High-yield cultivation of Sunflower

The environment requires that sunflowers have strong low temperature tolerance in both seedling stage and mature stage. The seeds began to swell and germinate at 2 ℃-4 ℃, germinated at 4 ℃, could emerge at 5 ℃, and could meet the needs of normal emergence at 8 ℃-10 ℃. The seedlings can withstand a low temperature of several hours-4 ℃, and can still return to normal growth after low temperature, with strong cold resistance. When the temperature is as high as 50 ℃ and the relative humidity is 30%-55%, the body temperature can be regulated by the transpiration of leaves and normal physiological activities can still be carried out. However, if the temperature is higher than 40 ℃ and the relative humidity reaches 90%, the growth stops, the disease resistance weakens, and the occurrence of leaf spot and rust occurs. Before sowing and planting, 1520 tons of high-quality agricultural fertilizer were applied per hectare. Sunflower sowing time is from late March to mid-April. Direct seeding or seedling transplanting can be done, and the planting density is 65 cm × 60 cm, one plant per hole. Sunflower seedlings with soil transplanting between seedlings, the survival rate is as high as 90%. Replanting should be early and small, and it is best to plant two pairs of real leaves in 1, and the height of the seedlings is no more than 15ml / 20cm, and the seedlings should be fixed according to the distance between rows and plants, one in each hole. Three times of middle ploughing, weeding and middle ploughing. The first hand hoe thinning seedling weeding, the second weeding combined with fixed seedling ploughing, seedling height of 50 cm-60 cm, soil ridging to prevent toppling. The herbicide "fluralin" has a good effect on narrow-leaf weeds, with 300 grams per mu plus 20 kilograms of water, sprayed 10 days before sowing, raked into the soil layer 10 centimeters, so as to avoid damage to seedlings; 50% trimethoprim has a good effect on broadleaf weeds, with 200 grams and 20 kilograms of water per mu. Spraying within 3 days after sowing can kill sprouting weeds and so on. To control the length of the fork, we can take early forking to control the infinite length of the fork and apply fertilizer reasonably. 7Mel 8 has a good effect on applying nitrogen and potassium fertilizer to true leaves. Fields that are not fertilized with base fertilizer when sowing must be fertilized early. In the first ploughing, 15 kg of ammonium nitrate was applied, or 25 kg of ammonium bicarbonate, or 8 kg of urea plus 15 kg of potassium chloride. Assisted pollination sunflower white flower is not fruiting, artificial pollination or insect cross-pollination can bear fruit. Otherwise, the blighted grains of sunflower seeds account for 35%, 50%, and when they are serious, they will be completely empty. The main results are as follows: (1) artificial pollination is to use cotton as a powder puff to help the pollen of different disk spread to each other on the disk. The seed setting rate can be increased by more than 30%. (2) release bees for pollination. In full bloom, when the temperature is about 28 ℃ and there is no strong wind or rain, bee pollination can increase the seed setting rate by about 40%. (3) during the fruiting period, fertilizer and water should be supplied reasonably, potassium should be increased and phosphorus should be applied. If leaf spot or rust occurs, it can be sprayed with 1500 times of Fenru Ning wettable powder; about 10 days after pollination, spray with 1000 times of 40% dimethoate EC or 1500 times of 20% Aifudin 2 to control aphids and mites. Harvest leaves seeds when the florets in the center of the sunflower disk wither and the seeds turn black to show maturity and can be harvested at the right time. Choose the disk with large disk, short plant, thick stem, no diseases and insect pests and full seeds to plant. Leave the seed on the disk and place it for 5 days, threshing and drying.