Effects of Pressure and Moisture Content on Bulk Density of Triticale Grain Under Compaction

Abstract

The objective of this study was to determine the combined effects of moisture content (MC) and pressure on the changes in bulk density of triticale grain under compaction at conditions typical of those seen in storage structures and to develop mathematical models to describe the compression behavior. Triticale compaction was measured at three MCs (8%, 12%, and 16% wet basis) and four compaction pressures (7, 14, 34, and 55 kPa) using a square metal box based on the design used in an earlier study by Thompson and Ross. Data from the compaction tests were used to calculate bulk densities for the three MCs and four pressures. Bulk densities were found to be significantly (p < 0.0001) dependent on both MC and pressure. Bulk densities varied with increasing MC, as has been observed in similar studies for other agricultural grains such as rye and wheat. These results provide guidance for estimating the bulk density of triticale in bins and other storage structures. The Verhulst logistic equation was found to best describe the changes in bulk density of triticale caused by rearrangement of the grain kernels at lower pressures for the three MCs. At higher pressures, the grain was observed to be more compliant, and Hooke’s law was used to accurately describe the observed changes. Data from the compaction tests were used to estimate the model parameters, with a correlation coefficient (R2) of 0.986. The model was then used in WPACKING to compare the results of this study to pack factor predictions for triticale and wheat. WPACKING is a computer program that is the basis for ASABE Standard S413. The results of this comparison showed that this method can be used with the methods of ASABE Standard S413 to predict the quantity of triticale grain stored in bins. © 2022 American Society of Agricultural and Biological Engineers.