Sunflower seeds, those plump little seeds, are not only a delicious snack source, but also an important oil crop. When planting sunflower seeds, understanding the time it takes from sowing to harvesting and the key points in the growing cycle is vital for growers. Whether it is large-scale agricultural planting or small-scale cultivation in home gardening, mastering these knowledge helps to rationally arrange agricultural activities and improve the yield and quality of sunflower seeds.
Overview Of The Growth Cycle Of Sunflower Seeds
1. Germination period
Sowing conditions and time
Sunflower seeds are usually sown in spring when the soil temperature reaches 10-15 ° C. The sowing depth is generally 3-5 cm, too deep may cause the seeds to be difficult to dig, too shallow is prone to drought and birds and animals. Under suitable conditions, sunflower seeds will begin to germinate 7-10 days after sowing. For example, in the northern regions of China, generally in late April to early May to sow, after a week or so you can see the green buds breaking through the ground.
Factors affecting germination
The quality of seeds has a key influence on germination rate. High quality, full and pest free seeds germinate quickly and have a high germination rate. Soil moisture and permeability should not be ignored. Keep the soil moist but not stagnant, loose and breathable soil environment can provide good conditions for germination. If the soil is too dry, the seeds may not be able to start the germination process due to lack of water; If the soil is compact and has poor permeability, the seeds will be difficult to germinate due to lack of oxygen.
2. Seedling stage
Seedling growth characteristics
The stage from germination to the growth of 4-6 true leaves is seedling stage, which lasts about 20-30 days. The growth of sunflower plants in the seedling stage is relatively slow, mainly because the root system is constantly spreading downward to absorb more water and nutrients. At this time, the leaves are small and the photosynthetic capacity is relatively weak, but with the gradual increase of true leaves, the photosynthetic efficiency will gradually improve.
Management essentials
During the seedling period, attention should be paid to timely weeding to prevent weeds from competing with seedlings for nutrients, water and light. At the same time, seedlings can be thinned appropriately to maintain a reasonable plant distance, generally 10-15 cm, to ensure that each seedling has enough growth space. If the planting density is too large, it will lead to weak seedling growth, easy to lodging in the later stage, affecting the yield.
3. Budding period
Plant morphological change
When sunflower plants grow to a certain extent, about 30-40 days after sowing, they will enter the bud stage. At this point, buds begin to form at the top of the plant, marking the beginning of reproductive growth. The height of the plant increased rapidly, the leaves became wider, and photosynthesis increased, providing sufficient nutrients for the development of the buds.
Environmental and nutritional requirements
The demand for nutrients and water of sunflower in the bud stage is increasing gradually. In terms of fertilizer, nitrogen fertilizer, phosphate fertilizer and potassium fertilizer need to be supplemented in time to promote the development of buds and plant growth. Generally, urea 10-15 kg, diammonium phosphate 5-10 kg, potassium chloride 5-8 kg can be applied per mu. At the same time, to ensure adequate water supply, but also to avoid water, so as not to cause root disease. At this time, the ambient temperature is 20-25 ℃, and too high or too low temperature will affect the formation and development of flower buds.
4. Flowering period
Flowering process and time span
The flowering period of sunflower flowers usually begins 10-15 days after bud and lasts about 7-10 days. Flowers generally open in the morning, gradually unfold their petals as the sun rises, reach full bloom in the afternoon, and begin to close in the evening. Sunflower is a typical media flower, which needs to be pollinated by insects such as bees. When planting on a large scale, in order to increase pollination rates, beehives are sometimes placed in the field.
Relationship between pollination and yield
The success of pollination is directly related to the yield of sunflower seeds. If pollination is insufficient, it will lead to an increase in empty shell rates. In the case of natural pollination conditions are not ideal, artificial assisted pollination can be used. For example, pollen is collected by gently touching flowers with a soft brush and then applied to the stigmas of other flowers to improve pollination efficiency.
5. Maturity period
Seed ripening characteristics
About 30-40 days after flowering, sunflower seeds reach maturity. At this time, the back of the flower tray begins to turn yellow, the petals dry and fall off, the seed shell becomes hard, the color changes from light to dark, and the seed kernel inside is full and full. When the seed water content is reduced to 10%-15%, it can be harvested.
Harvest time and method
Timing the harvest is crucial. Early harvest, seeds are not fully mature, low 1000-grain weight, less oil content, affect the yield and quality; Harvesting too late may lead to seed shedding, mildew and other problems. When harvesting, manual harvesting or mechanical harvesting can be used. Artificial harvesting is suitable for small area planting, after cutting the flower tray, drying for a period of time, and then beating with a stick or threshing machine; Mechanical harvesting is efficient and suitable for large-scale planting, but the parameters of harvesting equipment need to be adjusted according to the actual situation to reduce seed loss.
The Influence Of Different Regions And Varieties On Growth Time
1. Regional differences
Influence of climate factors
Climatic conditions such as temperature, light and precipitation in different regions have significant effects on the growth cycle of sunflower seeds. In northern regions, due to the slow rise in temperature in spring, the planting time is relatively late, and the whole growth cycle will be extended accordingly. For example, in the Heilongjiang region, sunflower seeds may take around 100-120 days from sowing to harvesting. In the southern region, the temperature is higher, the sowing time can be advanced, the growth cycle is relatively short, and the process from sowing to harvest may be completed in 80-100 days.
Soil condition difference
Soil fertility, pH and texture also affect the growth rate of sunflower seeds. Fertile, loose and well-drained soil is conducive to the growth of sunflower seeds and can shorten the growth cycle. For example, sunflower seeds planted in the black soil zone, because the soil is fertile, the root system is well developed, the plant growth is robust, and the maturity is relatively fast. In some poor sandy or acidic soils, sunflower seeds may grow slowly and need more time to complete their development.
2. Variety differences
Early variety characteristics
The growth cycle of sunflower seeds of early maturing varieties is shorter, generally about 80-90 days from sowing to harvesting. These varieties are suitable for planting in areas with short growing seasons, or for multiple cropping. For example, some hybrid early sunflower varieties, they can complete flowering, fruiting and other processes in a short period of time, but the seed 1000-grain weight may be relatively small, and the oil content is slightly lower.
Characteristics of late maturing varieties
Late varieties have a longer growth cycle, usually 110-130 days. Late varieties of sunflower seeds tend to have larger particles and high oil content, which is suitable for industrial uses such as oil pressing. However, due to the long growth cycle, the requirements for environmental conditions and cultivation management are relatively high, requiring adequate light, water and nutrient supply, while paying attention to the prevention of pests and natural disasters.
Key Management Measures In The Planting Process And Their Effects On Growth Time
1. Fertilization management
The importance and application of base fertilizer
Base fertilizer is the basic fertilizer for the growth of sunflower seeds, and applying enough base fertilizer before sowing can provide continuous nutrient support for the whole growth cycle. Generally, 2000-3000 kg of decomposed farm manure can be applied per mu, 30-50 kg of superphosphate, and 10-15 kg of potassium chloride. Sufficient base fertilizer can promote seed germination and seedling growth, make the plant establish a good root system and nutrient reserve in the early stage, help shorten the growth cycle and increase the yield.
Timing and type of topdressing
At different growth stages, topdressing should be carried out according to the nutritional requirements of sunflower seeds. If the demand for nitrogen fertilizer, phosphate fertilizer and potassium fertilizer is large in the bud stage and flowering stage, timely topdressing can meet the needs of plant growth and reproductive growth, ensure the development of flower disk and seed formation. If the topdressing is not timely or the type and amount of fertilizer is improper, it will lead to poor plant growth, prolong the growth cycle, and even affect the yield.
2. Water management
The needs of different growth stages
Sunflower seeds require relatively little water during the germination and seedling stages, but it is important to keep the soil moist and prevent soil drought. There is a large increase in water demand during the bud and flowering periods, and adequate water supply should be ensured at this time to promote bud development and pollination. At maturity, the water should be properly controlled to prevent the seeds from mildew or falling off due to excessive water. Reasonable water management can make sunflower seeds grow normally in each growth stage and avoid prolonging the growth cycle due to water stress.
Irrigation and drainage measures
In dry areas or during dry seasons, irrigation is needed. Water-saving irrigation methods such as drip irrigation and sprinkler irrigation can be used to meet the water demand of sunflower seeds and save water. In areas or seasons with more rain, drainage work should be done to prevent water accumulation in the field. For example, in the plum rain season in the south, it is necessary to clean the ditches in time to ensure smooth drainage to ensure a good growing environment for sunflower seeds.
3. Disease and pest control
Common pests and diseases and their harms
The common diseases and pests of sunflower seeds include black spot, downy mildew, sunflower borer and so on. Black spot will harm the leaves and flower discs, lead to leaf yellowing, flower disc rot, affect photosynthesis and seed development; Downy mildew mainly harms seedlings and leaves, and inhibits the growth of plants. The sunflower borer eats seeds, causing serious crop loss. If these diseases and pests are not controlled in time, the growth of sunflower seeds will be inhibited, the growth cycle will be prolonged, and the yield and quality will be reduced.
Prevention methods and opportunities
For the prevention and control of pests and diseases, we should adopt the strategy of prevention and comprehensive control. Disinfection of seeds before sowing can effectively prevent many diseases. In the process of growth, the field is regularly inspected to find signs of diseases and pests in time, and the method of biological control, physical control and chemical control is combined. For example, trichogramma is used to control sunflower borer, and aphids and other pests are killed by hanging yellow plates; In the early stage of the disease, spray fungicide in time for prevention and control. Reasonable pest control can ensure the healthy growth of sunflower seeds and make them mature according to the normal growth cycle.
Conclusion
Planting sunflower seeds from sowing to harvesting is a process full of expectations and challenges, and the time required is affected by many factors. Understanding the growth cycle of sunflower seeds, the differences between different regions and varieties, and the key management measures in the planting process can help growers better plan planting programs and improve planting efficiency. Whether you are pursuing efficient agricultural production or enjoying the fun of family planting, you can harvest sunflower seeds at the right time and feel the fruitful results given by nature by carefully caring for these sunlight-born plants.
