Establishing alfalfa–grass mixtures
Alfalfa fields continue to dominate the forage landscape across Midwestern states. Increasing, however, is the practice of mixing an alfalfa variety with grass species creating "hay" fields popularized decades ago by beef producers and quite popular in Eastern U.S. dairy regions. While initial hay fields may have evolved naturally from grasses filling in areas of lost alfalfa plants, today's production is much more intensively managed.
Benefits of an alfalfa–grass mixture
The reasons for mixing alfalfa and grasses include seeding year yield (tonnage), drying rate, persistence, animal intake and palatability, weed suppression, erosion control, in season manure applications, wheel traffic tolerance, and livestock bloat management in grazing systems. Once perceived as a low input/low management forage crop, these have evolved into a highly productive cropping system.
Keys to successful forage establishment
Unlike annual commodity crops where genetics and inputs are evaluated and selected each year, forage production is a three to six year commitment depending on a producer's decision making and implementation of management practices combined with field rotations to benefit the farm as a whole system. It is because of this expanded commitment that management considerations need to be recognized, understood, and implemented.
Critical to successful forage production are the genetics of varieties selected as well as grass species to be mixed. This is a strong production first step that must also include stand establishment, harvesting schedules, fertility, and pest management considerations.
Alfalfa variety considerations
Having a productive stand over years depends first on the mixture to be planted. The easy part is the alfalfa variety which is selected based on proven University yields over locations and years. Target and evaluate significant genetic traits such as tonnage, quality, winter hardiness, fall dormancy, and pest resistances (insects/diseases). University of Minnesota alfalfa performance results are available here.
Grass varieties are also important
Producers commonly take the most time in deciding which grass specie(s) to mix with the alfalfa. A common mistake is concentrating too long on which species to include instead of which variety. University of Wisconsin research shows that the grass specie has marginal effects on total season yield, but rather variety selection is crucial. While it is understood that orchardgrass, tall and meadow fescue, and bromegrasses are dominant species to use in mixtures, varieties of these grasses should be chosen for yield, yield seasonal distribution, maturity matching alfalfa, winter hardiness, and disease resistance focusing on rusts. Producers often determine which grass species to include and then settle for whichever varieties are available with the nearest retailers.
Few producers realize that over 30 orchardgrass varieties are available and large genetic differences exist contributing to production success and failure depending on needs and expectations. Dr. Dan Undersander and the forage team at the University of Wisconsin have tremendous lists of yield and quality data specific to grass species and varieties, in addition to information on seed companies and outlets.
Maximizing the mixture is achieved with a goal of 30 to 40% of the stand comprised of grasses. The focus should be seeds per square foot planted vs. pounds per acre. Seeding rate recommendations are generally accepted as 60 to 75 seeds per square foot resulting in a final stand at the end of the first year of 30 to 35 plants in the same area to maximize yield. A rule of thumb has the alfalfa at 10 pounds per acre which is 47 seeds/ft2 with the remainder grasses. It has been found that adding a low rate of annual ryegrass at seeding will significantly add to first cut yield while providing additional early weed competition and soil erosion control.
Seeding the hay mix is where many mistakes occur and unfortunately can cause annual problems with yield, weeds and stand longevity. While many planting methods and techniques are available to successfully establish the forage mix, three things are essential. Planting failures commonly are traced back to poor seed/soil contact, seed placed too deep, or soil pH problems not compatible to the mix created.
Carefully select forage field locations understanding topography, drainage, soil types and pH matching genetics and management to them. Make certain seedbed preparations are optimized including soil moisture, firmness, and residue management. Regardless of equipment used, check often to ensure your method is delivering the correct amount of seed uniformly at a target depth of ¼ inch. Larger equipment, faster planting speeds, varying soil types and residue are all complications in successful seed placement. Many producers over years have found it much easier to correctly plant a field then try to renovate a poorly established one. It is well documented that a field requiring "patching" or seed supplementing will never perform as well as the initial seeding operation.
Cutting height at harvest
An essential consideration important to alfalfa grass mixtures is cutting height. Target a remaining height of three to four inches at harvest. This unharvested material is essential as it serves as the photosynthetic base needed for regrowth and stand persistence over time.
Other considerations include an annual fertility program including nitrogen and sulfur, harvesting quality, and pest management (diseases/ insects). These differ somewhat from pure alfalfa stands and warrant understanding in order to maximize production. Other regions across the U.S. have well documented success with hay mixtures on a high percentage of the total forage acres. Planted and managed correctly, mixtures have multiple benefits by adding diversity to your operations in genetics and utility.
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