How to prevent flower and pod drop in soybean cultivation
1. Topdressing according to local conditions and seedling condition. For fields where the plants cannot close the rows in time during the flowering period due to lack of fertilizer, topdress once more at the early flowering stage. Generally, apply 5 kg of urea or 10 kg of ammonium sulfate per mu, which can reduce flower and pod drop.
2. Foliar spraying. During the flowering and podding stage, generally use 0.5 kg of urea, 1.5 kg of superphosphate, 0.25 kg of potassium sulfate and 25 g of borax per mu, add 50 kg of water to extract the infusion, and spray it on the leaves. It is best to spray on cloudy days or after 4 pm, which helps preserve flowers, increase pods and grains, reduce shriveled grains and increase grain weight. Foliar spraying can be combined with disease and pest control to improve labor efficiency.
3. Chemical regulation. The use of paclobutrazol on soybean has the effects of strengthening the plants, increasing branching, shaping an ideal plant type and increasing yield. In high-yield fields, 20 g of 15% paclobutrazol can be sprayed per mu at the early flowering stage mixed with 50 kg of water. This can improve the soybean plant type, prolong the functional period of the leaves, improve field ventilation and light transmission conditions, and optimize the soybean growing environment, thereby promoting growth and reducing drop.
4. Pay attention to drought prevention and drainage. From the flowering stage to the podding stage is the period in the whole life of soybean when water absorption is fastest and water consumption is greatest. During this period, if the absolute water content of the soil is lower than 25%, irrigation should be carried out. Generally, irrigate once every 5-7 days, for 2-3 consecutive times, and avoid flood irrigation. Soybean is also a crop with relatively poor waterlogging tolerance, and after flooding it is also easy to cause flower and pod drop, so attention should be paid to drainage to prevent waterlogging damage.
5. Strengthen disease and pest control. For viral disease, spray with 5% Junduqing 250-fold solution at the early stage of onset; for purple spot disease, spray with 50% benlate or zineb 800-fold solution after flowering; for aboveground insect pests of soybean, 1.8% abamectin 3000-fold solution can be used for control.