Achieving adequate packing density is a crucial component in creating high-quality silage. That’s because plant respiration continues after the harvest is done and the silo is sealed, which increases the opportunity for growth of undesirable organisms. Poor packing means increased silage porosity. This can result in additional spoilage and dry matter (DM) loss at feedout due to greater oxygen infiltration.
Achieving good packing density starts in the field, and the specific steps have been covered in other articles.
Once harvest is over, it’s long been standard practice to take a core sample to determine the actual density achieved. Taking core samples can be a time-consuming process when there are multiple storage sites evaluated. Most importantly, there are safety risks for approaching any silage face to take samples.
Prior to harvest, there is an online calculator available from the University of Wisconsin-Madison Extension Team Forage that helps producers predict their necessary silage density. There are specific measurements required to make this calculation, including number of packing tractors, tractor weights, layer thickness, harvest rate, percent packing time, DM content and height of silage within storage. The calculator can be used at any time and has no safety concerns.1
There is a third option — the feed-out method — that involves dividing the weight of silage removed by the estimated volume of silage removed. However, researchers from the University of Idaho found the feedout method was not a reliable way to estimate density.1
Whatever method is chosen, it’s important to keep safety top of mind. Important tips include:
- Use a reflective vest/piece of clothing
- Don’t forget the buddy system
- Do not take core samples if the feedout face is more than 8' tall
- Never allow a person to ride in the bucket of a front-end loader to take samples from the silage feedout face
- When sampling silage, take samples from a loader bucket after it is moved to a safe distance from the feed-out face
Assessing density is a pillar of good silage management, and research shows there is room for improvement. The packing density achieved on commercial operations has been shown to vary considerably. Understanding how to safely and accurately assess silage density can improve the quantity and quality of silage available.
1 Norell RJ et al. Comparing Three Different Methods for Assessing Corn Silage Density. Journal of Extension. October 2013 (51);51. https://www.joe.org/joe/2013october/rb9.php