Long-term research aimed at eliminating the need to cover bunker silos with plastic and tires has been put on hold.

Animal scientist Larry Berger started working on the concept of an edible silage cover in 1999 while at the University of Illinois. The idea was to develop an environmentally friendly cover that would provide weather protection for silage and supplement its nutritional value.

Berger's early research focused on finding a suitable material for covering silos. After experimenting with nearly 40 compounds, he settled on a starch (wheat) and salt mixture similar to playdough. Storage and feeding research trials with alfalfa haylage were promising enough that Berger eventually applied for a patent.

A major glitch developed when Berger turned to applying the covering to silage in a bunker. Applying the material with a cement pump powered by tractor hydraulics worked well on the flat surface on top of the bunker but not so well on the curved surfaces along the outside walls.

A system using a tractor-mounted applicator and roller (for applying a layer of wax coating over the wheat-salt covering material) shows promise. But Berger says commercial interest hasn't materialized.

“We had some talks with (representatives from a major farm equipment maker) about it. They thought the concept was sound enough, but they also thought it represented too much of a niche market for them.” Even so, Berger, who now heads the University of Nebraska animal science department, isn't ready to pronounce the project finished. “Others have expressed interest in continuing to work on it. The concept is sound. We often lose 10-20% of dry matter in a bunker due to spoilage and fermentation losses. Edible bunker covers offer the advantage of reducing losses while adding nutrients to the diet.”