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Giving New Life to Tired Pastures

ANR-0159
Agriculture and Natural Resources
Date: 
01/23/2025
Dean Kreager, Educator, Agriculture & Natural Resources, Ohio State University Extension, Licking County
Christine Gelley, Educator, Agriculture & Natural Resources, Ohio State University Extension, Noble County
Theodore Wiseman, Educator, Agriculture & Natural Resources, Ohio State University Extension, Perry County

This factsheet outlines a stepwise process for developing an effective plan of action for improving older pastures that are not meeting productivity expectations. In many cases it is more inexpensive to improve ‘tired’ pastures than it is to replant new pastures.

The first step is to carefully evaluate 10–15 one-square-foot areas across the pasture. It is also important to identify the most limiting factors that need to be addressed in the renovation process:

  • When was the last soil test collected? Are the recommendations current for nutrient status and pH?
  • What is the stand density? Define this by the percentage of bare soil and the percentage of live desirable plant cover. Grass and grass legume stands should have less than 10% bare soil visible with two or more legume plants per square foot.
  • What is the percentage of undesirable plants and what species are they?
  • Describe the density of the desirable plant species. Each square should have at least five desirable plants as a basis for improvement.
  • Describe the soil’s compaction and erosion problems.
  • What is the yield or carrying capacity?

An excellent printable assessment tool is the Natural Resources Conservation Pasture Condition Score Sheet (Natural Resources Conservation Service, n.d.). This assessment helps reveal the most limiting factors to productivity that should be addressed first.

It is also important to determine the acceptable amount of time needed to reach the desired productivity level. This is accomplished by identifying if improvement is needed quickly or if a longer, more gradual process of improvement is acceptable. If drastic improvement is desired quickly, and the resources are available, then termination of the stand and a new seeding might be the best option. However, this option also requires preparation a year before seeding for good success and is usually more expensive.

If the stand density of desirable plants is deemed reasonable and a more gradual process of improvement is acceptable, then the following steps should be considered in the order listed:Tractor with implement in field of tall, green forage with numerous weeds.

  • Make corrective lime and fertilizer applications where needed.
  • Implement managed grazing in pastures.
  • Work on suppressing weeds and controlling serious infestations with herbicides, targeted grazing, and/or mechanical/cultural methods.
  • Enhance the stand by interseeding or frost seeding improved seed into the existing pasture with careful management that favors seed germination and growth.

Correcting Soil Acidity and Nutrient Status

The carrying capacity of a pasture can be greatly affected by the forage species grown, soil fertility, and soil pH. Work in Ohio by Van Keuren (1979, pp. 11–16) demonstrated that cow-calf days per acre could vary from 59 days on mixed-grass with no fertilizer on low-fertility ground to 189 days on an alfalfa-orchard grass mix on moderate-fertility ground. Available phosphorous, potassium, and nitrogen, as well as germination and development of new seedings, can dramatically affect forage performance. The addition of fertilizer to balance these nutrients is critical for providing an environment where desirable forage species will thrive.

Efforts to improve pastures should begin with evaluating soil fertility. This is accomplished by collecting representative soil samples and having a soil analysis completed. More information on proper soil sampling can be found at Soil Sampling to Develop Nutrient Recommendations (LaBarge & Lindsey, 2012). Information on soil pH, phosphate (P2O5), and potash (K2O)  is provided with the soil analysis results. For grass or grass-legume-mix pastures, soils over 30 ppm Mehlich-3 P and 150 ppm Mehlich-3 K do not require additional P2O5 and K2O respectively.

The pH of the soil has a great influence on both the availability of nutrients and the type of plants that will thrive. Legumes prefer a soil pH of 6.5–6.8 while most grasses will do well at 6.0–6.5. Adding lime to adjust the pH and provide desirable growing conditions is the first step after receiving soil test results. Lime can interfere with the availability of nutrients, especially phosphorus, and should not be applied at the same time. Lime takes time to change soil pH, so additions of liming material may need six to 12 months to have an effect. See Soil Acidity and Liming for Agronomic Production for more information on soil acidity and liming (Mullen et al., 2016). Liming materials also vary in effectiveness based on the source. Ag lime is considered to be 100% effective at neutralizing pH. Before purchasing lime, check the effective neutralizing power (ENP) or calcium carbonate equivalent (CCE) rankings to determine which source of lime is most effective and economical to apply. More information about understanding the value of lime can be found at Understanding Value in Lime (ohioline.osu.edu/factsheet/anr-9). You can contact your local quarry for lime CCE rankings or review an Ohio Aglime sample analysis chart by visiting the Ohio Aglime Council website and clicking the “Aglime Chart” link.

Cattle that graze on hay remove less nutrients. Typically, 70%–90% of N, P, and K that are ingested by cattle are returned to the pasture through manure and urine (Haynes & Williams, 1993). The 10%–30% of nutrients not returned to pasture are the building blocks for the growth of animals sold by the farm. As animals are raised and sold, these nutrients go with them. When hay is removed, each ton of hay, on a dry matter basis, takes away 12 pounds of P2O5 and 49 pounds of K2O. Replacing these removed nutrients is expensive, but crucial to prevent soil depletion.

Options are available for strategically timing fertilizer applications to renovate pastures. If the fertilizer application is for maintenance, then application after first cutting or early in the fall are good options. Application of K in the spring should be avoided due to the potential of grass tetany. High rates of N, P, K, and lime are best split into two applications.

Using stored forages as feed helps pastures replace nutrients that are removed when animals are sold, or hay is harvested. Also, managing pastures with rotational grazing improves the even distribution of manure and urine and, as a result, improves the utilization of nutrients. Simple steps such as thoughtful access to water, minerals, and shade for animals, along with fencing to adjust the size and shape of pastures, can more evenly distribute their manure and increase utilization of pasture through their grazing. Rotating grazing to different fields periodically helps redistribute nutrients found in their in manure.

Nitrogen is a critical nutrient for plant development and can be provided by either the addition of nitrogen fertilizer or legume plants. Pastures with <20% legumes can benefit from the addition of 100–180 pounds of N per acre. If legumes are present in 25%–35% of a pasture, then 50–130 pounds per acre is helpful. If legume presence is >35%, no additional nitrogen is needed (Lindsey, 2017). Inoculated legumes can capture nitrogen from the air and place it in nodules on the roots through a symbiotic relationship with rhizobia bacteria. In the process, a small amount of this nitrogen enters the soil where other plants can access it. In pastures, much of the nitrogen is recycled through forage consumption, protein digestion, and feces and urine containing the remaining nitrogen. Nitrogen is also held in the plant and root nodules until those portions of the plant die and the nitrogen is released by breakdown into the soil. When defoliation occurs, some roots that are not needed die and release nitrogen during decomposition. As the plant regrows, so do the roots. This system continues to supply nitrogen to the plants around the legumes.

Accurately estimating the percentage of legumes in a pasture field is challenging. The percentages of the stand previously described are based on dry matter yield, rather than visible soil cover. The surface area taken up by legumes can often lead to an overestimation of the percentage of legumes. Clipping samples and determining dry matter yield from various parts of the pasture, and then determining an average, will increase the accuracy of this estimation.

Nitrogen applications are best utilized by the forages when split. This allows them to be strategically scheduled to fit your needs. If stored forages are running short in March, the addition of 20–40 pounds of nitrogen per acre can provide a two week jump in production. Reserve this strategy for a small percent of acres that will be lightly grazed. Another option is to provide 30–50 pounds per acre in May or June to help reduce the severity of the summer slump. This application should occur after grazing. A third option is to apply 40–60 pounds of nitrogen in late-July to encourage a flush of grass growth that could be grazed well into the winter. A rule-of-thumb is each pound of N will add 20 pounds of forage dry matter.

Managing Forage Removal

In addition to the already mentioned nutrient management benefits, control of forage removal through managed grazing can improve forage quality, forage productivity, and assist with weed management. Often significant improvements can be observed in pastures that are given periodic rest.

Overhead, medium close-up view of pasture with a large amount of clover.Grazing to minimize seed head development keeps plants in a vegetative stage where nutrient value is highest. Rotating grazing through smaller pastures at timely intervals can lengthen the vegetative stage. Removing animals before forages are grazed below critical levels is important. Determining the correct ‘grazing residual’ is the art of grazing management, and recommendations are to retain 4–6 inches of the forage depending on the grazing objectives.

Several problems are associated with overgrazing. If too much leaf mass is removed, there will not be sufficient leaf area for photosynthesis to occur. As a result, plant growth will draw resources from stored energy reserves, which weakens the plants over time and slows growth. Chronically overgrazed plants do not have the energy production necessary to maintain the larger root system, so excess roots will die off. Overgrazing opens the soil to sunlight which will aid germination of weed seed that was previously dormant in the soil. Overgrazing also reduces moisture retention in the soil as the sun reaches the surface and leads to poor root growth. Maintaining the proper thresholds to start and stop grazing based on residual forage height and regrowth, in combination with allowing rest periods, improves the quality and quantity of the forage stand.

Controlling Weeds

Weeds can dramatically reduce pasture productivity and quality, and in some cases can be poisonous to livestock. Cultural, mechanical, and chemical options should be used as components of an integrated pest management (IPM) plan. As previously mentioned, grazing management practices can be useful in reducing weed pressure.

In 2021, a group of Extension educators concluded a three-year study evaluating a timed pasture mowing. Mechanically mowing pastures is one method producers can use rather than spraying herbicides. The purpose of this project was to determine if weed populations in pastured forages could be changed or reduced by varying the timing of mowing throughout the late spring and summer growing period without the use of herbicides. Mowing height for this experiment was targeted at 10 cm from the soil surface. This study measured various treatments:

  1. Control (no mowing).
  2. June-only mowing.
  3. July-only mowing.
  4. August-only mowing.
  5. September-only mowing.
  6. June and August mowing.
  7. July and September mowing.
  8. Mown each month; June, July, August, and September.

Forages within the plots were predominately tall fescue (Schedonorous arundinaceus L.) with small amounts of orchard grass (Dactylis glomerata L.) and white clover (Trifolium repens L.). Common weeds were not separated and weighed individually, but cocklebur (Xanthium strumarium L.) was consistently found throughout all treatments. Other weeds observed included Canada thistle (Cirsium arvense L.), Pennsylvania smartweed (Polygonum pensylvanicum L.), horsenettle (Solanum carolinense L.), burdock (Arctium L.), yellow nutsedge (Cyperus esculentus L.), and ribwort plantain (Plantago lanceolata L.).

Under the conditions of this study, mowing monthly reduced the total quantity of weeds (Table 1). Mowing this often would not be a realistic or economic option for most producers. This treatment also had the lowest quantity of forages. Mowing only in the month of July or September had similar results for the single mowing treatments.

Table 1 (click to download PDF).
Table displaying mowing treatments for pastures.

 

For some weed problems and situations, the use of herbicides may be the most effective option. The Weed Control Guide for Ohio, Indiana, Illinois, and Missouri (Loux et al., 2025) contains detailed information on approved products, proven effectiveness on various weeds, and label restrictions for a number of products that can be used on pastures. Always refer to the pesticide label for current use and restriction requirements.

Enhancing Species Diversity

Interseeding provides an option to increase the population of certain desired plants. This could be legumes, grasses, or both. For grasses or mixes, the two best times to interseed are early-spring and early-fall. Each time has advantages and disadvantages.

Spring seeding usually faces the most weed pressure, as this is when many plant species are most active. New spring seedings will have time to establish before going into winter dormancy. Early-fall seeding typically results in less weed pressure. Sometimes there is a concern about having enough time for forage to establish before frost if it is an abnormally dry year.

Preparation for interseeding includes removing current forage to reduce competition. Low-mowing, close-grazing, and disturbing the soil with a disc are a few options for improving seed-to-soil contact and reducing competition. Disturbing 30%–50% of the existing sod is a good guide for interseeding. Your options may be determined by the terrain. Seeding with a no-till drill provides the best seed placement but broadcasting and cultipacking can be an alternative. If broadcasting, seeding rates should be increased. Seeding rates are available in the Ohio Agronomy Guide (Lindsey, 2017).

For small hard seed, such as clover, frost-seeding can be a simple and effective method of increasing legume populations in a stand. Grazing a pasture short and broadcasting seed in late-winter (February to early-March in Ohio) allows the natural movement of seed into soil cracks as the ground freezes and thaws.

Another option for adding desirable species is to spread feeding hay in the area that needs improvement. Stored hay can be a good source of seed. When bales are unrolled, mature seed in the hay can find its way to the ground and hoof action can help the seed contact the soil. Knowledge of the hay source is required to prevent the introduction of unwanted weeds.

Keeping forages in a vegetative stage reduces natural reseeding. However, stockpiling forages for winter grazing can allow mature seed heads to develop and enable natural reseeding. This can be a concern with introducing weed seeds if the removal of weeds is not addressed prior to stockpiling.

For the first year after interseeding, the pasture should be managed for maximum growth. As new plants grow, removal of the top of the existing stand by light grazing or mowing will improve the survival of new plants. Do not graze new plants until they are firmly rooted.

Complete Re-establishment

If fertility and management improvements are not enough to transform the pasture into an acceptable condition, complete re-establishment may be necessary. This process takes time. Consult the Ohio Agronomy Guide for forage re-establishment guidelines.

Summary

Making improvements to a pasture that will result in long-term benefits requires a comprehensive approach. Setting goals, evaluating forages and soil, and adjusting management protocols to reach and maintain those goals will help with overall pasture productivity.

As individual results can vary, experimenting with various methods of forage management and documenting results on the farm can lead to the development of better recommendations for Ohioans. Reach out to your local Extension educator to inquire about on-farm research opportunities in your area.

For more information on forages, visit the Forages website at Ohio State University Extension (forages.osu.edu).

Acknowledgments

The authors and our fellow Ohioans extend our thanks to Dr. Mark Sulc, Extension State Specialist for Forage Production from 1992–2023 for his lifetime contributions to this and many other forage resources.

Additional Resources

Visit the following resources for more information on giving life to tired pastures:

References

Haynes, R.J., & P.H. Williams. (1993). Nutrient cycling and soil fertility in the grazed pasture ecosystem. Adv. Agron. 49, 119–199.
doi.org/10.1016/S0065-2113(08)60794-4

LaBarge, G., & Lindsey, L. (2012). Soil sampling to develop nutrient recommendations [Fact sheet]. Ohioline, Ohio State University Extension.
ohioline.osu.edu/factsheet/AGF-513

Lindsey, L., ed. (2017). Ohio agronomy guide, 15th Edition, Bulletin 472. Ohio State University Extension.
extensionpubs.osu.edu/search.php?search_query=472&section=product

Loux, M. M., Dobbels, A. F., Johnson, W. G., Young B. G., Butts, T. R., Zimmer, M., Hager, A., Wepprecht, C., Mausback, J., Miller, L., & Bradley, K. (2025).Weed control guide for Ohio, Indiana, Illinois, and Missouri ANR-789. Ohio State University Extension.
extensionpubs.osu.edu/2023-weed-control-guide-for-ohio-indiana-illinois-and-missouri/

Mullen, R., Lentz, E., & Watson, M. (2016). Soil acidity and liming for agronomic production [Fact sheet]. Ohioline, Ohio State University Extension.
ohioline.osu.edu/factsheet/AGF-505-07

Natural Resources Conservation Service. (n.d.). Pasture condition score sheet. U.S. Department of Agriculture.
nrcs.usda.gov/sites/default/files/2022-09/Pasture%20Condition%20Score%20Sheet.pdf

Van Keuren, R. W. (1979, pp. 11–16). Beef cows and calves—1979: A summary of research. Ohio Agricultural Research and Development Center.
kb.osu.edu/bitstream/1811/70712/1/OARDC_research_circular_n251.pdf

Originally posted Jan 23, 2025.
Ohioline https://ohioline.osu.edu