What Is Phosphate Fertilizer?
Phosphate fertilizer is a general term for fertilizers that contain phosphorus (P) as a major component.
Phosphorus is considered one of the three major components of fertilizers, alongside nitrogen (N) and potassium (K).
Phosphate fertilizer is also known as “flower fertilizer” or “fruit fertilizer”. Crops deficient in phosphorus not only weaken growth but flowering and ripening are likely to be delayed.
It is an important nutrient for crops because the resulting fruit yield is reduced and the taste is bland. Phosphoric acid also plays an important role in converting solar and respiration energy created by sunlight and photosynthesis into growth energy for crops.
In the past, phosphate-rich materials such as bone meal, rice bran, and ash were used as organic phosphate fertilizers. However, today inorganic phosphate fertilizers made from lime superphosphate are the most common. In addition, compound fertilizers containing two or more components are used more frequently nowadays, and phosphate fertilizer is rarely applied alone.
Uses of Phosphate Fertilizers
Phosphate fertilizers are essential for supplementing plants with phosphorus. They’re particularly effective during reproductive growth stages, enhancing bud formation, fruiting, and improving fruit quality. Phosphorus is also integral to nucleic acids, vital for plant development from early stages.
Different types, such as superphosphate lime, offer varied effects. Some are fast-acting, quickly dissolving in water for immediate absorption by plants, while others, like dissolved phosphorus fertilizers, are slow-acting with prolonged effects. Fused phosphorus fertilizers, being alkaline, can adjust soil pH and mitigate alumina‘s (an oxide of aluminum) adverse effects on phosphoric acid absorption.
Features of Phosphate Fertilizers
Advantages
- Appropriate amount and frequency of application can lead to more flowers, buds, and improved fruit quality.
- They are usable as foliar spray, for timely effects during critical growth phases, such as during flower and fruit production or the fruit enlargement period, and can take effect quickly.
- Some of them can be mixed with pesticides, which saves labor.
Disadvantages
- Too much phosphoric acid can cause crops to grow too tall, resulting in poor growth, and can inhibit the absorption of trace elements such as zinc and iron.
- Phosphoric acid is absorbed by plants at a lower rate than other components. Unless measures are taken, such as spraying both solid and liquid forms, a phosphoric acid deficiency may occur.
Types of Phosphate Fertilizers
Phosphate fertilizers can be classified into the following types according to their form:
1. Solid Phosphate Fertilizers
Solid phosphate fertilizers are in the form of powder or granules. Solid phosphate fertilizers are spread or mixed into the soil before planting crops to absorb phosphoric acid from the roots of plants.
Since phosphate fertilizers move little in the soil and are difficult to compensate for by fertilizing from the roots, it is important to ensure that there is no shortage of phosphate fertilizers by spraying before planting.
2. Liquid Phosphate Fertilizers
Liquid phosphate fertilizers are diluted and applied to the foliar surface of the crop. Since it is applied to the foliar surface and absorbed by the plant, it should be used after the crop has grown to a certain extent.
Compared to solid phosphate fertilizers, liquid phosphate fertilizers are absorbed by crops more quickly. Therefore, they are effective when applied as fertilizer, during flower bud formation, and the fruit fertilization period. Some liquid phosphate fertilizers can also be mixed with pesticide sprays to save labor.
Other Information on Phosphate Fertilizers
Cautions for Phosphate Fertilizers
- Liquid phosphate fertilizers cannot be mixed with alkaline substances or lime sulfur compounds.
- It is important to use the appropriate concentration, as spraying at high concentrations may cause inflammation of roots and leaves.