Pasture Prime

 

Most people have heard the phrase, "You are what you eat," but horse owners should take that statement a step further and see that, "Your horse is what he eats!" While the supplementing of grains and vitamins helps, the bulk of the horse's necessary nutrients are provided by grazing. A typical horse can normally eat up to 10% of its body weight in grass per day or 1% in dry weight (hay). From just a rough calculation, you can see why your pasture is an important part of your horse's health when a 1000 lb. horse can consume 100 lbs. of pasture a day.

A really green healthy pasture just doesn't happen by itself, and no matter how good your pasture looks in the spring, it's not likely to stay that way in the hot summer months unless you manage it properly. A good pasture does not just provide your horse with an economical food source, it provides him with the essential vitamins and minerals he needs to develop and stay in good health. Where to begin? Well you're not alone; in the following paragraphs we will take you through the process of setting up your pasture management plan, and help you prepare for changes in conditions and weather.

Pasture Planning Decisions

The first decision you need to make is to determine if your pasture can provide an adequate amount of forage or if it should be used as an exercise lot in which they can nibble as well. Climate and size best determine a pasture's nutritional value and capacity. The climate of your region has a dramatic impact on a pasture's potential, and things such as soil composition, rainfall, and mineral content are some of the most significant factors to consider.

For example, in areas of heavy rainfall (sixty inches or more per year), you need at least one acre of pasture to produce sufficient forage to sustain the needs of each horse. In areas of moderate rainfall (forty inches annually), it is best to allocate an acre and a half to two acres per horse. In arid regions where the rainfall is less than ten inches per year, you need at least two acres per horse - and you may need to seriously consider irrigating those areas to maintain your forage throughout the year. If you're in an area you cannot irrigate for physical or fiscal reasons, you may need up to fifty acres to feed one horse. If you allocate an area smaller than this recommended acreage, it will end up as an exercise lot by default, because a horse is a forage predator and can quickly defoliate any undersized lot. Another danger with pasture over-usage is that a horse may start consuming 'toxic' plants he would normally ignore, thus raising a serious health risk.

Pasture Use

Next, you need to establish a system for pasture use. Horses tend to graze in spots and are usually fond of one particular type of grass over another, which can quickly decimate a pasture or a species of grass if inadequate in size. One of the best methods of preventing this is to establish a system of pasture grazing rotation. By allowing your grazing areas a chance to reestablish after heavy use, you give the grass and legumes (which are especially sensitive to overgrazing) a chance to renew. By moving your horses from one pasture to another, you avoid beating the grass back; therefore you will prevent weeds from overrunning your pasture and also help break the life cycle of some parasites.

When you move your horses off a pasture, you should clip your pasture to 2-3 inches height to help control weeds, to prevent grasses from heading (going to seed), and to help return nutrients to the soil through the mulch of the clippings. Additionally, you should drag your pasture with a chain drag or similar device to break up and scatter the manure; this helps re-fertilize the soil and provides some parasitic control by exposing them to air and sunlight. Dragging is important because it allows the nutrients of the manure to be properly spread around and reabsorbed by the soil. It is estimated that 85 percent of the phosphorus and 50 percent of the potassium a pasture requires can be recycled through manure spreading. This can greatly reduce your need to fertilize and the cost you would incur to replace lost nutrients.

You can rotate your pasture in one of two ways:

1. Divide your pasture in quarters (ideally) or halves depending on the amount of acreage you have. If you only have an acre (a quarter acre isn't enough room for exercise) let your horse graze one section while the other recovers. If you're limited to a small lot and have a neighbor keeping horses (and both the humans and the horses get along) you may want to combine acreage and rotate between the two lots.

2. If you do not have a large enough area to section your pasture, you can use this second method. Establish a sacrifice lot where you don't worry about growing grass and can keep your horse while your pasture recovers (making sure you give your horse plenty of hay to keep his digestive system occupied). Whenever your pasture gets below 3", or under extreme weather conditions such as drought, excessive rain, or in winter, move your horse to the lot until it recovers. A horse needs a fenced off lot at least 1/10 of an acre per horse to have an adequate room. The advantages to free exercise are that it reduces behavior and respiratory problems, increases vitamin metabolism, and improves bone and muscle growth.

Three inches is the magic number for a pasture because below this level the blades of grass do not have enough surface area to collect the energy needed for the grass to grow and be renewed properly. Once your grass reaches this level, allow it to grow three inches more to fully establish, especially if you plan to have horses on it all day. You should not allow your pasture to grow higher than six inches because it will not convert sunlight at its maximum efficiency and is less palatable to your horse.

If you are limited on space and forced to put your horse in a sacrifice lot while your pasture recovers, you should gradually reintroduce him, a few hours at a time, to the new grass over a period of 7 to 10 days. This is to prevent the chance that your horse will colic when switching back to the new rich grass after eating hay for any extended period of time. The rate that your pasture will recover varies with the season and the weather. In the spring, growth is fastest and may only take two weeks, but in the summer when growth is slower it may take as long as thirty days.

What's in that Dirt?

Once you have decided on how you plan to use your pasture, the next step is to get your soil tested to see what nutrients your particular type of grass needs to grow and what nutrients it needs to feed your horse. Your local county or farm extension service can help you with this; give them a call to find out how to proceed. Most soil analysis reports only cost a few dollars, and they can give you a wealth of information such as the mineral and nutrient content of your pasture, and recommendations on what quantities of fertilizer, lime or other minerals are needed to bring your pasture back to its maximum potential. One of the three most important values in your soil analysis report is the pH or acidity of the soil; the other two are the phosphorus and potassium levels.

The pH is a scale in which the soil's acidity is measured. Values below 5 are considered acidic, and above 5 are considered alkaline. Most pasture crops have a preferred pH level. Grasses do best in the 5.5 to 6.5 pH ranges and legumes in the 6.0 to 7.0 ranges depending on the mineral/organic content. From this report you can determine the amount of lime (calcium carbonate or magnesium carbonate) needed to reduce acidity, or the amount of gypsum (calcium sulfate) needed to raise the acidity per acre. These rates will vary significantly if you are renovating or reestablishing your pasture. Soil reports will typically report the amount of lime necessary as the SMP buffer pH or "lime index"; this value is a measurement of how readily a soil will change its pH when limestone is applied. A highly buffered soil (one that binds its minerals) will have a lower lime index, requiring more limestone to change than a soil with a high lime index.

Lime is a premier pasture fertilizer and is not just a means of altering soil pH. Lime is essential in creating a high-energy pasture and is necessary on an annual basis because of the surface decay of grass. Without annual liming the surface area of your pasture becomes an acid zone, something not normally detected in soil analysis because they sample three inches below the surface. This acid zone can prevent the germination of some species of grass and legumes, clover especially. Most clovers will not grow if planted deeper than the seed is tall and this acid zone will prevent the germination of the seed. Acid surfaces will also inhibit earthworms from feeding and allows a buildup of dead grass thatch. Earthworms are a major player in keeping your soil healthy; they provide a means for the carbon dioxide to release up through the soil and for water movement downward. Their castings are rich in nutrients and have stabilizing properties for your soil.

However, for earthworms to thrive, you need a higher soil calcium ratio than what is normally available. Some of the added benefits of liming are (if not just for raising earthworms):

    • Increases the total nutrient potential of the soil by supporting bacteria, fungi, protozoa and other beneficial soil life forms
    • Helps a pasture resist drought better
    • Releases other important trace minerals and nutrients that can be locked up in calcium-poor soils
    • Sustains clover and other legumes that require twice the calcium as grass
    • Prevents some weeds from growing in excess (dandelion, plantain, chickweed, and buttercup).
    • Improves palatability of the grass and legumes
    • Helps prevent the horses from pulling out the grass.

Lime is better applied in little dustings than heavy applications and should be applied every few years to prevent acid surface buildup. Putting more lime on your pasture does not speed up the soil pH conversion; this process is a very slow conversion. Too much at once can cause an imbalance with your phosphorous levels. It is also better applied during the rainy season of the year to insure it is washed off the grass and into the soil.

Phosphorus and potassium can be returned to the soil through fertilizers or by dragging the manure, but be careful when applying the fertilizer because it can "burn" the grass. When applying either lime or fertilizer, it is best to do so in early spring or late fall to maximize growth and minimize burn. Also remember that after fertilizing or applying any similar substances, you should not have horses on the pasture for at least 4 weeks. Don't expect your soil to be corrected overnight; it may take 3 years to achieve a thick productive pasture, after which time you can take soil tests every 3-5 years. Another way to help your grass receive its nutrients is to aerate your pasture every two years and to plant legumes. Aerating your soil will allow nutrients and oxygen to reach the roots much more quickly, and will stimulate your grass to expand its root system. This is especially true in thick pasture areas where dense root systems can actually block or retard nutrients and growth. Legumes provide nitrogen.

Renovating a Pasture with Legumes

The best additions to your pasture are soil-enriching legumes such as clover and alfalfa which eliminate the need to apply nitrogen-rich fertilizers. They also provide a better forage throughout the season because they are generally more productive during the summer months than grass, and provide a higher forage protein. Legumes improve forage; they are more digestible and palatable, contain higher calcium and magnesium levels for better health, and reduce feed requirements and cost. Legumes should be introduced into a pasture when they contribute less than 30% of the pasture's total forage (approximately two legume plants per square foot). How often you need to reintroduce legumes depends on environmental conditions (drought), the level of management you provide and the types of legumes.

When tall fescue is the major source of nutrition, a potential horse health problem exists called fescue toxicosis. This condition will cause poor conception rates in brood mares, thickening of the placentas in pregnant mares resulting in foal death, long gestation periods, and poor milk production during lactation.

Chances of tall fescue toxicosis can be reduced by not applying nitrogen on established stands, using low-endophytic-fungus fescue varieties, renovating the fescue pasture with legumes, and moving or applying enough grazing pressure to keep the fescue immature (no seed heads). If tall fescue is the predominant nutrition source, make sure that at least 1/3 of the pasture is legumes.

When renovating a pasture with legumes, it is important to reduce the competition with grasses and weeds. To control grass, it's best to plant legumes when the grass has been reduced through overgrazing, and not to use fertilizer which stimulates the growth of grass.

Is it Time to Start Over?

If your pasture does not contain desirable species of grasses and legumes, you may want to renovate the pasture by destroying the existing plants and introducing the productive mixtures best suited to your climate and locale. Renovation is usually the best way to create a pasture with the most productive yield per acre. The following steps are necessary to renovate your pasture:

  1. Get a comprehensive soil test and determine how much lime and fertilizer you need.
  2. Make several applications of the lime and fertilizer, tilling it into the soil each time for even distribution before planting. If large amounts of fertilizer are required, allow additional time before planting seed so that the new seed does not get 'burned' by the fertilizer.
  3. Select a seed mixture that is best suited for the pasture drainage and conditions (see Seed Chart).
  4. Destroy or suppress the old pasture by tilling or plowing it in; we do not recommend using herbicides because of the residual effects to the ecology and possible contamination to your animals and the water supply. Do not till your soil in wet conditions.
  5. Seed your pasture.
  6. Protect the seeded area until new plants are well established. In good conditions this can take a minimum of six weeks, and as much as a full season. Make sure that no weeds take control, as this can severely affect the end result.

In areas that are considered high traffic areas, tall fescue is a good choice because it is a tougher species and can endure more wear. As mentioned earlier, though, care should be taken to prevent the fescue from maturing so that you do not risk the potential problem of fescue toxicosis. When planting legumes, it's a good idea to plant a secondary legume because of differing growth rates and conditions. If you are seeding both legumes and grasses, it is best to have a ratio of about 10-20% legume to grass ratio.

Seeding Charts (Grasses):

Spring

Grass Species

Seeding Dates

Pounds of seed Per Acre

Kentucky Bluegrass

Feb. 1 to May 1

5 -10

Orchardgrass

Mar. 1 to May 1

10

Reed Canarygrass

Mar. 1 to May 1

6-8

Smooth Bromegrass

Feb. 1 to May 1

10-15

Tall Fescue

Mar. 1 to May 1

15

Timothy

Feb. 1 to May 1

5-6

 

 

Fall

Grass Species

Seeding Dates

Pounds of seed Per Acre

Kentucky Bluegrass

Aug. 1 to Sept. 15

5 -10

Orchardgrass

Aug. 1 to Sept. 1

10

Reed Canarygrass

Aug. 1 to Sept. 1

6-8

Smooth Bromegrass

Aug. 1 to Sept. 1

10-15

Tall Fescue

Aug. 1 to Sept. 1

15

Timothy

Aug. 1 to Nov. 1

3-4

When seeding legumes you should select species that are best suited for your region and growing conditions. Selecting the proper seeding dates for each is important. If you plant too early or too late, the young seedlings can be killed by drought or frost. When seeding with legumes it is helpful to select a seed that is inoculated with the proper rhizobia bacteria or buy a pre-inoculated seed to insure that the nitrogen-fixation process will occur. (This is accepted and recommended for organic growing too.) The chart below gives you legume to grass ratios when planting the two together.

Seeding Chart (Legumes and Grasses):

Principle Legume / Rate per acre

Secondary Legume / Rate per Acre

Alfalfa / 8-10 lb.

--

Alfalfa / 4-6 lb.

Red Clover / 4-6 lb.

Alfalfa / 6-8 lb.

Ladino Clover / ¼ lb.

Red Clover / 6-8 lb.

--

Red Clover / 4-6 lb.

Ladino Clover / ¼ lb.

Red Clover / 4-6 lb.

Korean lespedeza / 8 lb

Alsike Clover / 3-4 lb.

--

Alsike Clover / 2 lb.

Ladino Clover / ¼ lb.

Birdsfoot trefoil / 5

--

Ladino Clover / 1 lb.

--

 

Other concerns

During the establishment process it is important to control weeds. Proper timing of your planting and some environmentally safe means of controlling weeds are important to giving your stand a good start. Two good methods for controlling weeds - periodic mowing to a height just above the new forage (being careful not to smother your new seedlings with the mulch) and the removal of weeds by hand - can help get your pasture established with little fuss. We do not endorse the application of herbicides to suppress weeds because of the threat they pose to the environment and your animals. Note: Some broadleaf weeds (if not in abundance) are quite beneficial to your animals. Dandelion and plantain are two examples that are good nutritional sources of forage.

You should identify and remove any poisonous plants from your pasture. They can cause all sorts of health problems and even death if ingested by your horse. Ornamental shrubs and nightshades are the most common poisonous plants. Also the trees that lie within or border your pasture should be identified. If they are toxic to horses they should be isolated or removed from your pasture. Even dead leaves can be lethal (i.e. the dead or wilted leaves from a cherry tree can cause instant fatality if ingested). Fortunately, most poisonous plants are not palatable to horses, but in poor pasture conditions your horse may start looking for other things to eat.

Wrapping it up

Remember the success or failure of your pasture is mostly in your hands. Feed the soil properly and the soil will provide the correct combination of nutrients to the plant; the plant can then provide a balanced diet for the horse. If you neglect your pasture, the results, if not immediate, will cost you more in the long run, especially after your pasture predator and a season of hard use take their toll. If you go through the steps of planning, testing, correcting, planting (if necessary) and pasture rotation, your results should prove your efforts worthwhile. With time and patience you should have a pasture that remains strong even through difficult conditions.

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