There are many measures to prevent soybean from falling flowers and pods.

The drop of flowers and pods is an important factor affecting the yield of soybean. Under general cultivation conditions, the shedding number of flowers and pods can account for more than 50% of the total number of flowers, and seriously up to 70%. The shedding of soybean flowers and pods is mainly due to the internal physiological imbalance of the plant and poor external environmental conditions. According to our practical experience, the following measures can be taken to prevent the shedding of soybean flowers and pods:

1. Increase the application of phosphorus and potassium fertilizer, appropriate topdressing nitrogen fertilizer and micro-fertilizer. The application of phosphorus and potassium fertilizer to soybean can reduce the shedding of flowers and pods and promote the fullness of grains. Therefore, on the basis of sufficient basic fertilizer, 25kg of calcium magnesium phosphate fertilizer and 500kg of fire soil ash are used for every 667 square meters (1 mu) when sowing, and the covered seeds are fully mixed as seed fertilizer, which can make the plant grow healthily, branch early and bear more pods. In order to meet the nutrient needs of plants at flowering and reduce the shedding of flowers and pods, urea 5kg and potassium chloride 7.5kg / 667 square meters were applied to the plots with poor soil fertility and slow growth of soybean seedlings at the beginning of flowering. It is also necessary to apply appropriate amount of micro-fertilizer at flowering stage, that is, 1 gram of ammonium molybdate per 667 square meters, dissolve with a small amount of warm hot water, then add 150g of potassium dihydrogen phosphate, 50kg of water, and spray fertilizer on the leaf, which has an obvious effect on increasing podding rate and grain weight.

two。 According to local conditions, reasonable close planting. If the sowing of soybean is too dense, the lower part of the plant will be shaded, which will also cause falling flowers and pods. Therefore, according to the characteristics of varieties, soil fat and thin, sowing sooner or later, the planting density should be determined reasonably. The varieties with strong luxuriancy should be thinner, and the varieties with poor fertility should be denser; the fertile land should be thinner and the lean land should be denser; the growing period of early sowing is longer, the vegetative body is luxuriant, the planting density should be thinner, and the planting density of late sowing should be increased appropriately. At present, the general dense planting in the field is 15000 ~ 20 000 plants per 667m2, and it is suitable to keep 15000 seedlings in fertile land and 20 000 in thin land.

3. Take off your heart at the right time. For the varieties with unlimited growth habits, the apical dominance of soybean can be effectively controlled by picking the top of the main stem from 2 cm to 3 cm after drying in clear dew from the beginning of flowering to the peak stage of soybean. Timely coring under the condition of sufficient fertilizer can also control overgrowth, promote seed ripening and increase yield.

4. To prevent drought in time. The flowering and podding stage of soybean needs more water, at this time, if the drought continues, it will cause a large number of flowers and pods to fall off. Therefore, it is necessary to do a good job in drought prevention and drought resistance as soon as possible, watering frequently and carefully and watering every 5 to 7 days. In case of waterlogging, the stagnant water in the field should be eliminated in time to prevent waterlogging.

5. Control diseases and insect pests. To do a good job in the control of diseases and insect pests is also an effective measure to prevent the shedding of soybean flowers and pods. To control aphids, spray with 40% omethoate emulsion 1500-2000 times; control pod borer, 100 grams with 50% marathon emulsion and 100 kg water; for purple spot, spray with Dysen zinc 500 times or Bordeaux solution twice to suppress its harm.