The emergence of the humus theory explains how complete fertilizers work
In the 19th century, people noticed that after a few years of cultivation, fields no longer produced much yield. But they didn't yet have any knowledge of nutrients, which is why they couldn't explain this. If the fields were not worked for a few years, the yields increased again. This caused scientists like Albrecht Thaer to put forward theories as to why this was the case. A humus theory emerged which stated that plants fed on decaying animals and plants. Since something was taken away from the field during the harvest, a disproportion arose in the cycle. According to the theory, you have to add something “dead”, i.e. rotting plant parts or animal parts, to the soil in the form of humus so that new “life” can grow again. Humus is dead organic substances in and on the soil. With the humus theory, soil fertility was equated with the humus content of the soil.
Theory of mineral nutrition - this is how organic and mineral ones arose NPK -Fertilizer
In 1850 the theory of mineral nutrition replaced the humus theory. The German chemist Justus von Liebig realized that plants do not feed on humus per se, but on the minerals it contains. So if a field produced little or no yield, it was because chemical elements were missing in the soil. In this context, Liebig also realized that chemical analyzes could be used to determine which minerals were missing in the soil and then introduce them into the soil in a targeted manner. This was the origin of fertilizer and the relevance of the nutrients nitrogen, phosphorus and potassium (NPK) was also recognized.
Liebig's minimum law about fertilizing plants
The same scientist also popularized the minimum law, also called Liebig's minimum law or minimum factor. But it was published in 1829 by another scientist named Carl Sprengel. Carl Sprengel realized that plants need 12 minerals for their growth and cannot grow if one of these substances is completely missing. If a substance is only present in small quantities, the plant will also grow poorly. Finally, Justus von Liebig's minimum law shows the connection between the growth of plants and the factors that influence it. The growth of plants is determined by the most scarce resource available. This resource is also known as the minimum factor. It can be nutrients, but also water and light. The minimum factor is the limiting element that influences the entire growth of the plant, regardless of whether all other required resources are available.
The minimum law: example with NPK -Fertilizer
A plant is in a place where there is not enough light and has met 70% of its nutrient needs. Fertilizer is now added and the plant reaches 100% of its nutrient requirements. However, the plant's growth does not improve because the minimum factor is light. A plant therefore only develops as far as the scarcest resources allow.
You can find out more about how fertilizers are created in this video.
What does the optimum law say?
In 1895, Georg Liebscher's minimum law was expanded to include the optimum law. It states that there is an optimum level of growth factors at which plants grow fastest. A minimum factor has a more negative effect on the growth of a plant, the closer all other factors are to the optimum.
What do the laws mean for our plant care? - Tips for using NPK fertilizer
The minimum law forms an important basis for the use of fertilizers. It shows that regular fertilization is essential for steady plant growth. Since it is particularly important to provide the plants with all the necessary nutrients in a plant-available form, care must also be taken to ensure an adequate supply of micronutrients. It should also be noted that regular fertilization can only promote growth if the plant is given a location that meets its needs. Depending on the type of plant, appropriate light, water or dryness must be provided. This is the only way fertilization can have its effect.
Advantages and disadvantages of NPK -Fertilize
NPK fertilizers are organic or mineral fertilizers that contain the most important nutrients called nitrogen, phosphorus and potassium. A big advantage of these fertilizers is that they provide plants with a basic supply that meets their needs. In addition, the appropriate composition promotes fruit formation and the growth of houseplants, vegetable crops, lawns and flowering plants. Long-acting fertilizers provide plants with a long-term supply. A disadvantage of adding fertilizer can be the possibility of it being washed out. Organo-mineral fertilizers contain artificial and natural components - they are more expensive compared to pure organic fertilizer. Overall, the choice of fertilizer depends on many factors, such as the soil type and the needs of the respective plants.
Composition and application of NPK -Fertilize
The three main nutrients nitrogen (N), phosphorus (P) and potassium (K) are essential for the growth and development of houseplants and promote the formation of leaves, roots and flowers. Natural fertilizers can be of animal or plant origin. They also contain other important nutrients and micronutrients required for the healthy growth of plants. They provide a sustainable option for fertilizing houseplants as they gradually release nutrients and contribute to soil fertility. The application of organic NPK fertilizers should be carried out according to the instructions on the packaging to avoid over-application. Applying liquid fertilizer is easy because it can be easily dosed and strengthens the plants very quickly.
You can find the right fertilizer for your plants among the FARBIO® organic liquid fertilizers .
