How do growers store harvested soybean for safe and secured storage in the grain bins?

Soybeans start to mature when days get shorter (for example mid-August to mid-September). The state of maturity when a field should be harvested depends on many factors including variety, geography, seed size, and growth stage. Generally, cultivars need at least 90 days to mature. Environmental conditions like hot summer weather can accelerate the maturation process but these environmental effects cannot be controlled by growers. Thereafter, an effective grain bin monitoring system is required for storing the grains effectively and safely in the storage bin for long periods of time.

When should soybean be harvested?

Soybean can be harvested any time after pods are mature enough to make shattering minimal or not at all and kernels are creamy white in color with no green coloration left on the seed coat. Before soybean enters the storage bin it is also important to evaluate soybeans for signs of mold growth, insect damage, and disease.

Soybean plants are very sensitive to frosts after flowering. At maturity when temperatures drop below freezing at night, blossoms may start to fall off the pods and within a few days, the whole plant will die. Although soybean may be mature at this point, you do not want to take the chance of losing your crop in storage.

A well-designed and maintained grain bin monitoring system can help to reduce problems associated with moisture content, aeration, and temperature that can lead to mold development.

How do growers store harvested soybean for safe and secured storage in the grain bins?

Growers can store soybean with moisture content above 18% for a short period of time and it is recommended that growers bring soybeans into storage as soon as possible after harvest.

Soybeans can be stored safely at moisture levels between 15 and 20%. However, growers need to consider that dehydrating soybean will reduce the volume.

Soybean can be stored in bins or silos for long periods of time if the proper moisture content is maintained.

They are a few things that growers need to consider to store harvested soybeans properly at moisture levels above 18%. In order for the harvest grain storage system to achieve adequate aeration, it must be designed for the moisture level being stored with consideration for airspeed and grain flow pattern.

An important point to consider when storing soybean in bins or silos is that there must be sufficient aeration to produce an oxygen partial pressure of 4–5 lbs/in2 at the bin floor level. This pressure assures adequate diffusion into the stored grain and will prevent or reduce the potential for mold development.

Silos can be designed to provide sufficient aeration using a blower system with large diameter tubes that are placed close to the bin floor. Or, a blower system with smaller diameter tubes can be used at higher velocities (higher air speed) as long as they are placed close to the bin floor.

Grain Moisture Content

The amount of moisture removed from a given quantity of soybean will vary depending on the time and temperature used during drying. As grain temperatures increase, so does the potential for mold growth if proper aeration is not present. Growers should be aware that mold can begin to grow in stored grain when the temperature reaches about 72–74 degrees F.

Mold spores can be present on harvested soybean and they will begin to germinate when conditions are favorable for their growth (moisture content, aeration and temperature). Once mold growth starts it can spread rapidly through a bin load of soybean if changes in moisture, temperature or aeration are not favorable for the growth of mold. Molds will continue to grow as long as there is a source of moisture and an adequate stream of air for them to grow on.

What are the important points to consider when storing the soybean in the storage bin during summers or early fall?

The important points to consider while storing harvested soybean in the storage bin during summers or early fall are as follows:

1. Grain should be dried down quickly, especially if bins are used, with consideration for lowering the moisture level below 25%. High humidity is more likely to occur in summer and air conditioning may not be enough to lower grain moisture quickly.

2. Proper aeration is critical for the safe storage of harvested soybean at a moisture content above 25%. Air velocities need to be checked and adjusted in order to maintain a bin oxygen partial pressure of 4–5 lbs/in. If air velocities are low, more forced ventilation may be required. During the hot summer months, if aeration is not adequate, bin temperatures will rise. This can lead to mold growth if the grain moisture content is high.

3. Bins should be properly sealed and stored away from direct sunlight, hot air vents, or any other heating sources such as dryers in order to avoid excessive heat build-up during the summer months.

4. A grain storage expert should be consulted for designing the proper bin aeration system.

5. Proper record keeping is important in order to know when a harvest was stored and the date of harvest must be recorded on the seed tag with information about moisture content at the time of drying and bin temperature (if using) to verify that the correct moisture content and temperature conditions are being used at the time of grain storage.

6. Proper cleaning for harvest bins is recommended to prevent cross-contamination from one soybean crop to another soybean load. An empty bin should be thoroughly cleaned before filling it with a new soybean harvest. Cleaning involves removing all dust, broken kernels, foreign material, insects, and all other types of foreign material that could be introduced to the new soybean load.

7. Using EndZone Fan Controls will eliminate the problem of manually operating the aeration fan. It can add or remove the moisture content of the grains according to the preset temperature levels. It will automatically turn on and off the fan to maintain the right temperature

Conclusion

Properly designed and operated storage bins and aeration systems can help growers to minimize the risk of mold development on stored soybean. Storage bin design includes consideration of grain moisture content, temperature, and air velocity, and these factors are critical for preventing the growth of mold during storage. Growers should be aware that high humidity with low airspeed is the most common situation when mold growth develops on stored soybean. Proper maintenance of bins, grain storage fan automation, and harvesting equipment is also very important for the safe storage of soybean in the bin during summer or early fall.