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Alfalfa establishment: Management strategies

Quick facts

  • Select fields with deep, well-drained soils.

  • Fertilizer soils to mitigate soil nutrient deficiencies.

  • Spring seed into smooth yet firm seedbeds with at least 13 pounds of pure live seed per acre.

  • Plant seeds from 1/4 to 3/4 inch deep.

  • Control weeds with herbicide or companion crops.

  • Check for herbicide carryover from previous crop use.

Management strategies

Because alfalfa production spans several years, it’s important to start off with the most productive stands possible. In addition, seeding year forage yields can provide a revenue stream to off-set establishment costs. Here, we’ll cover management strategies for optimal alfalfa establishment. These are also provided in the Alfalfa Management Guide:

  • Field selection.

  • Fertility management.

  • Seeding alfalfa.

    • Seeding dates.

    • Field preparations and seeders.

    • Seeding depth.

    • Seed-to-soil contact.

    • Weed control and companion crops.

    • Seed quality and  coatings.

    • Seeding rates.

  • Checking for herbicide carryover

  • Variety selection

Field selection

Photo 1. Flooded alfalfa field in early spring.

Site selection is important because alfalfa prefers well-drained, deep soils. Under ideal growing conditions, alfalfa roots can explore soils to depths over 20 feet. 

When selecting fields, try to avoid hilltops, shallow and highly eroded soils and fields with low spots where water is known to pool (Photo 1). Wet soils not only reduce diffused oxygen (O2 (g)), but also benefit diseases and increase the risk of ice sheeting.

In addition to locating well-drained, deep soils, following alfalfa with newly-seeded alfalfa in the rotation is not advisable due to autotoxicity. Alfalfa produces toxins that reduce germination and impair taproot development. Ultimately, this limits water and nutrient uptake,  directly impacting yield and performance (Figure 1).

Figure 1. Impact of tillage and time of planting on alfalfa autotoxicity. Source: Dennis Cosgrove, University of Wisconsin

Soil fertility management

After selecting the field, soil sampling and analysis will identify soil nutrient deficiencies. Because alfalfa has both initial and annual fertilizer needs, yearly soil sampling will provide detailed information on available nutrients.

Fertility management ensures good stands and vigorous growth during the establishment years, while increasing productivity and persistence throughout the production years. Several parameters and nutrients are critical for optimal stand health, although here we’ll focus on soil pH, potassium,  phosphorus, and sulfur.

Soil pH

Maintaining soil pH between 6.5 and 7.0 is extremely important because nutrients are most available to alfalfa roots within that range. In addition, Rhizobia microorganisms responsible for biological nitrogen fixation are most active in the pH range.

Because buffering soil pH can take time, soil test and apply and incorporate lime (calcium carbonate) 6 to 12  months prior to alfalfa seeding based on soil reports. This will allow adequate time for the lime treatment to neutralize soil acidity. Typically, you won’t need to re-apply lime during alfalfa’s lifecycle.

Phosphorus, potassium, and sulfur

Soil phosphorus (P), potassium (K), and sulfur (S) levels should be assess before seeding and annually throughout the alfalfa lifecycle. Large amounts of P and K are removed with harvest (Table 1). Maintaining non-limiting levels of these nutrients will improve alfalfa stand establishment, yield and persistence.

Reduction in atmospheric deposition of S due to reduced industrial emissions has led to S deficits in soils containing low organic matter levels. Annual applications of as much as 25 pounds per acre of S are needed on sandy, low organic matter soils. S can be supplied by manure or fertilizers. See Fertilizing alfalfa for more information.

Table 1. Pounds of nutrient removed per ton of alfalfa produced.

Nutrient Nutrient removal
pounds removed per ton of alfalfa
Phosphorus (P) 6
Phosphate (P2O5) 14
Potassium (K) 48
Potash (K2O) 58
Sulfur (s) 6

Seeding alfalfa


Check for herbicide carryover

Before seeding alfalfa following corn, soybean, or wheat, review the herbicides that were used for these crops. Some herbicides can carry-over and affect alfalfa establishment. Herbicides have evolved to include residual chemistry to target weeds with resistance to commonly used herbicides such as glyphosate. Therefore, it's important to read rotational restrictions on herbicide labels to determine the number of months required before alfalfa planting is allowed following that herbicide application.

Variety selection

Select high yielding alfalfa varieties with adequate winterhardiness and disease resistance for long-term profitability of the crop. While we have no evidence of significant differences in seeding year establishment or yields among varieties, varieties should be selected for long-term stand performance. Variety traits are described in the Alfalfa Variety Leaflet. Consult local seed dealers for yield results before selecting a variety.

Craig Sheaffer, Extension forage agronomist

Revised edition of M. Samantha Wells, Doug Holen, former Extension agronomists, and Craig Sheaffer, Agronomist, College of Food, Agricultural and Natural Resource Sciences

Reviewed in 2023

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