Soil Preparation In The Greenhouse And Feeding Regime For Growing Cucumbers

2024 Author: Sebastian Paterson | [email protected]. Last modified: 2023-12-16 13:47

Read part 1. Characteristics of peat and soil preparation in the greenhouse

Nutrition and fertilization of cucumbers grown in greenhouses

Cucumber is the most demanding crop for soil fertility. For the formation of high yields of cucumber - 30-35 kg / m² and more, it is necessary to have, on the one hand, a large amount of nutrients in the soil, and, on the other, the cucumber does not tolerate a high concentration of nutrients in the substrate. Therefore, to meet the needs of plants for nutrients, they resort to fractional application of fertilizers.

Cucumbers planted in the ground consume a significant amount of nutrients for the formation of a crop unit, which are commensurate with the applied doses of fertilizers. Nitrogen 23 g, phosphorus 14, potassium 58, calcium 19 and magnesium 5 g are consumed per plant. Nitrogen 2.64 g, phosphorus 1.55, potassium 6.60, calcium 2 are used per 1 kg of plant fruit. 19 and magnesium 0.57 g. Cucumber is characterized by an extended period of absorption of nutrients. However, during the period of fruit formation, each cucumber plant daily consumes a lot of nitrogen - 0.6 g of N and potassium - up to 1 g of K ₂ O, therefore, the lack of nutrients during this period sharply leads to a decrease in the yield of fruits.

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In general, with a yield of 25-30 kg from each 1 m², cucumber carries up to 100 g K ₂ O, 55 g CaO, 45 g N, 25 g P ₂ O ₅ and 8 g Mg. The maximum need of a culture for nutrients falls on the period of fruit formation, because the main amount of nitrogen, phosphorus and potassium is contained in fruits. Hence, it is clear why, with a lack of nutrients, the ovaries begin to fall off, and the cucumber fruits take on an ugly shape. As for calcium, the main amounts of this element are concentrated in the leaves. The fruits contain significantly more magnesium than calcium. Therefore, you need to constantly take care of the sufficient content of available nutrients in the soil.

2-3 days before planting in greenhouses, it is advisable to spray the seedlings with a solution of trace elements and feed them so that they can more easily survive stress and transplant to a permanent place.

For growing cucumbers in greenhouses, you can prepare a soil consisting of sod land and manure. Such a mixture for preliminary composting is prepared as follows: layers of sod 10-15 cm thick are shifted with layers of manure 30 cm thick and sprinkled with phosphate rock. If the soil is acidic, then add lime. In this case, the piles are made 2-3 m high. The compost prepared in this way is shoveled every two to three months and watered with slurry.

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In greenhouses that have just been put into operation, it is recommended to apply organic fertilizers and soil mixtures layer by layer. Manure or compost is applied to the underlying layer at the rate of 25-40 kg per 1 m² and dug to a depth of 20-25 cm. Fresh horse manure on sawdust (up to 70%) is applied to this loosened layer. The soil-sawdust-manure pad serves as drainage and improves nutrition of the root system and microorganisms.

Prepared compost soil 25 cm thick is applied to the prepared layer. Then mineral fertilizers are applied. The main filling is filled with a full dose of phosphorus fertilizers, 0.75 doses of potash, 0.5 doses of magnesium, 0.5 doses of nitrogen fertilizers. The rest of them should be applied in the form of dressings.

There are the following degrees of supply of greenhouse soil with nutrients for cucumber: low, if the soil contains nitrogen less than 40 mg, phosphorus - less than 120 mg, potassium - less than 160 mg per 100 g of soil; optimal - in the range of 40-60 mg of nitrogen, 120-180 mg of phosphorus and 160-240 mg of potassium per 100 g of soil; increased - more than 60, 180 and 240 mg of elements per 100 g of soil, respectively.

The total doses of fertilizers for application to greenhouse soil when growing cucumber are as follows:

1. For soil with a low degree of nutrient supply, nitrogen - 25 (8), phosphorus - 20-30 (20), potassium - 35 (30), magnesium - 8-12 (5) g / m² are introduced. The maximum doses of fertilizers applied to top dressing at one time are shown in parentheses;

2. For soil with an optimal degree of provision –10-18 g / m² nitrogen, 10-15 phosphorus, 12-25 potassium and 5-8 g / m² magnesium.

If the amount of nutrients in the compost soil is at the level of the third group, where there is an excess of them, then mineral fertilizers are not added to the main dressing for cucumbers. For soils with an excessive content of nutrients, it is recommended either to remove a part of the upper layer (8-10 cm, which is replaced by new soil), or to flush the greenhouse soil by sprinkling, or to dilute the soil with fresh calcified peat, which, as an initial one, contains few nutrients.

When applying nitrogen fertilizers to the main dressing, special attention should be paid to the content of ammonia nitrogen in the greenhouse soil, since cucumber plants at a young age are very sensitive to an increased content of ammonia. In greenhouse soil, nitrogen in the ammonia form should not exceed 25-30% of its total content.

Particular attention should be paid to this fact in winter, in heated greenhouses, when plants do not use ammonia for the formation of amino acids and protein substances due to a lack of light and carbohydrates. At this time, it is better to apply nitrogen in a nitrate form.

On reused soils, usually before planting cucumbers, manure is applied at the rate of 20-25 kg / m² and dug up. To improve the physical properties of the soil, loosening materials are introduced - sawdust, straw cutting. Further, after the introduction of manure and loosening materials, the soil is taken for analysis.

Let us assume that the soil has an optimal supply of mobile nitrogen, high supply with available phosphorus and low supply with mobile forms of potassium and magnesium. Based on these levels of security, before planting seedlings, 10 g of N (28 g of ammonium nitrate) and 30 g of K ₂ O in the form of potassium magnesium (about 100 g of salt per 1 m²) are applied per 1 m². If there is no potassium magnesium, then potassium sulfate (about 58 g of salt per 1 m²) is added, as well as magnesium in the form of magnesium sulfate, if the soil contains a low amount of this element available to plants. Phosphate fertilizers are not used until the content of available phosphorus is reduced to a moderate level of availability of available phosphorus.

When growing cucumbers in greenhouses, feeding is necessary. On a limited volume of soil in a greenhouse, it is difficult to keep in the soil-absorption complex such an amount of nutrients that is necessary to obtain 30-40 kg of cucumbers from 1 m². Food elements such as nitrogen and potassium are washed out very quickly. In addition, when loosening materials are introduced, nitrogen is intensively spent on the decomposition of organic matter and nutrition of microorganisms.

Phosphorus can be excluded from top dressing by giving it only to the main dressing. This especially applies to soils not the first year of use. Top dressing is best done in the morning.

The first root fertilization with mineral fertilizers is carried out four weeks after planting, taking into account the results of the next agrochemical analysis of soil samples. Top dressing is given only at low and optimal levels of supply of mobile nutrients. At the same time, 20 and 10 g of N, 40 and 20 g of P ₂ O ₅ and 30 and 15 g of K ₂ O per 1 m² are added to the dressing for a cucumber, respectively. The indicated doses of fertilizers are applied within a month until new results of the agrochemical analysis of the soil are obtained. It is best to add these amounts of nutrients in 2-3 feeding. This kind of root dressing based on agrochemical analyzes is given until the end of the harvest.

If the plants show signs of magnesium and iron deficiency, then the cucumber is sprayed with salts of these elements. For spraying, a 0.1% solution of magnesium sulfate and a 0.1% solution of sulfate or ferric citrate are prepared. If sod land, manure or composts were used for the preparation of soil, then the lack of trace elements in plants does not appear.

To obtain a high yield, it is also necessary to constantly monitor the air nutrition of the cucumbers. The maximum productivity of photosynthesis in a cucumber occurs when the carbon dioxide content in the air of greenhouses is maintained at a level of 0.2-0.3% (by volume) during the daytime. To create such conditions, dry ice is brought into greenhouses, which is placed over the plants in the morning. For every 10 m² of area, 200 g of dry ice is required daily.

When calculating the amount of fertilizers that must be applied to one top dressing, it should be borne in mind that the total amount of fertilizers should not exceed 40-70 g per 1 m². Fertilizers in top dressing are applied in dissolved form, while the total concentration should not exceed 0.4-0.7% when applied to the soil surface. Before feeding, the soil must be moistened. If the nutrients in the greenhouse soil are at the level of the first group, then feeding is carried out weekly - at 50-60 g / m² or once every 10 days at 70 g / m²; at the level of the second group - 40-50 g / m² or once every two weeks at 70 g / m². The content of elements at the level of the third group is considered optimal and feeding is not carried out.

It is useful to combine root dressing with foliar dressing. Spraying a solution of fertilizers on the leaves is especially effective during periods of poor illumination of greenhouses, at low soil temperatures, high saturation of soil with salts, etc., that is, when the root system does not work well. Foliar dressing has a beneficial effect on diseased plants, especially those affected by root nematode. Such dressings can quickly make up for the deficiency of one or another element, which is detected by soil analysis or by the state of the plant. However, foliar feeding cannot replace basic nutrition through the root system.

As a rule, foliar feeding is carried out on cloudy days; in sunny weather it is done in the afternoon towards the evening.

For foliar dressing, an aqueous extract of superphosphate, a solution of potassium sulfate, urea and trace elements (boron, manganese, copper, zinc, molybdenum) are used. A solution of macronutrients is prepared per 10 liters of water: superphosphate - 10-12 g, potassium sulfate - 7-8 g, ammonium nitrate - 5-7 g or up to 20 g of urea.

To prepare a solution of trace elements per 1 liter of water, add: boric acid - 2.86 g, manganese sulfate - 1.8, copper sulfate - 0.08, ammonium molybdenum - 0.1 g. So a mother liquor is obtained. For 10 l of solution of macroelements take 10 ml of stock solution of microelements. For 10 m² greenhouses consume 2.5-3 liters of ready-made solution of macro- and micronutrient fertilizers.

Read part 3. Soil preparation in the greenhouse and feeding regime for growing tomatoes