What causes soybean pods to be not plump? How to prevent it

Soybean pods that are not plump seriously affect the high yield and quality of soybean. Through investigation, research and analysis, the main causes are:

1. Insufficient nutrition in the late stage. Soybean consumes a lot of nutrients after flowering, and in various places when soybean is intercropped or relay-cropped, no fertilizer is applied and no topdressing is done. After full flowering of soybean, nutrition is insufficient, leaves turn yellow prematurely, plants are short, stems are thin, and leaves are small. This makes late pods or weak pods of the same node flower cluster unfilled, and it often occurs on sloping barren land and in varieties with many flowers and many pods.

2. Nutritional imbalance. In fertile land, or when nitrogen fertilizer is excessive in fertilization, under shaded conditions of intercropping and relay cropping, carbon assimilation is weak, and it is caused by an imbalance in the carbon-to-nitrogen ratio. It is manifested as taller plants, longer internodes, luxuriant branches and leaves with delayed senescence, sparse flowers and pods, forming empty pods and half-shriveled pods, and the maturity period is delayed. It is especially serious in years with excessive rain and insufficient sunshine.

3. Long-term drought and severe water shortage. After soybean flowering, encountering a relatively long period of drought as summer drought causes soybean leaves to wilt and turn dry yellow, young pods to stop growing, and even the whole plant to die. In plots with shallow plough layers and lack of water sources for irrigation, soybean pods that do not fill are even more serious.

4. Cold damage in late autumn. Due to late sowing or late-maturing varieties, in plots still flowering from late September to early October, because of autumn wind and autumn rain, the temperature drops, soybean leaf photosynthesis weakens, and young pod development is slow or stops. It often occurs in high-cold areas.

5. Damage from diseases and pests. In summer and autumn, soybean viral disease causes leaves to shrink and young pods to be deformed and unfilled, and damage from soybean pod borer causes empty and shriveled pods with worm holes.

6. Uncoordinated light and temperature. In low-altitude areas, from mid-July to mid-August, conditions are exactly under long-day and high-temperature conditions. Long days delay soybean grain development, while high temperature promotes rapid development and aging of pods, resulting in soybean having many flowers and many pods but not filling.

Measures to prevent soybean pods from not filling

1. According to the climatic characteristics of different regions, select and sow suitable soybean varieties, avoid harm and seek advantages, and strive for high soybean yield.

2. According to different planting systems and the light and temperature changes during the soybean growth period in different regions, select suitable light-temperature ecotype varieties, such as spring soybean requiring the light-insensitive and temperature-sensitive type, summer soybean requiring the light-sensitive and temperature-insensitive type, and autumn soybean requiring the light- and temperature-sensitive type.

3. In low-heat areas, early-maturing spring soybean or late-sown medium-maturing summer soybean should be actively developed, and autumn soybean should be developed in low-heat river valley areas, so as to avoid the long-day high temperature from mid-July to mid-August, and use the relatively short-day low temperature from mid-June and from mid-August to September, so that soybean can smoothly enter the pod-filling stage and prevent pods from not filling.

4. Select improved varieties with determinate inflorescences, use the conditions of long and short suitable temperature periods, adjust the sowing period, so that soybean growth and development are in an appropriate photoperiod period, normally complete grain development and seed filling, and avoid pods not filling.

5. Change the bad habit of not fertilizing when planting soybean. According to the fertilizer requirement pattern of soybean, carry out scientific formula fertilization. If fertilizer deficiency appears in the middle and late stages, appropriately spray 0.1-0.2% potassium dihydrogen phosphate solution to supplement nutrition and avoid premature senescence caused by fertilizer deficiency in the middle and late stages.

6. Strengthen field management and control diseases and pests. During drought, irrigate in a timely and appropriate amount to meet the water demand of soybean growth and development, and strive for a bumper soybean harvest.