What are the causes of flower and pod drop in soybean cultivation?
Causes of flower and pod drop in soybean? Please provide an introduction and guidance on control methods. The main factors for flower and pod drop in soybean are: 1. Poor ventilation and light penetration; due to excessive planting density and poor planting techniques, excessive vegetative growth occurs, rows close too early, and light conditions in the lower part of the plant deteriorate, causing leaves to yellow and drop, reducing nutrient production and accumulation...
Causes of flower and pod drop in soybean? Please provide an introduction and guidance on control methods.The main factors for flower and pod drop in soybean are:
1. Poor ventilation and light penetration: Due to excessive planting density and poor planting techniques, excessive vegetative growth occurs, rows close too early, and light conditions in the lower part of the plant deteriorate, causing leaves to yellow and drop, reducing nutrient production and accumulation, resulting in flower and pod drop.
2. Imbalanced nutrient supply: The flowering and podding stage of soybean is the period of greatest nutrient demand. If nutrient supply is insufficient or imbalanced, it will cause massive flower and pod drop.
3. Unreasonable water supply: If water is too scarce during the flowering and podding stage, plants wilt, nutrient uptake from the soil decreases, and the imbalance in water and nutrient metabolism causes massive flower and pod drop. However, if water is excessive, soil temperature decreases, humidity increases, the field becomes shaded, photosynthesis weakens, affecting the synthesis and transport of organic nutrients, and flower and pod drop increases.
4. Damage from pests and diseases: This damages plant leaves, reduces photosynthetic intensity, decreases nutrient production and distribution, and causes flower and pod drop.
Control methods for flower and pod drop in soybean:
1. Reasonable dense planting: Reasonable dense planting is the central link in coordinating the contradiction between individual plants and the population, fully utilizing soil fertility and light energy, and achieving high soybean yields. Reasonable dense planting allows the population per unit area to fully develop, achieving the highest degree of light energy utilization and land utilization. Due to the increase in pod number, seed number, and seed weight per unit area, high yields are obtained. The specific density should be determined according to soil fertility, water conservancy conditions, and variety characteristics, generally 10,000 to 20,000 plants is appropriate.
2. Skillful application of flower fertilizer: During the flowering and podding stage, a large amount of nutrients is needed. Relying solely on basal fertilizer and seed fertilizer is often insufficient to meet the demand. Therefore, topdressing should be carried out at the initial flowering stage, especially in poor thin soil where seedlings are weak and cannot close rows in time, apply 8-10 kg of urea per mu. Foliar spraying can also be used, spraying 60-70 kg of 0.3% potassium dihydrogen phosphate solution per mu, or using 50 kg of water plus 20-25 g of ammonium molybdate to make a solution for foliar spraying, with particularly significant results.
3. Timely drainage and irrigation: The flowering and podding stage is precisely the period of most vigorous vegetative and reproductive growth, and also the critical period for water demand. Insufficient water severely affects transpiration and photosynthesis, causing massive young pod drop. When soybean growth slows, leaves remain old green, and leaves wilt at noon, this indicates water deficiency in soybean, and irrigation should be carried out promptly. If rainstorms cause waterlogging in the field, it should be drained promptly to prevent waterlogging damage.
4. Prevent excessive vegetative growth: Because some fields have good water and fertilizer conditions, combined with relatively high density, branches and leaves grow excessively, and the field becomes closed. To control this, spray 40 g of 15% paclobutrazol plus 60 kg of water during the flowering stage. Or spray 0.2% chlormequat chloride to inhibit excessive vegetative growth.
5. Control pests and diseases: The main disease of soybean is leaf spot. At the initial stage of disease and the initial stage of podding, spray with 800-1000 times dilution of 70% thiophanate-methyl wettable powder, or 600-800 times dilution of 50% carbendazim wettable powder. The main pests include soybean pod borer, soybean pod worm, soybean aphid, etc., which can be controlled by spraying insecticides to reduce flower and pod drop caused by pests and diseases.
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