Alfalfa in rotation – how to know when it’s time

Crop rotation is the practice of growing different crops in sequence on the same land across seasons or years. Alfalfa is well suited to rotation systems because of the benefits it provides to soil health and the crops that follow. Whether you are transitioning out of an established stand or planning alfalfa as part of a broader cropping program, managing the rotation well is the key to maintaining long-term productivity.

Here’s how to make the most of alfalfa in your rotation, and how to manage the transition out.

Alfalfa provides benefits beyond grazing or hay production. It improves soil health in ways that support the next crop or pasture phase. 

Key advantages:

• Nitrogen(N) fixation: Alfalfa can fix 150–300kg N/ha/year, reducing the need for synthetic N in following crops
• Weed suppression: A dense alfalfa stand can suppress broadleaf weeds and annual grasses, cleaning up fields before cropping
• Soil conditioning: Deep roots improve structure, reduce compaction, and enhance infiltration,  particularly valuable ahead of cereals

As tiller density declines and gaps form, production drops, and so does the value of alfalfa  in the system.

Signs it’s time to rotate out:

• Yield drops below 60–70% of peak
• Crown rot, disease or weed burden increases
• Spring growth slows or becomes patchy
• A lot of bare soil is visible between plants

Understanding Alfalfa types:

• Dormant/semi-dormant alfalfa can last 7+ years with good management
• Winter-active types last 5–7 years

Non-dormant varieties may last 3–4 years, especially under cutting

Alfalfa is persistent.

If you’re planting a crop after alfalfa:

• Terminate properly with knockdown herbicide and/or tillage
• Monitor for regrowth in early crop phases, especially under conservation tillage
• Avoid residual herbicides in the final alfalfa season that could affect follow-up crop germination

Many producers return to alfalfa after one or two rotations. If that’s your plan:

• Get your field ready first  — clean up weeds, manage soil fertility, and think about variety selection
• Refer back to Blog 1: Establishing a high-performing alfalfa crop
• Choose a variety that suits your new system (cutting, grazing, or dual-purpose)

Alfalfa improves the soil it leaves behind — but only if you manage the transition well. Know when to rotate out, pick your follow-on crop wisely, and use the break to set up for your next successful alfalfa stand.

Whether you’re rotating out or bringing alfalfa back in, these guides can help you prepare for a stronger, more resilient stand next season:

• Establishing a high-performing alfalfa crop
• Managing your first season alfalfa for longevity

While we don’t supply seed directly to farmers, AlfaGen Seeds alfalfa is available through trusted distributors and farm supply stores. If you don’t know who your local distributor is, please reach out via the enquiry form and we can assist.