A System to Assess Grain Bag Storage Internal Environment

Abstract

<abstract><title><italic>Abstract.</italic></title> Alternative grain storage systems have been adopted when traditional bin storage capacity is exceeded or unavailable. One method is grain bag (silo bag) storage systems. This system has been used for silage or high-moisture grain storage, has been employed for dry grain in other regions of the world, and is gaining acceptance in the U.S. Little peer-reviewed research is available to describe the grain bag internal environment and its effect on grain quality. In the reviewed studies, there was no consistency in the approach taken to characterize the grain bag environment. The objectives of this study were to design and fabricate a sensor system to measure the internal environment of a grain bag, to apply this sensor system under field conditions, and describe instrumentation considerations for grain bags. An instrumentation system of linearly mounted thermocouples and relative humidity (RH) sensors was developed. The linear sensor arrays have a sampling interval as low as 30 s. The system RMS error for measuring temperature (T) and RH were 0.6°C and 3.1%, respectively. The system was field tested and recorded internal environmental parameters for corn stored in grain bags. A defined peripheral layer that strongly responded to external ambient conditions was identified, which was expected. Temperatures were stratified within the peripheral region. To characterize the internal temperature of a grain bag, temperature measurements need to be taken at a minimum of three depths: at the internal bag surface, within the peripheral temperature region, and within the core temperature region. Collected T and RH data were used to describe the grain equilibrium moisture content. There were errors associated with both the measurement and calculation of EMC. Errors caused by measurement error were less than 2% for all temperatures between 20% and 80% RH. Researchers, producers, and grain managers could use a similar system to monitor grains stored using this alternative storage system and to make effective management decisions.