Management of horse pasture is an ongoing process that takes time, equipment, knowledge, and dollars. If managed wisely and well, pasture will be an economical source of high-quality feed as well as a healthy place for horses to exercise. It managed poorly or ignored, pasture can soon become nothing more than an overgrazed weed patch that not only has little nutritional value, but may even contribute to horse health problems.
The purpose of this publication is to help horse owners get the most out of the time, effort, and money they are (or should be) putting into permanent pasture management. Discussed first are two basic pasture-planning decisions: (1) the nutritional role of your pasture acreage whether it's to be a major feed source or just an exercise lot; and (2) the options for pasture improvement-whether to renovate, reestablish, or merely maintain. Presented next are step- by-step procedures for renovating or reestablishing an existing pasture, and for establishing a new one. The final section reviews those practices that help maintain-even extend-pasture productivity.
The agronomic practices described in this publication (including lime and fertilizer rates; forage seeding mixtures, rates and planting dates; seedbed preparation; and weed control) are also applicable to pasture management for other livestock species.
The first decision is whether to use the pasture for exercise purposes only or as a major part of your nutritional program. Most horses benefit from being outside regularly to exercise. This need can be met on relatively small, well-drained lots. Free exercise reduces behavior and respiratory problems, improves bone growth, and increases vitamin metabolism.
If your desire, however, is for the pasture to serve as a feed source, other factors need to be considered including its potential nutritional value and its carrying capacity.
Pasture nutritional value. Most horses can be maintained nutritionally through the growing season on well-managed pasture if provided with fresh water and a supply of trace-mineralized salt. Table 1 compares the nutrient composition of three pastures with the nutritional needs of various types of horses. Productive pasture during the growing season can replace the hay and reduce the concentrate required by most horses, and can replace all feed for those that are laid up, mature, idle, or pregnant. Note in Table 1 that lactating mares and fast-growing weanlings will probably need additional energy, protein, and minerals.
The values in this table also indicate a marked decrease in nutrient availability as forages mature. Consequently, management practices need to be utilized that keep the forage actively growing. The key to nutritional management is to continually observe the horses and supplement the pasture only it their body condition so indicates.
Pasture carrying capacity. Horses should consume 1 percent or more of their body weight per day in forage dry-matter. If the major nutrient source is pasture, a 1000-pound horse will collectively consume and waste approximately 3 tons of forage dry matter during a typical 6-month grazing season. Thus, with average management, it would take about 2 acres of pasture to meet the nutrient needs of a mature horse.
Of course, the carrying capacity of any particular pasture will depend on such things as type of horses, soil type, soil fertility, drainage conditions, amount of rainfall, time of year, and type of forage species present. For instance, in mid- to late-summer or in droughty periods, grass-only pastures will not carry as many horses as grass-legume pastures. Many annual forage species can be planted to provide supplemental feed in times of short permanent pasture supply. Cooperative Extension Service publication, AY-263, provides complete detail on their utilization. For most individuals, purchasing hay is a more economical solution to the crisis.
Pasture species Dry Digestible Crude Phos- and maturity matter energy protein calcium phorus Vitamin A --------------------------------------------------------------------- pct. Meal/lb. pct. pct. pct. 1000 IU/lb. Kentucky bluegrass Vegetative 31 1.44 17.4 0.33 0.30 72.7 Mature 42 1.12 9.5 0.30 0.25 694 Orchardgrass Vegetative 23 1.44 18.4 0.57 0.54 34.9 Mature 35 1.06 8.4 0.45 0.35 32.1 Orchardgrass/ Alfalfa Vegetative 22 1.35 19.2 1.27 0.42 34.3 Mature 30 1.08 11.2 1.13 0.32 30.5 Type of horse Minimum requirements ------------------------ Mature or idle 1.00 10.0 0.30 0.20 0.5 Pregnant (last 90 days) 1.10 11.0 0.50 0.40 1.6 Lactation 1.20 14.0 0.60 0.40 1.3 Weanling 1.40 15.0 0.70 0.40 0.9 Work 1.20 11.0 0.35 0.25 0.9 -------------------------------------------------------------------- * From "Nutrient Requirements of Horses"(1989) and "Tables of Feed composition" (1982), National Research Council, National Academy of Sciences.
Well-managed Kentucky bluegrass pasture will produce approximately 2 tons of dry matter per acre. Tall-growing, cool-season grasses such as orchardgrass or smooth bromegrass may yield 4 tons of dry matter, but most of that will be produced in the spring and fall. When a legume is incorporated with the grass, yields can top 6 tons dry matter per acre, with more of it produced in the summer than would be the case with cool-season grass alone. (Figure 1 shows the normal production period(s) of various grass and legume species.)
A pasture's anticipated use and its present condition together determine if it should be renovated, reestablished, or left alone.
If the pasture is predominantly a place for horses to exercise and the stocking rate averages more than one 1000-pound horse per acre, it should probably be left alone. Under high stocking rates, forage crops will always lack vigor and never have the opportunity to attain their production potential. Areas that will remain exercise lots and that have an adequate sod cover should not be considered for major overhaul, since improvement costs will likely exceed any realized benefits.
If, on the other hand, the pasture is to be an important feed source but is currently unimproved and overstocked, then renovation or reestablishment is justified, provided improved pasture management practices will be employed to maintain it.
When a pasture is renovated, it is "renewed" through a set of proven management practices that usually include controlling weeds, liming and fertilizing according to soil test, reducing vigor of the existing sod, then seeding into that sod an adapted legume or grass-legume mixture. When a pasture is reestablished, the existing vegetation is completely destroyed by tillage or a herbicide, the soil is limed and fertilized (again according to soil test), then a seedbed is prepared and planted with adapted forage species.
Reestablishment is usually more costly than renovation, since it involves additional tillage or herbicide use. However, the extra expense may be justified if a higher-yielding forage is desired (e.g., smooth bromegrass to replace Kentucky bluegrass) or if the existing pasture is predominately bare ground, or weeds with little sod cover beneath. Localized high-traffic areas near the water supply and gates might also be reestablished to tall fescue, which is better able to withstand heavy trampling.
Often the best way of renovating grass pasture is to introduce an adapted legume into the existing sod. Sometimes, however, this is not possible because grazing pressure would be too intense for legume survival or because inaccessibility to water would make rotational grazing impractical. Thus, pasture improvement has to be accomplished without the benefit of legumes.
The recommended way to improve a grass pasture involves the following sequence of practices including weed control, soil testing, liming, fertilizing, and grazing management.
The presence of weeds and brush in a pasture often indicates poor management, particularly over-grazing and inadequate fertilization. If broadleaf weeds are a problem, control with herbicides may be necessary. (See Table 2 for specific herbicide rates and grazing restrictions.) Herbicides listed will kill any legumes present. Therefore, if the pasture contains legumes that are making a contribution, apply the herbicides only to the severely weed-infested areas.
After weeds and brush are controlled, proper pasture management practices must be used or the weeds and brush will reappear.
A soil test is essential to realizing optimum grass pasture production, for it determines precisely how much lime and fertilizer should be applied. Too little prevents optimum yields; too much not only is an unnecessary expense, but can also cause plant growth and environmental problems.
Weeds Controlled** Herbicide*** Rate Restrictions -------------------------------------------------------------------------------------------------- Curly dock, dan- Crossbow 1-2 qt/a. for annuals Avoid drift to suscep- delion, bull and musk (2,4-D + triclopyr) and biennials; 2-4 tible crops. No graz- thistle, ironweed, wild qt./a. for perennials; ing restrictions if carrot, marestail, 1-1.5% solution for applied 2 gal./a. or fleabane, wild mus- spot treatments. less (delay until 14 tard, top growth only days after treatment of Canada thistle and if applied > 2 gal/a. hemp dogbane, plus See label for haying other annual and restrictions. Do not perennial weeds. Will seed pastures for a control certain woody minimum of 3 weeks species as well (i.e. after treatment. multiflora rose). Curly dock, hemp Banvel 0.5-3 pt./a. for annu- No waiting period dogbane, ironweed, (dicamba) als and biennials; between treatment marestail, milkweed, 0.5-6 qt./a. for peren- and grazing for non- swamp smartweed, nials; 0.5 qt.-2 gal/a. lactating animals. Canada thistle, musk for woody species. Avoid drift. For the 4 and bull thistle, wild pt./a. rate, corn and carrot, burcucumber, soybeans may be fleabane, morning- planted the next glory, and several spring after treat- other annual and ment; wheat may be perennial weeds. planted in the fall or Woody species also spring following the listed on label. treatment. Dandelion, bindweed, Weedar 64 2 pt./a. for annuals; Avoid drift. Do not hemp dogbane, net- (2,4-D amine) 2-4 pt./a. for biennials reseed legumes or tles, ironweed, mor- and perennials. rotate to other crops ningglory, musk and for 3 months or until bull thistle, fleabane, the chemical disap- wild carrot, mustards, pears from soil. Do and several other an- not graze dairy cattle nual and perennial tor 7 days after treat- weeds. ment. Many of the same Weedone LV4 2 pt./a. for annuals; Do not graze animals species as 2,4-D (2,4-D ester) 3-4 pt./a. for biennials on treated areas for 7 amine. Ester formula- and perennials. days after treatment. tion works better on Avoid drift. (See wild garlic and onion 2,4-D amine for than the amine. further restrictions.) Mayweed, buttercup, Ally 1/10 to 3/10 oz/a. No grazing restric- henbit, wild garlic, (metsulfuron methyl) (add a surfactant); 1 tions. Avoid drift. musk thistle, Canada oz. per 100 gal. of Treated fescue may thistle, curly dock, water for spot treat- be stunted. If applied marestail, common ment. 2/10 oz/a., wait 12 chickweed, common mo. before planting mullein and others, legumes and 6 mo. certain woody spe- for cool-season cies such as buck- grasses; If applied > brush, multiflora rose. 2/10 oz./a., do not plant rotational crop for 34 mo. unless a field bioassay is per- formed. Woody plant and Spike 20P 3.75-20 lb/a. May cause temporary brush control. (Avoid (tebuthiuron) herbicidal symptoms applications near de- to appear on peren- sirable trees, shrubs, nial grasses. Dor- etc.) mant season applica- tion is recommended to minimize herbicidal effects on desirable forage grasses. Grazing is only al- lowed in areas treated with 20 lb. per a. or less. Allow 2 yr. after application be- fore reseeding. Nonselective weed Roundup Spot treatment For spot treatment: and brush control. (glyphosate) 1-2% solution apply in areas where the movement of livestock can be con- trolled. No more than 1/10 of any acre should be treated at one time. Remove livestock before ap- plication and wait 14 days after application before grazing. Allow 10-14 days after treatment before reseeding treated areas. Common burdock, Stinger 1/3 - 1 pt./a. Do not transfer lives- cocklebur, dandelion, (clopyralid) tock from treated curly dock, ground- grazing areas onto sel, marestail, prickly sensitive broadleaf lettuce, jimsonweed, crop areas without oxeye daisy, rag- first allowing 7 days weed, red sorrel, of grazing on an sowthistle, Canada untreated pasture thistle, musk thistle, (allowing clopyralid to and others. pass through urine). Avoid drift. Alfalfa may be planted 12 mo. after treatment. ---------------------------------------------------------------------------------------------------- *Herbicide information compiled by Dan Childs, Extension Weed Specialist, Department of Botany and Plant Pathology, Purdue University. Refer to the label for more complete information. ** Weeds appearing in this table are just a few of the weeds listed on the herbicide label. *** Be sure to read entire label before applying to any pasture; to be used only in grass pastures. Injury to forage legumes may occur from the application of these herbicides.
To take soil samples for testing, a sampling tube, auger or spade, and a clean plastic pail are needed. Soil sample containers plus field and cropping information sheets may be obtained from a commercial soil testing service. The field and cropping information sheets tell where the samples were taken and what the past cropping and fertility practices were on that particular field.
Divide the pasture into areas (10 acres maximum) that are uniform in soil color and texture, and that have similar cropping and fertilization histories. Sample each area separately, drawing 15 random soil cores at 2-3 inches deep. Do not sample within 200 feet of a gravel road, along field borders or other distinctly different areas, such as sandy ridges and eroded spots. These can be sampled separately, however, if soil test information about them is desired. Place the 15 cores from each area in the plastic pail and mix them thoroughly. If the soil is wet, let the cores dry first on clean paper before mixing. Put each sample in a separate mailing container with the appropriate information and send to the soil testing laboratory as per instructions provided. Soil pH (a measure of soil acidity) and phosphorus and potassium levels are the three critical factors that need to be analyzed by the lab.
Table 3 shows the recommended rates of lime for different soil pH levels. If the pH is greater than 6.0 on mineral soils and greater than 5.4 on organic soils, no limestone will be needed on already- established grass pastures. The SMP buffer pH or "lime index," as it is commonly referred to in soil test reports, measures how readily a soil will change pH when limestone is applied. A highly buffered soil (one with a high cation exchange capacity) will have a lower lime index value, thus require more limestone than soils with high lime index values.
Mineral soils Organic soils (less than 20% (more than 20% organic matter) organic matter) SMP Soil pH Soil pH Soil pH Soil pH buffer <6.0 <6.6 <5.4 <5.4 pH (lime Grass Grass- Grass Grass- index) only legume only legume ---------------------------------------------------- tons limestone/acre Renovation/Maintenance 7.1 & over 0 1 0 0 7.0 1 1 0 0 6.9 1 1 1 1 6.8 1 1 1 1 6.7 1 2 1 1 6.6 2 2 1 1 6.5 3 4 2 2 6.4 3 4 2 2 6.3 3 4 3 3 6.2 & less 3 4 4 4 ---------------------------------------------------- Establishment/Reestablishment 7.1 & over 1 2 0 0 7.0 2 2 0 0 6.9 2 2 2 2 6.8 2 3 2 2 6.7 3 4 3 3 6.6 4 5 3 3 6.5 6 8 4 4 6.4 7 8 5 5 6.3 7 8 7 7 6.2 & less 7 8 8 8 --------------------------------------------------- *These rate recommendations are based on certain assumptions about previous limestone applications, tillage depth, and present limestone quality. Make rate adjustments for the following conditions: 1. If limestone was applied within the last year, subtract the rate applied then from the amount recommended in this table. 2. The establishment/reestablishment rates are based on a 9-inch tillage depth. Adjust rates 10% for each 1 inch difference from the assumed tillage depth, to a maximum of 30% (3 inches). 3. The table rates are based on 25 to 30% of the limestone passing through a 60-mesh sieve. If your liming product's fineness differs from this, check with your Extension agent on the appropriate adjusted rate at that level of fineness. 4. If the rate you need exceeds 5 tons/acre, a split application is recommended, with one-half broadcast and plowed down, and the other half broadcast and incorporated with a secondary tillage. 5. Two cubic yards of marl containing at least 70% calcium carbonate equivalent may be applied in place of 1 ton of standard agricultural ground limestone.
The liming rates in Table 3 for pasture maintenance are about one-half those recommended for pasture establishment, since tillage is not done when limestone is applied to already-established grasses. Most limestone recommendations are based on a 9-inch plowing depth.
The phosphorus and potassium fertilizer rates shown in Table 4 for renovating permanent grass pasture are lower than those for grass hay production because of the nutrient value of manure left on the pasture. Some estimate that as much as 85 percent of the phosphorus and 50 percent of the potassium in consumed forage is recycled in the manure.
Because manure is not evenly distributed, the pasture should be dragged periodically with a harrow. If dragging is not done, phosphorus and potassium should be applied at the rates recommended in Table 4 for pasture establishment.
When considering nitrogen fertilization of grass pasture, timing of application is just as critical as proper rate. The best way to fertilize is to apply one-half of the nitrogen in very early spring (mid- to late- March), one-fourth after the initial spring grazing, and the last one-fourth in late August or early September; this maximizes summer production of the cool-season grasses.
A second alternative is to apply two-thirds of the nitrogen in very early spring and one-third in late August or early September. If nitrogen can only be applied once each year, it should be broadcast in the very early spring.
Table 5 gives the per-acre nitrogen rates recommended for established grass pasture at various yield levels. Realistic pasture yield goals are 2 tons of dry matter per acre for Kentucky bluegrass and 4 tons of dry matter per acre for tall-growing cool-season grass species like orchardgrass. Remember that the actual application rates will differ depending on the elemental analysis of the fertilizer used.
The preferred source of nitrogen for grasses, especially under dry soil conditions, is ammonium nitrate, which is less likely to volatilize to nitrogen gas. However, urea can also be used effectively without volatilization loss if applied when the soil is moist or just before a rain.
Proper grazing management, soil retesting and fertilization, pasture clipping, dragging, and weed control will help ensure that a renovated grass stand not only survives but thrives. These practices are discussed in the last section of this publication.
As already mentioned, often the best way of renovating grass pasture is to introduce an adapted legume into the existing sod. A grass-legume pasture provides the following benefits over one composed of just cool-season grass species alone:
Grass-Only pasture Grass-legume pasture Recommendation when per-acre Recommendation when per acre Soil test rang. yield (dry matter basis) Is- yield (dry matter basis) is-- 2 tons 4 tons 6 tons 2 tons 4 tons 6 tons 8 tons Bray Exchange- soil test __________ _________ _________ ________ ________ P1 able K level P205 K2O P205 K20 P2O5 K20 P205 K20 P205 K20 P205 K20 P205 K20 ---------------------------------------------------------------------------------------------------- pounds/acre pounds/acre pounds/acre Renovation/Maintenance 0-10 0-80 Very low 80 60 100 120 120 180 80 120 100 240 120 360 140 480 11-20 81-150 Low 40 10 40 20 40 30 40 60 40 120 40 180 40 260 21-30 151-210 Medium 10 0 10 0 10 0 10 10 10 70 10 120 10 200 31-50 211-300 High 0 0 0 0 0 0 0 0 0 0 0 60 0 140 51+ 301+ Very high 0 0 0 0 0 0 0 0 0 0 0 0 0 80 Establishment/Reestablishment 0-10 0-80 Very low 80 60 100 120 120 180 80 120 100 240 120 360 140 480 11-20 81-150 Low 60 50 80 100 100 150 60 100 80 200 100 300 120 420 21-30 151-210 Medium 30 40 50 80 70 120 30 50 50 150 70 240 90 360 31-50 211-300 High 20 30 40 50 60 90 20 0 30 80 50 180 70 300 51+ 301+ Very high 0 0 20 0 20 0 0 0 20 0 40 120 50 240 ----------------------------------------------------------------------------------------------------- * The recommendations for pasture renovation/maintenance have been adjusted to credit value of livestock waste on the basis that 85% of the phosphorus and 50% of the potassium in the forage dry matter produced is recycled. No adjustment is made for P205 and K20 when the soil test is very low.
Seeding legumes into a grass sod needs to be done on a regular basis since they are shorter-lived than grasses. Legumes should be reintroduced when they contribute less than 30 percent of the pasture's total forage production (or approximately two legume plants per square foot). How often that is will depend on environmental conditions (especially drought), level of management provided, and the legume species sown.
When tall fescue is the major source of nutrition, a potential horse health problem exists called fescue toxicosis. This condition causes thickened placentas in the pregnant mare resulting in death of the foal, long gestation periods, poor milk production from the lactating mare, and poor conception rates when the mare is rebred.
Chances of fescue toxicosis can be lessened by not applying nitrogen on established stands, using low-endophytic-fungus fescue varieties, renovating the fescue with legumes, and mowing or applying enough grazing pressure to keep the fescue immature (no seed heads). If a tall fescue-legume pasture is to be the predominant nutrition source, make sure the proportion of legume to grass is at least one-third.
The following practices are essential to successfully introduce legumes into a grass pasture.
The year before seeding the legume, control broadleaf weeds with appropriate herbicides as described in the previous section.
Test the soil as discussed previously. Then according to the results, apply limestone and fertilizer the summer or fall before late-winter seeding. Tables 3 and 4 show the lime and fertilizer rates for grass-legume pastures based upon soil tests. These rates may differ from those suggested by soil testing services, because Table 3 assumes that the soil amendments are not incorporated to plow depth and Table 4 assumes some nutrients from manure are returned to the pasture.
Nitrogen fertilizer should not be used, because it will encourage grass growth and make legume establishment more difficult.
The fall prior to seeding, overgraze the pasture to help reduce grass vigor. Then, if erosion will not be a problem, till it later that fall with a tandem disk or field cultivator to further reduce grass competition as well as incorporate the limestone and fertilizer. Grass sod should be disturbed 50-70 percent if seeding clovers and 80-90 percent if seeding alfalfa or birdsfoot trefoil. The disturbed sod will recover by mid-season from undisturbed tillers that initiate spring growth. (Do not till while the soil is wet.)
Recommendation when per-acre yield (dry matter basis) is 2 tons 4 tons 6 tons -------------------------------------------- pounds/acre 55 100 150 --------------------------------------------- * These recommendations have been adjusted to credit value of livestock waste on the basis that 10 lb. nitrogen per ton of forage dry matter produced is recycled.
On sloping land with highly erosive soils where tillage is not practical or seeding is delayed until late March or early April, the grass sod can be "knocked down" with the herbicide, Gramoxone Extra. Gramoxone Extra is a restricted-use, nonselective contact herbicide that kills all vegetation sprayed Apply it at a rate of .8-I pint (in 20 gallons of water; per acre (1.5 pints for tall fescue or smooth bromegrass) when the grass has grown an inch or two and just ahead of or immediately after seeding the legume with a no-till drill. Add an approved non-ionic surfactant at 1-2 pints per 100 gallons of spray.
Caution: Do not broadcast legume seed onto Gramoxone Extra-treated sod because there is no frost action to provide seed-soil contact once spring growth has begun. Also when using Gramoxone Extra, keep horses off the pasture for at least 2 months as the legume seedlings develop and the grass recovers.
No matter the size of the pasture or paddock, there are workable methods for introducing a legume into established grass sod. If the pasture was adequately overgrazed (and preferably also tilled) the preceding fall, one inexpensive yet effective way is to broadcast the seed in late winter with a tractor-attached broadcaster. This implement costs about one-tenth the price of a no-till drill.
If a no-till drill is used (and one should be for seeding into Gramoxone Extra-sprayed sod), set the planting depth for 3/8-inch maximum. Many equipment dealers and Soil & Water Conservation District offices rent no-till drills to those who have limited acreage and can't justify owning one.
It the acreage is very small or the terrain too rough for a tractor and seeder, consider using a small, shoulder-held, hand-cranked broadcaster. These can be purchased at most seed stores.
Table 6 lists the legume species (alone or in mixture) that could be used in a pasture renovation program and their proper seeding rates. To help select the right one, Table 7 summarizes the major agronomic and utilization characteristics as well as important management considerations.
Pasture renovation can often fail after the legume has been sown. The key to getting a legume established-and maintaining it-is grazing management.
Once the grass is growing vigorously and the ground has dried out enough to support horses (usually mid-April to early May), graze the newly-renovated pasture until the horses begin to defoliate the small legume seedlings. Then remove them for 6-10 weeks, until the legumes reach a grazing height of approximately 6 inches. If there are not enough horses to keep the pasture's early growth in check, it may be necessary to reduce the grass competition in mid- to late-May by cutting the grass off above the legume seedlings and removing it for hay.
Here are suggested steps for establishing a new pasture or reestablishing one that is now predominately bare ground or weeds with little sod cover beneath. These steps include liming and fertilizing, seedbed preparation, seeding, and weed control.
Pounds pure live Legume species seed per acre ------------------------------------------- Alfalfa 12 Red clover 10 Alfalfa & 8 Red clover 4 Red clover & 8 Ladino clover 0.5 Ladino clover 1 Birdsfoot trefoil 5 Korean lespedeza 20 -(with hulls) Alsike clover 6 Alsike clover & 4 Ladino clover 0.5 ------------------------------------------ * Lb. pure live seed = 1b. bulk seed x % pure live seed. (% pure live seed = % purity x % germination).
The first step in pasture establishment or reestablishment is to lime and fertilize the soil according to soil test results. Sampling should be done as previously described, except that the soil cores should be taken as deep as the tillage to be performed. Tables 3 and 4 show that lime and fertilizer rates are greater for pasture establishment than for pasture maintenance because a primary tillage is performed and no manure fertilizer value is credited.
If limestone is needed, preferably it should be applied 6-12 months ahead of seeding to ensure sufficient time to lower soil acidity (i.e., raise the pH). If rates recommended by soil test are 5 tons or more per acre, apply one-half before the primary tillage and the other half prior to a subsequent secondary tillage.
Phosphorus is the key nutrient to getting a pasture stand established. Use rates recommended for grass-only or grass-legume establishment (Table 4) that are based upon soil test level and yield goal. Where soil P levels are low or very low, apply at least two-thirds of the phosphorus broadcast ahead of the primary tillage operation. Also consider broadcasting and disking 30-40 pounds per acre of the recommendation just ahead of seeding to provide the needed starter effect.
Potassium aids in pasture establishment by keeping the various forage species healthy and competitive. Since grasses are much more competitive than legumes for available potassium, the rates recommended by soil test and yield goal level are significantly higher for grass-legume establishment than for grass-only (Table 4). If applying additional phosphorus at seeding, include an equal amount of potassium for a starter effect.
Nitrogen can also be important to pasture establishment. For instance, 15 pounds of nitrogen per acre at seeding may benefit a grass-legume stand being established on light colored soils having less than 3 percent organic matter and on coarse-textured (sandy) soils. For establishing a grass-only pasture, apply 50 pounds of nitrogen per acre prior to the last tillage on mineral soils. No nitrogen needs to be applied on organic soils.
Recommended methods for preparing the seedbed will vary depending upon a field's surface and the previous crop grown. Basically, less tillage is required where the field surface is smooth and little crop residue is present. In fact, if the surface is smooth and the previous crop was corn silage, soybeans, small grain, or sod, tillage may not be needed at all. In these cases, one would merely have to seed using a no-till drill, provided soil pH, phosphorus, and potassium were found to be adequate. Renovating the existing sod by seeding a legume is usually preferred to destroying the sod with a moldboard plow or the herbicide Roundup.
If the field surface is uneven and the previous crop was corn silage, soybeans, or a small grain, a straight-shanked chisel plow or tandem disk should provide adequate primary tillage. These implements incorporate most of the residue but leave enough on the surface to minimize soil erosion until additional tillage is performed. Use a tandem disk or field cultivator for the first secondary tillage, then harrow either at the same time or as a separate operation. For the final tillage, consider using a soil conditioner. Also consider firming the field with a cultipacker just ahead of seeding. A loose seedbed can reduce stand establishment because of poor seed-soil contact.
If the previous crop was corn grain, a moldboard plow or twisted-shanked chisel plow should be the primary tillage tool since more residue will be incorporated. To minimize soil erosion, use the chisel plow (not a moldboard) it the land slopes more than 4 percent. The secondary tillage and optional soil-firming operations are discussed above.
Pounds pure live seed Grass species Seeding date(s) per acre -------------------------------------------- Kentucky Feb. 1 - May 1 or 5-10 bluegrass Aug. 1 - Sept. 15 Orchardgrass Mar. 1 - May 1 or 10 Aug. 1 - Sept. 1 Reed Mar. 1 - May 1 or 6-8 canarygrass Aug. 1 - Sept. 1 Ryegrass Mar. 1 - May 1 or 15-20 Aug. 1 - Sept. 1 Smooth Feb. 1 - May 1 or 10-15 bromegrass Aug. 1 - Sept. 1 Tall fescue Mar. 1 - May 1 or 15 Aug. 1 - Sept. 1 Timothy Feb. 1 - May 1 or 5-6 Aug. 1 - Nov. 1 3-4 -------------------------------------------
Use Table 7 for selecting the grass or grass-legume species best suited to your needs and conditions. Then refer to Table 8 for recommended seeding rates and planting dates of grass species, and Table 9 for seeding rates of grass-legume mixtures.
Sow a grass-legume mixture within the time span suggested in Table 8 for pure grass seedings, with the following exceptions: (1) a timothy-legume late-summer seeding should be completed before September 1 in southern Indiana and August 15 in northern Indiana, and (2) the clovers and Korean lespedeza should be spring-seeded only.
Selection of the proper seeding date is important. Planting too early or too late in the summer-seeding period can cause the young seedlings to be killed by drought in summer or by cold weather in winter; and Weed pressure may be greater if spring planting is delayed. Generally, in northern Indiana, plan to plant in the latter part of the spring-seeding period and earlier part of the late-summer-seeding period shown in Table 8. In southern Indiana, plant earlier in the spring-seeding period and later in the late-summer- seeding period.
Be sure that all legume seed has been inoculated with the proper rhizobia bacteria or buy pre-inoculated seed. This ensures that the nitrogen-fixation process will occur.
There are several ways to sow forage crops successfully. These include a grain drill with small seed legume box attached, the "Brillion" seeder, a no-till drill with small seed legume box, and a broadcast seeder. If the seedbed is not firm before seeding, it should be cultipacked. If the grain drill has chain drags or has press wheels that are not firming the soil after seed placement, attach a cultipacker behind the drill or do it in a separate operation. If broadcasting, the field should be cultipacked immediately after seeding.
Minimizing weed pressure is very important to successful pasture establishment. Here are four ways to reduce this pressure during the critical period of forage seedling establishment.
1.Timely seeding. Seeding early in the spring permits the forage seedlings to begin growth before summer-annual weeds germinate.
2.Providing a companion crop. A small grain companion crop (e.g. oats or wheat) will reduce weed pressure by competitive growth. Because they establish so quickly, small grains will also reduce soil loss where erosion is a concern. The crop eventually can be harvested for forage or for grain. If grain from the companion crop is to be harvested, do not graze after the plants begin to joint (elongation of the stem internodes).
In the late winter, forage seed can be interseeded or broadcast into established and adapted small grains (soft red winter wheat, statewide, and winter barley in southern Indiana). If the small grain is too competitive, chances for forage establishment are reduced. Reducing the seeding rate and nitrogen fertilizer rate can improve chances of forage seeding establishment.
3.Applying herbicides. An excellent choice for annual broadleaf weed control in newly sown grass-legume pastures is 2,4-DB. Application should occur before weeds are greater than 3 inches tall and when legumes are 2-3 inches tall or in the 3- to 4-leaf stage of growth. Do not graze or feed treated plant parts for 60 days after application.
4.Mowing. Weed pressure, particularly broadleaf weeds, can also be reduced by mowing several times during forage establishment. Set the cutting height above the young forage plants. The mulch created by mowing should not smother the forage seedlings. If it does, the mulch should be removed or mowing discontinued and a herbicide application considered.
Once a pasture has been renovated or reestablished, the following management practices will promote vigorous, healthy plant growth and also extend the pasture's productive life.
Divide the acreage into at least two and preferably more pastures so the horses can be kept off each pasture for periods of 3-4 weeks. This amount of time is necessary to permit forage regrowth and increase plant vigor. The length of the rest period will depend greatly upon stocking rate, time of year, rainfall, and the forage species present.
Remove horses from a pasture when tall-growing grasses are 4 inches in height and Kentucky bluegrass is 2 inches in height. Do not overgraze any one area, since this quickly reduces the amount of legume in the stand and increases the presence of weeds. On the other hand, don't undergraze either because this allows the forages to mature and become less palatable and nutritious. If the grass is beginning to head, consider making hay on that acreage.
Horses have been known to selectively graze one forage species in preference to another and to avoid eating forage soiled with manure. One solution would be to follow the horses with other species of livestock (if you have them), since they will often graze what horses ignore.
As with all livestock, horses can easily founder (a severe, chronic hoof lameness) when they are first introduced to a lush pasture in the spring. This can be avoided by turning them out into the new pasture only a few hours at a time initially, then building up gradually to full-time grazing. Feeding horses hay before the initial turn out to pasture also decreases overconsumption of lush forage. Grazing is not recommended when the soil is wet and muddy as the horses' hooves can cause damage to the small forage seedlings. A holding area or dry lot for such occasions is recommended.
Grass-ONE only (lb. pure live seed/arce) Smooth Reed Orchard Tall brome- canary- Tim- Kentucky Legumes (lb. pure live seed/arce) grass fescue grass grass othy bluegrass Primary legume Secondary legume ----------------------------------------------------------------------------------------- Alfalfa 8-10 ---- 4-6 8-10 5-7 --- 2-4 2-4 Alfalfa 4-6 Red clover 4-6 4-6 8-10 5-7 --- 2-4 2-4 Alfalfa 6-8 Ladino clover 1/4 4-6 8-10 5-7 --- 2-4 2-4 Red clover 6-8 --- 4-6 8-10 5-7 --- 2-4 2-4 Red clover 4-6 Ladino clover 1/4 4-6 8-10 5-7 --- 2-4 2-4 Red clover 4-6 Korean lespedeza 8 4-6 8-10 5-7 --- 2-4 2-4 Alsike clover 3-4 ---- 4-6 8-10 5-7 3-5 2-4 2-4 Alsike clover 2 Ladino clover 1/4 4-6 8-10 5-7 3-5 2-4 2-4 Birdsfoot trefoil 5 ---- 4-6 8-10 -- 3-5 2-4 2-4 Ladino clover 1 ---- 4-6 8-10 5-7 3-5 2-4 2-4 ---------------------------------------------------------------------------------------
After the horses are moved to a new pasture, mow the just-grazed pasture to the desired height for the species present, as discussed in the section above. Pasture regrowth is more palatable to the horse and has higher nutrient composition than mature plants. Clipping also helps reduce weed pressure and the risk of eye irritation caused by mature seed heads.
A properly managed pasture that is not over-grazed and is well-fertilized should not allow weeds to predominate. However, if this occurs, apply appropriate herbicides in the weed-infested areas.
While the pasture is being rested, drag it with a chain harrow to spread out the manure piles. Dragging should be done at least twice during the grazing season and preferably immediately after clipping.
Dragging destroys many internal parasite eggs by exposing them to the sun, and reduces selective grazing by horses, which tend to avoid areas that are soiled by manure. The fertilizer value of manure is also enhanced when it is evenly distributed on the pasture.
Nitrogen fertilizer will be needed each year in any predominately grass pasture. One-half should be applied in the very early spring, one-fourth after the initial spring grazing, and one-fourth in early September. This will improve summer production of cool-season grasses. A pasture with greater than 30 percent legumes will require no nitrogen fertilizer. Preferred sources of nitrogen, application alternatives, and rates needed depending on yield expectations are discussed earlier and summarized in Table 5.
Phosphorus and potassium should also be applied on an annual basis according to the yield goal and type of pasture (see Table 4). Periodic Soil Testing
Pastures should be soil tested about every 3-4 years to determine the need for additional lime and fertilizer. To maintain legumes in the pasture, the soil pH, phosphorus and potassium levels are critical factors. Procedures for taking soil samples and recommended application rates depending on the soil test report were presented earlier.
Legumes do not persist in grass-legume pastures forever and need to be reseeded periodically. Over-grazing and poor soil fertility shorten legume longevity. Legumes should be re-introduced when they contribute less than 30 percent of the pasture's total forage production. Methods for renovating a predominately grass pasture with legumes have already been discussed.
Copies of the following publications are available free to Indiana residents through your Purdue University Cooperative Extension Service Office or from the Publications Mailing Room, 301 South Second Street, Lafayette, IN 47905-1092:
AY-251 Improving Pastures by Renovation
AY-253 Forage Selection and Seeding Guide for Indiana
AY-258 Minimizing Tall Fescue Toxicity
AY-263 Producing Emergency or Supplemental Forages for Livestock
ID-139 Birdsfoot Trefoil Production and Utilization in Indiana
EC-623 Pasture Leases
WS-9 Indiana Plants Poisonous to Livestock and Pets
ID-189 Moldy Corn Poisoning in Horses
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. It is the policy of the Cooperative Extension Service of Purdue University that all persons shall have equal opportunity and access to our programs and facilities.