When is the best time to sow autumn soybeans?

Soybeans can be planted in spring, summer, and autumn; autumn soybeans simply means soybeans planted in autumn. So when should autumn soybeans be sown?

1. When to sow autumn soybeans?

Autumn soybeans are generally best sown from mid-July to early August, with a growth cycle of 70-80 days. They can be sown slightly early, as long as they flower around White Dew.

2. Pre-sowing preparation

1. Pre-sowing land preparation: Pre-sowing land preparation for soybeans includes soil tillage as well as harrowing, hoeing, and rolling. Different land preparation techniques involve different pre-sowing preparation, such as flat plowing, ridge planting, harrowing stubble, and deep loosening.

2. Pre-sowing irrigation: For plots with poor soil moisture before sowing soybeans, where irrigation conditions allow, water once 1-2 days before sowing, just enough to moisten the soil, to help the seeds germinate after sowing.

3. Pre-emergence weed control: If large-scale soybean cultivation is not managed in time, weeds can cause serious damage, so herbicides are often applied mechanically before sowing for pre-emergence weed control in the field.

4. Seed selection: Good soybean varieties have high germination rates and germination vigor, and the seedlings are neat and robust, so before sowing, diseased seeds, insect-damaged seeds, small seeds, shriveled seeds, and broken seeds should be picked out.

5. Seed treatment: Soybean seeds are commonly treated with 0.1-0.15% phoxim, or 0.7% lindane powder, or 0.3-0.4% carbendazim plus thiram, or 0.3-0.5% carbendazim plus captan for seed dressing.

3. Sowing methods

1. Narrow-row dense sowing method: Reducing ridge width and increasing row number, narrow-row dense planting is a cultivation method actively adopted at home and abroad; changing from 60-70 cm to 40-50 cm narrow-row dense planting can generally increase yield by 10-20%.

2. Equal-spacing hill sowing method: Equal-spacing hill sowing improves sowing efficiency and quality; after emergence, plant spacing is suitable, plants are distributed reasonably, individual growth is balanced, and yields are generally about 10% higher than drilling.

3. Double-row sowing method: The double-row sowing method uses mechanical flat sowing on the basis of deep plowing and fine land preparation or fine harrowing of stubble, followed by ridging combined with intertillage after sowing.

4. Precision hill-drop sowing method: On the basis of autumn plowing and harrowing or autumn plowing and ridging, the stubble is completely dug out, and a precision hill-drop seeder or improved harrow is used on the original ridges for single-seed or double-seed flat sowing or hill-drop sowing on the ridges.

5. Original-ridge sowing method: To prevent soil moisture loss, sowing is done on the stubble of the original ridges, which plays an important role in drought resistance, moisture conservation, and seedling protection, and also has benefits such as raising soil temperature and eliminating weeds.

The planting time for autumn soybeans should be determined according to local conditions, and sowing can be done appropriately early.