What are the planting methods and growing conditions for sunflower seeds?
The sunflower is a plant that opens toward the sun, and it is an economic crop that combines edible and ornamental value. So, what planting methods are there for sunflower seeds? What growing conditions do sunflowers need? Let's find out together.
I. Planting methods for sunflower seeds
1. Choosing and preparing the land
Choosing a good plot when planting is an important factor in increasing yield and boosting returns. Sunflowers adapt to a wide range of soils, from heavy clay to light sandy soil, and they also have a certain tolerance for acidity and alkalinity; generally the pH is between 5.5 and 8.5, and greater acidity or alkalinity will have a certain effect on their growth. Choose deep soil layers and level terrain, and a crop rotation period of more than 3—4 years is also required. When preparing the land, prepare it finely, plow the soil deeply, break up the soil, remove stones and other hard objects, and then apply sufficient base fertilizer.
2. Seed selection and treatment
When selecting, be sure to choose varieties with excellent quality, fast growth, high yield, and strong stress resistance and disease resistance. When selecting seeds, keep seeds that are plump and consistent in shape, size and color, and discard those of poorer quality. Before sowing, the seeds must first be treated to increase the germination rate. First place the selected seeds in the sun to dry for 2-3 days, and remember to turn them promptly while sun-drying. Then use 150 ml of 40% zinc phoxim, mixed with 5—7.5 kg of water, to soak the seeds, eliminating pathogens on the seed surface and preventing disease.
3. Sowing
The sowing time depends on the local climate and soil; generally the sowing period is between April and May. Sowing methods can be hole sowing and furrow drilling, with hole sowing generally being the main method. Generally the holes are 5-6 cm deep, the sowing rate is about 1-1.5 kg per mu, with 4-5 seeds per hole, using wide-and-narrow row sowing, with a large row spacing of 1 m, a small row spacing of 60 cm, and a plant spacing of 60 cm. After the seedlings emerge, promptly thin and fill in the seedlings according to the actual emergence situation; leaving about 1400 plants per mu is optimal.
4. Later field management
Later field management mainly includes cultivating and weeding, fertilizer and water management, and supplementary pollination. Carry out cultivating and weeding 2-3 times each year to ensure strong growth. The first can be done together with thinning, cultivating 3-4 cm, and applying an appropriate amount of urea as a top dressing. The second is one week later, when deep cultivation is 8-10 cm. The third is at the heading stage, with deep cultivation of 3-4 cm, along with top dressing. Artificial supplementary pollination of sunflowers is extremely important; it is a cross-pollinated crop, and pollinating it by hand can increase the seed-setting rate, raise yield and increase returns. The specific method is: wear gloves, and 2-3 days after the flowers open, touch them one by one by hand. Artificial supplementary pollination is best done in the morning or evening, avoiding the high-temperature period at noon.
II. Growing conditions for sunflowers
1. Temperature: Sunflowers are a temperature-loving but cold-tolerant crop, with strong adaptability to temperature. The seeds have very strong low-temperature tolerance; when the soil temperature is stable above 2°C they begin to germinate, at 4-5°C they can sprout and take root, and when the soil temperature reaches 8-10°C it can meet the needs of seed germination and emergence. Throughout the entire growth process, sunflowers can grow normally as long as the temperature is not lower than 10°C.
2. Water: Sunflowers are a crop that consumes a relatively large amount of water. The plants are tall, with many dense leaves, and their water uptake is 1.74 times that of corn; but because their growth and development mostly coincide with the local rain and heat, the contradiction between water supply and demand is not prominent, and water requirements differ greatly at different growth stages. From sowing to budding, water demand is not great; from budding to flowering is the peak water-demand period; and from flowering to maturity, water demand is also relatively large.
3. Light: Sunflowers are a short-day crop and are not very sensitive to day length. They like ample sunlight, and their seedlings, leaves and flower disks all have strong phototropism. With ample sunlight, the seedlings are sturdy and can be prevented from growing leggy. Ample sunlight in the mid-growth period can promote vigorous stem and leaf growth, normal flowering and pollination, and a higher seed-setting rate. Ample sunlight in the late growth period makes the seeds plump and full.
4. Soil: Sunflowers have low soil requirements and can grow in all kinds of soil, from fertile soil to dry land, poor soil and saline-alkali land. They not only have a relatively strong salt-alkali tolerance, but also have salt-absorbing properties. At the same time, sunflowers have well-developed root systems and relatively strong drought resistance. Moreover, the roots and stems of sunflowers have well-developed aeration tissue, making them very tolerant of waterlogging.