General technology of growing sunflower
Depth of sowing depends on soil and climatic conditions. Sunflower seeds have a low moisture demand for germination, which can occur in sufficiently dry soil under the following conditions: the necessary contact with the soil and its intact capillary system providing access to the seeds of soil moisture; The soil layer above the seeds should be loose and not very thick; Supply of oxygen, sufficient for the germination of seeds. In this case the seeds should be well covered with soil. With the normal condition of the seedbed and normal moistening, it is necessary to choose the depth of sowing 3 … 5 cm. The easier the soil, the deeper you can sow, in more continental conditions, you should also choose a greater depth. The decisive factor is the contact of seeds with the intact capillary system of the seed bed. The widespread embedding of herbicides in the soil before sowing leaves too loose and dried its top layer. Under such conditions, it is difficult to maintain a uniform seeding depth, on which uniform shoots depend critically. Later, the ascending plants lag behind in development until harvesting. Therefore, when sowing, you should constantly monitor its depth.
Sunflower seeds are sown in a dotted way, which should ensure:
– the optimal nutrition area for an individual plant;
– uniform shoots determined by the same depth of sowing and the contact of the sown seeds with the capillary layer of the soil;
– saving of seeds;
– reduction of costs when harvesting;
– prerequisites for harvesting seeds without complications and with minimal losses.
Pneumatic seeders are used for dotted seeding. Since sunflower seeds even after calibration have different sizes and shapes, mechanical seeders of precise seeding, which work very well when sowing sugar beets, are not suitable for sowing sunflower. They admit, even at a slow working speed, too many omissions and double seeding of seeds. The maximum limit for them is 20% of a given number of seeds, but the lower they are, the better the development of crops.
For pneumatic seeders, the correct choice of the seeding disc is important, on which the number of omissions and double seizures depends. It is necessary to choose sowing discs with a hole diameter of 2.5 mm. It is very important to properly adjust the excess seeder, as there are different forms of seeds at a relatively equal value. It is better to use seeders, the process of which can be constantly observed. The air pressure mode must be adjusted according to the weight of the seeds. With increased pressure, the number of passes is reduced, but the number of double and triple fences increases. In addition, seed embryos suffer, which are very sensitive to increased pressure. The best seeding quality is achieved by seeders working on a vacuum principle.
Quality work of the presses and cone sealing rollers is very important. They must ensure complete seed coverage of the soil and their direct contact with the undamaged capillary layer of the soil.
The working speed of the units up to 6 km / h ensures high-quality sowing. Higher – negatively affects the depth of embedding and uniform distribution of seeds. In addition, the risk of seed damage increases.
The decisive factor of precise seeding is a careful adjustment of the seeder, its correct installation on the seed rate by a manual crimping device and checking the accuracy of seeding in the soil and in a row. Before sowing it is necessary to check:
– presence of sowing discs;
– whether the disk cells are cleaned of dirt and dust;
– easy mobility of the drive shaft and discs;
– the condition of ejectors which quickly worn out;
– condition of the sowing disk housing;
– the size and cutting edge of the coulters.
During seeding it is necessary to check:
– adjustment of the towing height for horizontal operation of the seed drill;
– distribution of seeds in a row and observance of a given distance between them;
– the width of the rows;
– depth of seeding and their contact with a densified capillary layer of soil;
– whether the coulters of the wheels are free from stuck moist soil;
– working speed of the seeder.
Care of sunflower crops
With intensive technology of cultivation of sunflower, care for crops includes work related to the destruction of weeds, loosening the soil, protecting against pests and diseases, fertilizing plants, improving their pollination. Herbicidal and non-herbicidal variants of cultivation of sunflower differ only in the quantity and quality of the mechanical treatments of the soil during the care of crops.
The first after-sowing operations are rolling, harrowing. Their goal is to align the soil surface, make it denser if it is excessively loose. These operations are carried out by wide-gripping aggregates only on ripe soil. Rolling: MTZ-82 + 3KKSH6. Harrowing: MTZ-82 + (C-8 + BZSS-1.0).
On the compacted soil the germination of seeds of weed plants is accelerated, which are destroyed by subsequent harrowing. On the aligned, normally loose soil, packing as an independent operation is not carried out. Rolling compactors of seeders compact the soil in a row enough to make sunflower seeds contact with it.
Pre-emergence harrowing. It is carried out by medium tooth harrows БЗСС-1.0 or spring harrows of “Kalina” type across the direction of sowing or diagonally. This technique should be taken during the period of mass germination of weeds, when the teeth or springs of the harrows are easily “combed” by their sprouts (white strands) and shoots. The depth of the working bodies should not exceed 4-5 cm. At a shallower depth both the harrows and springs work unsteadily, weakly destroying the weeds, with the greatest possible damage to the sunflower. Pre-emergence harrowing should be stopped 3-4 days before sunflower emergence occurs.
Pre-emergence harrowing is also necessary in the event that a soil herbicide was applied before sowing. Such herbicides, like prometrin, give the best effect when applied under pre-emergence harrowing, rather than under pre-sowing cultivation.
Harrowing on shoots. The goal of post-emergence harrowing is the destruction of late as well as mid-spring weeds. This method is carried out by medium tooth harrows BZSS 1-0 or spring type “Kalina”. When using soil herbicides, harrowing on shoots is usually not used, as it is not necessary, but with non-herbicidal technology it is mandatory.
Sunflower is most resistant to the action of the harrow in the phase of 2-3 pairs of real leaves, at a speed of 4-5 km / h.
Young sunflower plants in the morning because of the increased turgor are very fragile and easily damaged by harrows. When harrowing in the morning (6-8 hours), 1.5-2 times plants die more than in the daytime (at 10-16 hours). Consequently, post-emergence harrowing is best spent in the daytime.
Inter-row cultivation of crops.
When using the herbicide technology of sunflower cultivation, it is possible to significantly reduce the number of inter-row treatments, but their complete exclusion under production conditions does not justify itself. Especially obvious is the need for such treatment in fields contaminated with weed-resistant weeds. Also, this operation is necessary to improve the water-air and food regimes, to prevent excessive cracking of the soil in the summer. For inter-row cultivation of sunflower crops, carried out by six-row seeders, KRN-4.2 cultivators, eight-row cultivators KRN-5.6 are used. During the whole period of sunflower growing, agronomists of farms should conduct regular inspections of crops for the presence of pests and diseases. In identifying such, conduct appropriate techniques associated with the application of pesticides. Sowing is also necessary to produce seeds treated with insecticidally-fungicidal agents.
Sunflower is a typical entomophilous plant, therefore, at the moment of flowering for better pollination of the heads, it is recommended to export apiaries on the fields at the rate of 1-2 clues per hectare. Timely and high-quality carried out all operations to care for crops, it allows to grow high and stable yields of sunflower in all soil-climatic zones of its cultivation.
The optimal harvesting time is of great importance for the effective cultivation of sunflower. Determine it is not so easy, because the seeds and the head ripen in different ways. The phase of sunflower ripening lasts several weeks.
Seeds quickly lose moisture than parts of the head. Under good ripening conditions, the seeds lose 1.2 … 1.6% moisture / day. The moisture content of the seeds decreases within four weeks from approximately 60 to 10%. In contrast, the bottom of the head retains moisture 80 … 85% until the stem (brown stem) is dried. The bottom of the head dries noticeably only when the moisture content of the seeds is already 28 … 25%. Since the physiological ripeness, which is achieved with a seed moisture of about 25%, the weight of thousands of seeds and the content of oil in them is no longer increased. Parts of the head have a humidity of about 25 … 50% higher than the seeds, so when passing through the harvester the seeds can become wet again.
Heads with a large diameter, as well as damaged, especially gray rot, ripen more slowly than smaller heads. A healthy, uniform stem with medium-sized heads gives the least crop losses during harvesting.
Pre-harvest desiccation is carried out in order to accelerate the maturation of sunflower, drying the plants on the root and obtaining dry seeds. It allows you to start harvesting for 8 … 10 days before. In Ukraine, a number of preparations have been registered for desiccation. From a technical point of view, the implementation of this agro-technique is complex, expensive and not problem-free. Requires airplanes, helicopters, special aircraft (SLA) or portal tractors and sprayers. Of the registered pesticides air treatment is allowed only with Reglon Super. Preparations are used at air temperatures from 13 to 20 ° C, in the absence of heavy rains and winds not more than 5 m / sec. In hot weather, it is better to process the treatment in the evening hours. Experience with growing sunflower showed that its early ripening hybrids quickly ripen and, as a rule, do not require desiccation. For ecological reasons, the use of desiccants should be limited to only the necessary cases.
For harvesting sunflower with low losses, special adaptations are necessary to combine harvesters, for example, PSP-1.5 for SK-5 Niva, PSP-10 for grain harvester Don-1500. Currently, all manufacturers of combine harvesters offer the appropriate tools. Without their application, losses are up to 50%. There are two different types of header changes:
1. Replacement of combine harvester with a prefix of corn type, adapted for the width of row spacing 45 … 55 cm. Feeding chains and special knives are completed with these prefixes. In regions where maize is grown for grain, the use of such attachments is economically very profitable.
2. When converting the grain header: only three reel blades are left, the teeth are removed or covered with rubber bands and the speed of rotation of the reel is regulated so that it corresponds to the working speed of the combine or slightly exceeds it. Cover four, preferably three, opposing fingers tapering in front of the sailors of different types with a minimum length of 1.4 m and with raised by 3 … 5 cm edges. Mount side shields 1.5 m high on both sides of the cutting device and a large-mesh grate with a height of at least 60 cm at the rear end, close the collector and increase the auger screw by 2.5 cm. To clean loosely sowing crops, shippers are fitted with skids. Crops with broken and wind-swept stems are removed with the help of such slides with large losses. For these crops, the above mentioned prefixes are the most suitable.
The distance between the drum and the concave is chosen depending on the diameter of the baskets: at the entrance to the threshing apparatus 23 … 40 mm, at the outlet – 17 … 30 mm, so that the baskets are less broken and their parts do not complicate the cleaning. If the baskets are still very wet, the distance between the drum and the concave should be adjusted so that the basket breaks up into no more than 2 … 3 pieces to prevent the increase of impurities and the re-moistening of the seeds. If too many collapsed achenes are encountered during inspection, the distance between the drum and the concave should be increased, and the drum speed should be reduced. Cleaning is regulated depending on cleaning conditions. When harvesting dry crops, the upper louvre sieves are opened up to 10 … 15 mm, and the lower ones – up to 8 … 13 mm. With a seed moisture content of less than 20%, a return elevator is often closed to avoid collapse. With a strong mushroom damage and a high moisture content of the seeds, sieves with large holes are better – upper sieves with holes 18 mm in diameter, lower ones – 16 mm. Since the bulk density of sunflower seeds is low (Harvester should have a sufficiently high working speed (5 … 6 km / h)). At a low operating speed, there are too few residual parts in the threshing apparatus, which increases seed damage and loss.
When harvesting sunflower, fatty acids are released, which exert a highly corrosive effect on parts of the threshing apparatus. Therefore, after harvesting the sunflower, it is necessary to clean the combine with a jet of warm water, if possible, with the addition of detergents.
Vegetable residues of sunflower after harvesting should be crushed and superficially sealed for their rapid decomposition and prevention of the spread of various fungal diseases. It is best to carry out this work with disc harrows, serrated rotors and cutters.
Drying and storage
Post-harvest processing of sunflower allows you to bring the seeds to certain conditions – depending on their purpose (for sowing or processing).
Sunflower seedlings are stored without quality reduction only when the moisture content in them is about 8 … 9%. Therefore, after cleaning, they usually need to be dried. For these purposes, all methods of drying can be used, but with an initial moisture content of more than 20%, drying by venting with unheated air is of little use. Best in these cases, drying plants with heated air. The drying temperature should be about 70%, and in the seed material – not higher than 43 ° С.
Sunflower seeds with the same humidity per unit volume contain less water than corn and cereals. In this regard, when drying sunflower, you can reduce air blowing per unit volume of seeds by half compared to corn and grain.
If the temperature is too high and the air is blown intensively, the sunflower seeds are easily over-dried, so they become stiff and easily broken during transportation and processing.
Before drying, the harvested seeds must be cleaned, since the impurities complicate the drying.
Storage of seeds of sunflower is suitable for storages used for cereals. Purified batches of seeds with a moisture content of 8 … 9% are stored at 60% air humidity and air temperature below 25 ° C. The larger the batch, the more important the ventilation. Interim temporary storage (several days) can be carried out at 12% of the moisture content of the seeds.