Detailed Explanation of Key Soybean Field Management Techniques

1. Thin seedlings early.

As the farming proverb says: "Thin seedlings an inch early, and it is as good as a load of manure." Thinning is especially important for mechanically drilled soybeans or hand-sown beans planted with a large plow in furrows. After thinning, the seedlings are distributed evenly and reasonably, which promptly prevents seedlings from crowding one another, reduces consumption of soil nutrients and water, and allows the seedlings to develop evenly and vigorously, thereby increasing soybean yield. Thinning is generally carried out during the soybean seedling stage, when the two opposite single leaves are flat and spreading and compound leaves have appeared. During thinning, diseased seedlings, weak seedlings, and mixed seedlings must be pulled out.

2. Cultivation and weeding.

Generally, three hoeings and three hillings are required. Specific timing: the first around June 1, the second around June 20, and the third at the end of June or the beginning of July. According to the growth of the soybeans, complete the third hoeing and hilling, then ridge up the soil.

3. Topdressing according to the seedlings.

For poor and thin plots, nitrogen fertilizer should be applied according to soil fertility and seedling growth, generally 75-100 kg of ammonium nitrate per hectare. It can be applied in furrows together with the second hoeing and hilling, or potassium dihydrogen phosphate can be sprayed on the leaves, using 0.5 kg of potassium dihydrogen phosphate mixed with 400 kg of water per hectare. It can also be done together with aphid control.

4. Control of aphids and pod borers.

The soybean aphid is the main pest harming soybean production. If it breaks out severely, it will cause soybean leaves to curl, spread viruses, and cause large yield reductions. From early June to early July, if aphid damage reaches the control threshold, that is, when the rate of aphid-infested plants in the field reaches 30%-40% and the number of aphids per 100 plants reaches more than 1,500, spray immediately with a 10% imidacloprid solution diluted 2,000 times for control, or spray with omethoate and fenvalerate emulsifiable concentrate prepared as a 2,000-3,000 times solution, using 600-700 kg of spray solution per hectare.

The soybean pod borer enters the adult peak period in early August each year, laying eggs that hatch into larvae that feed on the soybean seeds, seriously affecting soybean quality and reducing the commercial value of soybeans. At present, the more commonly used method for controlling the soybean pod borer is: soak 50 kg of peeled corn stalks in 0.5 kg of 80% dichlorvos emulsifiable concentrate, then evenly scatter them in l hectare of soybean field in the evening for fumigation control.

5. Clear large weeds from the field.

During cultivation and weeding, weeds are often left behind. By the late growth stage of soybeans, although the branches and leaves are lush, they cannot suppress these weeds. These weeds grow quickly and are tall, competing with soybeans for light, water, and fertilizer, seriously affecting the normal development of soybeans. Therefore, after the hoeing and hilling of soybeans is completed, at the end of July or the beginning of August, these large weeds must be pulled out to help soybeans ventilate and receive light, promote ripening, and increase yield. Doing so can also reduce weed damage to the following crop.