Mowing
Mowing is an important component of pasture management because it minimizes the spread of weeds and maintains high quality forage. Mowing weeds before seedheads are produced limits the spread of weeds by seed. Mowing also maintains a pasture stand that is uniform in maturity. Horses prefer to eat shorter grasses because it they have less fiber and are higher in protein. Mowing helps promote a nutritionally higher quality pasture. Shorter grass species such as Kentucky bluegrass and perennial ryegrass should be mowed to 2-3 inches, while a 3-4 inch mowing height is recommended for taller grass species such as orchardgrass and tall fescue.
Dragging
Dragging manure is a controversial topic because of conflicting information about the spread of parasites. Although from a nutrient management perspective, dragging manure distributes nutrients more evenly throughout the pasture and may reduce the potential for hot spots within the pasture of very high nutrient contents that could contribute to negative off-site environmental problems. Because most horse owners provide parasite control, dragging manure is recommended from a nutrient management perspective.
Rotation
Resting pastures is critical to maintain productive pastures. Horses tend to feed on grasses in the same area and can eventually weaken and kill pasture plants in these localized feeding areas. Removing horses from pasture allows plant species to recover by storing nutrients for subsequent regrowth. The recommended rule of thumb is to let horses graze for one week, or until the short grass species (Kentucky bluegrass and perennial ryegrass) are 2 to 3 inches high and the tall grass species are 3 to 4 inches high. Then let the pasture rest for three weeks, or when the short grasses have recovered to 5-6 inches and the tall grasses are about 7 inches in height.
The recommended stocking rate for horse pastures in temperate climates is 1-2 acres per horse. Stocking rates change as the seasons and weather conditions change. Pastures that can support 3 horses per acre in the spring, when pasture grasses are actively growing may only support half a horse per acre in the summer. Stocking rates vary according to the number of horses, hours of turnout, and level of management (rotation, mowing, fertilization, and weed control).
Continuous and rotational grazing are the two most common grazing systems used today. Rotating horses in equal-sized paddocks provides the benefit of reduced grazing pressure, improved yields, and (mid-season) opportunities for fertilization. Strip grazing within a paddock using portable electric fencing also utilizes pasture more efficiently. If continuous pasture must be used, overgrazing may be minimized by leaving horses on pasture for only a few hours a day or by removing them to another area where they can be supplemented with hay for at least four hours daily. Supplementing horses with extra hay and grain while they are on pasture will not prevent overgrazing.
After developing a grazing plan, the stocking rate of each paddock must be established. Because horses are capable of great physical damage, it may be several seasons after establishment before a pasture can handle the pressure of maximum stocking. In rotational systems, the first paddocks grazed are able to regrow while others are being grazed, and will be available again in three or four weeks, allowing greater stocking rates than in a continuous grazing system. Any number of paddocks can be used in rotation, but a minimum of four paddocks is ideal barring problems with drainage, drought, poor fertility, and weed invasion.
Portable electric fencing provides the most efficient and economic way to create temporary paddocks for rotation. Wide-colored poly tape is inexpensive, but flags may be necessary on the fence to enable horses to see them clearly. The problem of stationary watering systems, feeders, and shelter is solved in the rotational system by creating a common area that runs the full length of each adjacent paddock and is accessible to the one in use by opening the fence while the others are closed.
More detailed information on fencing materials can be found at these sites:
Renovation
Renovating is usually recommended in lieu of re-establishing pastures. Renovation, particularly in high traffic areas, may be required frequently to maintain ground cover. To ensure renovation is successful, several steps should be followed. Soil testing is important to make sure soil fertility is optimum and pH is in the desired range for pasture species. Also, pastures should be mowed or grazed fairly short so the soil is not shaded, and weeds should be controlled to minimize competition with germinating species.
The most efficient method to renovate a pasture is with a no-till drill. Many farmers have no-till drills and may be willing to assist you for a reasonable fee. Many equipment companies manufacture no-till drills designed for pasture use.
Broadcasting seed on the soil surface is a less efficient method because seed to soil contact is reduced, which limits germination. If this is the only option available to you, every attempt should be made to loosen the soil surface. A disc, harrow, or even a de-thatcher can be used for this purpose. Seed should be broadcast twice at right angles and a then a harrow should be used to mix the seed and soil. After broadcasting and harrowing, the soil should be rolled/packed to enhance soil to seed contact. Because it can take up to four weeks for certain grass seeds to germinate, the best seeding time is in April or early fall (August 15-September 15).
Another critical component of renovation is the time period before putting horses back on the renovated pasture. The best approach is to allow the renovated pasture to grow to about 6-8 inches, mow it, and then allow it to regrow to 6-8 inches and then mow it again. After the second mowing, allow the pasture to regrow to about 4-6 inches before putting horses on the pasture. This process will ensure that the species have developed adequate root systems such that grazing horses will not dislodge the species from the soil during grazing. Because renovation requires that the pasture is out of use for several months, it is important to develop a master-plan to allow at least one paddock to be renovated each year.
Sacrifice Areas
Sacrifice areas are separate parcels of land where the main goal is exercise and not grazing. A sacrifice area is a small enclosure or paddock area that provides space during times when pastures are easily damaged. Examples include wet soil conditions, winter, and following renovation. When land area is limited a sacrifice area can be of value during the winter months because pastures cannot survive continuous grazing and trampling during this season. The use of a sacrifice area can result in increased pasture productivity on remaining pastures. It should be located on well-drained soils away from waterways. Vegetation will likely be sparse to non-existent, as the area will be subjected to significant wear and tear. Consider locating your sacrifice area so that vegetated areas surround it; these will serve as a filtration system to reduce sediment and nutrient movement.
The following publications offer more information: