sunflower | Արցախի Հանրապետության գյուղատնտեսության նախարարություն

sunflower

Technology of sunflower cultivation

Plant growing
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, 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.).

Soil processing
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, after the growth of the long-term weeds the soil is processed on a depth of 10-12 cm. After the repeated growth of the weeds, the autumn tilled field is plowed in September-October on the depth of 25-27 cm.

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.

Fertilization system.
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 increase the yield by 3.4 t / ha.

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).

Sowing
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.

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.

Harvest
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.