Dairy-Quality Grass Forage Research Update

Paul Peterson, Extension Forage Agronomist

August 8, 2009

Well-managed perennial grasses can provide good agronomic, economic, and nutritive complements to alfalfa on Minnesota dairy farms. This article provides an overview of some of the research we are conducting throughout the state on grass forage options and management and some results and implications to date. The research includes essential collaborators and funders to whom I am most grateful.

Alfalfa-Grass Mixtures: Grass Species, Nitrogen Fertilization, and Seeding Ratio Effects. This research has been conducted at two UMN research stations, Grand Rapids (trial is finished) and Rosemount (in its third and final harvest year). The primary grass species in these trials were perennial ryegrass and tall fescue, seeded in several different seeding ratios with alfalfa, with or without ~30 lb N/ac applied per harvest. Check plots of alfalfa alone, grasses alone, and binary mixtures of alfalfa with reed canarygrass, orchardgrass, and meadow fescue were also included. For binary mixtures, alfalfa and grasses were seeded in alternate rows ~3” apart to attempt to minimize potential within-row competition between the two species.

Some findings to date:

• My concern that some grasses might be too competitive with alfalfa was unfounded, as alfalfa persisted better than any of the grasses in the trial. This may have been due to cutting too closely at times. Perennial cool-season grasses may require a 4” residual to be competitive with alfalfa in mixtures in our environment.
• Perennial ryegrass/alfalfa mixtures looked very good in their first production year, and produced dairy-quality forage. However, perennial ryegrass did not persist. Thus, while it may benefit a mixed seeding in the short term, another more-persistent grass should be included for longer-term grass presence.
• Low-alkaloid reed canarygrass was the most persistent and compatible grass with alfalfa in these trials. However, it may have somewhat inferior forage quality compared to the other grasses.
• Strategic use of nitrogen fertilizer and/or manure on alfalfa/grass mixtures may be economical during spring and late summer when weather favors grass growth.

On-Farm Evaluation of Alfalfa-Grass Mixtures. This research was initiated in August 2008 and includes three on-farm sites; near Underwood (seeded August 25), Hutchinson (seeded August 29), and Avon (seeded May 4, 2009). Treatments include three different alfalfa varieties: Rebound 5.0 (standard type), 4S419 (hybrid), and Spredor IV (persistent); each mixed with 2 different varieties of 9 different cool-season perennial grasses. The grasses include smooth bromegrass, meadow bromegrass, orchardgrass, tall fescue, meadow fescue, festulolium, reed canarygrass, perennial ryegrass, and timothy. Alfalfa and grasses were seeded together in the same rows. Plots of the alfalfa varieties alone were also seeded.

Preliminary results are all over the map (in more ways than one):

• The Hutchinson site had tremendous alfalfa catch and limited grass catch. We think this may have been due to fall and spring weather that favored alfalfa over grass establishment. The plots have been harvested twice so far in 2009, averaging 2.1 total ton DM/ac, but ranging from 1.2 to 2.9. Two more harvests are planned for mid-August and mid-October.
• The Underwood site had tremendous grass catch and good alfalfa catch. At least one variety of every grass species is abundant in mixtures. Timothy was particularly competitive during establishment, to the point where alfalfa in its mixtures is clearly suppressed so far. This is especially interesting since established timothy is far from competitive. Cumulative yields from two harvests so far in 2009 are only about half those at Hutchinson, but grass presence is significantly greater, so long-term performance will be interesting to assess.
• The Avon site exemplifies a common challenge with spring establishment of alfalfa/grass mixtures; lots of weeds, particularly annual grasses. Thus, seeded-grass establishment is difficult to assess. Alfalfa is coming slowly. For this site, we included red clover mixtures, and the red clover is doing quite well. The site is droughty, and amendments were needed prior to seeding, so the seeded species are challenged.

Tall Fescue, Meadow Fescue, and Timothy Varietal Evaluations. These trials are collaborative with Barenbrug USA. We are conducting meadow fescue varietal trials at both Grand Rapids and the St. Paul Campus. Timothy trials are at Grand Rapids, and a tall fescue trial at St. Paul. The Grand Rapids trial plots were drilled in early September 2006; the St. Paul plots were broadcast seeded in late August 2007. To date, persistence of most entries has been excellent. All trials have suffered periodic yield suppression due to droughts. The St. Paul plots have been harvested twice in 2009, and are regrowing well now thanks to recent rains.

Look for results of these trials in future Extension outlets. You may want to experiment with grasses on a small scale on your own farm to see what species and management work best for you.