Beware of falling flowers and pods of soybean

Soybean flower and pod drop is the main factor affecting the increase of soybean yield. In production, the soybean flower and pod drop rate is generally about 45% and 70%. The most flowers fell at 5 days after flowering, and the most pods were dropped at 10 days after flowering. In order to increase the yield of soybeans, great efforts must be made to prevent flowers and pods from falling.

First, the reasons for falling flowers and pods

1. Poor ventilation and light transmission due to excessive planting density and poor planting technology, resulting in overgrowth, premature closure of rows, deterioration of light conditions in the lower part of the plant, yellowing and shedding of leaves, less nutrition production and accumulation, resulting in shedding of flowers and pods.

2. The soybean flower and pod stage needs the most nutrients. If the nutrient supply is insufficient or out of balance, it will cause a large number of flowers and pods to fall off.

3. Unreasonable water supply during flowering and pod stage, soybean had too little water, plant wilted, soil nutrient absorption decreased, and the imbalance of water and nutrient metabolism caused a large number of flowers and pods to fall off. However, too much water reduces the soil temperature, increases the humidity, shades the field, weakens the light and effect, affects the synthesis and transport of organic nutrients, and increases the shedding of flowers and pods.

4. Diseases and insect pests damage plant leaves, reduce light and intensity, reduce the production and distribution of nutrients, resulting in flower and pod shedding.

Measures to prevent the shedding of flowers and pods

1. Reasonable close planting is the central link to coordinate the contradiction between individual and population, make full use of soil fertility and light energy, and obtain high yield of soybean. Reasonable close planting can fully develop the population per unit area, reach the highest degree of light energy utilization and land utilization, and obtain high yield due to the increase of pod number, grain number and grain weight per unit area. The specific density should be determined according to soil fertility, water conservancy conditions and variety characteristics.

2. Skillfully topdressing the flowering and podding stage requires a lot of nutrients, and the application of base fertilizer and seed fertilizer alone can not meet the demand. Therefore, topdressing at the early flowering stage, especially in barren land, where the seedlings are weak and cannot be closed in time, the fields that can not be closed in time are topdressing 10 kg of urea per 667 square meters. You can also spray fertilizer on the leaf, spraying 0.3% potassium dihydrogen phosphate solution 60ml 70kg every 667 square meters, or using 50kg water and 20ml 25g ammonium molybdate to make a solution and spraying it on the leaf.

3. The flowering and podding period of timely irrigation and drainage is not only the most exuberant period of vegetative growth and reproductive growth, but also the critical period of water demand. Lack of water seriously affects transpiration and photosynthesis, which will cause a large number of young pods to fall off. When the growth of soybean is slow, the leaves are old and green, and the leaves wilt at noon, that is, the soybean is short of water, so it should be irrigated in time. If there is stagnant water in the field after heavy rain, it should be eliminated in time to prevent waterlogging.

4. To prevent overgrowth due to good water and fertilizer conditions, high density, long branches and leaves, and closed fields. In this regard, we should control it.

5. Coring at flowering stage can control the vegetative growth of soybean, promote the redistribution of nutrients, and concentrate on the supply of flowers and pods, which is beneficial to increase flowers and protect pods, control overgrowth and reduce the shedding of flowers and pods. It can thicken soybean leaves, decrease plant height, increase pods per plant, promote early maturity, and improve yield and quality. According to the experiment, if the heart is picked at the full flowering stage, the yield can be increased by 1015%. The effect was the most significant when the heart was removed from the full flowering stage to the final flowering stage of soybean. Generally, the top of the soybean main stem can be removed by about 2 centimeters. However, for the barren soil, poor water and fertilizer conditions, weak growth potential of soybean and premature senescence, it is not suitable to remove the heart to prevent the number of flowers and pods from falling off.

6. the main diseases of soybean are leaf spot, and the main pests are soybean heart-eating insects, bean pod borer, soybean aphids and so on.