The problem of availability of phosphorus for agricultural crops has been known for a long time. As a rule, the rate of use of an element from fertilizers by plants is 10–15% and rarely exceeds 25%. In this article, we will consider the importance of the correct application of phosphorus fertilizers to increase the efficiency of their use.

"Bound and inaccessible" - these are the words that no agronomist wants to hear when analyzing their soil for phosphorus content. However, these characteristics adequately describe one of the most important nutrients for plants - phosphorus (P).

Although the total concentration of phosphorus in the soil is quite high, crops rarely receive more than 15–20% of the phosphorus applied with fertilizers. Therefore, fields usually become phosphorus-deficient with intensive agricultural practice. This steady decline is due to increased yields combined with phosphorus application rates that do not match the level of nutrient uptake by plants.

Knowing this, what advice can be given to growers so that they can provide their fields with this important element?

Controlling phosphorus content and its effectiveness comes down to understanding each crop's needs, soil properties, and making informed decisions about the type and rate of fertilizer used for those crops. Let's take a closer look at this problem.

An irreplaceable element

Phosphorus, along with nitrogen and potassium, is one of the three main macronutrients necessary for crop production.

Although phosphorus plays a key role in many processes occurring in plants, one of its primary functions is energy storage and transfer. As a result of this dynamic relationship with energy, an insufficient level of phosphorus leads to a decrease in cell division and a slowdown (delay) in plant growth.

When the deficiency increases, the leaves may turn purple in places. This is mainly due to the accumulation of sugars when the plant does not have enough energy to transport and use them.

Phosphorus is also important for the growth and development of seedlings and the root system, that is, at the beginning of the growing season.

The root system of a young plant has a limited ability to extract phosphorus, so phosphorus-based fertilizers are often added directly near the developing roots.

Everything starts with the soil

It is important to understand how soil affects phosphorus availability.

Soil phosphorus consists of two forms: organic (not for plants) and inorganic (for plants). Although these forms exist in equilibrium and complement each other, the process is very slow, so the amount of available phosphorus may be low.

The inorganic, plant-available form of phosphorus is characterized by high reactivity and can be bound by soils. Therefore, you often hear the term "P solution" - it is used to describe the amount of inorganic P that is actually available to plants.

You may also have heard the phrase "plants drink", and that is absolutely correct, as inorganic P must be "diluted" in solution (P-solution) in order for the plant to absorb it.

Soil pH has different values ​​due to the solubility of different minerals in the soil.

Phosphorus binds and forms insoluble sediments (salts) with various trace elements of the soil. Iron and aluminum, for example, are micronutrients whose solubility increases as soil pH decreases, so the potential for unavailable salts to form increases as more iron and aluminum are added.

A more neutral pH of 6.0-7.0 is ideal for maximum phosphorus availability.

Soil testing is one of the best tools for measuring nutrient levels in a field, and its results can be used to guide the development of an effective phosphorus management plan.

However, when it comes to phosphorus, most soil tests measure total P removed, not necessarily what will be available to plants. Of course, low phosphorus in field trials also indicates the likelihood that the plant will benefit from a phosphorus application, but soil properties will affect how much phosphorus will be needed.

Increased availability

Application of fertilizers is recommended to increase the concentration of phosphorus available to plants during the current growing season.

Due to the indestructibility of phosphorus, which is required to move less than 3 cm from the same place, when applied, string application and application into the furrow is a miraculous strategy in the algae.

Galuzev's experts have documented that the deposition of phosphorus is only 20% effective, and therefore it is also necessary to properly place the element for maximum aggregation and vicorization.

The application of phosphorus-rich fertilizers near the soil can increase the concentration of P in the soil by more than a hundred times, which gives the plant a head start, especially when the soil is cold.

In addition, the time of application is also important: the effectiveness of phosphorus-based additives will be maximum when they are frozen shortly before or before the hour of death.

Experts also strongly recommend vicoristic additives to add chelates on soils that are sensitive to phosphorus binding. In the chelate stage, these microelements will not bind phosphorus, which will, in turn, increase the availability of both phosphorus and microelements.

Source: agronom.com.ua