Testing is key for silage success

Silage harvest is likely to begin in earnest soon in Colorado.
Photo by Curt Dennison

David Brachtenbach, technical agronomist for DeKalb Asgrow, said the most important factor that influences silage quality is the moisture. Traditionally, he said the rule of thumb has been to begin sampling at 25 percent milk line but it can vary based upon environment, hybrid types and other factors.

Utilizing the moisture line is a good way to time sampling using either a commercial forage moisture tester or a microwave.

Using a microwave safe plate, Brachtenbach said a 100-gram sample can be weighed and dried in the microwave and then reweighed. The difference between the two, he said, represents the moisture level.

Appropriate moisture levels vary based on the silo type utilized. Horizontal bunker-style storage, he said, is the most common in his service area of western Kansas and Colorado. Silage harvested at 65 to 70 percent is ideal, with 65 percent maximizing quality and reducing losses. In tower-style storage, ideal moisture ranges from 63 to 68 percent, limited oxygen silos should range from 55 to 60 percent, and silo bag storage works best with 65 percent moisture.

Storing at improper moisture decreases the digestibility of both the fiber and starch. Silage that is stored too wet results in seepage and a loss of nutrients through water loss. Silage harvested too dry is fluffy and difficult to properly pack, resulting in spoilage.

“A good rule of thumb to go by is a plant is going to dry down 0.5 to 0.6 units per day in moisture,” he said. “You can back figure that to when you pull that first sample how many days it’ll take.”

As a technical agronomist, it is Brachtenbach’s role to determine where varieties are best suited to the diverse growing areas in Colorado and Kansas. Understanding how different varieties will work within different geographies involves test plots used to characterize different types, understand the good and bad, and focus on different management practices to make varieties the best fit in different areas for individual growers. Versatility is always a goal, he said, but there are certainly varieties that offer stress tolerance.

Dekalb Asgrow has developed two varieties specifically for silage that provide the necessary milk per ton and acre as opposed to a grain variety. Brand new, the varieties have an advantage in nutrition and are longer season, ranging from 105 to 120 days.

Brachtenbach said the company’s research has found advantages for the silage market in short corn. The shorter statured corn has stacked internodes and less lignin in the stalk, making it more easily digestible. With the same amount of biomass, the volume of feed harvested remains, with the added benefits of water savings and the ability to withstand winds and ground spray application. Research on these varieties is continuing and he expects they will be released in the next five years.

With dry conditions stretching across silage country, he said there is likely to be some dryland corn or acres of corn with water shortages cut for silage. He cautions that drought stressed corn can have a build up of nitrates and recommends sampling.

“Within the ensiling process, we can reduce that by about 50 percent of the nitrates so it’s actually a way to utilize that crop, but if you have a high amount of it out there that can cause problems with aborted calves if you don’t understand where that level is,” he said.

Backfilling with roughage can adjust the nitrate levels to within safe parameters. Moisture sampling becomes even more important with dry corn as he said dry leaves can make plants look drier than they actually are.

He anticipates silage harvest will begin by the end of August, with a few exceptions. He also reminds those involved in fast-paced silage harvest to be cautious to ensure a safe harvest season.​ ❖

— Gabel is an assistant editor and reporter for The Fence Post. She can be reached at or (970) 768-0024.