Up to 90% of applied phosphate fertilizer is locked or bound in the soil within days after application. Generally, there is only 1 kg of phosphate per hectare in the soil solution that can be used by the plant. Only a small part of the remaining soil phosphate is in a fraction with more or less good exchange capacity or in an unstable fraction, while most of the phosphate is in a stable fraction with little or no exchange capacity. Applying technologies that can reduce the binding of phosphate fertilizer and maintain its presence in the soil corresponds to good agricultural practices (GAP).
In acidic soil systems; Phosphates are bonded by reaction with aluminum, iron and manganese cations. In alkaline soil systems; Phosphates bind by reacting with calcium and magnesium cations.
Avail attracts these cations, allowing plants to utilize more reactive phosphate, either in solution or in an unstable state.
Soil pH and multivalent cations such as aluminum, iron, manganese, calcium and magnesium strongly influence phosphorus availability and solubility. Alkaline soil pH or acidic soil pH below pH 6 generally reduces the solubility of phosphorus. While alkaline soils are characterized by minerals containing basic metals such as calcium and magnesium, with the decreasing pH value, iron and aluminum gradually increase in acidic soil and bind phosphorus in aluminum and iron-phosphate. For example, minerals containing aluminum and iron become available more quickly in acidic soils, creating aluminum and iron phosphate precipitates that are less soluble and less usable by the plant. Similarly, increased calcium and magnesium concentrations also increase phosphorus precipitate formation in alkaline soils. In calcareous soils, CaCO3 (limestone) can reduce phosphorus solubility by causing calcium-phosphorus minerals to adhere to mineral surfaces. Due to all these factors, crops grown in soils with low phosphorus solubility have been proven to respond positively to Avail-treated phosphate fertilizers.
KEY FEATURES
Avail, used for phosphate fertilizer, contains 40% by weight of the sodium salt of maleic-itaconic copolymer. The pH value of the formulation is 7-8. Avail has a very high cation exchange capacity (CEC) of 1800 meq/100 g with a molecular weight of 3-4000 g/mol. Its specific gravity is 1.29 g/ml. The CAS number is 556055-76-6. Avail is a patented long chain polymer structure consisting of 30-40 mers, designed to attract multivalent cations such as aluminum, iron, manganese, calcium and magnesium, which are found in the soil and cause phosphate to bind in the soil.
MECHANISM OF EFFECT How AVAIL works:
It creates a negatively charged shield in the microenvironment around the phosphate particle.
The long-chain negatively charged copolymer in Avail binds with the positive ions of aluminium, iron, manganese, calcium and magnesium, reducing soil locking by up to 30%, thus ensuring that phosphate (PO43-) remains in a soluble form and can be effectively taken up by the crop roots. provides.
BENEFITS
Avail is completely water soluble, meaning that it acts with the phosphate fertilizer granule as it enters the soil, preserving phosphate by reducing phosphate lock-in by up to 30% for several months. This solubility ensures that the phosphate preserved in the soil is available to the plant from the very beginning. Once applied, Avail remains fully active throughout the storage period of the fertilizer to which it has been added.
Avail helps increase the efficiency of phosphorus by preventing fertilizer phosphate from binding to the soil.
Trials have shown that by improving the efficiency of phosphorus and under conditions where there is a positive response to phosphorus, application rates can be reduced by up to 20% without loss of efficiency. As of today, it has been used in more than 29 million hectares of land; It can be applied to all types of powder phosphate fertilizers such as MAP, DAP, TSP, NP. Phosphate fertilizers treated with Avail can also be used in mixtures.
*There are no restrictions regarding the product it can be applied to, soil type or soil pH.
*The polymer maintains its CEC activity as it is broken down into shorter chains and functional groups in the soil, therefore it provides protection to the fertilizer for several months by preserving the solubility of phosphate.
PRODUCT POSITIONING
Observations were made under conditions where a positive yield response to a phosphorus-enhancing product would be expected, i.e., soil analysis with a low phosphorus level (STP), a high alkaline or acidic pH, and a low phosphorus fertilizer rate. A mean yield response of 4.6% to AVAIL was noted in 116 observations evaluated under responsive conditions (P < 0.0001). AVAIL effectively increased yield when used appropriately where a positive response to phosphorus was expected.
Where phosphate restrictions exist, Verdesian recommends using 80% of your normal application rate when using Avail-treated phosphate fertilizer. In this way, you will gain both commercial benefit and a yield equal to your normal yield under phosphorus-sensitive conditions.
FIELD PERFORMANCE CRITERIA
Avail preserves phosphate under all field conditions. However, in our experience, growers will derive maximum benefit when they apply treated phosphate under the following conditions:
| Phosphate + Avail Number of trials Ave yield response kg/ha | ||
| Powder P-fertilizer | 177 | 559 ( +5.5% ) |
ENVIRONMENT
EVALUATION OF THE INDIRECT AND LONG-TERM EFFECT OF DEGRADATION OF AVAIL USED IN A MIXTURE WITH POWDERED PHOSPHATE FERTILIZERS – INCUBATION STUDY UNDER CONTROLLED CONDITIONS – RESULT
There was no negative effect on the rate of use of the AVAIL product and on the growth or mortality of earthworms when 3 to 10 times more than this rate was used. There are observations that the product has a positive effect on the growth of earthworms compared to untreated agricultural land considered as a control. It was observed that the AVAIL application applied in mixture with the agricultural soil used in the trial did not have a significant ecotoxic effect on the proliferation of earthworms, compared to soil alone.
Avail applied together with phosphate fertilizer; It does not affect soil bacteria, earthworms, other soil creatures, fish or fauna (animals).
Avail treated phosphate can be administered from reduced dose to normal dose. Since soil erosion caused by wind and water can direct phosphate to water resources and cause algae formation, reducing phosphorus mineral applications by around 20% can help reduce this environmental hazard.
Avail polymer dissolves in the soil as carbon, oxygen, hydrogen and sodium. Due to the size of the molecule, it is not taken up by the plant, therefore it does not leave any residue in the harvested product.
