (2%). This ranking of the regions is the same for all nutrients. The main users of inorganic fertilizers are, in descending order, China, India, Brazil, and the United States of America (see Table 15), with China the largest user of each nutrient. [31]

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, 20–25 kg per hectare. [32] Yara International is the world's largest producer of nitrogen-based fertilizers. [33]

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. Reuse of urine demonstration - fertilised and not fertilised tomato plant experiment (3617543234).jpg
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.
Inorganic fertilizer use by region Inorganic fertilizer use by region-.svg
Inorganic fertilizer use by region

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-holding capacity and aeration. [34] This article, like many on fertilizers, emphasizes the nutritional aspect.

Fertilizers typically provide, in varying proportions: [35]

Although calcium uptake by plant roots has long-time been considered as luxury consumption, [42] it is now considerd as an essential element for its various roles in the maintenance of the integrity of plant cell walls and membranes. [43] liming has also a decisive and positive influence on crop yields by couteracting soil acidification, [44] a side-effect of plant growth [45] and nutrient export by crops, [46] improving soil structure, and thus soil aeration, [47] and increasing soil biological actvity, thereby soil fertility, in particular through increased nitrification. [48]

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. Macro-nutrients are present in plant tissue in quantities from 0.15% to 6.0% on a dry matter (DM) (0% moisture) basis but they are sometimes consumed in larger quantities than required (luxury consumption), in particular when fertilizers are used in excess of plant requirements (overfertilization). [49] Plants are made up of four main elements: hydrogen, oxygen, carbon, and nitrogen. Carbon, hydrogen, and oxygen are widely available respectively in carbon dioxide and in water. 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 (amide bonds between amino acids), DNA (puric and pyrimidic bases), and other components (e.g., tetrapyrrolic heme in chlorophyll), but is absent from the parent rock and thus cannot be obtained from mineral weathering. To be nutritious to plants, nitrogen must be made available in a "fixed" form. Only some free-living (e.g. Clostridium ) and symbiotic bacteria living in root systems of host plants (notably legumes) can fix atmospheric nitrogen (N2) by converting it to ammonia (NH3). Phosphate (PO3−4) is required for the production of DNA (genetic code) and ATP, the main energy carrier in cells, as well as certain lipids (phospholipids, the main components of the lipidic double layer of the cell membranes).

Microbiological considerations

Two sets of enzymatic reactions are highly relevant to the efficiency of nitrogen-based fertilizers.

Urease

The first is the hydrolysis (reaction with water) of urea (CO(NH2)2). Many soil bacteria possess the enzyme urease, which catalyzes the conversion of urea to ammonium ion (NH+4) and bicarbonate ion (HCO−3). [50]

Ammonia oxidation

Ammonia-oxidizing bacteria (AOB), such as species of Nitrosomonas , oxidize ammonia (NH3) to nitrite (NO−2), a process termed nitrification. [51] Nitrite-oxidizing bacteria, especially Nitrobacter , oxidize nitrite (NO−2) to nitrate (NO−3), which is extremely soluble and mobile, being leached easily to groundwater then to rivers then to the sea, and is a major cause of eutrophication [52] and algal blooms in rivers, lakes and sea shores. [53]

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 combined. Fertilizers are also sometimes classified as inorganic (the topic of most of this article) versus organic . Inorganic fertilizers exclude carbon-containing materials except urea. Organic fertilizers are usually (recycled) plant- or animal-derived matter (e.g. compost, manure, respectively). Inorganic are sometimes called synthetic fertilizers since various chemical treatments are required for their manufacture. [54]

Single nutrient ("straight") fertilizers

The main nitrogen-based straight fertilizer is ammonia (NH3), ionized in solution as ammonium (NH4+), applied in the form of salts or derivatives, including:

The main straight phosphate fertilizers are the superphosphates:

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, 95–99% KCl). It 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

About 85% of MAP and DAP fertilizers are soluble in water.

NPK fertilizers
Compound fertiliser.jpg
Compound fertilizer
Bulk-blend fertiliser.jpg
Bulk-blend fertilizer

NPK fertilizers are three-component fertilizers providing nitrogen, phosphorus, and potassium. There exist two types of NPK fertilizers: compound and blends. Compound NPK fertilizers contain chemically bound ingredients, while blended NPK fertilizers are physical mixtures of single nutrient components.

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. [56] 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. [57]

Micronutrients

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 or less than 0.04% dry matter. [58] [59] These elements are often required as co-enzymes for enzymes essential to the plant's metabolism. Because these elements enable catalysts (enzymes), their impact far exceeds their concentration. Typical micronutrients are boron, zinc, molybdenum, iron, and manganese. [35] These elements are provided as water-soluble salts. Iron presents special problems because it converts from soluble (ferrous) to insoluble bio-unavailable (ferric) compounds at moderate soil pH and phosphate concentrations. [60] For this reason, iron is often administered as a chelate complex, e.g., the EDTA or EDDHA derivatives. 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, causing boron deficiency. [61]

Production

The production of synthetic, or inorganic, fertilizers require prepared chemicals, [62] whereas organic fertilizers are derived from the biological processing of plant and animal remains or excreta (e.g. urine, feces). [63]

Nitrogen fertilizers

Total nitrogenous fertilizer consumption per region, measured in tonnes of total nutrient per year. Nitrogen fertilizer consumption, OWID.svg
Total nitrogenous fertilizer consumption per region, measured in tonnes of total nutrient per year.

Nitrogen fertilizers are made from ammonia (NH3) produced by the Haber–Bosch process. [55] 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 were one of the original (1830) nitrogen-rich fertilizers used. [64] It is still mined for fertilizer use. [65] Nitrates are also produced from ammonia by the Ostwald process.

Phosphate fertilizers

An apatite mine for phosphates in Siilinjarvi, Finland Siilinjarvi Sarkijarvi pit.jpg
An apatite mine for phosphates in 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. [30] These minerals are converted into water-soluble phosphate salts by treatment with acids. [66] The large production of sulfuric acid is primarily motivated by this application. [67] 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. [68]

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). [69] 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. [70]

NPK fertilizers

NPK 19-19-19 Fertilizer in 1 KG Commercial Packing NPK 19-19-19 Fertilizer in 1 KG Commercial Packing (2).jpg
NPK 19-19-19 Fertilizer in 1 KG Commercial Packing
File:NPK 19-19-19 Fertilizer NPK 19-19-19 Fertilizer (4).jpg
File:NPK 19-19-19 Fertilizer

There are three major routes for manufacturing NPK fertilizers (named for their main ingredients: nitrogen (N), phosphorus (P), and potassium (K)):

Bulk blending. Ingredient kg/ton
Blend ingredientNPK 17-17-17NPK 19-19-19NPK 9-23-30NPK 8-32-16
ammonium nitrate310
urea256
diammonium phosphate (DAP)376421500462
triple superphosphate261
potassium chloride288323500277
filler26

Step 1. Nitrophosphates are made by acidiculating phosphate rock with nitric acid.

Step 2. Removal of Calcium Nitrate. It is important to remove the calcium nitrate because calcium nitrate is extremely hygroscopic.

Organic fertilizers

Compost bin for small-scale production of organic fertilizer HomeComposting Roubaix Fr59.JPG
Compost bin for small-scale production of organic fertilizer
A large commercial compost operation Krechty kompostarna.jpg
A large commercial compost operation

Organic fertilizers can describe those fertilizers with a biological origin, i.e. 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 farming and environmentally friendly gardening, i.e. 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 seashells (crab, oyster, etc.), other prepared products such as seed meal or kelp, and cultivated microorganisms and derivatives. [71]

Fertilizers of an organic origin (the first definition) include animal wastes, plant wastes from agriculture, seaweed, compost, and treated sewage sludge (biosolids). Beyond manures, animal sources can include products from animal slaughters: bloodmeal, bone meal, feather meal, hides, hoofs, and horns all are typical components. [35] Organically derived materials available to industry such as sewage sludge may not be acceptable components of organic farming and gardeining, because of factors ranging from residual contaminants [72] to public perception. [73] No matter the definition nor composition, most of these products contain less-concentrated nutrients, and the nutrients are not as easily quantified. [74] They can offer soil-building advantages as well as be appealing to those who are trying to farm or garden more naturally. [75]

In terms of volume, peat is the most widely used packaged organic soil amendment. It is an immature form of coal which improves soil aeration and moisture and thus soil biological activity but confers no direct nutritional value to the plants. It is therefore not a fertilizer as defined in the beginning of the article, but rather an amendment. [76] Coir (derived from coconut husks), bark, and sawdust are mainly applied as mulch and protects the soil from desiccation [77] while preventing the development of weeds [78] and improving soil structure, [79] but do not confer any nutritional value to the soil. Some organic additives can even have a reverse effect on nutrients. Fresh sawdust can consume soil nutrients as it breaks down and is colonized by wood-decay fungi, causing nitrogen deficiency (nitrogen drawdown) in the absence of nutrient addition. [80] However, this property can be used to capture excess mineral nitrogen. [81] These same organic soil texturizers (as well as compost, etc.) may increase the availability of nutrients through improved cation-exchange capacity, [82] or through increased growth of microorganisms that in turn increase availability of certain plant nutrients. [83] True organic fertilizers such as composts and manures may be distributed locally without going into industry production, making actual consumption more difficult to quantify.

Fertilizer consumption

Fertilizer use (2023). From FAO's World Food and Agriculture - Statistical Yearbook 2025 Inorganic fertilizer use (2023).svg
Fertilizer use (2023). From FAO's World Food and Agriculture – Statistical Yearbook 2025
The diagram displays the statistics of fertilizer consumption in western and central European countries from data published by The World Bank for 2012. Fertilizer consumption in Europe.png
The diagram displays the statistics of fertilizer consumption in western and central European countries from data published by The World Bank for 2012.

Top users of nitrogen-based fertilizer [84]
CountryTotal
N use
(Mt pa)		N use for
feed and
pasture
(Mt pa)
China18.73.0
India11.9n/a [85]
U.S.9.14.7
France2.51.3
Germany2.01.2
Brazil 1.70.7
Canada1.60.9
Turkey 1.50.3
UK1.30.9
Mexico 1.30.3
Spain1.20.5
Argentina 0.40.1

China has become the largest producer and consumer of nitrogen fertilizers [86] while Africa has little reliance on nitrogen fertilizers. [87] Agricultural and chemical minerals are very important in industrial use of fertilizers, which is valued at approximately $200 billion. [88] 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. [88] Potash is produced in Canada, Russia and Belarus, together making up over half of the world production. [88] Potash production in Canada rose in 2017 and 2018 by 18.6%. [89] [90] Conservative estimates report 30 to 50% of crop yields are attributed to natural or synthetic commercial fertilizers. [70] [91] Fertilizer consumption has surpassed the amount of farmland in the United States. [88]

Data on the fertilizer consumption per hectare arable land in 2012 are published by The World Bank. [92] The diagram below shows fertilizer consumption by the European Union (EU) countries as kilograms per hectare (pounds per acre). The total consumption of fertilizer in the EU reached a peak of 11.6 million tons in 2017 but decreased steadily since that time, down to 9.3 million tons in 2023 [93] for 157 million hectares arable land area in 2020, 1.5 million hectares less than in 2010. [94] This figure equates to 70 kg of fertilizers consumed per ha arable land on average by the EU countries in 2020.

Application

Fertilizer sprayer Farm fertilizer.jpg
Fertilizer sprayer
Drone crop fertilizer Drone crop fertilizer.jpg
Drone crop fertilizer
Applying superphosphate fertilizer by hand, New Zealand, 1938 7252 Hand top-dressing of super phosphate on Banks Peninsula.jpg
Applying superphosphate fertilizer by hand, New Zealand, 1938

Fertilizers are commonly used for growing all crops, with application rates depending on 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, hence their promising use for ensuring agriculture sustainability. [95]

Timing and amount of application

The timing of application of fertilizers (here only mineral fertilizers will be considered) is a function of crop requirements, weather condition and market opportunities. It varies in nature and amount according to the type of agriculture (e.g. intensive farming versus conservation agriculture, grassland versus arable land), and the presence or absence of signs of nutrient deficiencies. Timing fertilization with peak nutrient uptake demand is essential for optimizing both yield and quality. In general, nutrient uptake rates are highest from early to midgrowing season, which is why fertilization near the time of seeding is generally very effective. With fall-planted grains (e.g. winter wheat), fall N fertilization followed by spring topdressing is likely the best combination of fertilization practices to optimize yield. [96] The application of a soluble mineral fertilizer (e.g. ammonium nitrate) is avoided during heavy rainfall because most of it would be lost for the crop [97] and would rapidly pollute the aquifer. [98] In conservation agriculture (including no-till farming, permaculture) as well as other non-organic alternatives to intensive farming (e.g. smallholding agriculture) the application of mineral fertilizers is reduced to the strict requirements of the cultivated plants and sometimes is quite unnecessary. [99]

After harvest of a main crop (e.g. wheat, maize, potatoes) a catch crop can be sown, using plant species with a rapid growth rate and high demand of nitrogen (e.g. white mustard). [100] This allows excess nitrogen, in particular the very mobile nitrate anion, to be taken up and transformed in plant proteins [101] before contaminating the groundwater, and the associated geochemical processes, which would rapidly occur in the absence of plant cover. [102] The catch crop is further buried, allowing its tranformation in humus in which nitrogen is fixed according to various stable chemical bonds. [103]

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. [104] 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. [35] The addition of fertilizer to irrigation water is called fertigation . [70] Granulated fertilizers are more economical to ship and store, not to mention easier to apply. [105] [106]

Slow- and controlled-release fertilizers

A controlled-release fertiliser (CRF) is a granulated fertiliser that releases nutrients gradually into the soil (i.e., with a controlled release period). [107] Controlled-release fertilizer is also known as controlled-availability fertilizer, delayed-release fertilizer, metered-release fertilizer, or slow-acting fertilizer. Usually slow- and controlled-release fertilizers refer to nitrogen-based fertilizers, e.g. ureaform, needing degradation by a wide spectrum of soil organisms before nitrogen could be liberated as nitrate. [108] Slow-release fertilizers (SRF) and controlled-release fertilizers (CRF) offer various benefits over conventional ones, ensuring sustainability in fertilizing practice. [109] [110]

Foliar application

Foliar fertilizers are applied directly to leaves. They can reduce the total amounts of fertilizer applied and achieve high fertilizer efficiency. [111] This method is almost invariably used to apply water-soluble straight nitrogen fertilizers and used especially for high-value crops such as fruits. Urea is the most common foliar fertilizer. [35] However, chelation of the foliar-applied nutrient is recommanded for improving absorption and migration of the targeted nutrient and thereby avoiding loss to the soil and the groundwater. [111]

Chemicals that affect nitrogen uptake

N-Butylthiophosphoryltriamide, an enhanced efficiency fertilizer N-butylthiophosphoryltriamide.svg
N-Butylthiophosphoryltriamide, an enhanced efficiency fertilizer

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. [112] Urease inhibitors are used to slow the hydrolytic conversion of urea into ammonia catalyzed by ureases, ammonia being prone to evaporation [113] as well as nitrification. [114] A popular inhibitor of ureases is N-(n-butyl)thiophosphoric triamide (NBPT).

Overfertilization

Fertilizer burn Fertilizer-Burn.jpg
Fertilizer burn

Careful use of fertilization technologies is important because excess nutrients can be detrimental to the cultivated plant. [115] 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. [116] [117]

Environmental effects

Runoff of soil and fertilizer during a rain storm Runoff of soil & fertilizer.jpg
Runoff of soil and fertilizer during a rain storm

Synthetic fertilizers used in agriculture have wide-reaching environmental consequences.

According to the Intergovernmental Panel on Climate Change (IPCC) Special Report on Climate Change and Land, production of these fertilizers and associated land use practices are drivers of global warming. [6] The use of fertilizer has also led to a number of direct environmental consequences: agricultural runoff which leads to downstream effects like ocean dead zones [118] and waterway contamination, [119] soil microbiome degradation, [120] and accumulation of toxic compounds in ecosystems. [121] Indirect environmental impacts include: N-crop-pest cascades, [122] increased greenhouse gas emissions and environmental impacts of fracking for the natural gas used in the Haber process, [123] [124] the agricultural boom which is partially responsible for the rapid growth in human population [125] and large-scale industrial agricultural practices associated with it causing pressure on biodiversity, habitat destruction and fragmentation, [126] and agricultural soil loss. [127]

In order to mitigate environmental and food security concerns, the international community has included food systems in Sustainable Development Goal 2 which focuses on creating a climate-friendly and sustainable food production system. [128] Most policy and regulatory approaches to address these issues focus on pivoting agricultural practices towards sustainable or regenerative agricultural practices: these use less synthetic fertilizers, better soil management (for example no-till agriculture) and more organic fertilizers.

Large pile of phosphogypsum waste near Fort Meade, Florida GypStack.JPG
Large pile of phosphogypsum waste near Fort Meade, Florida

For each ton of phosphoric acid produced by the processing of phosphate rock, five tons of waste are generated. This waste takes the form of impure, useless, radioactive solid called phosphogypsum. Estimates range from 100,000,000 and 280,000,000 tons of phosphogypsum waste produced annually worldwide. [129]

Water

Red circles show the location and size of many dead zones Aquatic Dead Zones.jpg
Red circles show the location and size of many dead zones

Phosphorus and nitrogen fertilizers can affect soil, surface water, and groundwater [88] due to the dispersion of minerals into waterways under high rainfall, [130] [131] snowmelt and can leach into groundwater over time. [132] Agricultural run-off is a major contributor to the eutrophication of freshwater bodies. For example, in the US, about half of all the lakes surveyer by the United States Environmental Protection Agency (US EPA) were eutrophic in 2007 with a further alarming increase to 80 per cent in 2012. [133] The main contributor to eutrophication is phosphate, which is normally a limiting nutrient, besides nitrogen; high P concentrations promote the growth of cyanobacteria and algae, the demise of which consumes oxygen. [134] Cyanobacteria blooms ('algal blooms') can also produce harmful toxins that can accumulate in the food chain, and can be harmful to humans. [135] [136] Fertilizer run-off can be reduced by using weather-optimized fertilization strategies. [130]

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. [137] The number of oceanic dead zones near inhabited coastlines is increasing. [138]

As of 2006, the application of nitrogen fertilizer is being increasingly controlled in northwestern Europe [139] and the United States. [140] [141] In cases where eutrophication can be reversed, it may nevertheless take decades [142] and significant soil management [143] 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. [144] 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. [145] [146] [147] 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. [148]

Nitrate levels above 10 mg/L (10 ppm) in groundwater can cause 'blue baby syndrome' (acquired methemoglobinemia). [149] 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. [150] Run-off can lead to fertilizing blooms of algae that use up all the oxygen and leave huge "dead zones" behind where other fish and aquatic life can not live. [151]

Soil

Acidification

Soil acidification refers to the process by which the pH level of soil becomes more acidic over time. Soil pH is a measure of the soil's acidity or alkalinity and is determined on a scale from 0 to 14, with 7 being neutral. A pH value below 7 indicates acidic soil, while a pH value above 7 indicates alkaline or basic soil.

Soil acidification is a significant concern in agriculture and horticulture. It refers to the process of the soil becoming more acidic over time.

Nitrogen-containing fertilizers can cause soil acidification when added. [152] [153] This may lead to decrease in nutrient availability which may be offset by liming. These fertilizers release ammonium or nitrate ions, which can acidify the soil as they undergo chemical reactions.

When these nitrogen-containing fertilizers are added to the soil, they increase the concentration of hydrogen ions (H+) in the soil solution, which lowers the pH of the soil.

Accumulation of toxic elements

Cadmium

The concentration of cadmium in phosphorus-containing fertilizers varies considerably and can be problematic. [154] 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. [155] The phosphate rock used in their manufacture can contain as much as 188 mg/kg cadmium [156] (examples are deposits on Nauru [157] and the Christmas Islands [158] ). Continuous use of high-cadmium fertilizer can contaminate soil (as shown in New Zealand) [159] and plants. [160] Limits to the cadmium content of phosphate fertilizers has been considered by the European Commission. [161] [162] [163] Producers of phosphorus-containing fertilizers now select phosphate rock based on the cadmium content. [134]

Fluoride

Phosphate rocks contain high levels of fluoride. Consequently, the widespread use of phosphate fertilizers has increased soil fluoride concentrations. [160] 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. [164] [165] Also of possible concern are the effects of fluoride on soil microorganisms. [164] [165] [166]

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. [160] [167] Uranium-238 concentrations can range from 7 to 100 pCi/g (picocuries per gram) in phosphate rock [168] and from 1 to 67 pCi/g in phosphate fertilizers. [169] [170] [171] 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. [170] [172] 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). [170] [173] [174]

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 [175] arsenic, cadmium, [175] chromium, and nickel. The most common toxic elements in this type of fertilizer are mercury, lead, and arsenic. [176] [177] [178] 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. [179] [180] 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. [180] Although improved crop yields resulting from NPK fertilizers are known to dilute the concentrations of other nutrients in plants, [179] [181] 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. [179] [182] [183] 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. [179] [184]

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. [185] Soils in Western Australia are very old, highly weathered and deficient in many of the major nutrients and trace elements. [185] Since this time these trace elements are routinely added to fertilizers used in agriculture in this state. [185] 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. [186]

Changes in soil biology

High levels of fertilizer may cause the breakdown of the symbiotic relationships between plant roots and mycorrhizal fungi. [187]

Organic agriculture

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. [188]

Hydrogen consumption and sustainability

Most fertilizer is made from dirty hydrogen. [189] Ammonia is produced from natural gas and air. [190] The cost of natural gas makes up about 90% of the cost of producing ammonia. [191] 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. [192]

Contribution to climate change

The amount of greenhouse gases carbon dioxide, methane and nitrous oxide produced during the manufacture and use of nitrogen fertilizer is estimated as around 5% of anthropogenic greenhouse gas emissions. One third is produced during the production and two thirds during the use of fertilizers. [193] Nitrogen fertilizer can be converted by soil bacteria to nitrous oxide, a greenhouse gas. [194] Nitrous oxide emissions by humans, most of which are from fertilizer, between 2007 and 2016 have been estimated at 7 million tonnes per year, [195] which is incompatible with limiting global warming to below 2 °C. [196]

Atmosphere

Global methane concentrations (surface and atmospheric) for 2005; note distinct plumes AtmosphericMethane.png
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, [197] [198] 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. [199] By changing processes and procedures, it is possible to mitigate some, but not all, of these effects on anthropogenic climate change. [200]

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. [201] [202]

Policy

Regulation

In Europe, problems with high nitrate concentrations in runoff are being addressed by the European Union's Nitrates Directive. [203] Within Britain, farmers are encouraged to manage their land more sustainably in 'catchment-sensitive farming'. [204] In the US, high concentrations of nitrate and phosphorus in runoff and drainage water are classified as nonpoint source pollutants due to their diffuse origin; this pollution is regulated at the state level. [205] Oregon and Washington, both in the United States, have fertilizer registration programs with on-line databases listing chemical analyses of fertilizers. [206] [207] Carbon emission trading and eco-tariffs affect the production and price of fertilizer. [208]

Subsidies

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. [209]

In March 2022, the United States Department of Agriculture announced a new $250M grant to promote American fertilizer production. Part of the Commodity Credit Corporation, the grant program will support fertilizer production that is independent of dominant fertilizer suppliers, made in America, and utilizing innovative production techniques to jumpstart future competition. [210]

See also

References

  1. 1 2 3 Scherer, Heinrich W.; Mengel, Konrad; Kluge, Günter; Severin, Karl (15 July 2009). "Fertilizers, 1. General". Ullmann's Encyclopedia of Industrial Chemistry . Vol. 14. pp. 171–97. doi:10.1002/14356007.a10_323.pub3. ISBN   9783527306732 . Retrieved 5 December 2025.
  2. ↑ Güldner, Dino; Larsen, Laura; Cunfer, Geoff (20 August 2021). "Soil fertility transitions in the context of industrialization, 1750–2000". Social Science History . 45 (Special Issue 4): 785–811. doi:10.1017/ssh.2021.26 . Retrieved 5 December 2025.
  3. ↑ Russell, Darrell A.; Williams, Gerald G. (March–April 1977). "History of chemical fertilizer development". Soil Science Society of America Journal . 41 (2): 260–5. doi:10.2136/sssaj1977.03615995004100020020x . Retrieved 5 December 2025.
  4. ↑ Tilman, David; Cassman, Kenneth G.; Matson, Pamela A.; Naylor, Rosamond; Polasky, Stephen (8 August 2002). "Agricultural sustainability and intensive production practices". Nature . 418: 671–7. doi:10.1038/nature01014 . Retrieved 5 December 2025.
  5. ↑ "Fritz Haber". Science History Institute . 1 June 2016. Retrieved 5 December 2025.
  6. 1 2 Mbow, Cheikh; Rosenzweig, Cynthia (2019). "Food security" (PDF). Climate change and land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems. pp. 437–550. Retrieved 18 December 2025.
  7. ↑ McIsaac, Gregory (2003). "Surface water pollution by nitrogen fertilizers". In Steward, Bertram A.; Howell, Terry A. (eds.). Encyclopedia of water Science (1st ed.). Boca Raton, Florida: CRC Press. pp. 950–5. doi:10.1201/NOE0849396274. ISBN   9781351249829 . Retrieved 5 December 2025.
  8. ↑ Huang, Jing; Xu, Chang-chun; Ridoutt, Bradley G.; Wang, Xue-chun; Ren, Pin-an (15 August 2017). "Nitrogen and phosphorus losses and eutrophication potential associated with fertilizer application to cropland in China". Journal of Cleaner Production . 159: 171–9. doi:10.1016/j.jclepro.2017.05.008 . Retrieved 10 December 2025.
  9. ↑ Harmel, R. Daren; Pampell, Rehanon A.; Leytem, April B.; Smith, D. R.; Haney, Rick L. (1 January 2018). "Assessing edge-of-field nutrient runoff from agricultural lands in the United States: how clean is clean enough?". Journal of Soil and Water Conservation . 73 (1): 9–23. doi:10.2489/jswc.73.1.9 . Retrieved 5 December 2025.
  10. ↑ Brentrup, Frank; Hoxha, Antoine; Christensen, Bjarne (October 2016). "Carbon footprint analysis of mineral fertilizer production in Europe and other world regions". LCA Food 2016. Retrieved 5 December 2025.
  11. ↑ Zwolak, Aneta; Sarzyńska, Magdalena; Szpyrka, Ewa; Stawarczyk, Kinga (6 July 2019). "Sources of soil pollution by heavy metals and their accumulation in vegetables: a review". Water, Air, and Soil Pollution . 230 164. doi: 10.1007/s11270-019-4221-y .
  12. ↑ Muhie, Seid Hussen (December 2022). "Novel approaches and practices to sustainable agriculture". Journal of Agriculture and Food Research. 10 100446. doi: 10.1016/j.jafr.2022.100446 .
  13. ↑ "Fertilizer use per capita, World, 1961 to 2022". Our World in Data . Retrieved 8 December 2025.
  14. ↑ "World population with and without synthetic nitrogen fertilizers". Our World in Data . Retrieved 8 December 2025.
  15. 1 2 3 FAO (2025). World Food and Agriculture – Statistical Yearbook 2025. Rome, Italy: FAO. doi: 10.4060/cd4313en . ISBN   978-92-5-140174-3.
  16. ↑ Bellwood, Peter (2004). First farmers: the origins of agricultural societies. Hoboken, New Jersey: Wiley-Blackwell. ISBN   9780631205661 . Retrieved 8 December 2025.
  17. ↑ Liu, Min; Zhong, Taiyang; Lyu, Xiao (22 January 2024). "Spatial spillover effects of "New Farmers" on diffusion of sustainable agricultural practices: evidence from China". Land. 13 (1) 119. Bibcode:2024Land...13..119L. doi: 10.3390/land13010119 . ISSN   2073-445X.
  18. ↑ "Justus von Liebig and the agricultural revolution". 12 May 2020. Archived from the original on 12 July 2024.
  19. ↑ Uekötter, Frank (2010). Die Wahrheit ist auf dem Feld: eine Wissensgeschichte der deutschen Landwirtschaft (in German) (3rd ed.). Göttingen, Germany: Vandenhoeck & Ruprecht. ISBN   978-3-5253-1705-1.
  20. ↑ Uekötter, Frank (1 January 2014). "Why panaceas work: recasting science, knowledge, and fertilizer interests in German agriculture". Agricultural History . 88 (1): 68–86. doi:10.3098/ah.2014.88.1.68. ISSN   0002-1482. JSTOR   10.3098/ah.2014.88.1.68 . Retrieved 8 December 2025.
  21. ↑ Warington, Robert (13 September 1900). "Sir John Bennet Lawes, Bart., F.R.S." Nature . 62 (1611): 467–8. doi:10.1038/062467a0 . Retrieved 8 December 2025.
  22. ↑ Ihde, Aaron John (1964). The development of modern chemistry. New York, New York: Harper & Row. p. 678. ISBN   978-1124062938 . Retrieved 8 December 2025.{{cite book}}: ISBN / Date incompatibility (help)
  23. ↑ Leigh, G. Jeffery (9 September 2004). The world's greatest fix: a history of nitrogen and agriculture. Oxford, United Kingdom: Oxford University Press. pp. 134–9. ISBN   978-0-19-516582-1 . Retrieved 8 December 2025.
  24. ↑ Williams, Trevor Illtyd; Thomas Kingston, Derry (7 October 1982). A short history of twentieth-century technology c. 1900-c. 1950. Oxfors, United Kingdom: Oxford University Press. pp. 134–5. ISBN   978-0-19-858159-8 . Retrieved 8 December 2025.
  25. ↑ Smil, Vaclav (2004). Enriching the Earth: Fritz Haber, Carl Bosch, and the transformation of world food production. Cambridge, Massachusetts: MIT Press. p. 156. doi: 10.7551/mitpress/2767.003.0001 . ISBN   978-0-262-69313-4.
  26. ↑ Flavell-While, Claudia. "Fritz Haber and Carl Bosch: feed the world". www.thechemicalengineer.com. Archived from the original on 19 June 2021. Retrieved 8 December 2025.
  27. ↑ Philpott, Tom (19 April 2013). "A brief history of our deadly addiction to nitrogen fertilizer". Mother Jones. Retrieved 8 December 2025.
  28. ↑ Glass, Anthony (September 2003). "Nitrogen use efficiency of crop plants: physiological constraints upon nitrogen absorption". Critical Reviews in Plant Sciences. 22 (5): 453–70. doi:10.1080/713989757 . Retrieved 8 December 2025.
  29. ↑ Erisman, Jan Willem; Sutton, Mark A.; Galloway, James; Klimont, Zbigniew; Winiwarter, Wilfried (28 September 2008). "How a century of ammonia synthesis changed the world". Nature Geoscience . 1 (10): 636–9. Bibcode:2008NatGe...1..636E. doi:10.1038/ngeo325. S2CID   94880859 . Archived from the original on 23 July 2010. Retrieved 8 December 2025.
  30. 1 2 Blackwell, Martin; Darch, Tegan; Haslam, Richard (2019). "Phosphorus use efficiency and fertilizers: future opportunities for improvements". Frontiers of Agricultural Science and Engineering. 6 (4): 332–40. doi:10.15302/J-FASE-2019274 . Retrieved 8 December 2025.
  31. 1 2 FAO (2023). World Food and Agriculture – Statistical Yearbook 2023. Rome, Italy: FAO. doi: 10.4060/cc8166en . ISBN   978-92-5-138262-2.
  32. ↑ Vance, Carroll P.; Uhde-Stone, Claudia; Allan, Deborah L. (March 2003). "Phosphorus acquisition and use: critical adaptations by plants for securing a non renewable resource". New Phytologist . 157 (3): 423–47. Bibcode:2003NewPh.157..423V. doi: 10.1046/j.1469-8137.2003.00695.x . JSTOR   1514050. PMID   33873400. S2CID   53490640.
  33. ↑ "A growth business: feeding the world has become a mouth-watering opportunity". The Economist . 18 February 2010. Retrieved 9 December 2025.
  34. ↑ Naveed, Muhammad; Moldrup, Per; Vogel, Hans-Jörg; Lamandé, Mathieu; Wildenschild, Dorthe; Tuller, Markus; De Jonge, Lis Wollesen (April 2014). "Impact of long-term fertilization practice on soil structure evolution". Geoderma. 217–218: 181–9. doi:10.1016/j.geoderma.2013.12.001 . Retrieved 9 December 2025.
  35. 1 2 3 4 5 Dittmar, Heinrich; Drach, Manfred; Vosskamp, Ralf; Trenkel, Martin E.; Gutser, Reinhold; Steffens, Günter (15 July 2009). "Fertilizers, 2. Types". Ullmann's Encyclopedia of Industrial Chemistry, volume 14. pp. 199–246. doi:10.1002/14356007.n10_n01. ISBN   9783527306732 . Retrieved 5 December 2025.
  36. ↑ Pearman, I.; Thomas, Susan M.; Thorne, Gillian N. (January 1977). "Effects of nitrogen fertilizer on growth and yield of spring wheat". Annals of Botany . 41 (1): 93–108. doi:10.1093/oxfordjournals.aob.a085289 . Retrieved 9 December 2025.
  37. ↑ Majeed, Muhammad Atif; Ahmad, Rashid; Tahir, Muhammad; Tanveer, Asif; Ahmad, Muhammad (January–March 2014). "Effect of phosphorus fertilizer sources and rates on growth and yield of wheat (Triticum aestivum L.)" (PDF). Asian Journal of Agriculture and Biology. 2 (1): 14–9. Retrieved 9 December 2025.
  38. ↑ Pettigrew, William T. (August 2008). "Potassium influences on yield and quality production for maize, wheat, soybean and cotton". Physiologia Plantarum . 133 (4): 670–81. Retrieved 9 December 2025.
  39. ↑ Bekele, Demsew; Birhan, Muluadam (2021). "The impact of secondary macro nutrients on crop production". International Journal of Research Studies in Agricultural Sciences. 7 (5): 37–51. doi: 10.20431/2454-6224.0705005 .
  40. ↑ Saquee, Francess Sia; Diakite, Simbo; Kavhiza, Nyasha John; Pakina, Elena; Zargar, Meisam (16 February 2023). "The efficacy of micronutrient fertilizers on the yield formulation and quality of wheat grains". Agronomy . 13 (2) 566. doi: 10.3390/agronomy13020566 .
  41. ↑ Kaur, Simranjeet; Kaur, Navneet; Siddique, Kadambot H. M.; Nayyar, Harsh (27 October 2015). "Beneficial elements for agricultural crops and their functional relevance in defence against stresses". Archives of Agronomy and Soil Science. 62 (7): 905–20. doi:10.1080/03650340.2015.1101070 . Retrieved 9 December 2025.
  42. ↑ Loneragan, Jack F.; Snowball, K. (1 June 1969). "Calcium requirements of plants". Australian Journal of Agricultural Research . 20 (3): 465–78. doi:10.1071/AR9690465 . Retrieved 9 December 2025.
  43. ↑ White, Philip J.; Broadley, Martin R. (October 2003). "Calcium in plants". Annals of Botany . 92 (4): 487–511. doi:10.1093/aob/mcg164 . Retrieved 9 December 2025.
  44. ↑ Goulding, Keith W. T. (September 2016). "Soil acidification and the importance of liming agricultural soils with particular reference to the United Kingdom". Soil Use and Management. 32 (3): 390–9. doi: 10.1111/sum.12270 .
  45. ↑ Haynes, Richard J. (March 1983). "Soil acidification induced by leguminous crops". Grass and Forage Science. 38 (1): 1–11. doi:10.1111/j.1365-2494.1983.tb01614.x . Retrieved 9 December 2025.
  46. ↑ Burle, Marilia L.; Mielniczuk, João; Focchi, Sandro (March 1997). "Effect of cropping systems on soil chemical characteristics, with emphasis on soil acidification". Plant and Soil . 190 (2): 309–16. doi:10.1023/A:1004266831343 . Retrieved 9 December 2025.
  47. ↑ Schack-Kirchner, Helmer; Hildebrand, Ernst E. (February 1998). "Changes in soil structure and aeration due to liming and acid irrigation". Plant and Soil . 199 (1): 167–76. doi:10.1023/A:1004290226402 . Retrieved 9 December 2025.
  48. ↑ Fuentes, Juan P.; Bezdicek, David F.; Flury, Markus; Albrecht, Stefan; Smith, Jeffrey L. (July 2006). "Microbial activity affected by lime in a long-term no-till soil". Soil and Tillage Research. 88 (1–2): 123–31. Retrieved 9 December 2025.
  49. ↑ Van Wesenbeeck, Cornelia F. A.; Keyzer, Michiel A.; Van Veen, Wim C. M.; Qiu, Huanguang (May 2021). "Can China's overuse of fertilizer be reduced without threatening food security and farm incomes?". Agricultural Systems. 190 103093. Retrieved 10 December 2025.
  50. ↑ Lloyd, A. B.; Sheffe, M. Jane (August 1973). "Urease activity in soils". Plant and Soil . 39 (1): 71–80. Retrieved 10 December 2025.
  51. ↑ Marsh, K. L.; Sims, Gerald K.; Mulvaney, Richard L. (28 June 2005). "Availability of urea to autotrophic ammonia-oxidizing bacteria as related to the fate of 14C- and 15N-labeled urea added to soil". Biology and Fertility of Soils. 42 (2): 137–45. Retrieved 10 December 2025.
  52. ↑ Smolders, Alfons J. P.; Lucassen, Esther C. H. E. T.; Bobbink, Roland; Roelofs, Jan G. M.; Lamers, Leon P. M. (5 November 2009). "How nitrate leaching from agricultural lands provokes phosphate eutrophication in groundwater fed wetlands: the sulphur bridge". Biogeochemistry. 98 (1): 1–7. Retrieved 11 December 2025.
  53. ↑ Wurtsbaugh, Wayne A.; Paerl, Hans W.; Dodds, Walter K. (September–October 2019). "Nutrients, eutrophication and harmful algal blooms along the freshwater to marine continuum". Wiley Interdisciplinary Reviews Water . 6 (5) e1373. Retrieved 11 December 2025.
  54. ↑ Jones, J. Benton Jr (2012). "Inorganic chemical fertilizers and their properties". Plant nutrition and soil fertility manual (2nd ed.). pp. 157–67. doi:10.1201/b11577. ISBN   9780429130816 . Retrieved 11 December 2025.
  55. 1 2 Smil, Vaclav (2004). "Synthetic fertilizers". Enriching the Earth: Fritz Haber, Carl Bosch, and the transformation of world food production (PDF). Cambridge, Massachusetts: MIT Press. pp. 153–64. doi:10.7551/mitpress/2767.003.0009. ISBN   9780262283854 . Retrieved 11 December 2025.
  56. ↑ "Label requirements of specialty and other bagged fertilizers". Lansing, Michigan: Michigan Department of Agriculture and Rural Development . Retrieved 11 December 2025.
  57. ↑ "National code of practice for fertilizer description and labelling" (PDF). Australian Government Department of Agriculture and Water Resources . October 2024. Archived (PDF) from the original on 28 February 2015. Retrieved 11 December 2025.
  58. ↑ "Nutrient content of plants". University of Georgia, Agricultural & Environmental Services Laboratories. Retrieved 11 December 2025.
  59. ↑ Bryson, Gretchen M.; Mills, Harry A. (2014). Plant analysis handbook IV (PDF). Athens, Greece: Micro-Macro Publishing. ISBN   978-1-878148-03-2 . Retrieved 11 December 2025.
  60. ↑ Mitra, Ashim K.; Matthews, Michael L. (February 1985). "Effects of pH and phosphate on the oxidation of iron in aqueous solution". International Journal of Pharmaceutics . 23 (2): 185–93. Retrieved 11 December 2025.
  61. ↑ García-Sánchez, Francisco; Simón-Grao, Silvia; Martínez-Nicolás, Juan J.; Alfosea-Simón, Marina; Liu, Chunguang; Chatzissavvidis, Christos; Pérez-Pérez, Juan G.; Cámara-Zapata, José M. (5 October 2020). "Multiple stresses occurring with boron toxicity and deficiency in plants". Journal of Hazardous Materials . 397 122713. doi:10.1016/j.jhazmat.2020.122713 . Retrieved 11 December 2025.
  62. ↑ Rajani, Ashokkumar V. "Fertilizer production process" . Retrieved 11 December 2025.
  63. ↑ Hossain, Md. Mikail. "Advanced strategies in organic fertilizer production: comprehensive guide to sustainable practices and techniques" . Retrieved 11 December 2025.
  64. ↑ "Supplemental technical report for sodium nitrate (crops)" (PDF). ams.usda.gov. Archived from the original on 14 July 2014. Retrieved 11 December 2025.
  65. ↑ "Caliche ore". sqm.com. Archived from the original on 14 July 2014. Retrieved 6 July 2014.
  66. ↑ Cordell, Dana; Drangert, Jan-Olof; White, Stuart (May 2009). "The story of phosphorus: global food security and food for thought". Global Environmental Change . 19 (2): 292–305. Bibcode:2009GEC....19..292C. doi:10.1016/j.gloenvcha.2008.10.009. S2CID   1450932 . Retrieved 11 December 2025.
  67. ↑ Greenwood, Norman Neill; Earnshaw, Alan (1997). Chemistry of the elements (2nd ed.). doi:10.1016/C2009-0-30414-6. ISBN   978-0-7506-3365-9 . Retrieved 12 December 2025.
  68. ↑ EFMA (2000). "Production of NPK fertilizers by the nitrophosphate route" (PDF). fertilizerseurope.com. Brussels, Belgium: European Fertilizer Manufacturers' Association. Archived (PDF) from the original on 29 July 2014. Retrieved 12 December 2025.
  69. ↑ Myrenfors, Peter (August 1992). "Potassium chloride". www.inchem.org. Retrieved 12 December 2025.
  70. 1 2 3 Gowariker, Vasant; Krishnamurthy, V. N.; Gowariker, Sudha; Dhanorkar, Manik; Paranjape, Kalyani (2009). The fertilizer encyclopedia. doi:10.1002/9780470431771. ISBN   9780470431771 . Retrieved 12 December 2025.
  71. ↑ Bergstrand, Karl-Johan (15 March 2022). "Organic fertilizers in greenhouse production systems: a review" (PDF). Scientia Horticulturae. 295 110855. doi:10.1016/j.scienta.2021.110855 . Retrieved 12 December 2025.
  72. ↑ Smith, Stephen R. (13 October 2009). "Organic contaminants in sewage sludge (biosolids) and their significance for agricultural recycling". Philosophical Transactions A . 367 (1904): 4005–41. doi:10.1098/rsta.2009.0154 . Retrieved 12 December 2025.
  73. ↑ Ekane, Nelson; Barquet, Karina; Rosemarin, Arno (19 April 2021). "Resources and risks: perceptions on the application of sewage sludge on agricultural land in Sweden, a case study". Frontiers in Sustainable Food Systems . 5 647780. doi: 10.3389/fsufs.2021.647780 .
  74. ↑ Möller, Kurt; Schultheiß, Ute (14 November 2014). "Chemical characterization of commercial organic fertilizers". Archives of Agronomy and Soil Science. 61 (7): 989–1012. doi:10.1080/03650340.2014.978763 . Retrieved 12 December 2025.
  75. ↑ Haynes, Richard J.; Naidu, Ravi (June 1998). "Influence of lime, fertilizer and manure applications on soil organic matter content and soil physical conditions: a review". Nutrient Cycling in Agroecosystems. 51 (2): 123–37. doi:10.1023/A:1009738307837. S2CID   20113235 . Retrieved 12 December 2025.
  76. ↑ Vepsäläinen, Milja; Erkomaa, Kirsti; Kukkonen, Sanna; Vestberg, Mauritz; Wallenius, Kaisa; Niemi, R. Maarit (July 2004). "The impact of crop plant cultivation and peat amendment on soil microbial activity and structure". Plant and Soil . 264: 273–86. doi:10.1023/B:PLSO.0000047763.46795.cb . Retrieved 12 December 2025.
  77. ↑ Zhang, Jiayi; Fu, Guohua; Jin, Zhiyang; Chi, Lihang; Xu, Guocheng; Yue, Daran (4 December 2021). "Optimization of organic mulches thickness improves soil moisture retention under controlled conditions". Phyton. 91 (4): 841–57. doi:10.32604/phyton.2022.017938 . Retrieved 12 December 2025.
  78. ↑ Khamare, Yuvraj; Marble, S. Christopher (12 December 2023). "Mulching as a weed management tool in container plant production: review". Frontiers in Agronomy . 5 1235196. doi: 10.3389/fagro.2023.1235196 .
  79. ↑ Mulumba, Lukman Nagaya; Lal, Rattan (January 2008). "Mulching effects on selected soil physical properties". Soil and Tillage Research. 98 (1): 106–11. doi:10.1016/j.still.2007.10.011 . Retrieved 12 December 2025.
  80. ↑ Sharman, K. V.; Whitehouse, Michael (April 1993). "Nitrogen drawdown index as a predictor of nitrogen requirements for Nephrolepis in sawdust media". Scientia Horticulturae. 54 (1): 23–33. doi:10.1016/0304-4238(93)90080-A . Retrieved 15 December 2025.
  81. ↑ Clocchiatti, Anna; Hannula, S. Emilia; Hundscheid, Maria P. J.; Gunnewiek, Paulien J.A. klein; De Boer, Wietse (January 2023). "Utilizing woody materials for fungal-based management of soil nitrogen pools". Applied Soil Ecology. 181 104663. doi:10.1016/j.apsoil.2022.104663 . Retrieved 15 December 2025.
  82. ↑ Simsek, Ugur; Erdel, Erhan; Barik, Kenan (December 2017). "Effect of mulching on soil moisture and some soil characteristics". Fresenius Environmental Bulletin. 26 (12): 7437–43. Retrieved 15 December 2025.
  83. ↑ Tu, Cong; Ristaino, Jean B.; Hu, Shuijin (February 2006). "Soil microbial biomass and activity in organic tomato farming systems: effects of organic inputs and straw mulching". Soil Biology and Biochemistry . 38 (2): 247–55. Retrieved 15 December 2025.
  84. ↑ Livestock's Long Shadow: Environmental Issues and Options, Table 3.3. Retrieved 29 June 2009. United Nations Food and Agriculture Organization.
  85. ↑ "Production & Inputs | Government of India, Department of Fertilizers, Ministry of Chemicals and Fertilizers".
  86. ↑ Smil, Vaclav (December 2013). Making the modern world: materials and dematerialization. Hoboken, New Jersey: John Wiley & Sons. ISBN   978-1-119-94253-5 . Retrieved 15 December 2025.
  87. ↑ Smil, Vaclav (2012). Harvesting the biosphere: what we have taken from Nature. Cambridge, Massachusetts: MIT Press. doi:10.7551/mitpress/8990.001.0001. ISBN   978-0-262-01856-2 . Retrieved 15 December 2025.
  88. 1 2 3 4 5 Kesler, Stephen E.; Simon, Adam C. (2015). Mineral resources, economics and the environment (2nd ed.). Cambridge, United Kingdom: Cambridge University Press. ISBN   978-1-107-07491-0 . Retrieved 15 December 2025.
  89. ↑ "Industry stats – Fertilizer Canada". Fertilizer Canada. Archived from the original on 4 April 2018. Retrieved 28 March 2018.
  90. ↑ "Canadian fertilizer production, by product type and fertilizer year, cumulative data (x 1,000)". Statistics Canada . 3 September 2025. Retrieved 15 December 2025.
  91. ↑ Stewart, W. M.; Dibb, David W.; Johnston, Adrian E.; Smyth, T. J. (January 2005). "The contribution of commercial fertilizer nutrients to food production" (PDF). Agronomy Journal . 97 (1): 1–6. Bibcode:2005AgrJ...97....1S. doi:10.2134/agronj2005.0001 . Retrieved 15 December 2025.
  92. ↑ "Fertilizer consumption (kilograms per hectare of arable land)" . Retrieved 15 December 2025.
  93. ↑ "Agri-environmental indicator: mineral fertiliser consumption". Eurostat . Retrieved 15 December 2025.
  94. ↑ "Agri-environmental indicator: cropping patterns". Eurostat . Retrieved 15 December 2025.
  95. ↑ Stagnari, Fabio; Maggio, Albino; Galieni, Angelica; Pisante, Michele (2 February 2017). "Multiple benefits of legumes for agriculture sustainability: an overview". Chemical and Biological Technologies in Agriculture. 4 2. doi: 10.1186/s40538-016-0085-1 .
  96. ↑ Jones, Clain; Jacobsen, Jeff (May 2009). "Fertilizer placement and timing" (PDF). Montana State University . Retrieved 16 December 2025.
  97. ↑ Guo, Jiangying; Chen, Jiwei (29 November 2022). "The impact of heavy rainfall variability on fertilizer application rates: evidence from maize farmers in China". International Journal of Environmental Research and Public Health . 19 (23) 15906. doi: 10.3390/ijerph192315906 .
  98. ↑ Singh, Bijay; Craswell, Eric (31 March 2021). "Fertilizers and nitrate pollution of surface and ground water: an increasingly pervasive global problem". SN Applied Sciences . 3 (4) 518. doi: 10.1007/s42452-021-04521-8 .
  99. ↑ Dumanski, Julian; Peiretti, Roberto; Benites, José R.; McGarry, Diane; Pieri, Christian (31 August 2006). "The paradigm of conservation agriculture". World Association of Soil and Water Conservation (WASWAC). Retrieved 16 December 2025.
  100. ↑ Żuk-Gołaszewska, Krystyna; Wanic, Maria; Orzech, Krzysztof (29 January 2019). "The role of catch crops in field plant production: a review". Journal of Elementology. 24 (2): 575–87. doi: 10.5601/jelem.2018.23.3.1662 .
  101. ↑ Tischner, Rudolf (October 2000). "Nitrate uptake and reduction in higher and lower plants". Plant, Cell & Environment . 23 (10): 1005–24. doi: 10.1046/j.1365-3040.2000.00595.x .
  102. ↑ Menció, Anna; Mas-Pla, Josep; Otero, Neus; Regàs, Oriol; Boy-Roura, Mercè; Puig, Roger; Bach, Joan; Domènech, Cristina; Zamorano, Manel; Brusi, David; Folch, Albert (1 January 2016). "Nitrate pollution of groundwater: all right…, but nothing else?". Science of the Total Environment . 539: 241–51. doi:10.1016/j.scitotenv.2015.08.151 . Retrieved 16 December 2025.
  103. ↑ Stevenson, Frank J.; He, Xin-Tao (1 January 1990). "Nitrogen in humic substances as related to soil fertility". In MacCarthy, Patrick; Clapp, C. Edward; Malcolm, Ronald L.; Bloom, Paul R. (eds.). Humic substances in soil and crop sciences: selected readings. pp. 91–109. doi:10.2136/1990.humicsubstances.c5. ISBN   9780891181040 . Retrieved 16 December 2025.
  104. ↑ "About fertilizers: nutrients for crops and humans". fertilizer.org. International Fertilizer Association. Archived from the original on 30 March 2014. Retrieved 19 December 2017.
  105. ↑ Kiiski, Harri; Dittmar, Heinrich (15 July 2009). "Fertilizers, 4. Granulation". Ullmann's Encyclopedia of Industrial Chemistry . Vol. 14. pp. 1–32. doi:10.1002/14356007.n10_n03.pub2. ISBN   9783527306732 . Retrieved 16 December 2025.
  106. ↑ "Fertilizer granulation plant: a practical guide to high-quality NPK, DAP & custom blends". Ceylan Machine & Process. 19 August 2025. Retrieved 17 December 2025.
  107. ↑ Gregorich, Edward G.; Turchenek, Larry W.; Carter, Michael R.; Angers, Denis A., eds. (2001). Soil and environmental science dictionary. Boca Raton, Florida: CRC Press. p. 132. ISBN   978-0-8493-3115-2. LCCN   2001025292 . Retrieved 17 December 2025.
  108. ↑ Alexander, Alvin; Helm, Hans-Ulrich (1990). "Ureaform as a slow release fertilizer: a review". Zeitschrift für Pflanzenernährung und Bodenkunde. 153 (4): 249–55. doi:10.1002/jpln.19901530410 . Retrieved 17 December 2025.
  109. ↑ Priya, E.; Sarkar, Sudipta; Maji, Pradip K. (August 2024). "A review on slow-release fertilizer: nutrient release mechanism and agricultural sustainability". Journal of Environmental Chemical Engineering. 12 (4) 113211. doi:10.1016/j.jece.2024.113211 . Retrieved 17 December 2025.
  110. ↑ Vejan, Pravin; Khadiran, Tumirah; Abdullah, Rozaslin; Ahmad, Noraini (10 November 2021). "Controlled release fertilizer: a review on developments, applications and potential in agriculture". Journal of Controlled Release . 339: 321–34. doi:10.1016/j.jconrel.2021.10.003 . Retrieved 17 December 2025.
  111. 1 2 Niu, Junhao; Liu, Chang; Huang, Mingli; Liu, Kezhong; Yan, Dongyun (9 October 2020). "Effects of foliar fertilization: a review of current status and future perspectives". Journal of Soil Science and Plant Nutrition. 21 (1): 1–15. doi:10.1007/s42729-020-00346-3 . Retrieved 18 December 2025.
  112. ↑ Yang, Ming; Fang, Yunting; Sun, Di; Shi, Yuanliang (23 February 2016). "Efficiency of two nitrification inhibitors (dicyandiamide and 3, 4-dimethypyrazole phosphate) on soil nitrogen transformations and plant productivity: a meta-analysis". Scientific Reports . 6 (1) 22075. Bibcode:2016NatSR...622075Y. doi: 10.1038/srep22075 . ISSN   2045-2322. PMC   4763264 . PMID   26902689.
  113. ↑ Hayashi, Kentaro; Nishimura, Seiichi; Yagi, Kazuyuki (15 February 2008). "Ammonia volatilization from a paddy field following applications of urea: rice plants are both an absorber and an emitter for atmospheric ammonia". Science of the Total Environment . 390 (2–3): 485–94. doi:10.1016/j.scitotenv.2007.10.037 . Retrieved 18 December 2025.
  114. ↑ Wendeborn, Sebastian (3 February 2020). "The chemistry, biology, and modulation of ammonium nitrification in soil". Angewandte Chemie . 59 (6): 2182–202. doi:10.1002/anie.201903014 . Retrieved 18 December 2025.
  115. ↑ "Nitrogen fertilization: general information". Hubcap.clemson.edu. Archived from the original on 29 June 2012. Retrieved 17 June 2012.
  116. ↑ Garrett, Howard (2014). Organic lawn care: growing grass the natural way. Austin, Texas: University of Texas Press. pp. 55–6. ISBN   978-0-292-72849-3 . Retrieved 18 December 2025.
  117. ↑ Laboski, Carrie. "Understanding salt index of fertilizers" (PDF). Archived from the original (PDF) on 28 May 2013. Retrieved 22 July 2012.
  118. ↑ Bailey, Anna; Meyer, Lauren; Pettingell, Neilson; Macie, Madeline; Korstad, John (2020). "Agricultural practices contributing to aquatic dead zones". In Bauddh, Kuldeep; Kumar, Sanjeev; Singh, Rana Pratap; Korstad, John Pratap (eds.). Ecological and practical applications for sustainable agriculture (1st ed.). Singapore, Singapore: Springer Singapore. pp. 373–93. doi:10.1007/978-981-15-3372-3_17. ISBN   978-981-15-3372-3 . Retrieved 18 December 2025.
  119. ↑ Manuel, John (1 November 2014). "Nutrient pollution: a persistent threat to waterways" (PDF). Environmental Health Perspectives . 122 (11): A304 –A309. doi:10.1289/ehp.122-A304 . Retrieved 18 December 2025.
  120. ↑ Chen, Huaihai; Yang, Zamin K.; Yip, Dan; Morris, Reese H.; Lebreux, Steven J.; Cregger, Melissa A.; Klingeman, Dawn M.; Hui, Dafeng; Hettich, Robert L.; Wilhelm, Steven W.; Wang, Gangsheng (18 June 2019). "One-time nitrogen fertilization shifts switchgrass soil microbiomes within a context of larger spatial and temporal variation". PLOS ONE . 14 (6) e0211310. Bibcode:2019PLoSO..1411310C. doi: 10.1371/journal.pone.0211310 . ISSN   1932-6203. PMC   6581249 . PMID   31211785.
  121. ↑ Hu, Jun; Wang, Zhen; Williams, Gordon D. Z.; Dwyer, Gary S.; Gatiboni, Luke; Duckworth, Owen W.; Vengosh, Avner (10 January 2024). "Evidence for the accumulation of toxic metal(loid)s in agricultural soils impacted from long-term application of phosphate fertilizer". Science of the Total Environment . 907 167863. doi:10.1016/j.scitotenv.2023.167863 . Retrieved 18 December 2025.
  122. ↑ Yang, Quanfeng; Ma, Junhua; Yang, Fei; Zheng, Hua; Lu, Zengbin; Qiao, Fei; Zhang, Kening; Gong, Huarui; Men, Xingyuan; Li, Jing; Ouyang, Fang; Ge, Feng (10 November 2023). "The hidden indirect environmental effect undercuts the contribution of crop nitrogen fertilizer application to the net ecosystem economic benefit". Journal of Cleaner Production . 426 139204. doi:10.1016/j.jclepro.2023.139204 . Retrieved 18 December 2025.
  123. ↑ Liu, Xuejun; Zhang, Fusuo (October 2011). "Nitrogen fertilizer induced greenhouse gas emissions in China". Current Opinion in Environmental Sustainability . 3 (5): 407–13. doi:10.1016/j.cosust.2011.08.006 . Retrieved 19 December 2025.
  124. ↑ Jackson, Robert B.; Vengosh, Avner; Carey, J. William; Davies, Richard J.; Darrah, Thomas H.; O'Sullivan, Francis; Pétron, Gabrielle (October 2014). "The environmental costs and benefits of fracking". Annual Review of Environment and Resources . 39: 327–62. doi:10.1146/annurev-environ-031113-144051 . Retrieved 19 December 2025.
  125. ↑ Hopfenberg, Russell (22 October 2014). "An expansion of the demographic transition model: the dynamic link between agricultural productivity and population". Biodiversity. 15 (4): 246–54. doi:10.1080/14888386.2014.973904 . Retrieved 19 December 2025.
  126. ↑ Scanes, Colin G. (2018). "Human activity and habitat loss: destruction, fragmentation, and degradation". In Scanes, Colin G.; Toukhsati, Samia R. (eds.). Animals and human society. Academic Press. pp. 451–82. doi:10.1016/B978-0-12-805247-1.00026-5. ISBN   978-0-12-805247-1 . Retrieved 19 December 2025.
  127. ↑ Montgomery, David R. (14 August 2007). "Soil erosion and agricultural sustainability". Proceedings of the National Academy of Sciences of the United States of America . 104 (33): 13268–72. doi:10.1073/pnas.061150810 . Retrieved 19 December 2025.
  128. ↑ "Resolution adopted by the General Assembly on 6 July 2017" (PDF). United Nations . Retrieved 19 December 2025.
  129. ↑ Tayibi, Hanan; Choura, Mohamed; López, Félix A.; Alguacil, Francisco J.; López-Delgado, Aurora (June 2009). "Environmental impact and management of phosphogypsum". Journal of Environmental Management . 90 (8): 2377–86. Bibcode:2009JEnvM..90.2377T. doi:10.1016/j.jenvman.2009.03.007. hdl:10261/45241. PMID   19406560. S2CID   24111765 . Retrieved 19 December 2025.
  130. 1 2 Fletcher, Daniel Marcus McKay; Ruiz, Siul A.; Dias, Tiago; Chadwick, Dave R.; Jones, Davey L.; Roose, Tiina (20 February 2021). "Precipitation-optimised targeting of nitrogen fertilisers in a model maize cropping system". Science of the Total Environment . 756 144051. Bibcode:2021ScTEn.75644051M. doi:10.1016/j.scitotenv.2020.144051. ISSN   0048-9697. PMID   33280884. S2CID   227522409 . Retrieved 19 December 2025.
  131. ↑ Watson, Catherine J.; Foy, Robert H. (June 2001). "Environmental impacts of nitrogen and phosphorus cycling in grassland systems". Outlook on Agriculture. 30 (2): 117–27. doi:10.5367/000000001101293562 . Retrieved 19 December 2025.
  132. ↑ "The sources and solutions: agriculture". United States Environmental Protection Agency . 20 March 2025. Archived from the original on 5 April 2023. Retrieved 19 December 2025.
  133. ↑ Stoddard, John L.; Van Sickle, John; Herlihy, Alan T.; Brahney, Janice; Paulsen, Steven; Peck, David V.; Mitchell, Richard; Pollard, Amina I. (25 February 2016). "Continental-scale increase in lake and stream phosphorus: are oligotrophic systems disappearing in the United States?". Environmental Science & Technology . 50 (7): 3409–15. doi: 10.1021/acs.est.5b05950 .
  134. 1 2 Werner, Wilfried (15 July 2009). "Fertilizers, 6. Environmental aspects". Ullmann's Encyclopedia of Industrial Chemistry . Vol. 14. pp. 295–314. doi:10.1002/14356007.n10_n05. ISBN   9783527306732 . Retrieved 19 December 2025.
  135. ↑ "UPDATE (9:30 a.m.): Do-not-drink water advisory lifted for City of Toledo | Toledo Free Press". Archived from the original on 5 August 2014. Retrieved 5 August 2014.
  136. ↑ Schmidt, JR; Shaskus, M; Estenik, JF; Oesch, C; Khidekel, R; Boyer, GL (2013). "Variations in the microcystin content of different fish species collected from a eutrophic lake". Toxins. 5 (5): 992–1009. doi: 10.3390/toxins5050992 . PMC   3709275 . PMID   23676698.
  137. ↑ "Rapid Growth Found in Oxygen-Starved Ocean 'Dead Zones'", NY Times, 14 August 2008
  138. ↑ John Heilprin, Associated Press. "Discovery Channel :: News – Animals :: U.N.: Ocean 'Dead Zones' Growing". Dsc.discovery.com. Archived from the original on 18 June 2010. Retrieved 25 August 2010.
  139. ↑ Van Grinsven, H. J. M.; Ten Berge, H. F. M.; Dalgaard, T.; Fraters, B.; Durand, P.; Hart, A.; Willems, W. J. (2012). "Management, regulation and environmental impacts of nitrogen fertilization in northwestern Europe under the Nitrates Directive; a benchmark study". Biogeosciences. 9 (12): 5143–5160. Bibcode:2012BGeo....9.5143V. doi: 10.5194/bg-9-5143-2012 . hdl: 1854/LU-3072131 .
  140. ↑ "A Farmer's Guide To Agriculture and Water Quality Issues: 3. Environmental Requirements & Incentive Programs For Nutrient Management". cals.ncsu.edu. Archived from the original on 23 September 2015. Retrieved 3 July 2014.
  141. ↑ State-EPA Nutrient Innovations Task Group (2009). "An Urgent Call to Action – Report of the State-EPA Nutrient Innovations Task Group" (PDF). epa.gov. Archived (PDF) from the original on 9 October 2022. Retrieved 3 July 2014.
  142. ↑ "Study shows eutrophic lakes may not recover for a millennium". news.wisc.edu. 13 June 2005. Retrieved 3 November 2022.
  143. ↑ Wilkinson, Grace M. (1 January 2017), "Eutrophication of Freshwater and Coastal Ecosystems" , in Abraham, Martin A. (ed.), Encyclopedia of Sustainable Technologies, Oxford: Elsevier, pp. 145–152, doi:10.1016/b978-0-12-409548-9.10160-5, ISBN   978-0-12-804792-7 , retrieved 3 November 2022
  144. ↑ Callisto, Marcos; Molozzi, Joseline; Barbosa, José Lucena Etham (2014). "Eutrophication of Lakes". Eutrophication: Causes, Consequences and Control. pp. 55–71. doi:10.1007/978-94-007-7814-6_5. ISBN   978-94-007-7813-9.
  145. ↑ C. J. Rosen; B. P. Horgan (9 January 2009). "Preventing Pollution Problems from Lawn and Garden Fertilizers". Extension.umn.edu. Archived from the original on 10 March 2014. Retrieved 25 August 2010.
  146. ↑ Bijay-Singh; Yadvinder-Singh; Sekhon, G.S. (1995). "Fertilizer-N use efficiency and nitrate pollution of groundwater in developing countries". Journal of Contaminant Hydrology. 20 (3–4): 167–184. Bibcode:1995JCHyd..20..167S. doi:10.1016/0169-7722(95)00067-4.
  147. ↑ "NOFA Interstate Council: The Natural Farmer. Ecologically Sound Nitrogen Management. Mark Schonbeck". Nofa.org. 25 February 2004. Archived from the original on 24 March 2004. Retrieved 25 August 2010.
  148. ↑ Jackson, Louise E.; Burger, Martin; Cavagnaro, Timothy R. (2008). "Roots, Nitrogen Transformations, and Ecosystem Services". Annual Review of Plant Biology. 59 (1): 341–363. Bibcode:2008AnRPB..59..341J. doi:10.1146/annurev.arplant.59.032607.092932. PMID   18444903.
  149. ↑ Knobeloch, L; Salna, B; Hogan, A; Postle, J; Anderson, H (2000). "Blue Babies and Nitrate-Contaminated Well Water". Environ. Health Perspect. 108 (7): 675–8. Bibcode:2000EnvHP.108..675K. doi:10.1289/ehp.00108675. PMC   1638204 . PMID   10903623.
  150. ↑ Nitrogen and Water
  151. ↑ Biello, David (14 March 2008). "Fertilizer Runoff Overwhelms Streams and Rivers--Creating Vast "Dead Zones"". Scientific American.
  152. ↑ Schindler, D. W.; Hecky, R. E. (2009). "Eutrophication: More Nitrogen Data Needed". Science. 324 (5928): 721–722. Bibcode:2009Sci...324..721S. doi:10.1126/science.324_721b. PMID   19423798.
  153. ↑ Penn, C. J.; Bryant, R. B. (2008). "Phosphorus Solubility in Response to Acidification of Dairy Manure Amended Soils". Soil Science Society of America Journal. 72 (1): 238. Bibcode:2008SSASJ..72..238P. doi:10.2136/sssaj2007.0071N.
  154. ↑ McLaughlin, M. J.; Tiller, K. G.; Naidu, R.; Stevens, D. P. (1996). "Review: the behaviour and environmental impact of contaminants in fertilizers". Soil Research. 34 (1): 1–54. Bibcode:1996SoilR..34....1M. doi:10.1071/sr9960001.
  155. ↑ Lugon-Moulin, N.; Ryan, L.; Donini, P.; Rossi, L. (2006). "Cadmium content of phosphate fertilizers used for tobacco production" (PDF). Agron. Sustain. Dev. 26 (3): 151–155. doi:10.1051/agro:2006010. S2CID   13996565. Archived (PDF) from the original on 9 October 2022. Retrieved 27 June 2014.
  156. ↑ Zapata, F.; Roy, R.N. (2004). "Use of Phosphate Rocks for Sustainable Agriculture: Secondary nutrients, micronutrients, liming effect and hazardous elements associated with phosphate rock use". fao.org. FAO. Retrieved 27 June 2014.
  157. ↑ Syers JK, Mackay AD, Brown MW, Currie CD (1986). "Chemical and physical characteristics of phosphate rock materials of varying reactivity". J Sci Food Agric. 37 (11): 1057–1064. Bibcode:1986JSFA...37.1057S. doi:10.1002/jsfa.2740371102.
  158. ↑ Trueman NA (1965). "The phosphate, volcanic and carbonate rocks of Christmas Island (Indian Ocean)". J Geol Soc Aust. 12 (2): 261–286. Bibcode:1965AuJES..12..261T. doi:10.1080/00167616508728596.
  159. ↑ Taylor MD (1997). "Accumulation of Cadmium derived from fertilizers in New Zealand soils". Science of the Total Environment. 208 (1–2): 123–126. Bibcode:1997ScTEn.208..123T. doi:10.1016/S0048-9697(97)00273-8. PMID   9496656.
  160. 1 2 3 Chaney, R.L. (2012). "Food safety issues for mineral and organic fertilizers". Advances in Agronomy. Vol. 117. Elsevier. pp. 51–99. doi:10.1016/b978-0-12-394278-4.00002-7. ISBN   978-0-12-394278-4.
  161. ↑ Oosterhuis, F.H.; Brouwer, F.M.; Wijnants, H.J. (2000). "A possible EU wide charge on cadmium in phosphate fertilisers: Economic and environmental implications" (PDF). dare.ubvu.vu.nl. Archived (PDF) from the original on 9 October 2022. Retrieved 27 June 2014.
  162. ↑ "Putting all the cards on the table" (PDF). Fertilizers International. fertilizerseurope.com. 2014. Archived from the original (PDF) on 8 August 2014.
  163. ↑ Wates, J. (2014). "Revision of the EU fertilizer regulation and cadmium content of fertilisers". iatp.org. Retrieved 27 June 2014.
  164. 1 2 Loganathan, P.; Hedley, M.J.; Grace, N.D. (2008). "Pasture Soils Contaminated with Fertilizer-Derived Cadmium and Fluorine: Livestock Effects". Reviews of Environmental Contamination and Toxicology. Vol. 192. pp. 29–66. doi:10.1007/978-0-387-71724-1_2. ISBN   978-0-387-71723-4. PMID   18020303.
  165. 1 2 Cronin, S. J.; Manoharan, V.; Hedley, M. J.; Loganathan, P. (2000). "Fluoride: A review of its fate, bioavailability, and risks of fluorosis in grazed-pasture systems in New Zealand". New Zealand Journal of Agricultural Research. 43 (3): 295–3214. Bibcode:2000NZJAR..43..295C. doi: 10.1080/00288233.2000.9513430 .
  166. ↑ Wilke, B.M. (1987). "Fluoride-induced changes in chemical properties and microbial activity of mull, moder and mor soils". Biology and Fertility of Soils. 5 (1): 49–55. Bibcode:1987BioFS...5...49W. doi:10.1007/BF00264346. S2CID   1225884.
  167. ↑ Mortvedt, JJ; Beaton, JD. "Heavy Metal and Radionuclide Contaminants in Phosphate Fertilizers". Archived from the original on 26 July 2014. Retrieved 16 July 2014.
  168. ↑ "TENORM: Fertilizer and Fertilizer Production Wastes". US EPA. 2016. Retrieved 30 August 2017.
  169. ↑ Khater, A. E. M. (2008). "Uranium and heavy metals in phosphate fertilizers" (PDF). radioecology.info. Archived from the original (PDF) on 24 July 2014. Retrieved 17 July 2014.
  170. 1 2 3 NCRP (1987). Radiation Exposure of the U.S. Population from Consumer Products and Miscellaneous Sources. National Council on Radiation Protection and Measurements. pp. 29–32. Retrieved 17 July 2014.[ permanent dead link ]
  171. ↑ Hussein EM (1994). "Radioactivity of phosphate ore, superphosphate, and phosphogypsum in Abu-zaabal phosphate". Health Physics. 67 (3): 280–282. doi:10.1097/00004032-199409000-00010. PMID   8056596.
  172. ↑ Barisic D, Lulic S, Miletic P (1992). "Radium and uranium in phosphate fertilizers and their impact on the radioactivity of waters". Water Research. 26 (5): 607–611. Bibcode:1992WatRe..26..607B. doi:10.1016/0043-1354(92)90234-U.
  173. ↑ Hanlon, E. A. (2012). "Naturally Occurring Radionuclides in Agricultural Products". edis.ifas.ufl.edu. University of Florida. Archived from the original on 25 July 2014. Retrieved 17 July 2014.
  174. ↑ Sharpley, A. N.; Menzel, R. G. (1987). "The impact of soil and fertilizer phosphorus on the environment". Advances in Agronomy. 41: 297–324. doi:10.1016/s0065-2113(08)60807-x. ISBN   978-0-12-000741-7. S2CID   83005521.
  175. 1 2 Wilson, Duff (3 July 1997). "Business | Fear in the Fields – How Hazardous Wastes Become Fertilizer – Spreading Heavy Metals on Farmland Is Perfectly Legal, But Little Research Has Been Done To Find Out Whether It's Safe". Community.seattletimes.nwsource.com. Archived from the original on 18 November 2010. Retrieved 25 August 2010.
  176. ↑ "Waste Lands: The Threat of Toxic Fertilizer". Pirg.org. 3 July 1997. Archived from the original on 26 November 2010. Retrieved 25 August 2010.
  177. ↑ mindfully.org. "Waste Lands: The Threat of Toxic Fertilizer Released by PIRG Toxic Wastes Found in Fertilizers Cat Lazaroff / ENS 7may01". Mindfully.org. Archived from the original on 11 January 2002. Retrieved 25 August 2010.
  178. ↑ Zapata, F; Roy, RN (2004). Use of phosphate rocks for sustainable agriculture (PDF). Rome: FAO. p. 82. Retrieved 16 July 2014.[ permanent dead link ]
  179. 1 2 3 4 Davis, D.R.; Epp, M.D.; Riordan, H.D. (2004). "Changes in USDA Food Composition Data for 43 Garden Crops, 1950 to 1999". Journal of the American College of Nutrition. 23 (6): 669–682. doi:10.1080/07315724.2004.10719409. PMID   15637215. S2CID   13595345.
  180. 1 2 Thomas, D. (2007). "The mineral depletion of foods available to us as a nation (1940–2002) – A Review of the 6th Edition of McCance and Widdowson". Nutrition and Health. 19 (1–2): 21–55. doi:10.1177/026010600701900205. PMID   18309763. S2CID   372456.
  181. ↑ Jarrell, W.M.; Beverly, R.B. (1981). "The Dilution Effect in Plant Nutrition Studies". Advances in Agronomy. 34: 197–224. doi:10.1016/s0065-2113(08)60887-1. ISBN   978-0-12-000734-9.
  182. ↑ Fan, M. S.; Zhao, F. J.; Fairweather-Tait, S. J.; Poulton, P. R.; Dunham, S. J.; McGrath, S. P. (2008). "Evidence of decreasing mineral density in wheat grain over the last 160 years". Journal of Trace Elements in Medicine and Biology . 22 (4): 315–324. Bibcode:2008JTEMB..22..315F. doi:10.1016/j.jtemb.2008.07.002. PMID   19013359.
  183. ↑ Zhao, F. J.; Su, Y. H.; Dunham, S. J.; Rakszegi, M.; Bedo, Z.; McGrath, S. P.; Shewry, P. R. (2009). "Variation in mineral micronutrient concentrations in grain of wheat lines of diverse origin". Journal of Cereal Science. 49 (2): 290–295. doi:10.1016/j.jcs.2008.11.007.
  184. ↑ Saltzman, A.; Birol, E.; Bouis, H. E.; Boy, E.; De Moura, F.F.; Islam, Y.; Pfeiffer, W. H. (2013). "Biofortification: progress toward a more nourishing future". Global Food Security. 2 (1): 9–17. Bibcode:2013GlFS....2....9S. doi:10.1016/j.gfs.2012.12.003.
  185. 1 2 3 Moore, Geoff (2001). Soilguide – A handbook for understanding and managing agricultural soils. Perth, Western Australia: Agriculture Western Australia. pp. 161–207. ISBN   978-0-7307-0057-9.
  186. ↑ "Zinc in Soils and Crop Nutrition". Scribd.com. 25 August 2010. Retrieved 17 June 2012.
  187. ↑ Carroll and Salt, Steven B. and Steven D. (2004). Ecology for Gardeners. Cambridge: Timber Press. ISBN   978-0-88192-611-8.
  188. ↑ Gomiero, T.; D. Pimental & M.G Paoletti (2011). "Environmental Impact of Different Agricultural Management Practices: Conventional vs. Organic Agriculture". Critical Reviews in Plant Sciences. 30 (1–2): 95–124. Bibcode:2011CRvPS..30...95G. doi:10.1080/07352689.2011.554355. S2CID   83736589 – via Taylor & Francis Online.
  189. ↑ "Hydrogen and Ammonia fertilizers for Sustainable Agriculture and New Global Framework for Managing Nature programs | Department of Economic and Social Affairs". sdgs.un.org. Retrieved 30 June 2024.
  190. ↑ Appl, Max (2000). "Ammonia, 2. Production Processes". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim, Germany: Wiley-VCH. pp. 139–225. doi:10.1002/14356007.o02_o11. ISBN   978-3-527-30673-2.
  191. ↑ Sawyer JE (2001). "Natural gas prices affect nitrogen fertilizer costs". IC-486. 1: 8. Archived from the original on 25 July 2017. Retrieved 3 April 2007.
  192. ↑ "Table 8—Fertilizer price indexes, 1960–2007". Archived from the original on 6 March 2010.
  193. ↑ "Carbon emissions from fertilizers could be reduced by as much as 80% by 2050". Science Daily. University of Cambridge. Retrieved 17 February 2023.
  194. ↑ Tullis, Paul (10 September 2020). "How Fertilizer Is Making Climate Change Worse". BloombergQuint. Retrieved 25 March 2021.
  195. ↑ Tian, Hanqin; Xu, Rongting; Canadell, Josep G.; Thompson, Rona L.; Winiwarter, Wilfried; Suntharalingam, Parvadha; Davidson, Eric A.; Ciais, Philippe; Jackson, Robert B.; Janssens-Maenhout, Greet; Prather, Michael J. (October 2020). "A comprehensive quantification of global nitrous oxide sources and sinks". Nature. 586 (7828): 248–256. Bibcode:2020Natur.586..248T. doi:10.1038/s41586-020-2780-0. hdl: 1871.1/c74d4b68-ecf4-4c6d-890d-a1d0aaef01c9 . ISSN   1476-4687. PMID   33028999. S2CID   222217027. Archived from the original on 13 October 2020. Alt URL
  196. ↑ "Nitrogen fertiliser use could 'threaten global climate goals'". Carbon Brief. 7 October 2020. Retrieved 25 March 2021.
  197. ↑ FAO (2012). Current world fertilizer trends and outlook to 2016 (PDF). Rome: Food and Agriculture Organization of the United Nations. p. 13. Archived from the original (PDF) on 18 May 2017. Retrieved 3 July 2014.
  198. ↑ Gruber, N; Galloway, JN (2008). "An Earth-system perspective of the global nitrogen cycle". Nature. 451 (7176): 293–296. Bibcode:2008Natur.451..293G. doi: 10.1038/nature06592 . PMID   18202647.
  199. ↑ "Human alteration of the nitrogen cycle, threats, benefits and opportunities" Archived 14 January 2009 at the Wayback Machine UNESCO  – SCOPE Policy briefs, April 2007
  200. ↑ Roy, R. N.; Misra, R. V.; Montanez, A. (2002). "Decreasing reliance on mineral nitrogen-yet more food" (PDF). Ambio: A Journal of the Human Environment. 31 (2): 177–183. Bibcode:2002Ambio..31..177R. doi:10.1579/0044-7447-31.2.177. PMID   12078007. S2CID   905322. Archived from the original (PDF) on 24 September 2015. Retrieved 3 July 2014.
  201. ↑ Bodelier, Paul; Peter Roslev; Thilo Henckel; Peter Frenzel (November 1999). "Stimulation by ammonium-based fertilizers of methane oxidation in soil around rice roots". Nature. 403 (6768): 421–424. Bibcode:2000Natur.403..421B. doi:10.1038/35000193. PMID   10667792. S2CID   4351801.
  202. ↑ Banger, K.; Tian, H.; Lu, C. (2012). "Do nitrogen fertilizers stimulate or inhibit methane emissions from rice fields?". Global Change Biology. 18 (10): 3259–3267. Bibcode:2012GCBio..18.3259B. doi:10.1111/j.1365-2486.2012.02762.x. PMID   28741830. S2CID   31666406.
  203. ↑ European Union (15 January 2024). "Nitrates Directive".
  204. ↑ Defra. "Catchment-Sensitive Farming". Defra. Archived from the original on 30 June 2011.
  205. ↑ "Polluted Runoff: Nonpoint Source Pollution". EPA. Archived from the original on 19 November 2010. Retrieved 23 July 2014.
  206. ↑ "Washington State Dept. of Agriculture Fertilizer Product Database". Agr.wa.gov. 23 May 2012. Archived from the original on 30 October 2013. Retrieved 17 June 2012.
  207. ↑ "Metals Content for Fertilizer and Soil Amendment Products". regulatory-info-sc.com. Retrieved 21 July 2022.
  208. ↑ Habib, Mehvish; Singh, Sakshi; Bist, Yograj; Kumar, Yogesh; Jan, Kulsum; Bashir, Khalid; Jan, Shumaila; Saxena, D.C. (2024). "Carbon pricing and the food system: Implications for sustainability and equity". Trends in Food Science & Technology. 150 104577. doi:10.1016/j.tifs.2024.104577.
  209. ↑ Ju, Xiaotang; Gu, B.; Wu, Y.; Galloway, J.N. (2016). "Reducing China's fertilizer use by increasing farm size". Global Environmental Change. 41: 26–32. Bibcode:2016GEC....41...26J. doi:10.1016/j.gloenvcha.2016.08.005.
  210. ↑ Andrew, Hannah (5 July 2022). "Addressing Consolidation in Agriculture: USDA's Response to President Biden's Directive to Promote Competition in the American Economy" (PDF). Center for Agriculture and Food Systems, Vermont Law and Graduate School. p. 7. Archived (PDF) from the original on 20 July 2022. Retrieved 7 November 2022.

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