Tips for fall planting of alfalfa

KSU eUpdate – Alfalfa is often considered as the “Queen of Forages” because it produces high yields that are highly digestible and high in protein. Alfalfa is a very important leguminous crop for dairy and other livestock industry in Kansas. Late summer and early fall are often the best times to plant alfalfa in Kansas due to less weed pressure than spring planting.

With the rains this spring and summer in most areas of Kansas, there may be enough moisture to achieve good stand establishment in many fields. Available moisture at planting is crucial for alfalfa establishment, but too much moisture can increase seedling disease incidence.

If soil moisture is available, growers in northwest Kansas can plant as early as Aug. 10-15. Those in southeast Kansas can plant in mid- to late-September. In other parts of Kansas, the optimal planting time is late August or early September. Producers just need to plant early enough to have three to five trifoliate leaves before the first frost.

Alfalfa is a three- to five-year, or longer, investment and therefore it is crucial to ensure proper establishment. Some producers shy away from alfalfa because of its high establishment cost and risk of stand failure. In the long run, however, it’s relatively inexpensive, if amortized over the life of the crop.

If managed properly and given favorable weather conditions, dryland alfalfa can produce 3 to 6 tons of forage per acre per year. Irrigated fields can produce 8 tons per acre per year or more.

When planting alfalfa, producers should keep the following in mind:

  • Soil test and correct soil acidity. Alfalfa grows best in well-drained soils with a pH of 6.5 to 7.5, and does not tolerate low soil pH. If the soil is acidic, add lime to raise soil pH to 6.8 before planting.
  • Soil test and meet fertilization needs. Apply the needed phosphorus (P) and potassium (K) amounts according to soil test recommendations. Phosphorus fertilizer will be required if soil test P levels are below 25 ppm, and potassium fertilizer will be required if soil K levels are below 120 ppm. Even soils that test higher than these thresholds may need additional fertilizer. Small amounts of nitrogen fertilizer (15 to 20 lb/acre) as a starter at planting are beneficial for alfalfa establishment.
  • Plant certified, inoculated seed. Ensuring the correct Rhizobium inoculation is crucial for alfalfa seedlings to fix available soil nitrogen to meet the needs of growing alfalfa for optimum production.
  • Plant in firm, moist soil. A firm seedbed ensures good seed-soil contact; therefore, use a press wheel with the drill to firm the soil over the planted seed. No-till planting in small-grains stubble will usually provide a good seedbed.
  • Don’t plant too deeply. Plant one-fourth to one-half inch deep on medium- and fine-textured soils and three-fourths inch deep on sandy soils. Don’t plant deeper than 10 times the seed diameter.
  • Use the right seeding rate. Plant 8 to12 pounds of seed per acre on dryland in western Kansas, 12 to15 pounds per acre on irrigated medium- to fine-textured soils, 15 to 20 pounds per acre on irrigated sandy soils, and 12 to 15 pounds per acre on dryland in central and eastern Kansas.
  • Check for herbicide carryover that could damage the new alfalfa crop – especially when planting alfalfa no-till into corn or grain sorghum stubble. In areas where row crops were drought-stressed and removed for silage, that sets up a great seedbed for alfalfa, but may still bring a risk of herbicide damage.
  • Choose pest-resistant varieties. Resistance to phytophthora root rot, bacterial wilt, fusarium wilt, verticillium wilt, anthracnose, the pea aphid, and the spotted alfalfa aphid is essential. Some varieties are resistant to even more diseases and insects.

Romulo Lollato, Wheat and Forages Specialist-KSU; and Doo-Hong Min, Forages Agronomist-KSU

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