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Abstract. Several million tons of cereal grain and oilseed are stored annually in large cylindrical grain bins after harvest. It is important that such commodities be dried and maintained at suitable moisture content to provide safe storage and avoid product degradation. While in the grain bin, they are dried from the bottom up by aeration, a process in which heated or ambient air is forced up through the material. As the bed of material dries from the bottom, the upper layers initially gain moisture before they begin to dry. This phenomenon occurs as the drying front traverses the bed from bottom to top. The movement of heat and moisture through the drying bed are influenced by many factors, including the thermal properties of the grain or seed. Therefore, a method to accurately monitor moisture content in real-time at different levels is needed. Existing techniques such as moisture cables are not as accurate in situations of high humidity and high moisture content. They also only monitor within a small area around the sensor. By using a microwave moisture sensor operating at 5.8 GHz, developed within USDA ARS, the moisture content of grain or oilseed can be measured continuously, providing real-time moisture content during drying. The microwave moisture sensor was implemented within an eighth-scale grain drying system equipped with eight temperature sensors and four relative humidity sensors to observe drying parameters and moisture migration throughout as grain or oilseed dried. The drying rate for soybean and wheat dried under the same conditions was observed. The time it took the bed to converge to the temperature of the drying air was also observed and compared among the commodities.