Detailed Explanation of Key Points for High-Benefit Soybean Cultivation Techniques

Soybean is one of China's important oil crops, and Shandong soybeans are renowned throughout China. Shandong Province has unique advantages in soybean seed breeding and is a stable year-round soybean seed production base. 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 higher yield level, improved varieties must be matched with improved methods to achieve the goal of high yield and bountiful harvest. The key points of improved soybean cultivation techniques are briefly described below for reference.

I. Timely sowing: Spring soybean: The area of spring soybean is relatively small, and its sowing is mostly flexibly determined by crop rotation and intercropping methods. A daily average temperature of 6-10 degrees C can allow germination, but it is very slow; at 18-20 degrees C, seedlings emerge quickly and uniformly; at 33-36 degrees C, seedlings emerge quickly but are thin and weak. Therefore, the most suitable sowing period is when the temperature is >=18 degrees C. Summer soybean: Summer soybean is generally directly sown after wheat, and can be arranged according to local crop rotation schedules; 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 with corn: Soybean varieties suitable for corn-soybean intercropping must have four traits: early maturity, short stature, determinate podding habit, and strong shade tolerance. Currently plantable varieties include Zaoshu No. 1, Zaoshu No. 2, Ludou No. 4, Ludou No. 11, Qihuang 24, etc.; four new lines under demonstration include Qifeng 918, 98229, etc. For intercropping patterns, corn//soybean at 1:6 or 8 rows are both acceptable.

II. Reasonable dense planting: Planting density should be determined by 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 and late-maturing varieties, planting density should generally be determined by the number of branches, that is, varieties 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.

III. Sowing with adequate soil moisture: Sowing with adequate soil moisture is the key to full emergence from a single sowing and is also an important measure for achieving high yields. Sowing with insufficient soil moisture and watering after sowing to follow the seed (covering water) are strictly prohibited.

IV. Seedling stage management: 1. Thin seedlings in time; the seedling thinning period is best at the two-leaf stage for final stand establishment. 2. Hoe and weed in time. (Chemical weeding is best for weed control.) 3. At the seedling stage, apply 15-20 kg per mu of N, P, K compound fertilizer.

V. 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 first measure is drought prevention. According to the climate in recent years, drought occurs in most years from the soybean seedling stage to the early flowering stage, so when drought occurs, irrigation must be timely. In particular, Ludou No. 4, Ludou No. 10, and Zaoshu No. 1 are greatly affected in yield when drought occurs at early flowering. In some years, yield is reduced by more than 50%. Ludou No. 2, Youbian 30, Doujiao 44, and Gaofeng are somewhat better. Second, soybean has a relatively large demand for nitrogen fertilizer. Although soybean rhizobia have nitrogen-fixing ability, this 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.

VI. Mid-season management: (flowering to podding stage) In addition to drought resistance and drainage of waterlogging, the main task in this period is pest control. Focus on controlling soybean geometrid, bean pod borer, soybean pod borer, and soybean stem black leafminer. In Shandong, late August and early September are generally the key control periods. It is worth noting that the soybean stem black leafminer has shown a spreading trend in recent years. It mainly damages soybean stems, branches, and petioles. In the field, soybeans show only flowering without podding, small pods, small seeds, no seed filling or no seed set, dark green leaves, and very low yield, or even total crop failure. However, there are great differences among plots and among varieties. That is to say, different varieties in the same plot suffer different degrees of damage, and the same variety in different plots also differs greatly in the degree of damage. Its control method is chemical control from the 6-leaf stage to the early flowering stage and at the podding stage.

VII. Harvesting and storage: After harvesting soybean, air-dry it on the plants to prevent the beans from splitting and fading. When seed moisture drops below 12%, thresh in time, air-dry slightly, and store in the warehouse. For soybean kept for seed, after harvest pay attention to rain protection and mold prevention, and threshing on roads is strictly prohibited.