What is a fertilizer? What are its types?
Currently, chemical fertilizers (the so-called black manure and white manure) play a role in providing something around 40 to 60% of the world's food resources. Chemical fertilizers include one or more food sources needed by plants, which can exist in all three forms of solid, liquid or gas phases. These compounds can be added to the soil, sprayed directly on the plant itself (plant leaves), or dissolved in water and added to the plant soil. The use of these materials is used to improve the quality of the soil, increase the amount of the product or improve the quality of the produced product. The use of these fertilizers dates back to the 19th century. When the agricultural industry expanded, the amount of animal or vegetable fertilizers needed was limited. The first attempts to produce chemical fertilizers on an industrial scale from the extraction of potassium from German mines began in 1860, around the same years, the first production unit of phosphate chemical fertilizers from urea phosphate was formed on a commercial scale. Inorganic fertilizers can be divided into three general categories: nitrogen, phosphate and potash:
1- Nitrogen fertilizers or nitrogen or so-called white fertilizer (n):
White chemical fertilizer contains nitrogen element in the form of nitrate, which is necessary for the growth of many plants, and for this reason, this fertilizer can be used to help the growth of a wide range of plants. It has a very good dissolution ability and easily dissolves in water and is quickly available to the plant.
Some nitrogen fertilizers include:
Urea fertilizer Ammonium sulfate Calcium nitrate
How to produce:
These fertilizers are often obtained from natural gas. During several stages, natural gas, especially methane, is combined with nitrogen in the air to produce nitrogen fertilizers. Note that 80% of natural gas is used to make nitrogen fertilizers. While only 20% of gas is used for heating processes and electricity generation With the help of this gas, two basic materials, ammonium nitrate and urea, are produced, and then by adding different types of additives, different nitrogen fertilizers can be produced. For example, phosphorus and potassium additives are used to make complete fertilizer. Dolomite additive is used to form CAN, or UAN can be produced by mixing urea and ammonium nitrate solution.
2- Phosphate fertilizers or so-called black fertilizer (p):
After nitrogen fertilizers, this type of chemical fertilizer is considered the most widely used type of fertilizer in the world. These compounds are necessary for the proper growth of plant roots. They help to increase the harvest yield and increase the resistance of plants against various diseases. Black chemical fertilizer provides phosphorus element for all kinds of plants, including potted plants, trees and crops.
Some phosphate fertilizers include:
diammonium phosphate Mono ammonium phosphate Triple superphosphate Simple superphosphate
How to produce:
Phosphate fertilizers are produced by acidifying phosphate rocks. It should be noted that phosphate rock is not soluble by itself and therefore cannot provide phosphorus to the plant. Most of the sources of phosphorus are sediments on the ocean floor that were later uplifted by land flooding. These sediments can contain various minerals, so contamination of these stones with heavy metals such as cadmium is another issue that should be considered. Other sources of phosphate rock are igneous rock deposits obtained from molten lava of volcanoes. This source contains less pollutants. The Yara mine in Finland is considered a good source for obtaining this type of phosphate rock. As mentioned, these stones are processed with acids such as phosphoric, sulfuric or nitric. The use of each of the mentioned acids has its own advantages and disadvantages. For example, the use of sulfuric acid produces phosphorus fertilizers with a low concentration, among these substances, simple superphosphate can be mentioned. However, the use of phosphoric acid can produce higher concentrations of these substances. The use of nitric acid also leaves almost no residue and produces two fertilizers: 1- Nitrophosphates, which are combined with potassium to produce NPK complex fertilizers such as YaraMila. 2-Calcium nitrate, which is obtained from the combination of nitric acid with calcium in phosphate rock. It should be noted that the limitation of using nitric acid is that when using it, the amount of phosphate in the fertilizer cannot exceed the amount of nitrogen.