Superphosphate: composition and instructions for use

Fertilizer composition

The main component of superphosphate is phosphorus. Its content varies from 26 to 50% depending on the type of fertilizer. The second component of superphosphate is nitrogen, its concentration is 6-17%. The composition of the fertilizer also includes some trace elements that are usually present in phosphorites: magnesium, calcium, potassium, sulfur. Fertilizer is a complex mixture that has two main varieties:

1. Superphosphate is simple. It is obtained in the process of processing phosphorites with sulfuric acid. It is a powder, which includes up to 26% phosphorus, 6-8% nitrogen, 10% sulfur and 40% calcium sulfate (insoluble gypsum). Gypsum does not bring any benefit to crops, but due to its presence, top dressing does not cake. From a simple powder superphosphate, a granular – loose fertilizer is produced in the form of granules with a diameter of up to 4 mm. It dissipates better and is considered more beneficial for plants, as it contains less gypsum (30%).

2. Double superphosphate. To obtain it, phosphorite is treated with phosphoric acid, due to which the dressing contains more phosphorus (up to 50%) in an easily digestible form and practically does not contain gypsum. The composition of the fertilizer also includes more nitrogen (17%) and 6% sulfur. Double superphosphate is produced only in granular form.

On sale you can find several varieties of fertilizer with additional components: ammoniated superphosphate (contains 1,6% ammonia, used to neutralize soil acidity), and superphosphate with humates (salts of humic acids, used to improve soil fertility).

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What is it needed for

Phosphorus is essential for horticultural and horticultural crops during the transition from the phase of active vegetation to the phase of ovary and fruiting. Superphosphate has a well-balanced composition of nutrients in an accessible form, so feeding with a mixture has the most beneficial effect on crops:

• promotes the development and growth of the root system, which increases the chances of seedlings to take root and take root in the ground – young seedlings must be fed when planting;

• accelerates flowering and ovary formation – with a lack of phosphorus, plants have a lot of barren flowers, and the resulting ovary disappears;

• after the introduction of superphosphate, the fruiting of crops increases, and the taste of fruits improves;

• the resistance of plants to diseases increases; superphosphate introduced in the fall improves the adaptation of crops to cold weather;

• after the introduction of phosphorus top dressing, metabolic processes are accelerated and oxidative ones slow down.

For young plants, phosphorus fertilizer is of particular importance – phosphorus promotes the development of the underground root part, which is very important for seedlings grown under artificial conditions and greenhouse crops. Autumn top dressing of the soil with superphosphate will help grow high-quality root crops. With a deficiency of phosphorus, potatoes and beets become stained, and black blotches form inside. Blue leaves of garden crops or home seedlings also indicate insufficient soil fertilization with phosphorus.

How to apply superphosphate

Superphosphate is a universal complex mixture that can be used as a fertilizer for the soil, as well as for feeding fruit trees and garden seedlings. Fertilizer can be applied to any soil, however, it should be borne in mind that this top dressing has little effect on acidic soil. Experienced gardeners fertilize acidic soil with superphosphate only after adding ash or lime – these materials help to equalize the pH of the soil, and thereby increase the effectiveness of superphosphate.

Simple superphosphate is fed by direct application to the holes or rows intended for planting seedlings. The granular preparation can be used to prepare a solution for foliar feeding (spraying). The application of phosphate fertilizer has some features:

• dry superphosphate fertilize the soil in the fall, since it takes time and a large amount of moisture to dissolve;

• the granular preparation is best distributed using a grain seeder, which will ensure a more uniform application of fertilizer;

• the main top dressing of the soil with superphosphate is carried out before planting and sowing garden plants (usually when digging);

• bulbous and tuberous crops: potatoes, carrots, beets, radishes, turnips are fed with superphosphate when directly applied to the wells during sowing, or planting seedlings;

The fertilizer application rates are as follows:

• when digging the soil in spring and autumn, phosphorus is added at the rate of 40-50 g / sq. m – fertile soil is fertilized at the rate of 20-30 g / sq. m;

• for feeding planted plants at the rate of 10-20 g of dry agent / sq. m;

• for planting seedlings, 3 g / well;

• horticultural crops are fed at the rate of 40-50 g / sq. m, depleted soil is fertilized in the amount of 70 g / sq. m

• under adult fruit crops (apple trees, pears), it is recommended to apply fertilizer in the amount of 300-1000 g / 1 tree, depending on the age of the plants – a solution can be prepared from a dry product, which is applied to the near-stem circle;

• cherries, plums, cherries are fed with superphosphate at the rate of 200-500 g / 1 tree;

• fruit bushes are fertilized at the rate of 100-200 g / bush;

• for stronger seedlings of cucumbers and tomatoes, a solution is used, which is used to water crops at the rate of 20 g / one bush;

• top dressing of tomatoes is carried out several times per season – they consume 95% of phosphorus during the period of fruit formation, therefore, the bushes are fertilized during the seedling planting period, then during flowering and fruit ripening. It should be noted that nightshade crops at the initial stage of growth do not require intensive phosphorus feeding – for normal development, they are fed for the first time at the rate of 10-15 g / one bush;

• standard solution for spraying with superphosphate is prepared at the rate of 20 g of double or 40 g of simple agent / bucket of water;

• irrigation solution can be more concentrated;

• soil for potatoes is fertilized at the rate of 2-3 tbsp. spoons / hole – feeding potatoes with a large amount of phosphorus is necessary for the formation of large and high-quality root crops;

• soil intended for sowing cereals and legumes is fed with phosphorus in the amount of 7-15 centners / 1 ha;

• oilseeds require not only phosphorus, but also the microelements present in the preparation – the soil for sunflower crops is fertilized in the amount of 10-20 centners / 1 ha.

Cooking hood

Phosphorus is not a highly soluble substance. Experienced gardeners feed the soil with superphosphate from autumn, so that it dissolves and becomes active under the action of moisture until spring. But how then to carry out spring and summer feeding of plants with phosphorus? – this question forced gardeners and gardeners to look for ways to quickly assimilate superphosphate.

Any top dressing, including phosphorus, plants absorb from the soil with the help of root hairs, so it is obvious that for them the only available form of fertilizer is a liquid solution. If superphosphate, before being applied to the soil, is dissolved in water, a concentrated extract with a high content of easily digestible phosphorus will be obtained. You can prepare the solution as follows:

1. Alternatively, the fertilizer can be poured with boiling water and insisted for a day in a warm place (diffusion occurs faster in heat).
2. 100 g of double superphosphate is poured into a liter of hot water, mixed thoroughly, and then boiled for half an hour until the granules are completely dissolved. It is important that only a granular preparation is used to prepare the extract, since the powder contains a lot of gypsum, which precipitates, and thus makes it difficult to dissolve the superphosphate.
3. Then the resulting solution is filtered (the appearance of high-quality top dressing should resemble fat milk), and after dilution with water, garden and horticultural crops are fertilized with this suspension.

Phosphorus extract is fed, taking into account that 100 ml of fertilizer contains 20 g of pure phosphorus, and this amount, diluted in 10 liters of water, is enough to process 1 sq. m. soil. The most effective working solution is obtained if the liquid dressing is diluted in a ratio of 2 tbsp. spoons / 3 liters of water. A large bucket of water will require at least 150 g of extract. Extract from superphosphate fertilize the soil, and also carry out foliar top dressing. The solution is quickly absorbed and has a long aftereffect, therefore it can be considered an ideal option for both garden trees and vegetable seedlings.

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