Corn silage harvest time is right around the corner.

Two major factors that ensure a better quality corn silage are within the producer’s control at harvest time, according to Greg Lardy, North Dakota State University Extension Service beef cattle specialist. These include harvesting silage at the correct moisture level and packing the silage well to exclude oxygen and ensure high-quality fermentation.

“Depending on the storage structure you are using, corn silage should be harvested at 65 percent to 70 percent moisture for optimum results,” Lardy says.

Moisture levels that are too low result in less favorable fermentation and poor packing characteristics in the silage, whereas moisture levels that are too high result in silage that has greater effluent losses (loss of nutrients in the water that oozes from the pile). High moisture levels also can result in a “sour” fermentation.

Corn silage can be harvested at slightly lower moisture levels for upright, oxygen-limiting structures.

Lardy also advises packing the silage correctly to ensure that oxygen is driven out. Excluding oxygen is a very important aspect of making good-quality silage.

Adequate packing involves a number of factors, including the correct chop length for a particular silage crop, as well as having the appropriately sized tractor for the amount of silage being placed in the pile. Because wheeled tractors exert more pressure per square inch, compared with crawler or track-type tractors, wheeled tractors are preferred for packing silage.

With the speed and volume of silage that modern harvesters can cut, having adequate packing capacity is imperative as well. Producers can run out of packing tractor capacity quickly when working with large forage harvesters.

“Be sure to use caution when packing silage,” Lardy says. “The weight of the tractors used and the height of many bunker silos make this a job for experienced tractor operators. Don’t become complacent about safety issues. Be sure to inspect the bunker walls and sides prior to silage packing to be sure the silo is safe and ready for the upcoming season.”

While packing, add thin layers of material and pack adequately as the silo is filled. This will ensure that the silage is packed adequately and oxygen is excluded.

One often overlooked item is the value of sharp knives during the chopping process. Sharp knives produce a uniform chop length and improve packing in the bunker. Take time before and during harvest to sharpen the knives. It will pay dividends in improved silage quality.

Making silage properly also includes covering the silage bunker after packing is complete because it ensures that spoilage due to oxygen penetration and potential damage from rodents and other wildlife will be kept to a minimum, Lardy says. He recommends using black or white plastic to cover the pile and plenty of tires to hold the plastic adequately on the bunker silo. If holes develop due to wildlife, be sure to tape them shut to prevent unnecessary spoilage.

In the western part of North Dakota, many producers are concerned about the nitrate levels in their corn silage due to the dry conditions. Producers with drought-stressed corn should have the nitrate level analyzed at a qualified lab prior to feeding the corn to their livestock.

“The good news is that the ensiling process will help reduce the nitrate level during fermentation,” Lardy says. “However, a laboratory analysis is still recommended prior to feeding with silage that has been drought-stressed.”

Many of the newer silage choppers have kernel processors installed on the machines. The kernel processor breaks up the corn kernel and helps improve digestibility of the silage. A kernel processor may be one feature producers who are in the market for a new chopper should consider, Lardy says.

For more information about ensiling corn, visit the NDSU Extension Service’s Web site at http://www.ag.ndsu.edu/procrop/crn/silage.htm.

NDSU Agriculture Communication