Seeding grasses with alfalfa
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Benefits of seeding grass with alfalfa
Higher yields with faster drying times.
More persistent crop through the winter.
Weed and erosion control.
Grasses have more digestible fiber than alfalfa.
Seeding grass with alfalfa can boost yield and drying rate while keeping animals healthy.
Only keep stands three to four years.
Don’t overseed competitive grasses.
Broadcast seed perennial forages and drill small grains and Italian/annual ryegrass.
Monitor soil potassium levels.
Reasons to seed grass with alfalfa
Yield is the largest driver of profit in stored forage production. Alfalfa-grass mixes often yield more than pure alfalfa. With high fixed harvest costs, each cutting must produce a bountiful harvest.
- A small grain or Italian/annual ryegrass companion crop with a spring seeding provides greater seeding-year yield than alfalfa seeded directly.
- Sod-forming grasses like reed canarygrass or smooth bromegrass allow traffic when fields are wetter. They also speed drying times, which reduces possible weather-related losses.
- Orchardgrass and tall fescue have good fall growth that allows a useful fall harvest or grazing. These grasses also provide more residue than alfalfa stubble. Residue catches snow and insulates alfalfa crowns.
Grasses with stems present speed-up swath drying rate. Some grasses produce stems with every growth cycle and create fluffy swaths that dry faster. These grasses include:
- Reed canarygrass
- Smooth bromegrass
- Timothy create
Some leafy grasses with shiny surfaces such as tall fescue and ryegrasses won’t speed drying rate.
- Grasses catch snow and insulate better than alfalfa alone.
- Grasses better protect alfalfa from winter injury.
- Winter hardy grasses provide insurance if the alfalfa winter kills.
At like growth stages, grass has higher neutral detergent fiber (NDF) than alfalfa. But grass has much higher NDF digestibility. NDF digestibility reflects the feed’s energy value.
Many dairies feed straw for fiber. Forage grasses provide fiber in a more digestible form.
The relative feed value (RFV) index is good for alfalfa quality but tends to undervalue grass feeding values. The new relative forage quality (RFQ) index:
- Better reflects higher fiber digestibility in grasses.
- Shows how feeding grass impacts energy and intake potential.
- Weeds show up in perennial forages if bare soil is present for too long.
- Some grasses help to quickly cover soil during the seeding year.
- Many grasses also provide long-term cover, particularly if the grass is a sod-former or if you broadcast seed the grass.
- Small grain companion crops can control erosion.
Grass-alfalfa mixes are less likely to cause bloat than pure alfalfa when grazed.
Managing alfalfa-grass mixes
Proper management of alfalfa-grass mixes can ensure that the crop will remain profitable for the duration of its growing time.
Keep alfalfa stands for three to four years for the most profit. This allows you to maximize yield potential and benefit from alfalfa’s nitrogen in crop rotations. Short rotations may be good
for grasses with less long-term persistence but high yield and quality. These grasses include:
- Tall fescue
- Perennial ryegrass
Seed enough grass to have a good mix but avoid overseeding competitive grasses. How often you cut and your cutting height can affect alfalfa-grass ratios. For example, cutting shorter and
less often lowers the percent of orchardgrass.
Broadcast seeding is likely the best method for seeding alfalfa-grass mixes. This is especially true when using bunch grasses to provide more even cover. Broadcast perennial forages.
Use a drill to seed a small grain or Italian/annual ryegrass companion crop.
Avoid seeding alfalfa in the same row as competitive grasses.
Since alfalfa-grass mixtures have few herbicide options, August may be the best time to seed if soil moisture is ideal. There’s less weed competition during late summer than spring.
Wide swaths speed drying and reduce the risk of weather-related losses, especially with leafy grasses.
Good potassium levels are key to growing alfalfa with competitive grasses. Grass takes-up soil potassium better than alfalfa.
Manure is a great fertility source when you apply it prior to seeding or right after cutting.
Grasses to seed with alfalfa in Minnesota
Choosing the right grass seed to mix with alfalfa is important when trying to maximize inputs.
Grasses to seed with alfalfa in Minnesota
|Grass species||Rate (lb/ac)||Alfalfa (lb/ac)||PROS||CONS|
|Small grain harvested at boot stage||1 – 1.5 (bu/ac)||12 – 15||
|Italian (annual) Ryegrass||2 – 5||12 – 15||
|Annual Ryegrass||2 – 5||12 – 15||
|Reed canarygrass||5 – 7||7 – 10||
|Smooth bromegrass||6 – 10||7 – 10||
|Timothy||2 – 5||7 – 10||
|Orchardgrass||2 – 5||7 – 10||
|Tall fescue||4 – 8||7 – 10||
|Festulolium||4 – 8||7 – 10||
|Perennial ryegrass||4 – 8||7 – 10||
Reviewed in 2018