Automated pressure regulation for a silage bagging machine

Ensiling and compaction of silage crops in bags is a well proved method to store fodder anaerobically to feed animals throughout the year. The essential process principle is to compact the silage substrate using a rotor into a press tunnel and the connected plastic bag to generate an oxygen-free environment. The objective of this study was to develop an automatic pressure-controlling system for the compaction process. The automatic system controls elongation of the bag film calculated based on the circumference during ensiling. Due to the different physical composition of pasture grass and maize substrates, only 2% of values in the case of maize silage deviated from the specified tolerance range (9.5 ± 0.5% elongation) while over 50% of the values with grass silage deviated from the tolerance range (8.5 ± 0.5% elongation). To determine the effect on crop density and stability of silage, investigations were made during feed-out. Accordingly, the identified storage density of the maize and grass silage varied between 179.0 and 280.8 kg DM m−3, and 89.3 and 197.7 kg DM m−3, respectively. Basically, the automated pressure control of silo bagging press machines is possible, and the machine operator can be relieved. However, the homogeneity of the silo bag contours is highly dependent on the stored ensiled material.