How to Select High-Quality Soybean Seeds

Aerodynamic selection is a method that uses wind to remove smaller and lighter seeds, retaining the heavier and larger ones. It takes advantage of the wind and gravity to disperse fine particles and debris downwards, while seeds at the top are used for planting, a practice commonly adopted by Chinese farmers for a long time. Mechanized aerodynamic selection can be achieved using a winnowing machine.

2. Screening utilizes the varying shapes and sizes of seeds, employing different sieve structures or separators to select seeds. The types of sieves include bamboo frame wire circular sieves, wooden frame wire rectangular hoist sieves, and rectangular sieve baskets woven with wire like musical strings, measuring about 2 meters in length and 1 meter in width. The distance between the wires is determined by the size of the seeds. During selection, the sieve is placed at a 30-degree slope, utilizing the inertia of seed rolling down to facilitate sliding selection. It also uses the gaps between two wires to sieve out small-grained seeds, weed seeds smaller than soybean seeds, cracked, chaffy, and sandy particles into the bottom of the sieve. As a result, soybean seeds and weed seeds can be separated. For instance, Xanthium sibiricum has poorer sliding performance than soybeans, often falling to the bottom of the sieve during the screening process. In contrast, soybean seeds are smooth and round, rolling faster and further from the bottom of the sieve. This method separates Xanthium sibiricum seeds from soybean seeds at different locations, saving labor and being highly efficient. It yields a higher quality of selected seeds, making it a good method for screening.

3. Selecting grains typically involves a process beyond wind and screen selection, further removing unripe, chaffy, diseased, insect-damaged, small, and mixed variety grains. The goal is to choose seeds that are large and plump with intact seed coats. Attention is also given to key characteristics such as grain shape, seed coat, hilum color, and luster. This is an effective method for improving purity and cleanliness of varieties, which can be done during spare time before sowing.

4. Seed selection machinery utilizes the principle of different rolling speeds of beans on slopes to create soybean seed selectors, which have been widely used across Northeast China in recent years. It is an efficient and high-quality seed selection tool, capable of processing 80 to 100 catties of soybean seeds per person per hour. A single pass through the seed selection or machine selection process can remove over two-thirds of infested seeds, cracked pods, malformed grains, empty seeds, and soil clumps. To enhance the quality of the selected seeds, a winnowing machine can be used first, followed by screening and then seed selection with the selector. In units with a higher degree of mechanization, winnowing machines, screening machines, seed selectors, conveyor machines, and reverse machines can be combined into a series of complex operations, enabling the mechanization of soybean seed selection.