What are the key points of soybean cultivation techniques?

Soybean is one of the important oil crops in our country, and Shandong soybeans are renowned throughout China. Shandong Province has unique advantages in soybean improved-variety breeding, with a stable soybean seed production base year after year. Its improved varieties are sold to hundreds of counties and cities across most of Shandong, as well as Henan, Jiangsu, Anhui, Shanxi, Hebei and other provinces, and have long been known as hybrid soybeans, becoming a famous-brand product in the Huang-Huai River basin. High-yield soybean cultivation techniques are one of the important technical measures for achieving high yields. To obtain a relatively high yield level, improved varieties must also be matched with improved methods, so as to achieve the goal of a high and abundant harvest. The key points of improved-variety soybean cultivation techniques are briefly described below for reference.

1. Timely sowing: Spring soybeans: the area of spring soybeans is relatively small, and their sowing is mostly flexibly arranged according to the previous crop and relay intercropping method. Although germination can occur at an average daily temperature of 6-10°C, it is very slow; at 18-20°C, seedlings emerge quickly and uniformly; at 33-36°C, although seedlings emerge quickly, the seedlings are slender and weak. Therefore, a sowing time when the temperature is ≥18°C is most suitable. Summer soybeans: summer soybeans are generally directly sown after wheat, and can be arranged according to the planting rotation in each area; in Shandong, late May to early and mid-June is generally suitable. Extremely early-maturing varieties (growth period about 80 days), such as Zaoshu No. 1, can be delayed until early July for sowing; mid-to-late-maturing varieties, such as Ludou 12 and Gaofeng, must not be sown later than June 15. Varieties suitable for intercropping and relay intercropping with corn: soybean varieties suitable for corn-soybean intercropping and relay intercropping must have four traits: early maturity, short stature, determinate podding habit, and strong shade tolerance. Varieties that can currently be planted include Zaoshu No. 1, Zaoshu No. 2, Ludou No. 4, Ludou No. 11, Qihuang 24, etc.; four new lines such as Qifeng 918 and 98229 are being demonstrated. For the relay intercropping method, corn//soybean at 1:6 or 8 rows is acceptable.

2. Reasonable close planting: planting density should be determined according to the local climate, soil fertility level (production conditions), and variety characteristics. Early sowing should be thinner, late sowing should be denser; fertile land should be thinner, poor land should be denser; high-yield fields should be thinner; low-yield fields should be denser. Between early-maturing varieties and late-maturing varieties, the general planting density should be determined by the number of branches, that is, those with many branches, tall plants, and high per-plant productivity should be thinner (such as Ludou 12, 88-60, Doujiao 44, etc.); otherwise they should be denser.

3. Sowing with sufficient soil moisture: sowing with sufficient soil moisture is the key to full emergence in one sowing, and is also an important measure for achieving a high yield level. Sowing with insufficient soil moisture and watering after sowing to help emergence (montou water) are strictly prohibited.

4. Seedling-stage management: 1. Thin seedlings in time; the thinning period is best when final thinning is done at the two-leaf stage. 2. Hoe and weed in time. (For weed control, chemical herbicides are best.) 3. At the seedling stage, apply 15-20 kg per mu of N, P, K compound fertilizer.

5. Early flowering stage management: the early flowering stage is an important period for field management, and whether management is appropriate has a great impact on yield. The primary measure is drought prevention. According to the climate in recent years, from the soybean seedling stage to the early flowering stage, drought occurs in most years, so when drought occurs, watering must be done in time. In particular, for Ludou No. 4, Ludou No. 10, and Zaoshu No. 1, drought at early flowering has a great impact on yield. In some years, yield was reduced by more than 50%. However, Ludou No. 2, Youbian 30, Doujiao 44, and Gaofeng are somewhat better. Second, soybeans have a relatively large demand for nitrogen fertilizer. Although soybean rhizobia have nitrogen-fixing ability, they still cannot meet the needs for reaching a high yield level. Therefore, applying 5-7 kg per mu of urea at the early flowering stage is an extremely important technical measure.

6. Mid-season management: (flowering to podding stage) In this period, in addition to drought resistance and drainage of waterlogged fields, the main task is pest control. The focus is on controlling soybean semilooper, soybean pod borer, soybean pod worm, and soybean stem black leaf miner. In Shandong, late August and early September are generally the key control periods. It is worth noting that the soybean stem black leaf miner has shown a spreading trend in recent years. It mainly damages soybean stems, branches, and petioles. In the field it appears as soybeans that only flower but do not set pods, with small pods, small seeds, no seed filling or no seed setting, dark green leaves, and very low yield, or even total crop failure. However, there are great differences between plots and between varieties. That is to say, the degree of damage to different varieties in the same plot is not the same, and the degree of damage to the same variety in different plots also differs greatly. Its control method is chemical control from the 6-leaf stage to the early flowering stage and at the podding stage.

7. Harvesting and storage: after soybean harvest, the plants should be stacked and sun-dried to prevent the beans from splitting and fading. When the seed moisture drops below 12%, thresh in time, sun-dry slightly, and store in the warehouse. Soybeans kept for seed should be protected from rain after harvest and from mildew, and threshing by beating on roads is strictly prohibited.