Alexander Shagaev tells about what fertilizers, in what amounts and how they are used in greenhouse in the production of vegetables.
Consumption of fertilizers by ordinary crop in the 3rd light zone is from 17 to 19 tons per hectare per year, which equates to about 1,500 tons. $ 1 ha. In the photoculture a year goes from 45 to 60 tons of fertilizers per 1 hectare. It matters what substrate is used. In Russia, unfortunately, there is a small choice of substrates: the main is mineral wool, the second place is coconut substrate, a small share is occupied by peat substrate, there is experience in working with perlite, zeolite, and airport, but it's only a fraction of a percent. So, if cucumber Meva is produced in photoculture in three turns on mineral wool, then an average of 45 tons / ha of fertilizer is used.
How does fertilizer consumption vary according to geographic location? Differences in the nutrition of plants grown in the northern and southern regions consist in the amount of water used in nutrient solutions per meter square effective area and the concentration of these solutions. The water in the south is usually higher than in the northern regions.
Take three points: St. Petersburg, Lipetsk and Krasnodar. In ordinary crop, St. Petersburg will spend 2 cubic meters of nutrient solution per 1 m2 per year, Lipetsk - 2.5-3 m3 per 1 m2, and Krasnodar - 3.5-4 m3. Photoculture can spend up to 9-10 m3. Also, the amount of fertilizer used depends on whether re-drainage is used.
Watering in summer and winter can also differ only in concentrations and doses of irrigation. Pick up a dose of irrigation from 100 to 200-250 ml per plant. The larger the dose of irrigation, the drier the mat, because more goes into drainage. If it is necessary to wash the mat, then give a large dose of watering, and if you need to increase the humidity of the mat - do a lot of frequent small irrigation.
We have very few producers of quality fertilizers in our country. Everyone states that they produce fertilizers, but there is not one plant in the country that would produce potassium monophosphate. All potassium monophosphate, even with the Russian label, is usually imported from abroad and prepacked in Russia. The product is mainly from China, Israel, Turkey. The best potassium monophosphate from Belgium, Portugal, Israel. The most expensive potassium monophosphate fertilizer comes from China and packaged in Russia, it costs about 30 rubles / kg.
In the Netherlands, all fertilizers that enter the greenhouse are liquid. They do not have dry fertilizers. The batcher automatically selects the required amount of liquid potassium or calcium nitrate and does not need to dissolve anything. In Russia, due to long distances, it is not profitable to transport liquid fertilizers. Bui Chemical Plant tried to produce liquid forms of fertilizer, but, unfortunately, did not stick. They supplied products in 60-liter barrels, which accumulated a lot in the greenhouse. Then these barrels were plundered, and I had to buy fertilizers in new barrels, which affected the price. For this reason, they returned to dry fertilizers again.
Data showing changes in the EU over the years suggests that the Dutch used to work less concentrated solutions, and now they are taking higher concentrations, but using a larger percentage of drainage. We have not yet reached this, because we are working very poorly with high concentration - it's difficult, and the training of agronomic personnel in the country is poor.
Sodium and Chlorine are ballast elements that do not participate in plant nutrition, but it is very important to know their content, because they prevent other elements from being absorbed. When other nutrients are selected from the solution, these two elements remain and create a picture that you are all right, but in fact, the plant may not have enough of certain elements. It is possible not to supplement the plant and this will be due to the fact that in the nutrient solution contains a lot of sodium and chlorine, so it is ballast elements that can harm. However, by itself, Chlorine can significantly improve the taste of tomato. If you grow tomatoes without Chlorine, they will not taste, therefore, this element in small quantities must still be present in the nutrient solution. To this end, 1 mmole of potassium chloride is added to the nutrient solution. But the taste also depends on the hybrid itself. If, for example, you take the Raisa sort, so that you do not, the taste will not be in it. This is just a beautiful tomato and everything.
Sulfur is considered not a very popular element, but in a nutrient solution without it, you will not grow anything. Sulfur should always be present, at least sulfate fertilizers should be used.
Chelates, by overcoming physiological barriers, facilitate faster delivery of the necessary elements. The metal chelate passes through the cell wall quickly, while the trace element itself overcomes it by the exchange method. The metal is attached to the cell wall and it will not pass until an electronic coup occurs. If there is a chelating form of the metal, then the chelate remains on the wall, and the element passes through the inside of the cell.
Chelates are different and they differ in activity at different pH values. It is convenient for the agronomist to work with chelates that have a large pH range, for example from 1.5 to 10, but as a rule they cost a lot of money, so either a mixture of chelates or cheap ones is used, but controlling the acidity in the mother tanks. In the mother tanks it is impossible to check the acidity of the device, because the glass membranes immediately fail, it is possible only litmus paper.
Chalked trace elements based on DTPA and EDTA are mostly used in the greenhouse, because EDDHA chelate is very expensive. It can take 20-30% of the total volume and make a mixture of two chelates. This approach is often used precisely in the summer. In northern regions, more commonly used chelates are used - it depends on water. Rigid water and high temperatures contribute to a faster decay of chelates, so combines in the southern regions spend more on these products. In addition, there are hybrids, which need to give twice as many ferric chelates, for example, the Admiral tomato variety.
The concentration of ferric chelate in the solution depends on the particular culture and fluctuates in the range: from 0.8 to 2 mg per 1 liter. On the rose are used more, on a cucumber less, on a salad the minimum value. If you work with a rinse and receive 50% drainage, then overpacking the plant does not threaten the ferrum. It must be taken into account that the growth stimulator (the same Ruther) or the chelate of the metal that you bring into the nutrient solution destroys when drainage is cleared. And this means that stimulants need to be introduced cyclically.
In the warehouse it is always worthwhile to have calcium chelate. A quality preparation of calcium chelate treats many diseases, especially in heat. This is an emergency remedy that is used: when a cucumber top or a leaf of lettuce burn or against blossom-end rot on tomato.
During the preparation of nutritional solution, use a little trick - use HOEDPA (Chelaton). Hydroxyethylidenphosphone acid (Chelaton) - used in boiler houses, so that calcium inside the pipes does not precipitate. This is a chillaton that makes chelate from any metal. For chelates not to fall apart, it is added to each tank of 400 g per cubic meter. Chelaton works in the range of pH from 2 to 7. It does not have a chelating element and when the metal from another chelate is released, it intercepts it and prevents it from precipitating. Therefore, if you use HOEDPA, you will never have Calcium or Ferrum in the precipitate. For example, if a chelate is present in the solution and it starts to fall apart, HOEDPA intercepts the released iron without allowing it to precipitate out. HOEDPA is not an element of nutrition, but it is a compulsory element for the preparation of a nutrient solution. Without HOEDPA in a tank, precipitate will always be formed. It allows to dissolve potassium sulfate, which is often domestic production and not very high quality.
More simple chelating agents are сіtric and succinic acids. They allow for changing the acidity of the nutrient solution, increase the availability of nutrients, mainly micro-groups. With additional addition, for example, in the absence of Cobalt or Molybdenum, succinic acid makes it possible to feed a little more and a little faster these elements into the plant. And without Molybdenum, plants cannot develop.
HOEDPA use more profitable than citric acid, since it costs 100 rubles / kg, and citric acid 800 rubles / kg. It also increases the acidity of the solution (it gives a lot of hydrogen), but nitric acid is used for these purposes that costs 60 rubles.
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