Chemistry of phosphorated fertilizers
Phosphorated fertilizers can mainly be produced by two process namely dry and wet process. In dry process the phosphor rock is treated in an electrical furnace which results in the production of phosphor that is very pure. This dry processed phosphor is referred as white phosphate. Due to the expensive nature of treatment the cost of this dry phosphor is high. Wet process is another method in which the phosphor rock is treated with acid to produce phosphoric acid. This phosphoric acid is not as pure as dry processed phosphoric acid but it is found to be suitable for fertilizer application. The color of this acid produced due to the impurities present does not affect the fertilizing effect of this ingredient. The cost of producing wet phosphoric acid is lower than that of dry phosphoric acid.
Orthophosphate- A key ingredient
Phosphoric acid that is produced by either of this process is heated in suitable environment such that considerable amount of water from acid mixture is removed and gives a composition that consists about 72 to 76 percent of phosphor. The important form in this composition is orthophosphate. It is in this form of orthophosphate which is used taken up be plants for producing positive effects. Another form in which phosphate is present is polyphosphate. Polyphosphate consists of group of orthophosphate that is chemically branched together. When polyphosphate comes in contact with soil it breaks into orthophosphate form that is readily taken up by plants. When ammonia is added to this mixture then liquid and solid fertilizers can be produced.
Types of phosphorated fertilizers
If we take a sample of phosphorated fertilizers it will be interesting to note that all the phosphorated fertilizers will not be dissolving in water. Some of the phosphate will be dissolving in water. There will also some amount of phosphate that will be dissolving in citrate medium. These two forms are known as water soluble phosphate and citrate soluble phosphate. The total amount of water soluble and citrate soluble phosphate which is present is the amount of phosphate that is available for plants. One of the most widely used phosphorated fertilizer includes N-P-K fertilizer.
Organic phosphorated fertilizers
The primary source for the production of organic phosphorated fertilizers are animal manure and also the sludge of sewage. One of the important features which are necessary for selecting the organic phosphorated fertilizers is the availability quotient of P in fertilizer. The actual amount of P that is present should come close to target level. Strictly speaking organic phosphorated fertilizers some amount of inorganic matter, this means that even in organic composition there will be orthophosphate that will be present
Factors influencing selection of phosphorated fertilizers
Various factors such as wet/dry phosphate, soil pH level, form of phosphate plays role in enhancing the nutrient requirement of plants. Orthophosphate will be readily absorbed by plants than polyphosphate fertilizers. The soil pH does not have much influence on plant growth and fertilizer though acidic medium will be more helpful.
Phosphorated fertilizers thus play a major role in development and growth of plant such that best results can be obtained.