From the top of the plant, sunflowers appear to have a star-shaped bud, and about 75% of the tongue-like flowers in the field bloom. This period is known as budding period. The quality of budding management is the key to determining whether the flowers on the flower disk can develop into fertile flowers. The flowering period is generally about 8 days. Improper flowering management will affect the yield and increase the empty shell rate. In the flowering period, four major managements should be grasped: Timely top dressing. Sunflowers need more fertilizer, and only relying on base fertilizer and seed fertilizer can not meet the needs of plants after budding, so timely fertilizer application is an important measure for increasing sunflower production. The nitrogen, phosphorus, and potassium needed for budding to anthesis accounted for 32%, 33%, and 26% of the total amount required for the entire growth period. Therefore, the best period for topdressing should be before this period. If it is postponed, it will lose the effect of topdressing. Practice has proved that top dressing should be dominated by nitrogen fertilizer, top dressing ammonium bicarbonate 20 kg - 25 kg, ammonium nitrate 15 kg, or 10 kg of urea per acre. Take a ditch or a hole and apply about 7 cm deep at 10 cm - 15 cm from the root of the sunflower. In the post-harvest period of sunflower, nitrogen fertilizer should generally not be applied again in order to prevent greed from being punished, resulting in late-maturing yield reduction and lower oil content. 2. Appropriate amount of water. Sunflowers require more water. For each kilogram of dry matter produced, 469 kg of water – 569 kg of water are required. The water requirement from flowering to flowering accounts for 43%--60% of the water requirement for the entire growth period. At the flower formation stage, flowering stage and grain filling stage, timely and appropriate irrigation according to the weather, soil and plant growth conditions can both increase the yield and increase the oil content. Take ridge ditch irrigation, irrigation depth to 2/3 ridge height is appropriate. Avoid flooding to prevent soil erosion and damage to the roots of sunflowers. After irrigating, the soil should be loosened in time to eliminate the hardened layer, which can prevent evaporation of water and prevent the return of alkali to the soil. 3. Timely fight. In order to avoid nutrient depletion due to multiple branches and promote the enlargement of the stem of the main stem, the grain should be full, and the branch should be promptly removed. The sooner and the more thoroughly, the better. From the bud stage to the flowering stage, it is necessary to continue burping 2 times - 3 times until all the net branches and lateral branches are eliminated. 4. Assistant pollination. Sunflower is a typical cross-pollination crop, mainly relying on bees and insects to complete pollination. Therefore, in the sunflower producing areas, it is necessary to actively develop apiculture or induce bee pollination. Generally, it is appropriate to put a box of bees every 5 mu. In the case of insufficient bees, artificial pollination should be carried out in two ways: First, pollen beat pollination method, that is, with a hard paper shell cut into a disc slightly smaller than the size of the disk, on top of cotton, and then covered with gauze , tightly tied with a rope. When pollinating, first use a pollen beat to gently rub a few on a faceplate, and then gently rub the pollen beat onto another faceplate. This will be granted in turn until the end of the training; the second is the flower contact method: that is, in the sunflower flowering period, the two adjacent faceplates “face to face†are gently rubbed a few times to achieve the purpose of pollination. Pollination time: Generally, it is appropriate to conduct pollination once a -2 times from 9:00 am to 11:00 am and after 3:00 pm. This can greatly reduce the shell rate, increase seed fullness and increase production. China Agricultural Network Editor
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