Sowing in summer should be done later than earlier, and it can be done from June 25th to early July, so as to avoid the rainy season when the flowering period is about 10 days, prevent diseases from occurring and affect pollination, increase empty seeds and affect yield.
Sun the seeds for 3-4 days before sowing to improve the germination rate and kill the germs on the surface of the seeds. After drying in the sun, carefully select the seeds to remove chaff, broken and rotten seeds and impurities. Seeding can be done by hand or by precision seeder.
Generally, 0.3-0.5 kg seeds are used per mu, and the seeds are planted in wide and narrow rows, with a large row spacing of 80 cm, a small row spacing of 50 cm, a plant spacing of 25-30 cm, or an equal row spacing of 50 cm. Generally, there are about 4000 seedlings per mu, and the sowing depth is 3-4 cm. It was suppressed after the broadcast.
Second, oil sunflower planting techniques and management points
1. Selection of oil sunflower varieties
Oil sunflower is mostly a hybrid variety with the characteristics of disease resistance, lodging resistance, large seeds and high yield, which is deeply loved by growers. The middle and early maturity oil sunflower hybrids suitable for planting in our region are: Short Head 567dw, 667dw, Aizaofeng, American Dika g 10 1, Kangdi No.5, Xinkuiza No.4, Xinkuiza No.6 and so on.
2. Oil sunflower seedling management technology.
(1) Check seedlings and replant: If seedlings are found missing during sowing, they should be marked and replanted; If seedlings are found missing after emergence, they should be germinated and replanted in time, or a line should be multicast for transplanting and replanting when sowing.
(2) Spacing seedlings: one pair of seedlings in real leaves and two pairs of seedlings in real leaves, requiring seedlings to be neat, leaving the weak and the strong, leaving the sick and staying healthy, and not leaving two plants.
(3) intertillage weeding: the first intertillage is combined with thinning seedlings, the depth is 3-4 cm, and the second intertillage is 7-8 cm after one week, and the topdressing urea is 5-10 kg per mu;
3. Key points of sunflower bud management.
(1) intertillage fertilization: intertillage for the third time before and after germination, with topdressing urea per mu intertillage 15 kg, the appropriate fertilization depth is 8- 10 cm, and intertillage is used for root intertillage.
(2) Water during drought and drain during waterlogging: There is abundant rainfall in summer, so it is generally unnecessary to water before budding. If the rain is too heavy, pay attention to drainage, and there can be no water on the ground. In case of drought, water should be supplied.
4. Management from flowering stage to filling stage
(1) Timely watering: After beginning of autumn, autumn drought often occurs, which is extremely unfavorable to the formation of yield. Adequate water supply must be ensured during flowering. In case of drought, it is necessary to water properly, and the last watering is usually finished within 15 days after the last flower.
(2) foliar spraying: Before flowering, foliar spraying is carried out with 0.3% boron fertilizer solution and 0.2% potassium dihydrogen phosphate solution, spraying water twice per mu (30kg) every 10 day/time, and spraying continuously for 2-3 times.
(3) Branching and artificial pollination: Some sunflower varieties have branching characteristics, which affect the development of the main stem disk. Therefore, when plants branch, they should be pruned in time. In places where bee resources are scarce, artificial pollination is needed, and the pollination time can be around 9- 1 1 in the morning.
Three, oil sunflower pest control methods
Attention should be paid to the prevention and control of cotton bollworm in its growing period. The control method is to control Helicoverpa armigera 1-2 times with bt emulsion in the egg stage and larval stage, or use pesticides such as emamectin benzoate and Kangkuan.
If it rains a lot after flowering, it is easy to cause Sclerotinia sclerotiorum and downy mildew, and 50% Sclerotinia sclerotiorum can be sprayed 500 times. 69% alkenyl manganese zinc wettable powder for preventing downy mildew was sprayed with 800 times solution.
Spraying once every 7 days and continuously for 2-3 times can effectively control the spread of downy mildew, and spraying foliar fertilizer is more effective.