Table of contents:
Video: Permanent Use Of Greenhouse Soils
Read part 1. Characteristics of peat and soil preparation in the greenhouse
Permanent operation of greenhouse soils
In the conditions of the non-chernozem zone, the soil can be used permanently for three to five years. In the future, it has to be replaced, which is associated with high costs. The change of greenhouse soils is caused by the accumulation in them of a large amount of salts, toxic substances, deterioration of physical properties, an increase in pests and pathogens spread through the soil.
Although changing greenhouse soil is a laborious undertaking, you should strive to change it more often. The old soil is taken out and a new one is brought to the vacant place. With a permanent culture, the greenhouse soil is disinfected by annual soil steaming. This method allows you to increase soil fertility, destroy harmful microflora. It also promotes the decomposition of organic fertilizers and creates conditions for the reproduction of beneficial microflora.
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Steaming tends to significantly speed up the development of vegetable crops. To eliminate pests and fungal pathogens of greenhouse crops, the soil at a depth of 30 cm must be heated to 80 ° C, after which the steam supply is stopped and the soil is left covered with a film for two hours. In this case, the soil is disinfected from most soil pests and pathogens. It is very difficult to achieve such conditions in amateur vegetable growing when steaming the soil.
The correct use of soils largely depends on the use of fertilizers. Fertilization should be strictly linked to agrochemical soil analyzes, which should be carried out systematically once a month. For each greenhouse, it is necessary to have an agrochemical passport, which records the results of agrochemical analyzes of greenhouse soils, the timing and doses of fertilizers applied to the crop in the main dressing and feeding.
The book on the history of each greenhouse should contain a description of the agrochemical composition of soils, characteristics of varieties of greenhouse vegetable crops, their yield; it should indicate the timing of the introduction of mineral and organic fertilizers, foliar dressing, the content of macro- and microelements should be shown, soil cultivation and other agricultural activities should be told, and the appearance of pests and diseases of vegetable crops, the pesticides used, their doses and preventive activities.
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With irreplaceable or rarely replaced soils, it is necessary to constantly monitor so that they are not exposed to salinity from inept exploitation. Salinization occurs mainly on soils poor in organic matter, without regular fertilization with manure or peat, where mineral fertilizers with ballast admixtures or fertilizers with a high content of sodium and chlorine are applied in excess and uncontrollably.
Salinization of soils can dramatically increase the use of manure, which has got lick salt. Manure or mineral fertilizers containing a lot of sodium chloride create an excess of sodium and chlorine in the soil, which often causes plant poisoning. Salinization with sodium chloride or sulphates impairs the physical properties of soils - water permeability, aeration. On saline soils, plant leaves wither, lose turgor, despite abundant watering.
Salinization of greenhouse soils also occurs with the uncontrolled use of manure from slaughterhouses, which contains a large amount of sodium and chlorine. The use of such manure in the main dressing or in top dressing can lead to partial or complete death of plants. On such soils, sodium accumulates in the organs of greenhouse plants (in the leaves and roots), this is especially typical when growing cucumbers. In tomatoes in such conditions, apical rot begins to appear intensively due to a lack of calcium.
The absence of a drainage system, the use of high-ash peats containing iron, aluminum and manganese sesquioxides, the use of poor-quality water for irrigation, the use of fertilizers with a large amount of ballast - all this greatly affects the salinity of greenhouse soils, causing a decrease in yields, especially early ones, and a deterioration in their quality …
To combat salinization of greenhouse soil, it is most effective to flush it. Depending on the degree of salinity, texture and drainage, 400 liters of water and more are consumed for flushing 1 m². Typically, flushing is repeated after two to three days with a water flow rate of 100-150 l / m².
To ensure long-term operation of soils without salinization and to obtain high yields, 15-20 kg of horse or cow manure is applied annually when growing cucumbers per 1 m², followed by its incorporation to the entire depth of the soil, in a layer of at least 25-30 cm. Good effect for reducing salinity soil provides additional introduction of peat, straw cutting, sawdust.
On saline soils, it is preferable to use water-insoluble fertilizers available for plants (magnesium-ammonium-phosphate, potassium metaphosphate, urea form, defluorinated phosphate). From slowly decomposing fertilizers, fish, blood, bone and horn meal can be used.
Greenhouse soils should not be compacted during the entire growing season of plants, since compaction of the root layer of the soil worsens its water and gas regime. Compaction of greenhouse soil mainly occurs when caring for plants.
Agrochemical studies have shown that by the fourth or fifth year of using soils, the content of nutrients in them (per 100 g of air-dry soil) increases, phosphorus becomes over 350 mg, potassium - 400, calcium - over 1200, magnesium - over 300 mg. The high content of nutrients, the violation of the ratio between them, the deterioration of agrophysical properties, as well as the spread of diseases and pests - all this leads to a decrease in productivity.
When introduced into the peat-manure substrate, consisting of low-lying peat, 20 kg / m² of manure, 30% of sawdust (by volume to the soil), the greatest increase in yield is obtained. But when loosening materials are introduced, nitrogen disappears most quickly from the greenhouse soil. In greenhouses where sawdust and straw cutting were used, in the first month after planting the seedlings, the content of available nitrogen decreases by 2-6 times, potassium - by 2-3 times.
Therefore, the use of loosening materials when growing vegetables on a peat-manure substrate requires an increased dose of nitrogen fertilizers to improve microbiological processes. However, the nitrogen content in the soil should not be higher than 60-70 mg, phosphorus - not higher than 180 mg and potassium - not higher than 240 mg per 100 g of absolutely dry soil.
Fertilization of vegetable crops when grown on high peat
High peat as a substitute for soil or soil began to be used in greenhouse vegetable growing relatively recently. Now it is widely used in greenhouse vegetable growing in many countries.
Any peat, including moor peat, has the ability to absorb positively charged ions from solution and retain on its surface. With its high acidity, high-moor peat contains a large amount of hydrogen ions in an absorbed state, which can be exchanged for cations in the nutrient solution. High-moor peat usually contains less than 0.5% CaO and its pH ranges from 2.6 to 4.
High-moor peat is characterized by properties valuable for growing vegetable crops. Even when fully saturated with water, it is able to retain up to 40% of the air. Horse peat has an average density, 3-5 times lower (0.04-0.08 g / cm?) Than greenhouse soils. In this regard, replacing old high-moor peat with fresh one requires much less labor than when working with greenhouse soil soils.
Since high-moor peat is highly acidic, two weeks before laying it in greenhouses, it is lime at the rate of 3 kg or more CaCO 3 per 1 m? peat. For liming it is better to use limestone flour (CaCO 3). As a result of liming, the pH of peat rises to 5.5-6, which is beneficial for vegetable crops.
Horse peat can be used without replacement for four years. The vegetable yield on it is usually 15-25% higher than on the soil. Fertilization of vegetable crops when growing them on high-moor peat has some peculiarities. So, seedlings of tomatoes or cucumbers are grown in pots of calcified peat, to which macro- and micronutrient fertilizers are added. 1 m? high-moor peat is introduced: double superphosphate - 4.5 kg; potassium nitrate - 1.2 kg; anhydrous magnesium sulfate - 0.4 kg; iron sulfate and copper sulfate - 0.1 kg each; boric acid - 0.03 kg; manganese sulfate - 0.025 kg; ammonium molybdate - 0.015 kg; zinc sulfate - 0.005 kg. Seedlings of tomatoes and cucumbers are fed in two weeks with a solution of KNO 3 at the rate of 0.3 g of salt per plant.
The grown seedlings of tomatoes or cucumbers are planted in a previously prepared peat substrate. For this purpose, about 1.5 m? peat substrate, into which 3.5 kg of CaCO 3 are introduced before planting; 1.5 kg of potassium nitrate; 0.6 kg of double superphosphate; 0.6 kg magnesium sulfate; 0.3 kg of ammonium nitrate; 100 g of ferrous sulfate; 50 g of copper sulfate, 30 g of boric acid; 25 g of manganese sulfate; 15 g of ammonium molybdate and 5 g of zinc sulfate.
Thus, in a peat substrate, 1 plant accounts for 12 g of calcium; 3.1 g nitrogen; 5.5 g potassium; 2.5 g phosphorus; 1 g of magnesium and trace elements (their doses should fully satisfy the needs of plants during the entire growing season). Microelements are not added to top dressing. Since one cucumber or tomato plant during the growing season consumes more fertilizers (6-12 g of nitrogen, 2-3.5 g of phosphorus, 15-20 g of potassium and 4 g of magnesium plus losses) than was introduced with the main fertilization of peat, then after four, six and eight weeks after planting, the plants are fed with a solution of mineral fertilizers containing 0.33 kg of potassium nitrate per 100 plants; 0.12 kg magnesium sulfate; 0.06 kg of ammonium nitrate and 0.1 kg of ammophos.
Then 0.33 kg of potassium nitrate and 0.12 kg of magnesium sulfate are added with a 1-2-week interval (per 100 plants). The technology and conditions for fertilizing when using high-moor peat in greenhouses are the same as when cultivating vegetable crops on soil.
Numerous calculations indicate that the cultivation of vegetable crops on high-moor peat is economically more profitable than on conventional greenhouse soils.
We wish all vegetable growers success!