Often called the queen of the forages, alfalfa tops all other perennial forage crops as a producer of homegrown feed. High-yielding and versatile, alfalfa serves well for hay, silage, green chop, and pasture. It produces high-protein and palatable feed, which livestock like and do well on. Alfalfa also fills an important role in crop rotations, improving soil structure and building soil fertility for future grass and grain crops.
Alfalfa is a deep-rooted, drought-tolerant crop that does best on deep, well-drained soils. Alfalfa also needs a well-limed soil; it gives top performance on soils with pH levels of 6.5 or higher. It does poorly on acidic soils, and soil acidity is often noted as the major limiting factor on alfalfa growth in New York. Acidic soils must be limed to a pH of 6.5 or higher to maintain high-yielding alfalfa stands.
On well-drained soils, alfalfa can produce high yields for many years, but it will yield poorly and die soon on poorly drained soils. Tile and other drainage aids can improve the soil’s ability to grow good alfalfa. Trefoil and red clover offer better choices for good production on sites with poor or spotty drainage patterns.
Alfalfa seedlings need phosphorus and potassium at planting time. Older stands need topdressing to maintain high yields. An ample fertility program provides nutrients for recovery after harvest, good winter survival, and high yields. Phosphorus and potassium are musts, but nitrogen rarely, if ever, pays on alfalfa because nitrogen-fixing bacteria in root nodules can provide enough nitrogen for top yields. For details on fertilizer suggestions, see Table 4.6.1.
Insect pests cause sporadic damage in alfalfa, varying with season and locality. Potato leafhopper feeding can lower second-cut yields in some years. The alfalfa weevil and blotch leaf miner, formerly serious, are now largely controlled through introduced insect parasites and predators. The alfalfa snout beetle can cause severe damage in the several counties where it occurs. Check control guidelines in the section “Management of Insects in Forage Crops (section 4.10).”
New York alfalfa trials test yield of new varieties (Table 4.1.1). Modern alfalfa varieties have been bred for resistance to one or more of five diseases that can thin alfalfa stands in New York. These diseases include bacterial wilt, caused by bacteria present in most New York alfalfa soils; Verticillium wilt, a soilborne disease that can kill susceptible plants in their second or third year; Phytophthora root rot, caused by a soilborne water mold often found in wet areas of fields; anthracnose, found in warmer areas of the state, particularly the Hudson Valley; and Fusarium wilt, common in New York soils and may occur but is not documented as a widespread problem in New York. Phytophthora hits hardest in the seedling year, and the other diseases affect mature stands in their second and third years of production.
Check Table 4.1.3 for variety reactions to these specific diseases as well as for yield and fall dormancy data. Choose varieties that are listed as R (resistant) or HR (highly resistant) for diseases found in your area. Both Aphanomyces root rot and pea aphid occur here but the value of varietal resistance may not be established for these and some other pests.
Several varieties have been developed at Cornell for specific adaptation to New York State conditions. These include ReGen Ezra, N-R-Gee, Seedway 9558 SBR (selected for resistance to alfalfa snout beetle) and SW315LH (selected for resistance to potato leafhoppers).
Improved feeding value has been a goal of alfalfa breeders for years. Several recent varieties have been released with claims of improved feeding quality. Our tests show that minor differences in feeding quality do exist. However, effects on milk production have yet to be established. Timely cutting and leaf-saving harvest practices are far more important in affecting forage quality than leaf or plant type. Choose varieties with strong disease resistance and high yield potential that are well adapted to your farm and needs. Optimal yield and forage quality is at the one-tenth bloom stage.
New leafhopper-resistant varieties are available that have improved resistance and agronomic characteristics (see Table 4.1.2). Resistance comes from fine hairs on stems and leaves, and results in significantly lower numbers of hoppers in resistant alfalfa stands compared to conventional alfalfa. Resistant varieties will surpass other strains when leafhopper pressure is heavy. Spraying in the seeding year may still pay under heavy hopper pressure.
- Alfalfa - Quality, Maturity, and Mean Stage of Development - Information Bulletin 217 - Gary W. Fick and Sharon C. Mueller, 1989 (PDF)
Birdsfoot trefoil is a long-lived legume with high yield potential on slightly acidic soils with drainage less than the best for alfalfa. Trefoil also does well as perennial forage on hard-to-plow meadows and pastures. Trefoil is bloat free, and no case of bloat has ever been recorded in animals grazing on trefoil. On fields where drainage is a problem, trefoil can outyield alfalfa and outlive red clover by many years. Birdsfoot trefoil should always be planted with a perennial forage grass and at harvest time, leave 5 to 6 inches of stubble to allow for regrowth of the trefoil.
PARDEE (Cornell, 2000) is a vigorous, upright, hay-type variety. It resists the Fusarium wilt disease that often kills trefoil in New York meadows and pastures. Pardee has surpassed all other varieties in survival. Pardee flowers three to five days earlier than other trefoil varieties, and is earlier to flower than alfalfa in the spring.
Red clover is useful for short-term stands and on land where drainage is not suited for alfalfa. It can be high yielding and produce high-quality forage but typically is difficult to dry for haymaking. Red clover is normally a two-year crop, including the year of establishment and one year of top production. Modern varieties may persist for a second hay year because of their resistance to anthracnose stem disease. Root borers (the clover root borer and the clover root curculio) soon destroy clover root systems. These insects can and will kill most clover plants by the end of the second hay year. Red clover has been used successfully as a companion crop during establishment of reed canarygrass. As red clover dies out, it is replaced by the slow-to-establish reed canarygrass.
- Red Clover for Quality Forage for Dairies - Agronomy Fact Sheet 81 - 1/9/2015 (PDF)
Alsike clover persists on poorly drained sites and was commonly included in mixes for wet soils. Alsike will normally yield less than birdsfoot trefoil or several grasses. Individual alsike plants rarely persist beyond a year or two, although self-reseeding may maintain a partial stand. Alsike makes good feed for cows but not for horses. Horses will not graze alsike unless they have nothing else to eat. Horses forced to eat alsike may suffer a photochemical reaction that can cause hair loss and, in rare cases, liver damage and death.
Crownvetch is a perennial legume that spreads by underground roots and natural reseeding. It develops excellent ground cover for soil conservation purposes on steep slopes, road banks, and other easily eroded areas. Once established, crownvetch spreads over a wide area, and its vigorous, dense vegetation effectively suppresses weed growth. It grows on well- to moderately well-drained soils and has pH and plant nutrient requirements similar to those of birdsfoot trefoil.
Crownvetch can also be used as a hay and pasture crop, although its long stems make traditional hay harvest difficult. Normally crownvetch is not equal to alfalfa in hay yields but is more persistent under pasture situations when grazing pressure is kept moderate.