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Physical and chemical properties
Superphosphate is a friable powder or granular product. gray color with various shades - from almost white to dark gray. Dark gray superphosphate contains some liquid phase.
Application
Agriculture
Simple superphosphate is used as a fertilizer for all crops on all types of soil.
Superphosphate brands registered and approved for use in Russia as a fertilizer are in the table on the right.
Industry
Simple superphosphate is used in small quantities in the yeast and sugar industries, and also as a fire-retardant coating on wood.
Behavior in soil
The mechanism of behavior of superphosphate depends on the properties of the soil.
Phosphoric acid of superphosphate, when applied to the soil, can turn into a form that is difficult for plants to access.
On chernozem soil types with an alkaline or neutral reaction, with a content of calcium carbonate or calcium absorbed by the soil complex, monocalcium phosphate can turn into dicalcium and tricalcium phosphate.
Acidic soils that are not saturated with bases precipitate superphosphate in the form of aluminum and iron phosphates, which are poorly soluble in a slightly acidic environment and are difficult for plant root systems:
Fe(OH) 3 + H 3 PO 4 → FePO 4 + 3H 2 O
Intensity of chemical and colloid-chemical absorption by soil phosphoric acid superphosphate is directly dependent on the content of mobile forms of sesquioxides in the soil.
Acidic soils are characterized by intensive processes of fixation of soluble phosphates on the surface of soil colloids, which are rich in sesquioxides.
The fixation of phosphoric acid in the soil also occurs as a result of its biological absorption by soil microorganisms.
According to the intensity of energy with which the absorption of phosphoric acid occurs, soils can be arranged in the following sequence: red soils, podzolic soils, chernozems, gray soils.
Application on various types of soil
Superphosphate is applied on all types of soils, under all crops. Fertilizer efficiency can be improved by using techniques that reduce the chemical absorption of phosphoric acid by the soil, namely: the use of granular forms, row application, local application.
Application methods
The effect of superphosphate on the crop depends on the method of its application. The main part of the fertilizer dose is applied under the plough, in combination with row application. In highly humid conditions, as well as under irrigation conditions, part of the fertilizer can be applied at.
When applying fertilizer in the main application, it is important to choose the correct placement depth. It should be carried out precisely in that layer of soil where the bulk of the roots of the fertilized crop is located. Before sowing, superphosphate is recommended to be applied to the depth of the main processing.
The effectiveness of superphosphate increases when it is applied when sowing crops in holes, nests, etc. With this method, it is better to use granular superphosphate. necessary for plants at the very beginning of their growth. Superphosphate, like other phosphate fertilizers, increases yields and improves the quality of agricultural products (sugar content in beets increases, starchyness in potatoes, etc.). In winter crops, winter hardiness increases and maturation accelerates. Numerous experiments have established that the introduction of 0.5 centners of granulated superphosphate per 1 ha gives an increase of up to 2.5-3 centners / ha of cereals.
Receipt
Superphosphate production technology consists of three stages: decomposition of phosphorite ore with sulfuric acid, maturation and ripening of superphosphate. IN industrial production a continuous method of obtaining fertilizer is used, when the supply of ore and acid, as well as the unloading of the finished product, take place simultaneously and continuously.
It is believed that modern agriculture cannot do without chemical fertilizers. The issue is debatable, since in the wild, without any top dressing, plants feel great. However, intensive agricultural practices in agriculture and growing plants long time in one place they create conditions for soil depletion, and the application of mineral fertilizers, including superphosphate fertilizers, becomes a way to preserve soil fertility.
No plant will develop in the absence of phosphorus salts in the soil. All useful nutrients in the soil can only be absorbed after they have been processed by soil microorganisms. This applies to superphosphate fertilizer, the use of which in a soluble form, more effective, since bacteria feed only on the liquid component.
sparingly soluble salts phosphoric acid. In this case, the solubility of some depends on the medium. Since the entire periodic table is located in the earth, even a dissolved phosphorus compound can be bound and precipitated, meeting in the form of an acid residue with an aluminum or iron ion in acidic soil. Therefore, in the soil on which horsetail and wood lice grow, phosphate fertilizers are ineffective.
But if we already talked about the role of microorganisms in the assimilation of phosphorus, then this means that soil fertility will increase with the application of fertilizer, in the presence of an increased number of beneficial microorganisms. Increase soil fertility applying only fats, mineral fertilizers is impossible. It is necessary to restore the microflora of the earth, and an increase in the doses of chemicals introduced will destroy it.
The presence of phosphorus in the plant regulates energy metabolism in cells and promotes the development of the root system. The assimilation of other fertilizers, if there is enough phosphorus, is accelerated, and the plant absorbs all necessary elements. Phosphorus starvation is noticeable by changing the color of the leaves to a blue-violet hue and the general depression of the plant. In the presence of a sufficient amount of this element, the prevalence of nitrogen absorption does not occur, and the plants gain less nitrites, which are now saturated with all early greens grown intensively with the use of mineral fertilizers.
Ways to use phosphate fertilizers
On different stages soil preparation for growing plants are applied different ways adding superphosphate:
- autumn incorporation into the soil;
- spring application in holes or furrows;
- summer top dressing of fruit trees;
- liquid feed:
- compost preparation.
The use of superphosphate during the autumn digging of the soil is a well-known agricultural technique. But if the fall is scheduled site liming, then the application of the drug can be postponed to spring time. The fact is that the substances contained in these chemicals are on the same calcium basis.
Various substances, including insoluble gypsum and various soluble salts, create saturation of the soil with chemicals, and since superphosphate salt is acidic, and we add lime to remove the acidity of the soil, we get a mutual neutralization of properties. Funds were spent in vain and additional salinization of the land was created.
For another reason, superphosphate and urea cannot be added at the same time. Both compounds are acidic and soil acidification occurs. Simultaneous application of potash fertilizers is welcome. The autumn application of potassium in the chloride form, together with phosphorus, helps the soil to assimilate both.
The best way to use superphosphate is to add it to the compost. It is especially good to introduce powder simple superphosphate into the fertilizer mixture at the ripening stage. At this stage, gypsum is useful and all related substances are converted by bacteria into a form convenient for absorption by plants.
In the summer, top dressing with superphosphate are better absorbed extract based. flooded hot water the mass of superphosphate is kept for a day in an enameled or plastic container with occasional stirring. Then the light part of the sludge is drained, used for quick top dressing, if necessary, with breeding.
All application rates of superphosphates, and there are several varieties of them, are indicated on the packages, and the dose should not be exceeded.
The chemical composition of superphosphate
Superphosphate is a mixture of sesquicalcium salt of orthophosphoric acid and gypsum with impurities based on the same acid of ammonia, manganese, boron, molybdenum salts, that is, all those components that are present in apatites and phosphorites, minerals. These minerals are exposed to hydrochloric acid.
AND as a result chemical reaction the above products are obtained. Single superphosphate contains a little of orthophosphoric acid itself. However, half of all substances are gypsum, the insoluble part of superphosphate.
The chemical formula of superphosphate for the main substances looks like this: Ca (H 2 PO 4) 2 * H 2 O + CaSO 4. After a chemical reaction, superphosphate ripens, and it becomes free-flowing, not subject to clumping.
In addition to the single one obtained by treatment with sulfuric acid, double superphosphate is obtained, in which no plaster and twice as much phosphorus.
The industry produces several varieties of superphosphate:
- simple powder;
- simple granular;
- double granular;
- ammoniated superphosphate;
- granulated with humates.
All these varieties have their own scope and their own dosage, indicated in the instructions for use.
Physiological effects of superphosphate
With a balanced nutrition of the plant, it receives each element exactly as much as it needs for development. Therefore, the result of the balance will be:
- Increasing yield and improving the taste of fruits.
- The flowering of plants is accelerated.
- Put a barrier to diseases.
- goes accelerated exchange substances.
Precisely, we can say that there is not enough phosphorus fertilizers in the soil if the potato tubers brown spots appear or becomes with internal black dots of beets.
A sufficient amount of superphosphate especially affects early stages plant development. At this time, the development of the root system is important and it is phosphorus that contributes to the growth of the underground part of the seedlings at home. Therefore, when preparing the soil in the fall, it is necessary to add the right amount of superphosphate.
Spring blueing of leaves in a greenhouse or seedlings at home does not always require fertilizing with phosphorus fertilizers. Sometimes it is necessary to increase the temperature of the earth. Below 10 degrees of soil, the roots stop working to feed the plants.
Any top dressing in the ground gives its visible results in two weeks. Foliar acts two to three times faster. This must be taken into account when you need to urgently add the missing elements to the plant.
In superphosphate, a substance converted to a mass fraction of phosphorus oxide, P 2 O 5, is absorbed and taken into account. In these units, only 5% of the substance is in an easily digestible form, nature will have to work on the rest of the introduced substance for a long time to convert it into a form convenient for assimilation. Therefore, phosphate fertilizers have long term actions.
Even supporters of exclusively organic farming understand that without phosphorus it is impossible to grow good harvest tomatoes. Unfortunately, the natural saturation of the soil with phosphorus is very low, therefore, the use of phosphorus fertilizers is necessary for growing vegetable crops. Superphosphate - a complex mineral mixture containing nitrogen-phosphorus compounds, the most important trace elements and minerals, is ideal for feeding tomatoes, since phosphorus oxide is present in this fertilizer in an accessible and easily digestible form.
The use of superphosphate for feeding not only tomatoes, but also other vegetable, fruit and berry crops is convenient because the drug has a long aftereffect. It can be applied to the ground in large numbers without worrying about overdosing, as the plants consume exactly the amount of phosphorus they need. Experienced vegetable growers know how to calculate the right amount and duration of fertilizer, so they achieve high yield any vegetable crop.
With a sufficient content of phosphorus in the soil, plants develop better and faster, their vegetation period is extended, the quality and taste of fruits improve. And with a deficiency of this element, there is a lag in growth, which, of course, affects fruiting. The following external signs on plants indicate that it is time to apply superphosphate for feeding tomatoes:
- noticeable darkening of the leaf plates - the leaves become dark green with a bluish tinge;
- rusty spots appear on the stems and leaves;
- the underside of the leaf may acquire a purple color.
Most often, such signs appear on tomato seedlings that have been hardened off, or after a sudden cold snap. At low temperatures, the absorption of phosphorus by the roots is difficult, but with an increase in temperature, the color of the leaves, as a rule, is restored. If this does not happen, then the plants must be additionally fed with superphosphate. 
The drug is usually applied to the soil in the spring before planting or in the fall. Autumn application is more preferable for fruit and berry crops, since the mixture supports the root system and facilitates the wintering of the plant. For tomatoes, superphosphate is best applied in the spring when digging the soil. But you can also pour fertilizer directly into the hole when planting seedlings at the rate of 1 teaspoon / 1 plant.
Video “How to fertilize”
From the video you will learn how and when to fertilize tomatoes.
What soils to use
Phosphorus in the composition of the fertilizer is in a form in which superphosphate can be used for any soil. It always remains available to plants, and they can absorb it in required quantity. The most effective fertilizer manifests itself on fertile soils with a neutral or alkaline reaction. But on acidic soils, its absorption by plants is a little difficult. 
With an acid reaction, the absorption of phosphorus by the roots slows down, therefore, before applying the preparation, the acidity of the soil must first be leveled with ash (200 g / 1 m² of area) or lime (0.5 kg / m²). After leveling the acidity, superphosphate is applied no earlier than 1 month later. Otherwise, the fertilizer efficiency will be significantly reduced.
In acidic soil, the action of superphosphate can have unpredictable consequences. This is especially true for inexpensive mixtures, for the manufacture of which manufacturers use non-pure raw materials.
In any other soil, nothing bad will happen, but in an acidic environment, such a fertilizer can turn into iron phosphate, which makes it unavailable to plants. Therefore, with a noticeable deficiency of phosphorus in the soil, it is still better to use more expensive preparations. But if you are sure that the acidity of your soil is not increased, then any kind of superphosphate can be used.
Instructions for use
Superphosphate is applied directly to the soil in spring period or at the end of the season. Consumption rates of fertilizer for soil are 40-50 g / 1 m² of area for fertile lands and 50-70 g for soils that have long been used in crop rotation. The total amount of fertilizer for depleted soils should be increased by about 30%. Such an expense is acceptable for the areas where seedlings are grown, vegetable crops, greens, cereals and other types of agricultural plants. For growing crops in greenhouses, the norms of superphosphate increase to 80-100 g / 1 m² of soil. 
For top dressing fruit trees And berry bushes 40-60 g of fertilizer / 1 plant is used, depending on its age and size. When planting seedlings, up to 300-500 g / 1 planting hole can be applied once. If an adult tree or bush is fed, then the granules are embedded in the near-trunk circle before flowering. But it is also permissible to dissolve the indicated amount of the drug in water and use it for irrigation, but you should be aware that the dissolution of superphosphate does not occur quickly.
For nightshade crops: potatoes, eggplants, tomatoes, it is better to apply superphosphate in granular form directly into the hole during planting. With continuous application to the soil during digging, the preparation is scattered in the amount of 20-30 g / 1 m² of planting area. When using superphosphate in gardening, you need to know that it is not compatible with other nitrogen fertilizers (mixtures), as well as with chalk (lime).
Types of superphosphates
For ease of use, superphosphate is available in several forms and varieties:
Do not disregard another "folk" type of phosphorus top dressing - an extract from superphosphate. Since phosphorus is poorly soluble in water and this slows down its absorption by plants, gardeners have come up with a method that turns superphosphate into liquid fertilizer and how to apply it to tomatoes. To completely dissolve the granules or powder, they are poured with boiling water. This saves all beneficial features substances, but it passes into an easily digestible aggregate form.
Preparation of funds takes a whole day. At this time, the dishes with the solution are placed in a warm place and periodically stirred so that the drug dissolves better. The finished suspension should look like high-fat milk. 
Next, the extract must be diluted with water, first in a proportion of 20 tbsp. tablespoons / 3 l of water (a working solution is obtained, from which the top dressing itself is prepared later), and then prepare the main top dressing: add 150 ml of working solution, 20 g of nitrogen, 0.5 l of ash to 10 l of water. Nitrogen in the composition of top dressing is required - without it, phosphorus will not be absorbed. The hood is used for root application by irrigation.
Application for tomato
Superphosphate is a universal fertilizer, but it shows the highest efficiency when applied to garden crops: potatoes, eggplants, tomatoes. Tomatoes are especially responsive to this top dressing: the bushes become more powerful, and the fruits are sweeter and not watery. When applying superphosphate for tomatoes, you should adhere to the norm of 20 g / 1 plant (bush). 
As a rule, the drug is applied in a dry, better granular form. The powder is evenly distributed in top layer soil. It is not necessary to deepen the granules strongly. The optimum embedment depth is at the level of the roots. More than 90% of phosphorus is used by tomatoes for the formation and ripening of fruits, so the introduction of superphosphate should not be limited. spring top dressing and continue them until the end of the flowering period.
Phosphorus is necessary for plants as an element of nutrition, a participant in energy metabolism. After harvesting, the reserves in the soil are reduced, superphosphate makes up for the deficiency: the instruction for the use of fertilizer provides for several methods of application. This is one of the most effective means increase productivity and improve the quality of vegetables, fruits and berries.
Description and characteristics
Superphosphate is obtained from phosphorites and apatite concentrate. The composition of the fertilizer reflects it chemical formula Ca (H 2 RO 4) 2 ∙ H2 O + CaSO 4 ∙ 2 H 2 O. Assimilated phosphorus in terms of P 2 O 5 ranges from 16 to 20.5%. Depending on the type of raw material, impurities of gypsum CaSO 4 ∙ 2H 2 O of the order of 30–50%, silica, compounds of aluminum, iron, and fluorine are contained.
The fertilizer is produced mainly in the form of light gray or gray rounded granules with a diameter of about 3–5 mm. You can find in specialized stores and powdered phosphate fertilizers. They are very dusty when applied, caked during storage. Compared to powder, granular fertilizer spreads well and does not cake.
Double superphosphate
From the formula Ca (H 2 RO 4) 2 ∙ H 2 O, it can be seen that there is no gypsum in this fertilizer. The concentration of phosphorus in terms of P 2 O 5 is 43–48%. Impurities: calcium sulfate, magnesium, aluminum, iron phosphates.
Double superphosphate - gray granules, unequal size, up to 5 mm in diameter. The fertilizer is concentrated, water-soluble, suitable for open ground and greenhouses, used on all types of soil.
Superphosphates - simple and double - have similar outward signs, their physical and Chemical properties. These fats are interchangeable, but not in all cases. For cabbage, simple superphosphate is preferred due to the presence of sulfur. Double superphosphate is more economical.
When is it used?
The main condition for the effectiveness of the use of any fertilizers (tuks) is the correct determination of the dosage and method of application. It must be borne in mind that the needs of plants in individual phases of development are different. The content of batteries in different types soils is not the same, it depends on the climate, the previous crop in the crop rotation.
There are few readily available soluble phosphorus compounds in the soil, so phosphates are added. The needs of plants increase during the period of intensive growth and development of shoots, with the formation of buds and the formation of ovaries. In addition to phosphorus (P), cells in these important phases of life need potassium (K), nitrogen (N), magnesium, sulfur, and iron.
Phosphorus is involved in the construction of proteins, enzymes and the energy carrier - adenosine triphosphoric acid (ATP). Plants constantly need these substances. With a deficiency, the ovaries crumble more strongly, the fruits do not ripen. After the introduction of superphosphate, the most rapid and significant increase in yield is given by cereals, vegetables, potatoes and fruit trees.
Signs of a lack of phosphorus in plants are manifested by inhibition of shoot growth, darkening of leaves, abscission of ovaries and poor ripening of the remaining fruits.
The result after the introduction of phosphates:
- roots develop better;
- shoots appear faster;
- abundant flowering is stimulated;
- plants are simultaneously provided with sulfur;
- increases immunity to diseases;
- the taste of fruits, tubers and root crops improves.
With symptoms of a lack of phosphorus, spraying the leaves with a fertilizer solution is used to quickly fill the macronutrient deficiency. The disadvantage of foliar top dressing is the presence of insoluble gypsum in the composition.
Superphosphate is applied to all crops, used on all types of soil. The effect of fertilizer application is higher on loamy and sandy substrates. The result of the introduction of fertilizers on chernozems is less noticeable. The availability of phosphorus is reduced in strongly acidic and acidic soils (pH from 3 to 5). Optimal values The pH of the substrate for most agricultural plants is in the neutral range (pH 5.5 to 7).
Superphosphate decomposes better with the formation of a plant-accessible form with a neutral and slightly alkaline soil reaction (pH from 6.2 to 7.5).
To improve the absorption of phosphorus, it is necessary to neutralize the increased acidity of the substrate. Lime or ash is added, respectively, 0.5 or 0.2 kg per 1 m 2. After that, after a month, you can apply mineral fertilizer. Wood and peat ash neutralize acid, serve as additional sources of phosphorus and potassium.
Superphosphate is used in the fall when cultivating the soil, in the spring when digging. Joint application with manure, humus, litter is practiced, which contributes to better absorption of phosphorus by plants. You can fall asleep tuki directly into the grooves or holes immediately before sowing seeds, planting seedlings. Another way to use is top dressing in spring and summer during flowering and fruiting.
The nutrient enters the roots at temperatures above 15°C, gradually from spring to autumn. During the application season, plants use only one fifth of the phosphorus from the composition of superphosphate. It may take several years to fully assimilate.
How to apply to the soil?
Dosages and methods of application are determined taking into account the characteristics of plants and soil properties. Higher doses are applied under fruit trees and vegetables, medium - under potatoes.
In September or April, during plowing, deep cultivation, and digging of the site, approximately ¾ of the total norm of superphosphate is applied, embedded in the root layer of the soil. This is the main fertilizer. On acidic soils, it is desirable to use it closer to the sowing or planting of seedlings. In summer, it can be used in the form of granules or prepare a solution for foliar feeding (spraying).
Granular phosphorus fertilizers are used for the main and pre-sowing application. Top dressing is carried out in spring and summer in order to provide plants with nutrition during the period of maximum need. Effective method fast delivery of phosphorus - foliar application (spraying the leaves with a fertilizer solution).
Prepare a solution of 20 tbsp. l. fertilizer and 3 l hot water(one tablespoon contains 15 g of granules and 18 g of superphosphate powder). Fertilizer is poured with boiling water and infused for 8-24 hours. Then the liquid is drained from above, it is passed through the filter. Insoluble gypsum remains in the sediment, it can be thrown away.
For foliar top dressing, add 150 ml of working solution to 10 liters of water. Plants are sprayed with this liquid 2 times during the growing season.
Instructions for use
The average consumption rates for continuous application are 40–50 g of simple or 15–20 g of double superphosphate per 1 m 2. Scattered fertilizer should be embedded in the soil when digging. If the site was abandoned or never cultivated, then simple superphosphate is added 60–70 g / m 2, double - 25–30 g / m 2. A good effect is achieved by combining the main fertilizer with local addition to holes, rows in May during sowing. For feeding sufficient 1 tsp. phosphate per 1 m 2.
In the garden
Simple superphosphate is added to the pits when planting potatoes, fertilizer is mixed with the soil. Under one bush, 3-4 g are applied, which is less than half a teaspoon. You can use this fertilizer to feed potatoes during the growing season. In total, 15–20 g of fat will be required per 1 m 2 of the area of \u200b\u200bthe site.
Under the seedlings of vegetables, close up next to the grooves when sowing radishes, carrots, beets. The norm is 20–30 g / m 2. When planting seedlings of tomatoes and other vegetables in open ground it is recommended to add 1 tsp to each well. fertilizer mixed with compost and wood ash. Double superphosphate take half as much. Plant roots should not come into contact with the granules.
In greenhouses for vegetables, 40–50 g of simple superphosphate per 1 m 2 is used as the main fertilizer for digging. The double norm is 10–20 g per 1 m 2 of the plot. Fertilizer should be spread evenly and harrowed.
A solution for feeding vegetables is prepared from 20–30 g of fat and 10 liters of hot water. After cooling, water the ground under the plants. On poor or acidic soils, fertilizer doses should be increased by 20-30%.
In the garden
Under seedlings fruit trees 0.4–0.6 kg of superphosphate is added to each planting hole and mixed with the ground. Top dressing in spring and after flowering consists in scattering and embedding 10–15 g of fertilizer per 1 m 2 into the soil around the trunk trunk circle. In autumn, 0.5–0.6 kg of double superphosphate is applied under fruit-bearing trees.
Raspberries are fertilized during planting: 80–100 g per bush. Superphosphate is mixed with soil in landing pit. Under gooseberries and currants, 25–30 g of fertilizer is applied per 1 m 2 of area.
For flowers
When sowing flowers and planting seedlings ornamental shrubs add 2–3 g of double superphosphate per 1 m 2 of soil. Or prepare a solution of 20–30 g of fertilizer and 10 liters of hot water. After cooling, water the plants. Indoor flowers are watered once a month with a solution of 12 g of superphosphate and the same amount of potassium salt in 10 liters of water.
For foliar feeding of roses, a solution of superphosphate and potassium monophosphate is used. The first component is taken 25 g, the second - 10 g, water - 10 liters. Leaves are sprayed with this liquid.
Landing coniferous shrubs and trees, 60–70 g of superphosphate are added to each hole and mixed with the soil. The lawn needs 50–70 g of phosphorus fertilizer per 1 m 2 of the “green carpet” in autumn.
Buying fertilizer
Granular superphosphate is a valuable source of phosphorus for plants. This fertilizer is widely available in specialized stores, garden centers and nurseries.
Names of goods, manufacturers and approximate prices in rubles per 1 kg:
- Superphosphate, granulated. "Promkhim" - 47.50.
- Fertilizer Superphosphate double. "Sotka" - 99.
- Double superphosphate. "Fasco" - 104.
- Superphosphate "Fasco" -76.
There are types of this fertilizer with the addition of ammonium, humic acids, magnesium, boron, molybdenum.
Storage rules
Granular superphosphate - simple and double - is less demanding on the conditions of detention, compared with saltpeters. Each type of fertilizer is stored separately, not in residential, but in utility rooms.
The granules are left in their original packaging or poured into a dry container made of durable stainless material. Phosphorus fertilizer has a slight hygroscopicity, i.e., it absorbs little moisture from the air. Do not mix superphosphate with urea, ammonium, sodium and calcium nitrate, lime to avoid the formation of lumps.
Conclusion
Phosphorus is one of the three most important plant nutrients. With a sufficient amount of easily digestible phosphates in the soil, plants bloom in a timely manner and give a full harvest. Superphosphate does not accumulate like nitrates, its excess does not harm the quality of the fruit, however, the recommended application rates should be followed.
