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Fertilization with farmyard manure from the manure spreader
Application of mineral fertilizers (e.g. calcium ammonium nitrate , a nitrogen fertilizer )

Manure or fertilizer is a collective term for pure substances and mixtures used in the agriculture and forestry and in horticulture , and are used in private gardens to the nutrient offer for the cultivated crops to supplement. In addition to heat, light, air and water, plants also need nutrients for their growth. These are necessary to control and support the growth and development of plants.

The nutrients in the soil are often not in the optimally usable form and quantity. Either they are naturally not available in sufficient quantities or they are shifted to the soil through leaching or are withdrawn in considerable quantities by the harvested products. Only the supply of plant nutrients through fertilization makes it possible to replace these nutrient withdrawals.

Fertilization improves the nutrition of the plant , promotes plant growth, increases the yield, improves the quality of the harvested products and, ultimately, maintains and promotes soil fertility .

The plant nutrients are required by plants in different amounts. Therefore a distinction is made between macronutrients (main nutrients) and micronutrients (trace nutrients).

Macronutrients include nitrogen , potassium , phosphorus (see also phosphate fertilizers ), magnesium , sulfur and calcium . Of these, the agricultural crops need around 20-350 kilograms per hectare in the course of their development, depending on the nutrient (corresponds to grams per 10 square meters in the home garden).

The micronutrients are only around 5–1000 grams per hectare. This group of nutrients includes boron , chlorine , copper , iron , manganese , molybdenum , nickel and zinc . Micronutrients take on a variety of functions in plants, for example as components of enzymes , in metabolic reactions and in the hormonal balance . The fertilization of the plant or the soil should be adapted to the needs of the plants and adjusted to the nutrient conditions in the soil.

Influences on plants have also been demonstrated for the following chemical elements: aluminum , arsenic , cerium , chromium , fluorine , gallium , germanium , iodine , cobalt , lanthanum , lithium , manganese, sodium , rubidium , selenium , silicon , titanium , vanadium and others.

Classification of fertilizers

There are various ways in which fertilizers can be differentiated or classified , for example according to origin, formation or chemical compound. Accordingly, there are a variety of names used to describe fertilizers. The following groupings and definitions of terms were created according to these distinctions (according to). This should contribute to a better understanding and a clearer delimitation - a clear allocation to these groups is not always possible.

According to the origin / creation

Starting from their original state, the raw materials are converted into a form that is more readily available to plants in various processing processes.

  • Commercial fertilizers:
    Fertilizers in the trade are sold and in garden centers.
  • Natural fertilizer:
    Fertilizer that is used unprocessed in its accumulated form. Examples are natural products such as guano , Chile nitrate and rock flour.
  • Secondary
    raw material fertilizer : Collective term for fertilizers that are mainly produced from organic waste (biowaste) and residual materials, i.e. from secondary raw materials. This term includes products as diverse as compost , digestate products, meat bone meal, sewage sludge products , but also mixtures with z. B. summarized agricultural manure .
  • Manure :
    emergence of the farm. These include manure , liquid manure , liquid manure, straw, digestate from biogas plants .
  • Synthetic fertilizers:
    Fertilizers that are manufactured from natural raw materials using a high amount of energy. They are offered in stores as single or multiple nutrient fertilizers.

According to the speed of their effect

  • Fast-acting fertilizers:
    Contain the nutrients in a form that is immediately available to the plant. They work immediately after application, examples: amide, ammonium and nitrate-containing nitrogen fertilizers , water-soluble phosphates , potassium salts , quicklime .
  • Slow-acting fertilizers:
    the nutrients only have an effect or availability after they have been converted into the soil. Examples: Nitrogen fertilizers specially prepared by coating and also urea , rock phosphates, carbonate of lime, compost, horn shavings

According to chemical connection

Export of manure in a field
  • Organic fertilizers:
    Contain organic compounds, for example from parts of plants or animal excreta. A changing proportion of the nutrients is bound in organic compounds. Due to their carbon content, they help to maintain the humus content in the soil. In contrast to mineral fertilizers, the nutrients are contained in varying composition, plant availability and quantity. Examples: manure, liquid manure, digestate, straw, compost , horn shavings.
  • Mineral fertilizers:
    They consist of mineral salts. The nutrients are bound as oxides, chlorides, sulfates, carbonates etc. Depending on the type of fertilizer, the respective nutrients are contained in defined plant-available forms and precisely defined quantities. This means that fertilization can be precisely calculated and carried out in a targeted manner as required (see also Precision Farming ).

According to the number of nutritional elements

  • Single
    nutrient fertilizer: Contain only one nutrient. There are nitrogen, phosphate or potassium fertilizers. Lime fertilizers also belong to this group. Small amounts of other nutrients are possible.
  • Compound fertilizers :
    Also known as complex fertilizers . They contain several nutrients in different compositions. Common examples are phosphate-potassium (PK fertilizer) and nitrogen-phosphate fertilizer (NP fertilizer) as dual nutrient fertilizers; or NPK fertilizers (complete fertilizers), which contain up to five main nutrients plus trace nutrients. A distinction must also be made between the complex fertilizers of industrial production and mixed fertilizers. Complex fertilizers from industry are sold as brands. Mixed fertilizers are produced in special mixing plants by the agricultural trade and cooperatives. They are usually mixed from single-nutrient fertilizers.
    Farm and organic fertilizers can also be called compound fertilizers, as they contain several nutrients.

According to the quantity required by the plant

  • Macronutrient fertilizers:
    Contain the main nutrients for plants, which are needed in large quantities. These are mainly nitrogen , phosphorus and potassium . In addition, the nutrients sulfur , magnesium and calcium ; these three are sometimes referred to as secondary nutrients in specialist literature and legislation. Typically, macronutrient fertilizers are fertilized over the soil.
  • Micronutrient fertilizers:
    Contain micronutrients that are required by plants in small amounts (e.g. zinc , manganese , boron and iron ). They are applied in small quantities over the soil or over the leaf.

According to the type of application

  • Soil fertilizers:
    Are fertilized on or in the soil and thus absorbed through the roots. They are mainly used to supply macronutrients. Mainly improve the nutrient substrates (soil, substrates in horticulture, soil in agriculture). One of the goals is to promote growth. Examples are limes and composts .
  • Plant Fertilizers:
    Are intended to be absorbed directly by the plant and to improve soil fertility. They contain nutrients in plant-available bond forms. This includes most commercial fertilizers and also farm manures such as
    liquid manure and liquid manure .
    When applying the leaves, nutrients dissolved in water are sprayed onto the leaves and absorbed through the leaves, giving a direct effect. The uptake of nutrients via the leaves is low, however, so foliar fertilization supplements soil fertilization and is mainly used in the supply of trace nutrients.
  • Fertigation
    The nutrients are applied dissolved in the irrigation water.

According to the physical state

  • Solid fertilizers: fertilizer
    granules or salts
  • Liquid fertilizers: fertilizer
    solutions and suspensions.

According to special plant groups, for special nutritional requirements and against nutrient deficiencies


Shipping of guano in the 19th century

Since 3100 BC at the latest In BC, agricultural fields were sprinkled with animal and human feces to increase the harvest . The Romans and the Celts began to use carbonate of lime and marl as fertilizer.

Around 1840 the chemist Justus von Liebig was able to demonstrate the growth-promoting effects of nitrogen , phosphates and potassium . For example, nitrogen was initially obtained in the form of nitrates primarily through the use of guano , a substance that is formed from the excrement of sea birds. Since the natural supplies of mineral fertilizers are limited and most of them have to be imported from South America, a method of producing nitrogen compounds synthetically was considered .

Between 1905 and 1908, the chemist Fritz Haber developed the catalytic synthesis of ammonia . The industrialist Carl Bosch then succeeded in finding a process that enabled the mass production of ammonia. This Haber-Bosch process formed the basis for the production of synthetic nitrogen fertilizers.

Erling Johnson invented another process for the production of fertilizers in 1927 in the Odda smelting works (Odda Smelteverk); it was patented in 1932 and known as the Odda process .

Since the Second World War , the industry has increasingly brought fertilizers with different compositions onto the market. In the last quarter of the 20th century , however, the mineral fertilizer came under increasing criticism because its excessive use often causes ecological damage. With the discovery of the Edaphon and the functions of humus , it was possible to look for alternatives in the form of organic fertilization . Since around 1985 the consumption of mineral fertilizers has been falling, for example in Germany. However, in view of the rapidly growing world population , the use of fertilizers always remained in the focus of the discussion.

Increasing prosperity in countries such as China , Brazil and India led to changes in eating habits , increased meat consumption and increased use of fertilizers in some countries.

Legal bases

In some states, the manufacture, marketing and use of fertilizers are regulated by several legal provisions (Fertilizer Act, Fertilizer Ordinance, Fertilizer Ordinance and related legal areas). There are currently both national and European regulations with regard to the requirements for fertilizers and for their placing on the market: A fertilizer can therefore be approved according to national law or EU law.


In principle, fertilizers may only be placed on the market in Germany and at EU level if they correspond to precisely defined types of fertilizer (positive list). These type lists can be supplemented with new types on request, provided that no negative effects on the health of humans and animals or on the natural balance are to be expected and all requirements of the respective legal regulation are met.

In Germany, the Fertilizer Ordinance (Ordinance on the placing on the market of fertilizers, soil additives, growing media and plant additives - DüMV) regulates which fertilizers may be traded. It defines the types of fertilizer and specifies the minimum content for the individual nutrients. It also determines labeling thresholds and upper limits for pollutants, such as heavy metals. It also determines which information is to be given for proper labeling and for proper storage and use.

At the European level, the EU regulation 2003/2003 / EG on fertilizers stipulates which requirements mineral EU fertilizers must meet in order to be tradable. The EU regulation also defines minimum nutrient contents for the various types of fertilizer listed. The ordinance also determines details of proper labeling.


When farmers use fertilizers, it is above all “ good professional practice ” but also possible negative effects on the soil, surface water and groundwater that must be taken into account.

At the European level, the so-called Nitrates Directive is of major importance. It serves to protect water bodies from pollution by nitrate from agricultural sources. For this purpose, the member states must define endangered areas, issue regulations on good professional practice and implement action programs with various measures to protect water bodies.

Its national implementation in Germany is largely based on the Fertilizer Ordinance (DüV). The DüV defines good professional practice in the use of fertilizers on agricultural land and is intended to limit the material risks associated with the use of fertilizers.

The fertilizer ordinance came under increasing criticism. According to the assessment of the European Commission, Germany was only inadequately implementing the Nitrates Directive. She therefore opened infringement proceedings before the European Court of Justice. The lead Federal Ministry of Food and Agriculture therefore developed an amendment to the Fertilizer Ordinance, which came into force on June 2, 2017.

Types of fertilizer

A general distinction is made between fertilizers according to the way in which the fertilizing substance is bound. Further differentiation types are the form of the fertilizer (solid fertilizer and liquid fertilizer) and its effect (fast-acting fertilizer, long-term fertilizer, depot fertilizer). Improper use of fertilizer leads to over-fertilization (eutrophication) of adjacent areas and bodies of water and thus to a decline in species.

Mineral fertilizers

compound fertilizer with 8% nitrogen , 8% phosphate and 8% potash

In inorganic fertilizers or mineral fertilizers , the fertilizing components are mostly in the form of salts . Mineral fertilizers are used in granular, powder or liquid form ( liquid fertilizer ).

Mineral fertilizers have made great productivity gains in agriculture possible and are now widely used. Some of the mostly synthetic inorganic fertilizers are problematic, for example in view of the high energy consumption in their production. In the application, the water solubility plays an important role. In comparison, organic fertilizers with appropriate cultivation methods lead to a higher humus content and a higher soil quality (see humus ).

Phosphates were initially supplied via the natural product guano , but nowadays they are mainly obtained from mining. The decline or the depletion of minable phosphorus deposits is a sustainability problem . Phosphate ores contain heavy metals such as cadmium and uranium , which can also find their way into the food chain via mineral phosphate fertilizers. Annually with phosphorus fertilizers in German agriculture u. a. approx. 160 tons of uranium were released.

Nitrogen fertilizers are ammonium nitrate , ammonium sulfate , potassium nitrate and sodium nitrate . They are mostly made from atmospheric nitrogen, for example using the Haber-Bosch process and Ostwald process . The production of nitrogen fertilizer is very energy-intensive: The entire energy requirement for fertilization with 1 ton of nitrogen, including production, transport and application, corresponds to the energy content of around 2 tons of crude oil .

Potash salts are extracted, processed or converted into potassium sulfate in the salt mine . Conventional potash fertilizer production causes large amounts of saline waste liquors or landfills.

Gaseous fertilizer

The fertilization with carbon dioxide (CO 2 ) is important in the greenhouse horticulture. The reason for this is the lack of CO 2 caused by photosynthetic consumption when there is insufficient fresh air, especially in winter when the ventilation is closed. Plants need carbon as a basic substance.

The carbon dioxide is either bought in as liquid gas or brought in as a combustion product from propane or natural gas (coupling of fertilization and heating). The possible increase in yield depends on how severe the shortage of CO 2 is and how much light the plants have.

Organic fertilizer

Compost is more familiar from horticulture
Horn shavings are obtained from crushed horn from slaughtered cattle

In organic fertilizers , the fertilizing components are mostly bound to carbon-containing compounds. If these are already partially oxidized , for example in compost , then the fertilizing minerals are adsorbed on the degradation products ( humic acids ) etc. This means that they have a longer-term effect and are usually washed out less quickly than mineral fertilizers. Organic fertilizers are usually waste products from agriculture ( manure ). This mainly includes liquid manure and farmyard manure . Sewage sludge is also often used.

A key figure for the speed of action is the ratio between carbon and nitrogen : the C / N quotient. Organic fertilizers are usually of animal or vegetable origin, but can also be synthesized.

Frequent contents in farm manure
N P 2 O 5 K 2 O CaO MgO
total effective in the 1st year
Cattle manure kg / t 5 2 3 7th 4th 2
Pig manure 8th 3 8th 5 7th 2
Dry chicken manure 30th 21st 20th 15th 40 4th
Turkey dung 20th 11 23 23 0 5
Chicken manure 24 15th 21st 30th 0 6th
Horse manure 4th 2 3 11 0 1
Mushroom substrate 9 <1 9 14th 27 3
Biogas substrate (maize / slurry) 5 2 2 4th nn nn
Biogas substrate (pellets) 25th 9 30th 55 25th 15th
Fine compost (leaves and green waste) 6th <1 2 4th 6th 1

Fertilizer consumption

Fertilizer consumption per area in the European Union

The worldwide consumption of fertilizers in 1999 was 141.4 million tons.

The largest consumer countries were (2012 in million tons):

China 36.7
United States : 19.9
India : 18.4
Brazil : 5.9
France : 4.8
Germany : 3.0
Pakistan : 2.8
Indonesia : 2.7
Canada : 2.6
Spain : 2.3
Australia : 2.3
Turkey : 2.2
England : 2.0
Vietnam : 1.9
Mexico : 1.8
Netherlands : 1.4

These figures do not provide any information about the per capita or per hectare consumption . However, this can be read from the graphic for selected countries and regions.

The largest fertilizer producers

The most important producer of nitrogenous fertilizers is China, followed by India and the USA. In Europe, the main producers are Russia and Ukraine, followed by Poland, the Netherlands, Germany and France.

The main producers of fertilizers
The largest fertilizer producers worldwide (2002)
rank country Production
(in million t )
rank country Production
(in million t)
1 China 23.6 9 Egypt 1.5
2 India 10.6 10 Saudi Arabia 1.3
3 United States 9.4 11 Poland 1.2
4th Russian Federation 6.0 12 Bangladesh 1.1
5 Canada 3.8 13 Netherlands 1.1
6th Indonesia 2.9 14th Germany 1.0
7th Ukraine 2.3 15th France 1.0
8th Pakistan 2.2

It is believed that the global market for fertilizers by the year 2019, a volume of over 185 billion  US dollars have reached.

Nutrients and practical use

Fertilizer spreader for spreading granular solid fertilizer

Nutrient absorption of the plants

When it comes to nutrient uptake from the soil , a distinction must be made between the nutrition of summer and winter species and of perennial plants:

  • For summer species (e.g. potatoes ), the need for nutrients increases rapidly after emergence, depending on the length of the growing season, to a certain point before ripening, and then decreases or stops entirely.
  • In the case of winter species (e.g. winter grain or rape), the winter dormancy (frost) interrupts nutrient uptake.
  • Perennial plants with perennial underground organs, e.g. B. grasses, clover species, hops and wine , store nutrients in the roots and accelerate the development in the following spring with these reserve substances .

Nutrient absorption from the soil solution

The plant absorbs the nutrients from the aqueous soil solution through the roots . Most nutrients are present in the soil solution as electrically charged particles ( ions ). In addition, plant nutrients in the soil such as iron , manganese , copper and zinc can enter into water-soluble chelate compounds with organic substances and be absorbed in this form by the plants. Of the 16 indispensable elements, the plants meet their need for carbon , hydrogen and oxygen primarily from the carbon dioxide in the air and water from the soil. However, metal ions that are toxic to humans and animals (e.g. cadmium ) are also stored in plants (for example from soils polluted with inorganic pollutants ). A plant nutrient is increasingly absorbed by the roots and enriched in the plant organs beyond the need (luxury consumption) if it is contained in larger quantities in the soil solution due to strong mineralization (e.g. nitrogen release in humus soils) or one-sided high fertilization. The quantitative uptake of nutrients by the plant depends on the capacity of the roots to breathe. Easily heatable floors with a favorable air-water balance in the crumb area offer the best conditions for absorption.

Nutrient absorption through the leaf

The leaves can also absorb water and the nutrients dissolved in it through small pores. In theory, one could feed the plant entirely through the leaves. In integrated crop production, the targeted supply of minerals (spraying or spraying processes) in certain growth sections with diluted fertilizer salt solutions as foliar fertilization is becoming increasingly important. Through the foliar fertilization, a small but highly effective mineral layer is applied to the green parts of the plant with suitable application equipment. For years, the supplementary supply of nitrogen , magnesium and trace minerals through the leaf has primarily proven itself in practical cultivation . The advantage of this method of targeted nutrient supply lies in the high degree of utilization, the disadvantage in the limited amount of minerals possible with one dose. In order to avoid development-inhibiting leaf burns, the correct concentration of the solution and consideration for sensitive growth periods of the plant population must be observed when fertilizing the leaves. Today, foliar fertilization is given priority when a short-term nutrient requirement coverage is necessary in a certain growth stage, which cannot be easily satisfied from the soil replenishment (N late fertilization for wheat , P supply to maize or the elimination of suddenly occurring nutrient deficiencies, e.g. through Boron spray against heart and dry rot in sugar beet ). (See also the section mass transfer via the surface in the article sheet.)

Benefits of fertilizing

The minimum law of plant nutrition states that the genetic yield potential of a useful plant is limited by the main nutrient element , which is not available in sufficient quantity when the plants need it. The required fertilization requirement is usually determined by soil examinations and fertilization windows . If the plant population is undernourished, there are deficiencies with reduced yields and occasionally even a total loss of a crop population.

Disadvantages of fertilizing

If more fertilizer is applied than required, this leads to pollution of groundwater and surface water. It is also pointed out that heavily fertilized crops can have a higher water content and the ratio of carbohydrates to vitamins and minerals is less favorable, although this is mainly a question of the type of plant grown.

In the soil, bacteria convert nitrogen compounds into laughing gas (N 2 O) - a greenhouse gas that is 300 times more potent than carbon dioxide (CO 2 ).

At the same time as phosphate fertilizer, uranium gets into the soil and washed out into drinking water. A total of 100 tons of uranium land on German soil every year. According to the Federal Research Office for Agriculture ( Julius Kühn Institute ), the uranium input is on average 15.5 g uranium per hectare. In soil investigations at 1000 locations, an enrichment of an average of 0.15 mg uranium / kg was found in arable land compared to forest soils. An indication of the "creeping enrichment of uranium" in the arable soil.

Overfertilization burn
on a leaf

If fertilizers are applied too heavily, there is a risk that the soil will be over-fertilized and thus the soil fauna will be adversely affected, which in turn is at the expense of yields and the quality of the harvest. In extreme cases, the plants can be killed by plasmolysis .

The negative consequences for the environment ( eutrophication ) must be differentiated from the negative consequences of overfertilization on the quality of the products produced for human and animal nutrition even before the decline in yields: in particular, high levels of nitrogen also lead to high levels in plants Nitrate concentration. These nitrates are reduced to nitrites that are harmful to health in the intestines of humans and animals . In overfertilized vegetables that are not fresh and already in the soil, nitrites form as an intermediate stage in the oxidation of the components of nitrogen fertilizers, liquid manure or other nitrogenous substances.

In addition, the fertilizer components not absorbed by the plants are washed out into the groundwater and can thereby endanger its quality. In addition, rainwater on the fertilized soils, when it reaches surface waters, leads to an oversupply of nutrients (eutrophication), which can lead to algal blooms and thus cause a lack of oxygen in the deep water of lakes .

This problem exists above all in areas of intensive agricultural use with high livestock populations (e.g. in the Münsterland and in southwestern Lower Saxony) and poses considerable problems for the water supply there. The purpose of spreading liquid manure and manure is less to increase the yield than to dispose of the animal excrement in the fattening farms.

If the crops are over-fertilized, the yields can decrease. It is therefore important to optimally supply the plants with nutrients. Based on the soil tests that farmers have carried out, the fertilization can be adapted to the needs of the respective crop. A fertilizer analysis is also useful.

Influence of fertilization on the soil

The components of the fertilizer have the following effects on the soil:

  • Nitrogen: promoting soil life
  • Phosphorus: promotes crumb formation; Soil stabilizer; Bridges between humus particles
  • Potassium: K + ions destroy crumbs in high concentrations because they displace Ca 2+ ions (antagonism)
  • Magnesium: Like Ca, promotes crumb stability by displacing the hydronium ions from exchange sites
  • Calcium: Stabilizes the crumb structure / promotes soil life / pH regulation
  • Sulfur: promoting soil life

Influences on chemical and physical soil properties

Some fertilizers (especially N-fertilizers) contribute to soil acidification . Without compensatory measures, this can impair the structural conditions in the ground . However, well-planned fertilization measures (e.g. liming ) can counteract a drop in the pH value, so that negative effects on nutrient dynamics, soil organisms and soil structure are not to be feared.

Clay minerals in the soil are negatively charged and can bind positively charged particles (e.g. potassium [K + ] or ammonium [NH 4 + ] ions, ammonium fixation in clayey cohesive soils), which increases the availability of nitrogen after a fertilizer application can be restricted. The bond is reversible.

Influence on soil organisms

The lowering of the pH value and an excessive salt concentration can affect the soil life. In addition, the activity of N-binding bacteria decreases with increasing N fertilization. Overall, an adequate soil supply with organic and mineral fertilizers promotes the amount and diversity of soil organisms. These have a decisive influence on soil fertility. With proper mineral fertilization, the earthworm density remains largely stable. The earthworm population is promoted by the farm's own organic fertilizers.

A 21-year study summarized the following: “In order to assess the effectiveness of agricultural cultivation systems, an understanding of the agro-ecosystems is required. A 21-year study found that organic farming systems yielded 20 percent lower yields than conventional ones, although the use of fertilizers and energy was 34 to 53% and that of pesticides 97% lower. The increased soil fertility and the greater biological diversity in the ecological test plots probably mean that these systems are less dependent on external supplies ”.

Enrichment with metals

There are numerous studies on the enrichment of the soil with heavy metals through mineral fertilization. Of the mineral fertilizers used in agriculture and horticulture, many phosphate fertilizers contain natural uranium and cadmium . These pollutants can accumulate in the soil and also get into the groundwater.

The consequences of the use of phosphate fertilizers and the connection between the increased uranium content in mineral and drinking water and the geology of the groundwater storage rock were examined nationwide for the first time in 2009. It turned out that increased uranium contents are mainly linked to formations such as red sandstone or Keuper , which themselves have geogenically increased uranium contents. However, uranium levels from agricultural phosphate fertilization have already found their way into the groundwater. This is because rock phosphates contain 10–200 mg / kg uranium, which accumulates to even higher concentrations in the processing process for fertilizer. With the usual fertilization with mineral phosphate fertilizer, this leads to annual inputs of 10–22 g uranium per hectare. Organic fertilizers such as liquid manure and manure have lower uranium contents of often less than 2 mg / kg and correspondingly low uranium inputs. The uranium content of sewage sludge lies between these extremes.

Long-term, intensive fertilization with secondary raw materials can also lead to unwanted enrichment with metals . For this reason, when sewage sludge is spread on agricultural land, both the sewage sludge and the soil must be examined. The effects of fertilization on the chemical and physical soil properties can be corrected through certain agricultural and plant cultivation measures. In comparison, enrichment with metals cannot be changed, since metals are hardly washed out and the withdrawal by the plants is only slight. If the metal content in the soil is too high, soil fertility will be damaged in the long term.

Influence of fertilization on the water

Sodium nitrate ("Chiles nitrate")

A deterioration of the water quality through fertilization can occur with:

Nitrate pollution of the groundwater

Nitrate (NO 3 - ) is undesirable in drinking water because under certain circumstances it is converted into nitrite, which is harmful to health . It can form nitrosamines with secondary amines (ammonia base) that occur in food or are formed during digestion . Some of these are cancer-causing substances. In order to largely exclude the health risks, the nitrate content in drinking water should be as low as possible. The limit value for the nitrate content in drinking water was set in 1991 with the EC Directive 91/676 / EEC at 50 mg NO 3 - / liter. This limit value can be exceeded with improper fertilization, especially on light, permeable soils. By nature, groundwater usually contains less than 10 mg NO 3 - / liter. As the cause of the post-war z. Sometimes strongly increased nitrate levels are u. a. to call:

  • Denser settlement with increasing amounts of waste water from households, trade and industry and deficiencies in the sewage system.
  • Intensive agricultural land use; Here, farm fertilizers ( liquid manure , liquid manure ) are to be assessed more critically than mineral fertilizers , since they are often not used as targeted as mineral fertilizers and thus the degree of nitrogen utilization is worse. In addition, regionally by increasing the number of animals, u. The problem of nitrate leaching has also been exacerbated by the concentration of animal husbandry. However, the N leaching, ascertained with lysimeter systems or deep boreholes , is not automatically a consequence of increasing fertilizer quantities. The amount of fertilizer used has decreased significantly in recent years. Rather, the cause is to be found in the improper use of fertilizers.

The following measures to reduce nitrate pollution are recommended:

  • Take the N-supply of the soil into account when fertilizing . In spring, depending on crop rotation , soil type , soil type , organic fertilization and autumn or winter weather, very different amounts of mineralized, i.e. H. plant-available nitrogen in the soil. They can be recorded using the Nmin method and taken into account when determining the N fertilizer requirement.
  • Adjust N quantities to the mineral requirements of the plants. Avoid over-fertilization with special crops such as wine , hops and vegetables , but also with demanding arable crops such as maize .
  • Fertilize at the right time and, if necessary, divide the amount of fertilizer into parts
  • Selective use of manure
  • N-binding through plant growth all year round, so that the nitrogen not used by the previous crop and the nitrogen released by mineralization is biologically bound. In the case of high late fertilization of N for the production of quality wheat or for the cultivation of grain legumes , the N-leaching should be reduced by means of plant-building measures, such as crop rotation, catch crop cultivation or straw fertilization.
  • Plowing of perennial forage fields with legumes ( clover grass , alfalfa grass ) should not be carried out in autumn but in spring.

Phosphate pollution of surface waters

Eutrophication phenomena in the northern area of ​​the Caspian Sea east of the Volga estuary, algae bloom due to high fertilizer intake (satellite image from 2003)

Eutrophication describes a state of standing water, which is characterized by a high nutrient content and the resulting abundance of aquatic plants and algae . Most of the time, eutrophication is caused by a high intake of phosphate, as phosphate is naturally hardly present in surface waters. A high supply of P increases the growth of algae and aquatic plants. The decomposition of the dead algae and plant matter consumes an excessive amount of oxygen in the water . Therefore, the lack of oxygen can cause fish to die.

Phosphates get through to surface waters

  • Wastewater from residential areas (detergents); however, many sewage treatment plants now have a purification stage for phosphorus elimination
  • Leaching of phosphate or washing away of soil and fertilizers

Since fertilizer phosphate is mostly bound in the soil, the leaching of phosphate on loam and clay soils can practically be neglected. The P-runoff is to be assessed differently:

  • in connection with soil erosion by water erosion
  • in the case of improper use of proprietary fertilizers

Significant inputs of P into the waters can quickly occur here.

Influence of fertilization on the air

Manure is stored in a field for spreading

After the application of organic ( manure , liquid manure) and inorganic ( mineral fertilizer ) fertilizers, considerable gaseous nitrogen losses as ammonia can occur.

Organic fertilizer

The amount of ammonia losses depends on the type and composition of the organic fertilizer whose treatment, e.g. B. Incorporation into the soil , and depending on the weather during application. The following sequence for the amount of ammonia losses results

  • the type of manure : deep manure < manure  <Normal manure (pig manure <cattle manure) <biogas slurry or fresh manure;
  • of the dry matter ( dry matter ) content: water-rich manure <manure with a high dry matter content

Depending on the dry matter content of the manure, the time of incorporation, the animal species and the weather, losses of approx. 1% (with manure injection) and almost 100% (stubble application without incorporation) of the ammonium nitrogen present in the manure can be expected . In addition to the type of storage and application, the time of incorporation has a major influence on the level of losses. Immediate incorporation significantly reduces ammonia losses.

Solid mineral fertilizer

The ammonia losses of nitrogenous mineral fertilizers increase as follows: Calcium ammonium nitrate  < complex fertilizer  < diammon phosphate  < urea  < calcium cyanamide  < ammonium sulfate .

The share of mineral fertilizers in the total ammonia nitrogen losses in agriculture is low.

See also


  • Johannes Kotschi, Kathy Jo Wetter: Fertilizers: Paying consumers, scheming producers . In: Heinrich Böll Foundation, et al. (Ed.): Soil Atlas. Data and facts about Acker, Land und Erde, Berlin 2015, pp. 20–21.
  • Arnold Finck : Fertilizer and fertilization - Basics and instructions for fertilizing cultivated plants . Second, revised edition. VCH, Weinheim; New York; Basel; Cambridge 1992, ISBN 3-527-28356-0 , pp. 488 .
  • Sven Schubert: Plant Nutrition - Basic Knowledge Bachelor. Verlag Eugen Ulmer, Stuttgart, ISBN 3-8252-2802-9 .
  • Günther Schilling : Plant nutrition and fertilization (=  UTB . Volume 8189 ). Ulmer, Stuttgart (Hohenheim) 2000, ISBN 3-8252-8189-2 .
  • Udo Rettberg: Everything you need to know about raw materials. Successful with coffee, gold & co . FinanzBook-Verlag, Munich 2007, ISBN 978-3-89879-309-4 .

Individual evidence

  1. ^ Müfit Bahadir, Harun Parlar, Michael Spiteller: Springer Umweltlexikon . Springer-Verlag, 2013, ISBN 978-3-642-97335-2 , p. 301 ( limited preview in Google Book search).
  2. Guido A. Reinhardt: Energy and CO2 accounting for renewable raw materials Theoretical principles and case study of rapeseed . Springer-Verlag, 2013, ISBN 978-3-322-84192-6 , p. 78 ( limited preview in Google Book search).
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  27. ^ Uranium in soil and water, Claudia Dienemann, Jens Utermann, Federal Environment Agency, Dessau-Roßlau, 2012, page 15 .
  28. Paul Mäder, Andreas Fließbach, David Dubois, Lucie Gunst, Padruot Fried and Urs Niggli: Soil fertility and biological diversity in organic farming. ECOLOGY & AGRICULTURE 124, 4/2002 orgprints.org (PDF).
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  31. Tamara Kolbe, Jean-Raynald de Dreuzy a. a .: Stratification of reactivity determines nitrate removal in groundwater. In: Proceedings of the National Academy of Sciences. 116, 2019, p. 2494, doi : 10.1073 / pnas.1816892116 .

Web links

Commons : Fertilizer  - Collection of pictures, videos and audio files
Wiktionary: fertilizer  - explanations of meanings, word origins, synonyms, translations
Wiktionary: Fertilizers  - explanations of meanings, word origins, synonyms, translations