Planting techniques of Sunflower

Sunflower is native to South America. Domesticated species were brought to Europe from North America by the Spaniards in 1510. At the end of the 19th century, they were introduced back to North America from Russia. They are cultivated all over our country, and the cultivation value is very high. Seeds are often fried and eaten as snacks. Sunflower seed oil can also be extracted and oil dregs can be used as fodder. Let's take a look at the planting technology of sunflower.

Planting conditions of sunflower

1. Temperature: sunflower is a temperature-loving and cold-tolerant crop, which has strong adaptability to temperature and strong tolerance to low temperature. Seeds with stable local temperature begin to germinate when the local temperature is more than 2 ℃, and can germinate and take root at 4-5 ℃. When the ground temperature reaches 8-10 ℃, it can meet the needs of seed germination and emergence. During the whole growth process, sunflowers can grow normally as long as the temperature is not lower than 10 ℃.

2. Water: sunflower is a crop that consumes a lot of water, with tall plants, many leaves and dense leaves, and its water absorption is 1.74 times that of corn, but because its growth and development is synchronized with local rain and heat, the contradiction between water supply and demand is not prominent. there are great differences in water requirements at different growth stages. There is not much water from sowing to budding, the peak of water demand from budding to flowering, and more water from flowering to maturity.

3. Light: sunflower is a short-day crop, which is not very sensitive to sunlight. Like plenty of sunlight, its seedlings, leaves and disk have a strong phototropism. Sufficient sunshine and strong seedlings can prevent overgrowth. Sufficient sunshine in the middle growth stage can promote the vigorous growth of stems and leaves, normal flowering and pollination, and improve the seed setting rate. In the later stage of growth, the sunshine is sufficient, and the grain is full.

4. Soil: sunflowers have low requirements for soil and can grow on all kinds of soils, from fertile soil to dry land, barren and saline-alkali land. It not only has strong saline-alkali tolerance, but also has salt absorption ability. At the same time, sunflower has developed root system and strong drought resistance. Moreover, the root and stem aerosol tissue of sunflower is well developed, which is very resistant to waterlogging.

The growth cycle of sunflower

1. Seedling stage: sunflower is called seedling stage from emergence to budding, which generally takes 35-50 days and 28-35 days for summer sowing. This period is the stage of leaf, flower primordium formation and floret differentiation. Sunflower seedling stage is the strongest stage of drought resistance, the aboveground growth is slow, the underground root grows faster, and quickly forms a strong root system.

2. Budding period: it takes about 20 days for sunflower to blossom from budding to flowering. It is the most exuberant stage in life for both vegetative and reproductive growth. During this period, the largest amount of fertilizer and water is needed, accounting for about 4050% of the total amount of fertilizer and water. If the demand for water and fertilizer can not be met in time, the output will be seriously affected.

3. Flowering period: it usually takes 6-9 days for a sunflower disk to bloom from ligulate flower to tubular flower, and blossoms from the second day to the fifth day. Most of them bloom at 4: 6 a.m. and the unpollinated branches can be kept for 7-10 days the next morning. However, the seed setting rate of self-pollination is only about 3%, and the seed setting rate of cross-pollination is high.

4. Maturity: sunflower maturity refers to the stage from flowering to maturity, with 25-55 days of spring sowing and 25-40 days of summer sowing, with differences among different varieties. About 15 days after flowering and pollination shield is the stage of grain formation. Sunflower maturity needs sunny weather, large diurnal liquid temperature difference and suitable soil moisture.

Planting techniques of Sunflower

1. Land selection and soil preparation: sunflower cultivation should choose plots with flat land, medium fertility, convenient irrigation and drainage and relatively low soil viscosity, which should not be replanted. Reproduce in the way of seeds, and peat soil is suitable for sowing. Seed dressing with new high-fat membrane before sowing can ward off underground pests, isolate virus infection and improve seed germination rate.

2. Sowing at the right time: the sowing time of sunflower is generally from March to April, and the suitable temperature for sowing is 18-25 ℃, which usually sprouts about 5-7 days after sowing. The basic principle of sowing date selection is to sow early or late appropriately according to the occurrence law of saline-alkali, so that the seedlings can avoid the harm of saline-alkali. Spring sowing or summer sowing according to the growth period of the variety.

3. Field inspection and seedling supplement: sunflower is a dicotyledonous crop, and it is difficult to emerge from the top soil. In addition, the soil preparation and sowing quality is not high, or the topsoil is hardened after sowing, or diseases, insects, rats, finches and other damage are easy to cause lack of seedlings and broken ridges. In order to ensure the whole seedling sowing, the field-by-line inspection must be carried out at the seedling emergence stage, and the missing seedlings should be replanted in time.

4. Seedling fixing: sunflower cultivation should be early to prevent seedling squeezing, affecting the cultivation of strong seedlings, and even the future yield. As for saline-alkali land and land with heavy insect pests, the seedling fixing time can be postponed appropriately. At the same time, sunflower seedlings should be determined as early as possible, which is conducive to the cultivation of strong seedlings and disk development, which should be carried out at 2 pairs of true leaves.

5. Middle ploughing and weeding: sunflower general mid-tillage plays the role of weeding and loosening soil, breaking indentation, conserving water, reducing evaporation, reducing saline-alkali damage and so on. The first mid-tillage was carried out in 1-2 pairs of true leaves, the second mid-tillage was carried out one week after seedling setting, and the third mid-tillage was completed by ditching, soil cultivation and fertilization before ridge closure.

6. Ditch topdressing: sunflowers prefer fertilizer, which is usually carried out during the third intertillage, mainly nitrogen and phosphorus fertilizer, 5 kg diammonium phosphate per mu and 10 kg urea, which are mixed evenly and applied to the soil. Trenching and soil cultivation can effectively ensure the growth and development of secondary roots, prevent lodging and reduce the basal branches below cotyledon nodes.