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Improving Pastures by Renovation

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K.D. Johnson, C.L. Rhykerd,
and J.M. Hertel,
Department of Agronomy
and K.S. Hendrix,
Department of Animal Sciences,
Purdue University
Cooperative Extension Service
West Lafayette, IN 47907

Table 1. Effect of Forage Species and Fertility Levels
Table 2. Effect of Forage Species and Nitrogen Fertilization
Table 3. Suggested Legumes and Seeding Rates

In Indiana, pastures are generally relegated to land that is too steep and rocky for row crops. The soils lend to be shallow, low in fertility and droughty. The dominant plant species are often Kentucky bluegrass, tall fescue and weeds. The result of this combination of conditions is usually low yields of low quality forage.

One of the best ways to improve both forage yield and animal performance on these low-producing grass pastures is to periodically renovate them. Pasture renovation means "renewing" a pasture by the introduction of desired forage species into present plant stands. It usually involves partially destroying the sod, liming and fertilizing according to soil test, seeding a legume or legume-grass mixture, and controlling weeds.


Research and farmer experience show that introducing legumes into Kentucky bluegrass or tall fescue sods produces the following benefits:

image Elimination of the need for nitrogen fertilization.
image Better seasonal distribution of forage. (Legumes are more productive in mid-summer than cool-season grasses.)
image Increased forage protein content and quality.
image Improved forage digestibility and palatability.
image Higher mineral concentrations (especially calcium and magnesium), which help prevent animal health problems.
image Improved livestock performance, such as daily gain, milk and wool production.
image Improved beef breeding performance. (Legumes have been shown to reduce sheep breeding performance because of estrogenic compounds.)

Pasture renovation experiments in Ohio and Indiana illustrate the degree of improvement from the introduction of legumes into low-producing grass sods. An Ohio State University study (Table 1) revealed significant increases in cow-calf carrying capacity by renovating a permanent bluegrass pasture. Some improvement was made simply by adding a better forage grass. Further improvement was achieved by increasing soil fertility. However, the greatest improvement resulted from growing either a mixture of alfalfa and orchardgrass or a well-fertilized orchardgrass, both of which tripled animal carrying capacity as compared to the unfertilized bluegrass pasture.

A recent Purdue University experiment (Table 2) further supports two of the Ohio findings, suggesting they be carefully considered when making pasture renovation decisions. One is that some grass species are better than others as pasture for cow-calf herds. (Compare the daily gains and conception rates for herds on orchardgrass vs. tall fescue receiving the same amount of nitrogen.) The second finding is that seeding a legume into a tall fescue pasture gives better cow-calf production results than merely fertilizing the tall fescue pasture with nitrogen and gives similar results to N-fertilized orchardgrass. (Again in Table 2, compare animal performance on the tall fescue-clover mixture vs. tall fescue alone receiving N fertilizer. top of page


Pasture renovation needs to be done on a regular basis. The reason is that legumes, as compared to grasses, tend to be short-lived in a pasture. In fact, they will disappear rather quickly in the face of such "adversities" as lime, phosphorus and potassium deficiency, disease and insect damage, overgrazing, drought, or grass and weed competition.

Table 1. Effect of Forage Species and Fertility Levels on Pasture Grazing Days and Carrying Capacity, Ohio State University.

 Forage            Soil     grazing Acres per
 species          fertility  days   cow/calf
Bluegrass          Low        59     3.13

Bluegrass          Low        89     2.08

Bluegrass      Moderate +    106     1.74
Orchardgrass    50 lb N

Bluegrass        Good +      184     1.00
Orchardgrass      130 lb N

0rchardgrass      Moderate   189     0.97

Table 2. Effect of Forage Species and Nitrogen Fertilization on Conception Rate and Daily Gain of Cows and Calves on Pasture, Purdue University. top of page

                           Lb. daily gain  
 Forage     N fertilizer   ---------------   Conception
 species     treatment     Calves    Cows     rate
Orchardgrass   100 lb       1.8      0.8       90%
Tall fescue    100 lb       1.2      0.02      71%
Tall fescue
Red clover     None         1.8      0.6       92%
Ladino clover

Two problems associated with introducing a legume into pasture are the possibility of bloat and the difficulty in getting the legume established. Potential bloat problems can be minimized by seeding non-bloat species (birdsfoot trefoil or lespedeza), by introducing the animals slowly to legume-containing pasture, by feeding hay before turning animals into legume-containing pasture, or by supplement-feeding poloxalene (the active ingredient in "Bloat Guard").

The chances of getting a seeded legume successfully established in an existing sod depends on the farmer's ability to meet these two requirements:

* The existing vegetation must be sufficiently suppressed to permit the legume seed to germinate and emerge. This is accomplished either by tillage or by application of a "knockdown" herbicide in combination with overgrazing prior to seeding. If tillage or herbicide application cannot be made, the sod still should be overgrazed.

* Management after emergence of the legume must favor the legume if a mixture is to be maintained. top of page


To fulfill the above requirements for establishing and maintaining a good legume stand, the following steps are suggested:

1. Overgrazing and soil testing. Livestock should be allowed to overgraze the pasture in the fall so that tillage is more effective at tearing the sod. Even if tillage is not clone, the grass should he overgrazed so the mulch will not interfere with legume establishment. The soil should be tested, then limed and fertilized according to test results, preferably before tillage. Do not apply nitrogen since that will only promote grass growth and retard legume establishment.

2. Disturbing or suppressing the sod. If erosion is not a hazard, disk or field-cultivate to disturb the grass sod. (Renovation is more successful if tillage can be clone in the late fall.) To minimize soil loss, do not overwork the seedbed. The sod should be disturbed 50-70 percent if seeding clovers and 80-90 percent if seeding alfalfa and birdsfoot trefoil. It is not necessary to reseed the grass, since the undisturbed tillers will begin to grow the following spring.

On sloping land with highly erosive soils where tillage is not practical, the grass stand can be "knocked back" with Paraquat, which has been cleared for such use. However, the grass must be actively growing for Paraquat to be effective. Therefore, wait until the grass has "greened up" to apply it.

3. Seeding the legumes. Frost-seeding inoculated legumes in the late winter has provided good results in tillage-disturbed and undisturbed sod.

On Paraquat-treated sod, legumes can be seeded immediately after application. Seeding is best accomplished after Paraquat treatment with a no-till drill, because it places the seed in direct contact with the soil at the proper seeding depth (1/4 - 3/8 inch). Overseeding Paraquat-treated sod is not effective because there is no frost action to provide seed-soil contact that late in the season.

Table 3 lists the legume species, alone or in mixture, considered best for renovation and their proper seeding rates. Alfalfa should not be used on soils that heave severely. Lespedeza should not be sown in the northern half of Indiana. Birdsfoot trefoil complements bluegrass pastures very well. Always select "improved" varieties.

4. Grazing newly legume-seeded pasture. In the spring once the grass is growing and the ground has dried out enough to support livestock, graze the pasture until the animals start to defoliate the legume seedlings. Then remove the livestock and rest the pasture 8-10 weeks for the legumes to establish. top of page

Table 3. Suggested Legumes and Seeding Rates for Renovating Grass Pastures.

      Seed                    Lb. per acre
     mixture    Species       seeding rate
       1      Red Clover          8-10
              Ladino clover      0.5-1

       2      Alfalfa            10-12
              Red clover          2- 4

       3      Annual lespedeza   20-25

       4      Red clover          6- 7
              Ladino clover      0.5-1
              Annual lespedeza    8-10

       5      Birdsfoot trefoil      5
* Assumes high quality seed (90+% germination and 99+% pure)

5. Grazing established grass-legume pastures. Rotationally graze from spring to fall this favors the legumes. To rotate, use several fields or divide a field into paddocks with an electric fence. Adjust the stocking rate per field or paddock to defoliate grass-legumes within a 7 - to 10-day period. Do not overgraze, and plan on providing plenty of recovery time (usually from 21 to 35 clays, depending on time of season and rate of regrowth). A 7-day grazing period and 28-day rest period will require five fields or paddocks. A 10-day grazing period will require four fields.

One suggested grazing system is to: (a) harvest one or two hay crops in the spring and summer, (b) allow 30-35 clays for recovery, (c) graze off in 7-10 days, (d) repeat the resting-grazing cycle, and (e) allow 4 weeks of plant recovery before the first killing frost.

6. Fertilizing. Topdress annually with phosphorus and potassium according to soil test.

7. Re-renovating. Plan on it when the legume disappears and the fescue or bluegrass takes over.

AY-251 RR 2/92 top of page

Cooperative Extension work in Agriculture and Home Economics, State of Indiana, Purdue University and U.S. Department of Agriculture cooperating: H.A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the acts of May 8 and June 30, 1914. The Cooperative Extension Service of Purdue University is an equal opportunity/equal access institution.


For more forage information contact Dr. Keith Johnson: johnsonk@purdue.edu

Copyright © 2007, Purdue University, all rights reserved.
An equal access/opportunity university.

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