Planting corn for silage, 2011

Chad Lee, University of Kentucky

email: Chad Lee

Corn silage is a valuable feedstock for many dairy farms and some beef operations. The higher price of inputs this season puts even more pressure on maximizing yield without breaking the bank on inputs. Some of the following guidelines should help with a successful planting season and put the silage corn crop in the best position to reach high yields.

Soil test and fertilize accordingly. Many silage fields in Kentucky have two crops, wheat and corn, both for silage. Good yields of both of those crops can pull more than 300 pounds of potassium and 150 pounds of phosphorus from the soil, according to AGR-1 Lime and Nutrient Recommendations.  These nutrients must be replaced. Applying nutrients according to soil test will help identify exactly what is needed and where it is needed.

Select good hybrids. Based on the 2010 Silage Corn Hybrid Test, hybrid yields differed by as much as 6 tons per acre and milk yields differed by as much as 8500 pounds per acre.  Find as much data on hybrids as possible before purchasing them. Obviously, forage yield data is the best, but grain yields are an indicator of overall tonnage and can be useful as well. Finding no data on a hybrid is not a good sign. Stay away from hybrids with no track record.  

Plant on time. Corn planting is recommended from April 1 to May 1 in western and central Kentucky and April 15 to May 15 in eastern Kentucky.  However, many silage fields are planted after these dates, which most likely results in some yield losses. Planting corn in time means wheat must be harvested earlier. Earlier harvest of wheat will reduce wheat yields, but those yield losses will be more than offset by the large increases in corn yield from timely planting. The yield loss of wheat will also be offset by the improved quality of the wheat silage. Don’t be surprised to see milk production increase from the better wheat forage quality.

Increase the seeding rate on good soils. Corn grown for silage generally should be seeded about 2,000 to 3,000 seeds per acre higher than corn grown for grain.  On good soils with 30-inch rows, recommended seeding rates on corn for grain are about 30,000 to 33,000 seeds per acre. This means silage seeding rates could go as high as 36,000 seeds per acre on very productive fields. Drop back seeding rates for less productive soils or wider row widths. Seeding rates for silage should not be less than about 24,000 seeds per acre for most fields in Kentucky.

Avoid micronutrients, except for zinc. Soils with proper pH and adequate phosphorus may be low in zinc. Most other micronutrients on most soils in Kentucky have not been shown to increase yields. If you are applying manure to fields, you are supplying a lot of micronutrients anyhow. Some weathered soils in the Russell County area have shown a yield increase to Boron. However, these yield increases appear to be specific to one soil type. 

Check your planters now. Planting is a very short time away. Go over the planters to make sure discs, seed meters, press wheels, closing wheels, etc. are in good working order. The planter should deliver seed at the desired amount, the desired depth (1.5 inches), and the desired uniform spacing. A planter that does not do these three things well could result in erratic stands, which could lead to erratic yields. Any planter that sat outside over the winter is very likely to have some rust in areas that will hinder seed delivery. Go through these planters and remove the rust before planting begins in earnest. 

Finally, appoint someone to have priority for the corn crop. Dairy producers must focus on the cow above all else. The cow takes priority in logistics of the dairy farm. By having someone solely responsible to the corn crop, that person can better achieve timely management of the corn crop. 

For more information about corn for silage, review AGR-79 Producing Corn for Silage or contact your county extension office.