What is Fertilizer?
Soil that is fertile and supports good crop yields is a key element of food security, playing an important role in enabling agricultural producers to meet growing global demand for food. High-intensity agriculture, which produces the yields necessary to feed the world’s growing population, usually requires more nutrients than can be supplied by the soil. Fertilizers that contain one or more nutrients may be used to replenish the soil and support further plant growth. Fertilizers may be applied to the soil or, in some cases, directly to leaves. They not only replenish lost nutrients, but also provide additional stimulus to increase the volume and quality of crops. Fertilizers may be either organic (compost, manure, sludge) or mined from naturally-occurring inorganic resources like phosphate ore, in the case of phosphate-based fertilizers. The three main nutrients required by plants are nitrogen (N), phosphorus (P), and potassium (K), which are followed by secondary elements (sulphur, calcium and magnesium) as well as certain microelements such as boron, zinc, manganese, and others. Plants primarily require nitrogen, phosphorous and potassium. Therefore, most fertilizers will consist of one, if not all three.
|Nitrogen (N)||Phosphorus (P)||Potassium (K)|
|Effects on plant growth||Found in every living organism, supporting protein & amino-acid development, boosting yields & quality.||Plant’s source of energy, supporting photosynthesis, plant respiration & steady growth. Also increases/accelerates germination, root & seed development.||Supports energy transfer, boosting disease & weather resistance. A deficiency can lead to fruit deformation, lower quality & poor germination.|
|Production||Ammonia based, which itself is extracted from natural gas and/or coal. Key products include urea and ammonium nitrate.||Phosphate containing ore is processed and usually reacted sulphur and ammonia to produce fertilizers. Key products include di-/mono-ammonium phosphate.||Potassium-based fertilizers are made of potash containing salts. Key fertilizers include MOP, SOP and NOP.|
|Complex fertilizers||Complex fertilizers contain a combination of macro, secondary and micro-nutrients needed by plants in different proportions. Their use supports balanced nutrition.|
While humans have been using simple forms of fertilizer since the Neolithic Age, mineral or chemical fertilizers were first developed in the 1850s with an aim to replenish and to supplement nutrients already available in the soil. The first chemical manufacturing of phosphate-based fertilizers (made by treating bones with sulfuric acid) began in the 19th century. Potash fertilizer production started in Germany in 1861, and synthetic nitrogen fertilizers were first manufactured in 1903. Table 2 provides an overview of different types of mineral fertilizers used around the world.
Types of mineral fertilizers
Method of production
- natural (as found in nature or only slightly processed).
- synthetic (manufactured by industrial processes).
Number of nutrients
- single-nutrient or straight fertilizers (whether for major, secondary or micro nutrients).
- multi-nutrient (multiple nutrient) or compound fertilizers, with 2, 3 or more nutrients.
Type of combination
- mixed fertilizers, i.e. a physical mixture of two or more single-nutrient or multi- nutrient fertilizers (for granular products this may comprise a blend of separate granules of the individual ingredients, or granules each containing these ingredients).
- complex fertilizers, in which two or more of the nutrients are chemically combined (e.g. nitrophosphate, ammonium phosphates).
- solid (crystalline, powdered, prilled or granular) of various size ranges.
- liquid (solutions and suspensions).
- gaseous (liquid under pressure, e.g. ammonia).
Mode of action
- quick-acting (water-soluble and immediately available).
- slow-acting (transformation into soluble form required).