Place in a crop rotation
The Sunflower seeds are placed in the tilled field after the crop rotation, after winter or spring grain crops, on cleaned fields from malicious weeds – after barley, spring wheat, etc. It is not recommended to sow sunflower after the sugar beet crop, Lucerne and Sudanese grass as they strongly and deeply dry up the soil; it is not necessary to sow it after rape, peas, soya, string bean crops, because these cultures have in common a number of diseases (Sclerotinia, white, gray rot, etc.). The sunflower in a crop rotation should return on a former field not earlier than in 7-8 years to prevent the accumulation in soil of the broomrape (Orobanche) seeds and infectious diseases.
The main requirement to the basic processing of soil is the full suppression of long-term (perennial) weeds, good uniformity of the surface of the field, and the moisture reservation. On the fields loaded with annual weeds, it is used the semi-steam processing of the autumn tilled soil.
On the fields loaded with long-term weeds (thistle, sow-thistle, lettuce, bindweed, etc.) is applied the level-by-level (improved) processing of the soil. At the beginning it is processed the stubble field on a depth of 6-8 cm with the disk tools (ЛДГ-10, ЛДГ-15, DB-10), after the growth of the long-term weeds the soil is processed on a depth of 10-12 cm with hoeing plows of ППЛ-10-25 type or with a subsurface cultivator of КПШ-5 and КПШ-9 types. After the repeated growth of the weeds, the autumn tilled field is plowed in September-October on the depth of 25-27 cm.
In order to increase the moisture supply in the soil, it is performed the retention of the snow on the fields.
Soil processing before sowing
When the physical maturity of the soil is carried out, the autumn tilling is processed by harrowing and leveling the fields using surface- scrapers at an angle of 45-50 ° to the direction of the plowing, and by early cultivation on the depth of 8-10 cm with the use of the aggregate with harrows.
If we have a high-quality autumn tilling (friable and leveled soil, without proliferous weed roots), a single pre-sowing cultivation is usually used in the period of the mass growing of the weed sprouts and shoots.
The pre-sowing cultivation is performed on the depth of the sunflower crop sowing, namely at 6-8 cm, using for this purpose the cultivator of КПС-4 and КПШ-12 or УСМК-5,4 types, that are equipped with harrows and loops. In the case of the sunflower hybrids cultivation, which seeds are smaller than the grade seeds, the cultivation before the sowing is performed on a depth of 5-6 cm.
The yield of sunflower is increased by applying both organic and mineral fertilizers. The introduction of 20-40 t / ha of manure gives better yields of sunflower by 2-5 kg / ha, but the mineral fertilizers (N45P60K45) increase the yield by 3.4 t / ha.
The manure application under the sunflower crop in those areas where it is the basic technical plant of a crop rotation is especially important. The manure that was introduced under previous culture renders a positive action too.
In the steppe and forest-steppe zones with chernozem (black earth) soils, the mineral fertilizers are applied at the rate of N40P60.
In the experiments presented at the CCA, which consisted in applying the mineral fertilizers (45-60 kg/hectares) on leached chernozems, the increase of the sunflower productivity (qs/hectare) is received: from phosphorus – 2,3qs, from nitrogen with phosphorus – 3,1qs, from nitrogen, phosphorus and potassium – 3,1qs. Potash fertilizers on chernozem soils don’t raise the sunflower productivity as these soils are provided enough with potassium. It is used on sandy, podzolic, dark gray forest soils, which are poor in potassium, at the rate of К40-60. The doses of mineral fertilizers for a concrete field are specified proceeding from the planned crop and the data in the agrochemical cartograms.
The fertilizers are applied in the autumn or spring under autumn plowing through locally band method simultaneously with the sowing of the sunflower. You should not use fertilizers, especially phosphorus, in spring by scattering under the pre-sowing cultivation, since it does not produce the desired effect. When locally-band method is applied the fertilizers is applied together with the sowing seeds by distributing them using mineral fertilizer device of the seeding machines at the distance of 6-10 cm and at a depth of 10-12 cm. If fertilizers were applied in autumn, then phosphorus fertilizer must be used in the rows while sowing (P10-15). If it is necessary, liquid complex fertilizers (LCF) – N20R30 are used for feeding.
It is necessary to keep in mind the fact that the excess of the fertilizers, especially nitrogen, makes plants less resistant to the drought and illnesses, it conducts to the decrease of the oil content in the seeds. It is possible to use different forms of mineral fertilizers as simple and complex, dry and liquid, while the fertilizers are applied under the sunflower sowings. In this way is very important to observe strictly not only the recommended doses, but also a proper ratio in nitrogen to phosphorus fertilizer as-1:1,5.
The grade seeds (first reproduction) and hybrids (first generation), which are introduced in the register, are used for the sowing; these are the sorted (calibrated), big seeds, the weight of 1000 seeds being of 80-100 grams for grade seeds, and not less than 50 g for hybrids, with germination not less than 95 % (first class).
The modern grade and hybrid seeds of highly thin-skinned are distinguished by higher requirements for heat. They should be sown in a well-heated soil, when the temperature at the depth of the sowing (8-10 cm) reaches 10-12 ° C. In this case, the seeds germinate quickly and amiably, increasing their germination, which provides a more balanced development and maturation of the plants, and consequently, higher yields. In the case of early sowing these varieties of seeds do not germinate for a long time, and partly they lose their germination proprieties, which leads to the thinning of the crops. The sunflowers sowing in one field must be completed in 1-2 days.
The planting density of the plants according to the moisture content at the beginning of the harvest should be: in the wet forest-steppe areas and adjacent steppe regions – 40-50 thousand plants per 1 ha, and in the semi-arid steppe – 30-40 thousand plants per 1 ha. In the process of cultivation of the sunflower hybrids it is recommended to increase their density by 10-15%, but not higher than 55-60 thousand / ha.
The amendments to the sowing rules are set in the light of the field germination of the seeds (it is of 10-15% lower than in the laboratory conditions), the death of the plants as a result of the harrowing on shoots (is of 8-10%), and the natural waste of the plants is of 5%. When using high-performance herbicides, when there is no need for harrowing on shoots, the sowing rate increases by 20-25% in comparison with the optimal density of the standing plants. If you do not use herbicides and the weeds are destroyed by mechanical means, including the harrowing on shoots, then the sowing rate increases by 30-35%.
Thus, the sowing rate of the sunflower seeds depends on the seed size and density of the planned standing plants and it is of 6-10 kg / ha.
The sunflower sowing is performed by a dotted manner with a distance between the rows of 70 cm using pneumatic drills of SUPN-8, SKPP-12 and SPG-6 MF types with harrows and trails.
The normal depth for sowing of the grade seeds is of 6-8 cm, in dry conditions it is of 8-10 cm, on heavy soils in cold and wet spring, the seeds are sown at a depth of 5-6 cm. The small seeds of the hybrids are sown in the moist soil at a depth of 4-5 cm.
Care of crops.
The modern technology of the sunflower cultivation excludes the hand weeding of the crops. The care of the crops is carried out mainly mechanically (no herbicide version); and if it is necessary – in combination with the use of herbicides, which are applied basically by band means simultaneously with the sowing.
After the sowing, in dry weather the loose soil is rolled using ring-heel rollers. The rolling creates conditions for an amiable germination of the sunflower seeds, strengthening the contact of the seeds to soil and to the inflow of the moisture from its bottom layers. The quality of the subsequent processing of the soil increases.
The harrowing up and on the shoots in combination with the inter-row processing, using cultivators that are equipped with grub and sprinkle devices that can destroy the weeds, will permit the grow of higher yields of the sunflower crops without the use of herbicides.
The pre-rising harrowing is performed in the period of mass germination of the weed seeds by using spur harrows with trails of BZSS-1,0 type, with the help of the crawler tractors. The harrowing is performed across the rows or on the diagonal of the field in 5-6 days after the sowing. The harrowing on shoots is performed by the middle spur harrows when on the sunflower crop 2-3 pairs of true leaves are formed, in the daytime, when turgescense of the plants is reduced. The harrowing on shoots destroyed up to 80-90% of annual weeds.
The harrowing on shoots is not applied when the herbicides are used, but it is obligatory when the free herbicide technology is used.
The soil between the rows of the crops is treated by using cultivators for weeds destruction and soil loosening, improving the water, air and feed regimes, for the prevention of excessive cracking of the soil in summer period. The cultivators of SCC-5, 6 A, SCC-4, 2 A types, equipped with subsurface cultivator, arrow-shaped and shaving claws, wire harrows of KLT-38 type, sprinkle devices of KLT-360 and MDT-350 types are used in this process.
At the first inter-row cultivation it is set the width of the slit of 50 cm, at the second (third) – 45 cm, the depth of the processing – respectively of 6-8 and of 8-10 cm. For the first treatment the cultivator is equipped with wire harrows, for the following processing the cultivator is equipped with throwing claws, which covers with soil the weeds in the row.
For the sunflower crops is important to destroy the weeds in the first period, when the shoots are formed, as well as in the second period of its growing season, when the generative organs appear. The use of the soil herbicides in the pre-sowing or pre-rising periods in combination with the agronomic technical measures can solve this problem.
The herbicides are used on the sunflower crops by spraying the soil before the sowing under the cultivation during the sowing and till the shoots appears, applying them under the harrowing and on the shoots.
It is more economically to apply the herbicides through band method, simultaneously with the sowing crops. In this case the strip is processed along the rows at a width of 30-35 cm, and the hectare dose of herbicide is twice reduced. The herbicides are applied by rod sprinklers of ОПШ-15, ОП-200-2-01, ПОУ, and ПОМ-630 types, which carefully regulate on the set norm of the expense and uniformity of the working liquid dispersion of each spraying device separately and of the entire rod too.
The use of the elements of Astrakhan technology with the introduction of the herbicides by band method on the rows during the sowing, using the guiding slice cutter devices and wire rotors has improved the technology of sunflower cultivation.
For cutting guide slots simultaneously with the sowing it is necessary to install on a additional carriage two guiding slice cutters that go after the crawler tractor. The run depth of the slice cutter is of 25-30 cm. In the inter-row processing, some guiding knives, mounted on the cultivator carriage, which keep it no to move in a part, and consequently, this fact reduces the plants damage, go on these cracks. However, the described method has its drawbacks: it needs additional energy, it causes damage of the sunflower roots, and it increases the water loss.
The additional pollination of the crops with the bees’ help (estimated at 1.5-2.0 hives per 1 ha of crop) provides good results in the fight against the sunflower empty seeds.
Protection against diseases and pests
The sunflower crop is sensible to the defeat of many kinds of diseases and it is damaged by the pests, therefore it is necessary to provide for an integrated system of plant protection taking into consideration the phytosanitary situation.
The sunflower crops suffer from the following diseases: Sclerotinia of calathid, Sclerotinia of caulis, Phoma, Phomopsis, Plasmopara, rust and others. The calathid Sclerotinia is manifested throughout the growing season, but it is more intensive during the maturation of the calathids. The Sclerotinia infects the shoots, stems, flowers and very often the calathids. The Phomopsis causes a general wilting and drying of the whole plant, stem breakage. The Plasmopara affects the leaves, stems, and calathids. The disease manifests itself when 3-4 pairs of leaves are formed, the plants do not grow, the yield decreases.
The pests as wireworm, black bug (Platyscelis gages), wild cricket, meadow moth, aphids, and plant bugs cause great damage to the sunflower crops.
The measures for the protection of the sunflower crop from diseases and pests include the seed sterilization and the treatment of the plants with chemicals.
The cleaned and sorted sunflower seeds for 1.5-2 months (but no later than 2 weeks) before sowing are treated with disinfectants: against Sclerotinia is used the TMTD, with a concentration of 80%, dosing – 3 kg / t, against the calathid and caulis Sclerotinia is applied – rovral, with a concentration of 50% dosing – 4 kg / t, or ronilan, of 50% concentration, dosing 3 kg / t, against the caulis Sclerotinia is used aprocit, with a concentration of 50%, or benlat, with a concentration of 50%, dosing 3 kg / t, against Plasmopara is applied apron substance with a concentration of 35, 38.9% dosing 6 kg / t in a combination with the microelements (zinc sulfate and manganese sulfate – 0.3-0.5 kg / t). It is advisable for seed sterilization to apply the pesticides together with the film-forming substances – sodium carboxymethyl cellulose NaCMC (0.2 kg / t) or with polyvinyl alcohol – PVA (0.5 kg / t). The machines of KPS-10A, PS-10, and “Mobitox” types are used for the sterilization and encrustation of the seeds.
When the sunflower shoots appear, in order to combat the sugar beet weevil and steppe cricket the crops are sprayed with vofatox, with a concentration of 18%, dosing 0.4-1.0 kg / ha. In the struggle with the steppe cricket it is enough to treat the edges of the field.
In the mass emergence of the aphids the plants are treated with vofatox or karbofos (0.6-0.8 l / ha) prior to crop flowering.
The parasitic plant – broomrape (Orobanche) strongly affects the sunflower crop. The germ of its germinated seeds clings to the sunflower root, it embeds in this and it feeds itself only from the host plant.
Among the general protection methods of the sunflower crops should be included the followings: the crop rotation observance, the execution of the seed growing requirements, seed treatment, growth at the farm of 2 – 3 varieties or hybrids, which are different concerning the length of the growing period, and its resistance to the broomrape.
The signs, which show the maturation of the sunflower crop, include: the yellowing of the back of the basket (calathid), wilting and fall of the semiflorets, normal color of the grade and hybrids seeds, hardening of the seed core, and drying up of the majority of the leaves.
According to the moisture content of the seeds and color of the calathids there are three degrees of maturity: yellow, brown, and complete. When the leaves of the sunflower become yellow and the backside of the calathids get a lemon-yellow color, the seed moisture reaches 30-40% (biological maturity); with brown ripeness the calathids get a dark brown color, the seed moisture is of 12-14% (economic maturity), with complete ripeness the humidity of the seeds is of 10-12%, the plants are dry, brittle, and they shed its seeds.
The sunflower harvesting performed by the combines should begin when the browning of the calathids reaches 85-90% (when the seed moisture is of 12-14%). The delay in harvesting with 5-6 days leads to a significant loss of seeds. The threshed seeds should be cleaned and dried. The seeds for storage should be cleaned seeds with a moisture content not exceeding 8%. Wet seeds quickly get warm, become rancid and lose their germination.
For the sunflower harvesting is used the SK-5 “Niva” combine with ПСП–1, 5, or “Don 1500” attachment, which is equipped with a ПСП–10 device. The combine cuts the calathids threshes them, while the seeds fall into the hopper, and the thrashed calathids are loaded in vehicles (for animal food). The remaining standing stalks are crushed by disc skim plows of LDH-10 type. For shredding and spreading stems during the harvesting is used the straw universal shredder of PUN-5 type.
For the forest-steppe regions is recommended to perform a pre-harvesting dessication of the sunflower crops. The crops should be sprayed with a solution of chlorate of magnesium (20 kg / ha) or reglon (2-3 l / ha) or a mixture of magnesium chlorate with reglon (10 kg / m + 1 l / ha) per 100 liters of water per 1 ha in 40-45 days after mass flowering (10-20% of brownish calathids, 20-30% of yellow-brown calathids, 50-60% yellow calathids) with an average of the seed moisture content of 30-35%. The dessication permits to begin the harvesting up to 8-10 days earlier and reduce the harmfulness caused by the Calathid Sclerotinia and Caulis Sclerotinia. The humidity of the seeds after dessication is reduced to 12-16%. The productivity of the combines increase by 1.5-fold, the loss of seed is reduced.
- When the dessication is properly applied, the seeds and oil do not contain dessicant remnants, or their quantity corresponds to the maximum permissible concentration.