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Introduction
Silage pit compaction is traditionally performed using tractors or wheeled loaders, but some operators have explored the use of heavy tracked excavators for this task. A 20-ton digger, with its substantial weight and versatile movement, presents an unconventional yet potentially effective alternative. This article examines the practicality of using such machines for silage compaction, clarifies relevant terminology, and shares field-tested techniques, anecdotes, and historical context.
Understanding Silage Pit Compaction
Silage is fermented, high-moisture fodder stored in pits or bunkers and used to feed livestock. Proper compaction is critical to exclude oxygen and promote anaerobic fermentation, which preserves nutritional value and prevents spoilage.
Key goals of compaction include:
While tractors are commonly used due to their maneuverability and wheel-based compaction, excavators offer unique advantages and limitations.
Advantages of using a 20-ton excavator:
In Ireland, an operator considered using a 20-ton tracked excavator to compact grass silage. Traditionally, a 120hp 4WD tractor weighing 5 tons was used. While the excavator had significantly more mass, concerns arose about its lower ground pressure and lack of rolling action. Ultimately, the excavator was used to pull silage back from pit edges and assist in layering, but final compaction was still performed by the tractor.
Historical Context: Evolution of Silage Compaction
Silage pits have evolved from simple trenches to engineered bunkers with reinforced walls and drainage systems. In the 1970s, wheel loaders and tractors became standard for compaction. The rise of tracked machines introduced new possibilities, but their use remained niche due to compaction dynamics and maneuverability concerns.
Case Study: Wisconsin Farm with PC220 Excavator
A farm in southern Wisconsin used a Komatsu PC220 excavator for silage compaction over five seasons. The operator reported satisfactory results, especially when using the bucket to tamp down layers and lift the front end to concentrate weight on the rear tracks. However, they emphasized the importance of layering thinly and avoiding overcompaction in a single pass.
Techniques for Effective Excavator-Based Compaction
Using a 20-ton excavator for silage pit compaction is feasible under certain conditions, especially when combined with traditional methods. While it may not replace wheeled tractors in terms of rolling efficiency, its weight and versatility can enhance layering and edge management. With careful technique and awareness of limitations, excavators can play a valuable role in modern silage operations—proving that even machines built for earthmoving can help feed the herd.
Silage pit compaction is traditionally performed using tractors or wheeled loaders, but some operators have explored the use of heavy tracked excavators for this task. A 20-ton digger, with its substantial weight and versatile movement, presents an unconventional yet potentially effective alternative. This article examines the practicality of using such machines for silage compaction, clarifies relevant terminology, and shares field-tested techniques, anecdotes, and historical context.
Understanding Silage Pit Compaction
Silage is fermented, high-moisture fodder stored in pits or bunkers and used to feed livestock. Proper compaction is critical to exclude oxygen and promote anaerobic fermentation, which preserves nutritional value and prevents spoilage.
Key goals of compaction include:
- Maximizing density to reduce air pockets
- Creating uniform layers for consistent fermentation
- Preventing runoff and seepage
- Silage Pit: A trench or bunker where chopped forage is stored and compacted for fermentation.
- Ground Pressure: The pressure exerted by a machine on the surface, influenced by weight and contact area.
- Point Loading: Concentrated pressure applied by wheels or tracks, affecting compaction depth.
- Sheepfoot Roller: A compaction tool with protrusions that penetrate and compress soil or silage layers.
While tractors are commonly used due to their maneuverability and wheel-based compaction, excavators offer unique advantages and limitations.
Advantages of using a 20-ton excavator:
- High Machine Weight
Excavators in this class weigh around 40,000 lbs, offering deep compaction potential when properly applied.
- Controlled Movement
The ability to walk slowly and deliberately allows for targeted compaction.
- Bucket Versatility
Operators can use the bucket to push, pull, or tamp silage, especially near pit edges.
- Low Ground Pressure
Wide tracks distribute weight, reducing point loading compared to wheeled machines.
- Limited Rolling Action
Excavators lack the dynamic rolling compaction provided by tires.
- Risk of Getting Stuck
Silage, especially when wet or made from slick crops like oats or peas, can trap heavy machines.
In Ireland, an operator considered using a 20-ton tracked excavator to compact grass silage. Traditionally, a 120hp 4WD tractor weighing 5 tons was used. While the excavator had significantly more mass, concerns arose about its lower ground pressure and lack of rolling action. Ultimately, the excavator was used to pull silage back from pit edges and assist in layering, but final compaction was still performed by the tractor.
Historical Context: Evolution of Silage Compaction
Silage pits have evolved from simple trenches to engineered bunkers with reinforced walls and drainage systems. In the 1970s, wheel loaders and tractors became standard for compaction. The rise of tracked machines introduced new possibilities, but their use remained niche due to compaction dynamics and maneuverability concerns.
Case Study: Wisconsin Farm with PC220 Excavator
A farm in southern Wisconsin used a Komatsu PC220 excavator for silage compaction over five seasons. The operator reported satisfactory results, especially when using the bucket to tamp down layers and lift the front end to concentrate weight on the rear tracks. However, they emphasized the importance of layering thinly and avoiding overcompaction in a single pass.
Techniques for Effective Excavator-Based Compaction
- Layer Thinly
Apply silage in thin layers (6–8 inches) to allow effective compaction without trapping air.
- Use Bucket Tamping
Lower the bucket and apply downward pressure to compress silage, especially near walls.
- Rear Track Loading
Lift the front of the machine slightly using the bucket to concentrate weight on the rear tracks.
- Avoid Wet Conditions
Wet silage increases the risk of machine slippage and uneven compaction.
- Combine Methods
Use the excavator for edge work and layering, followed by a wheeled machine for final compaction.
- Monitor track slippage and avoid steep pit slopes
- Ensure silage is evenly distributed before compaction
- Maintain clear visibility and communication with ground crew
- Inspect undercarriage for silage buildup that may affect traction
- Use backup alarms and lighting during low-visibility operations
Using a 20-ton excavator for silage pit compaction is feasible under certain conditions, especially when combined with traditional methods. While it may not replace wheeled tractors in terms of rolling efficiency, its weight and versatility can enhance layering and edge management. With careful technique and awareness of limitations, excavators can play a valuable role in modern silage operations—proving that even machines built for earthmoving can help feed the herd.
