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RECOMMNDATIONS FOR SOYBEANS AND SOYBEAN MEAL STORAGE by Pablo Fernández , Southeast Asia Area Manager Silos Cordoba
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toring soybean and soybean meal leads to specific storage problems. That is why we need to know more about them. For example, the structure of the bean impacts its handling and: • Handling involves conveying and transporting from the farm to enduser. During this phase there are many different movements from harvest to the production into oil and meal • The structure of a soybean seed makes it susceptible to splitting and breakage during mechanical handling. The extent of breakage in soybeans during conveying varies with the impact force imposed on each individual seed. The least breakage occurs when soybeans are conveyed in a bucket elevator as compared to other conveying methods Figure 1 shows the extent of soya bean breakage with four methods of conveying: the first one represents the percentage of breakage of the grain in a free fall of 30, 21 and 12 meters. The storability of soybeans is affected by the degree of damage to the seed coat and by other factors such as mold or insect attack. It is therefore important to inspect soybeans for mechanical and other forms of damage prior to storage. If the amount of broken or split soybeans is very high, it may be prudent to separate the broken or split grains by sieving. This
material can then be used first as opposed to long-term storage within the original stock. Soybean meal is difficult to handle because of its poor flowability and bridging characteristics. Soybean meal tends to settle or consolidate over time. This phenomenon occurs in most granular materials and becomes more severe with increased moisture, time and when particle sizes are small.
Flow characteristcs The flow characteristics of bulk materials are dependent on individual particle shape, density, frictional property and moisture content. Granular materials have three typical flow patterns during discharge from hopper bottom bins: normal discharge pattern (there is no problem here), bridging and funneling. These two latter problems occur in grains containing high content of foreign material or moisture. Typical flow problems of meal products discharged from storage silos are hang-ups, dead pocket and piping (see figure 2). These are usually due to a combination of factors such as poor hopper design, high moisture content and storage time.
External factors Beside all of the above soybean and soybean meal consideration, we have to keep in mind the most important external factors: moisture content, temperature and duration of temperature. The general condition of the product and amount of foreign materials also affect its
#2 Table 1: Moisture content and safe storage durations Safe storage period
Moisture content, % wet basis
Market stock
Seed stock
10-11
4 years
1 year
1-3 years
6 months
13-14
6-9 months
Poor germination
14-15
6 months
Poor germination
10-12,5
storability. By focusing on these three elements, we can assure the perfect storage of soya bean and soya bean meal: Moisture content: Depending on the percentage of moisture, the periods of storage change. Soybeans contain moisture ranging from 12 percent to 15 percent at harvest time. Above 13 percent should be dried to reduce the risk of deterioration due to seed respiration, mold attack, spontaneous heating and reduced germination. Temperature: Temperature is another very important factor influencing in soybean storage. Growth of fungi and chemical changes, such as oxidation, increased with temperature in both meal and whole beans. Moreover, it is really important to con-