Falling out of soybeans is the main factor affecting the increase of soybean yield. In production, the falling rate of soybeans generally reaches about 45%-70%. In the 3 to 5 days after flowering, flowering was the most, and flowering after 10-15 days was the most. To increase the output of soybeans, it is necessary to make great efforts to prevent the falling of flowers.
First, the reasons for falling down
1, poor ventilation and light ventilation due to excessive planting density, poor planting techniques, causing leggy, premature closure, the deterioration of the lower light conditions of the plant, resulting in leaves yellow off, nutrient production and accumulation of less, resulting in flower buds off;
2, nutrient supply imbalance soybean bud stage is the period of need for the most nutrients, if the nutrient supply is insufficient or imbalance can cause a large number of flower buds fall off;
3. Unreasonable water supply During the flowering stage of soybean, the water content is too small, the plants are wilting, and the absorption of soil nutrients is reduced. The unbalanced metabolism of water and nutrients causes a large amount of flower buds to fall off. However, if the water content is too high, the ground temperature will decrease, the humidity will increase, the shade in the fields will be reduced, and the light and effects will weaken. This will affect the synthesis and transportation of organic nutrients and increase the loss of calyx.
4. Diseases and insects damage plant leaves, reduce light and intensity, reduce the production and distribution of nutrients, resulting in shedding of flower buds.
Second, to prevent the calyx off
1. Proper and close planting The rational and close planting is to coordinate the contradiction between plant individuals and groups, and to make full use of the land and light energy to obtain the central link of high soybean yield. The rational dense planting can fully develop the population on the unit area, reach the highest degree of utilization of light energy and land utilization rate, and obtain high yield due to the increase of the number of grains, grains, and grain weight per unit area. The specific density should be based on the soil fertility, water conditions, species characteristics.
2. Carefully chasing flowering and flowering stage requires a lot of nutrients. The base fertilizer and seed fertilizer used alone cannot meet the demand. Therefore, in the early flowering period, topdressing, especially barren, seedling development is thin, can not be closed in time for the block, topdressing urea 8-10 kg per 667 square meters. Foliar fertilizer can also be sprayed, sprayed with 0.3% potassium dihydrogen phosphate solution 60-70 kilograms per 667 square meters, can also be used 50 kg water plus 20-25 grams of ammonium molybdate, made into a solution, foliar spray.
3, timely irrigation and flowering, pod stage, it is the most vigorous period of vegetative growth and reproductive growth, but also a critical period of water demand. Insufficient moisture will severely affect transpiration and photosynthesis and cause a large number of shedding. When the soybean grows slowly, the leaves are old and green, and the leaves of the noon are wilting, that is, the performance of the soybean is deficient, and the water should be promptly filled. In the event of heavy rain, the accumulation of water in the field should be promptly eliminated to prevent floods.
4, to prevent leggy due to some fields of water and fertilizer conditions are good, combined with high density, branches and leaves long, field closed. This should be controlled.
5, flowering topping can control the vegetative growth of soybeans, promote the redistribution of nutrients, concentrated supply of flower buds, is conducive to increase flower protection, control leggy, reduce the loss of calyx. Thickening of soybean leaves, plant height reduction, increase the amount of scabs per plant, promote early maturity, improve yield and quality. According to experiments, picking up at the flowering stage can generally increase production by 10-15%. In the final flowering period of soybean flowering, the best results were obtained. Usually about 2 cm can be removed from the top of the main stem of soybean. However, with weak fertility, poor water and fertilizer conditions, weak soybean growth, and premature aging, it is not appropriate to take care of the heart to prevent increasing the number of scapes falling off.
6. Prevention and control of pests and diseases The main diseases of soybeans are leaf spot disease. The main insect pests are soybean borer, soybean meal, and soybean aphids, which must be promptly controlled.