Grass can fit well in your forage inventories and nutrient management plan

By Dr. Zach Sawall, Vita Plus dairy nutritionist and technical services specialist, and Pat Hoffman, Vita Plus dairy technical support specialist

“What else can we fit into our crop rotation to get more tonnage from the acres we have to work?”

The first step in answering this question is clarifying the goal.

• Are we rescuing an existing alfalfa field?  If so, is this field going to be terminal, or would we like it to last multiple years?
• Are we planting a straight grass field?  Would we like this to be an annual or perennial?

Once we have established a goal, we can discuss implementation.  In this article, we will focus primarily on the use of Italian ryegrass.

Rescue an existing field
Let’s begin with a winterkilled alfalfa field.  If looking to do something for one season only, depending on the winterkill severity, 15 to 25 pounds per acre of Italian ryegrass seed can be drilled into an existing alfalfa field.  The ideal time to plant is as soon as the field conditions will allow for wheel traffic.  If the field is expected to last a few years, interseeding options to maximize tonnage and quality include festulolium, meadow fescue, and orchardgrass.

Straight grass stand
When planting Italian ryegrass to achieve a grass forage, we have found it helpful to use triticale as a cover crop drilled into a field at 50 to 70 pounds per acre.  Triticale provides weed control and boosts first-cutting tonnage.  The Italian ryegrass is broadcast at 25 to 35 pounds per acre.  Typically, first cutting is about 50 to 60 days post-planting.

Italian ryegrass does well where moisture is readily available.  Depending on the year, fourth of fifth cutting needs to happen before September 15.  This will ensure enough time and heat to allow the last cutting of the year to grow into October or November.  This last cutting is the most valuable.  Because it grows slower during the cooler fall season, it enables greater fiber digestibility.

One of the challenges of Italian ryegrass is drying it.  Using a triple mower and spreading it out as wide as possible is the best option.  The windrow needs to be wide to enable drying.  It also is necessary, depending on the thickness of the crop, to use a tedder to further spread out the grass to promote drying.

Ensiling between 60% and 65% moisture helps promote packing and also helps avoid undesirable fermentations.   The final cutting of the year (in October or November) tends to be hard to dry, but, if it is fed during the winter, we have not seen adverse effects of having it a little on the wet side.

Grass and nutrients
After cutting, manure can be knifed into the grass field at a rate of 5,000 to 7,000 gallons per acre.  This application rate can be applied twice during the growing season.  Grass is a luxury consumer of potassium and phosphorus, which makes it an attractive option when dealing with tight land bases from a nutrient management standpoint.

Grass needs an ample supply of nitrogen as well.  We have seen consistent results when using the formula of 97 units of nitrogen to make 1.5 tons of dry matter at 20% crude protein.  If the crop runs short on nitrogen, tonnage and the amount of protein in the final product will be reduced.

This article was originally written for the January 10, 2021, issue of Hoard’s Dairyman.