Hay Production and Soil Fertility: Using Livestock and Cover Crops to Regenerate and Sustain Hayfields

Photo: Mark Stebnicki, NC Farm Bureau

By Lee Rinehart, NCAT Agriculture Specialist

Abstract

Although restoring nutrients removed by hay production is a constant challenge, both well-managed grazing and cover crops can supply replacement nutrients to make hayfields productive and profitable. This publication explains some strategies for grazing hayfields and adding cover crops in the rotation to build soil health, resilience to drought and floods, and added revenue for the farm. It also discusses options for recovering abandoned hayfields and reseeding to renovate existing hayfields.

Contents

Introduction
Adding Plant Diversity to a Hayfield
Hayfield Renovation
Grazing Cover Crops in the Hayfield Rotation
Conclusion
References
Further Resources

Introduction

Most hayfields are fertilized after each cutting to replace the nutrients removed during harvest. If the fields are not fertilized, hay yields will decline over time. Also, hayfields may succumb to weed pressure, resulting in a decline in forage quality. Organic producers and others who choose to avoid the use of synthetic fertilizers and herbicides need strategies to maintain and improve hay production without the use of these inputs.
Nutrient mining of hayfield soils doesn’t occur as much in fields that are grazed by livestock, because of the addition of manure and urine. In addition, strategic crop rotations with hayfields in the mix can add diversity, fertility, and resilience to hayfield and pasture soils. Both adding livestock and diversifying the plant communities in fields are options for producers who want to regenerate and maintain hay production without costly inputs that bypass the natural soil food web.

Photo: Nina Prater, NCAT

Adding Plant Diversity to a Hayfield

Meadows and prairies are naturally productive, due in part to the diversity of plant types and species within the plant community. If you add a more diverse plant population to your hayfields, through cover cropping and complex perennial mixes, you can build soil health and resilience. For example, you can frost seed or no-till drill legumes, such as red clover, crimson clover, or alfalfa. Or you might consider periodically rotating your hayfields to cover crops and livestock grazing to maintain fertility levels. This may necessitate managing the pastures as several separate units, to ensure hay is produced each year while part of the land is in annual cover crops and grazing to build soil health. After three to four years of diverse perennial pasture, convert the field to cover crops and graze for a year, then replant to perennial pasture in the fall for several more years of hay production.

The more diversity you can get into the fields, the better it will be for soil life. It’s a cycle where the soil organisms build soil structure and cycle nutrients, which feed the crops, and the crops provide nutrients back to the microbes. At the end of the summer of annual crops, you can go back to a fall cover crop, and then perennial hayfield the following year. This kind of rotation provides cover, reduces erosion, conserves water, buffers soil temperature, and adds organic matter while maintaining hay production without mining the soil, and it also adds a new enterprise. Producers who add cover crops and graze them can increase the profitability of their operation by selling animals or animal products.

Hayfield Renovation

When a hayfield begins to decline due to weed encroachment or lack of fertility, production also declines, and profitability suffers. When the stand begins to thin and weeds become prevalent, it may be time to renovate.

Renovation comes in many shapes and sizes, from adding new species to plowing the field and replanting. The least costly option is planting new species into existing stands. This works well when the hayfield is relatively healthy and you want to increase the quality of your forages. The decision to till the field and replant is a big one, and a costly one. Make sure you really need to renovate to this extent before bringing the tractor out of the barn.

Sorghum-sudan is a summer annual that fills a grazing gap in late summer and is a good transition to fall cover crops or a fall-planted perennial hay crop. Photo: Linda Coffey, NCAT

Livestock can be an effective management tool for renovating hayfields and pastures. Allow the hayfield to mature to seed stage with high biomass and graze with livestock that have low nutrient requirements, like dry cows. Stock at high density and move animals daily, allowing them to trample most of the forage. The high impact and mulch created by the grazing livestock will return high amounts of organic matter to the soil and kick-start the soil food web. A few grazing seasons of this treatment will result in new growth with higher quality, more diverse hayfields. For more information on grazing to renovate pastures with livestock, read ATTRA’s Pasture, Rangeland, and Adaptive Grazing.

Some other options for renovating hayfields include tilling or no-tilling summer annuals, followed by fall-planted cool-season perennials. Follow fall-planted rye and clover with summer sorghum-sudan, then cool-season perennial pasture or hayfield. For warm-season crops, fall-planted annual ryegrass and white clover can follow summer annuals, to be followed in turn by early-spring drill planting of warm-season grasses and legumes.

Renovating grass hayfields, especially by adding legumes, adds diversity, increases fertility, and optimizes forage quality. Two legumes that work well in most parts of the country are red clover and alfalfa. For planting into grass fields, a seeding rate of six to 12 pounds per acre for clovers and 12 to 20 pounds per acre for alfalfa is appropriate. Use the higher rates when broadcasting and the lower rates when drilling seed. Alfalfa and red clover are great legumes for haying, as they are tall-statured and produce more biomass than other legumes. A healthy stand of grasses and legumes can help reduce weed problems, as well, by outcompeting unwanted plants.

Before adding legumes to a hayfield, conduct a soil test in the fall and apply lime as needed to achieve a pH of around 6.5. Then, graze the hayfield hard (taking the grass down as low as possible) or mow on lowest setting in fall and winter. After that, you can frost-seed the legumes in late winter/early spring. This will allow the seeds the greatest access to the soil and ensure optimum germination.

Frost-seeding is most appropriate for small-seeded forages, such as clovers. This method works well in areas that experience a freeze-thaw pattern in the spring before green-up. Broadcast seeds around or after snowmelt and allow the natural freeze-thaw action that occurs each day to work the seed into the ground. If the timing is right, this can be an effective way to achieve seed-to-soil contact and incorporate legumes into a grass pasture. For the humid areas of the South or drier areas of the West, fall seeding of legumes allows seedlings to establish during the winter rainy season.

If legumes have been absent from your fields for a few years, plant seed with the appropriate inoculant to ensure an adequate bacterial population for nitrogen fixation. Use the strain Rhizobium leguminosarum bv. Trifolii for red clover, crimson clover, and white clover, and use Sinorhizobium meliloti for alfalfa. Purchase inoculants with your seed order and mix them with the seed prior to planting. It’s best to apply the inoculant with a sticky substance to prevent it from settling out in the seed bin. A 1-in-10 dilution of syrup or molasses, diluted cola, or milk works well as a sticking agent (Durst and Bosworth, 2025).

Stripe of crimson clover where round bales were rolled out to feed hay in winter. Photo: Prater farm, Cedarville, AR

Terminating and Replanting a Hayfield

Finally, if a complete renovation is necessary to correct deficiencies and improve productivity (evidenced by heavy weed pressure, low forage yield, and the need for better-yielding varieties), you can terminate the existing stand through tillage and replant. The first step is to test the soil and add lime to get the pH to around 6.5. Many producers and forage specialists recommend burning the stand down with an herbicide and then no-till drilling the new species into the field. For those who do not wish to use herbicides, a few tillage events to remove regrowth and harrowing to get a clean seedbed are crucial.

Choose species that are adapted to your area. For the southern United States, choices include tall fescue, bermudagrass, bahaigrass, white clover, red clover, and alfalfa. In the northeastern United States, orchardgrass, red clover, and alfalfa do well. The Intermountain West also has some adapted species, including meadow brome and alfalfa. Regardless of where you are, you can find good information on species selection and seeding rates from your state Extension service. Once you’ve chosen your seed mix, use a Brillion seed drill to plant the seeds to a depth of around ¼ inch or increase the seeding rate and broadcast seed, then pack the soil with a corrugated roller to ensure seed-to-soil contact. Forage seeds need adequate soil moisture for the first 30 to 40 days after planting to ensure germination, emergence, and a good stand.

Management of Newly Renovated Hayfields

One problem many producers encounter when planting legumes into a grass stand is competition. The grasses have an established root system and will easily outcompete the legumes if the producer does not intervene. There are a few tricks you can use to ensure the grass does not overtake and outcompete the new legume seedlings (Lacefield and Smith, 2009):

1. Do not apply nitrogen if the plant composition is greater than 25% legumes, to prevent grasses from outcompeting legumes.
2. Use the proper seeding rate and inoculation for the legumes at planting.
3. Drill or broadcast (after a light disc) seed and then pack the soil, for good seed-to-soil contact. Discing and broadcasting in the spring suppresses the grasses better than no-till drilling, to allow the legumes to establish. Another option is to frost-seed in late winter. The grass will need to be grazed heavily or mowed low prior to frost-seeding, to allow the seeds to obtain soil contact.
4. If weeds become an issue, mow the grasses until the legumes are about four inches tall.