Ask the Doctor: Guiding Crops through Spring’s Changes

Spring is the best time for the hydration of grains, particularly soybeans, due to the following reasons:

1. High humidity air is available for the hydration process to happen.
2. Farmers don't need to store the hydrated soybeans for an extended period. They can sell them immediately at a better price compared to fall pricing.

Do keep in mind that when storing hydrated soybeans beyond 3-4 weeks, there is risk of caking and spoilage, especially due to mold damage. Sometimes soybeans may not be able to hydrate fully within the 3-4 weeks' time; that is ok. Hydrating fully to 13% may lead to spoilage as the relative humidity of some of the hybrids of soybeans are above 75% at 13% moisture.

Looking at the economics of soybean hydration for a 48-diameter 8-ring wide bin with capacity of 42,184 bu, hydrating from 10% to 11.5% gives around 712 bu gain which is equal to $8,294 based on the current soybean price of $11.6/bu. Subtracting the estimated cost of running a fan and its electricity cost at around $800, the final gain will be $7,494.

Upon receiving a Hot Spot Alert, customers first need to study the moisture content and temperature level in the bin from the past few months. If the moisture is higher than the normal storage moisture content, 65% relative humidity (RH), then there is a possibility of spoilage occurring. For example, if corn is at 17% RH or soybeans are at 14% RH at some locations in the grain bin then the chance of getting a hot spot is higher. In that scenario, the grain needs to be cooled down immediately. This could be done with a conditioning bin, one where the airflow rate > 1 cfm/bu, or by shuffling the grain from one bin to another. If an empty bin isn’t available, and the hot spot doesn't die down, it’s better to sell the grain versus keeping it to avoid issues such as caking or spoilage.

Most farmers sell their grains in spring before the warm weather prevails. One of the reasons for this is that they are not ready to take risks due to grain warming. When the temperature increases, the safe storage moisture content of grain decreases. For example, the safe storage moisture of a corn hybrid is 15% at 40°F, whereas the safe storage moisture content of that corn hybrid at 14% at 70°F. There will be a risk of keeping 15% moisture corn during summer. In that sense, over-dried corn or soybeans can store well during summer months. However, if we keep the grain temperature at 30°F and outside ambient temperature is 60° F, then there will be condensation issues in the grain mass that leads to spoilage (caking or crust formation). To avoid condensation, we need to warm the grain 10-15°F below the average ambient temperature. For example, if the average ambient temperature is 60°F, we need to warm the grain to 45-50°F range.