Care & Feeding of Overgrazed Pastures
By John Ferris, Full Dip. Tech., Prod. Eng.
Good pastures depend on good soil. That’s why professional contractors see your pastures literally from the ground up. The quality of the growth above ground will tell them the state of the root growth and the soil. What is up top determines what is down below. If there is damaged, overgrazed, matted, and undernourished top growth, the roots will not grow as the short-cropped and sickly sward cannot make the chlorophyll necessary to feed and sustain healthy root growth.
Overgrazing compacts the soil, reducing water infiltration and moisture holding capacity, and stunting root growth; less moisture combined with less organic matter reduces soil fertility. Virile weed species, which thrive on poor and sick soils, will then take over.
Overgrazed grasslands have resulted in many desert-like features we see appearing more frequently in the world today; these dry, barren areas are unproductive and useless. Once the grass disappears, water (rain) cannot penetrate into the soil and instead goes elsewhere in the form of run-off or erosion. The dry lands of Australia and the Mediterranean for example are the result of overgrazing primarily by sheep in Australia and goats in Southern Europe and North Africa.
Overgrazing compacts the soil and reduces its moisture-hold capacity. Weed species that thrive on poor soil will then take over, and some of them may be toxic to horses. Photo: Wikimedia/Andrew Smith
Repairing the Damage
Land owners often comment, “I have a pasture full of weeds and overgrazed grass and want to plant something which is good for my horses.”
Some folks do not have the acreage or ability to completely renovate their fields to good soil by ploughing, putting green matter back into the soil, fertilizing, and reseeding. This takes time as a newly seeded pasture should not be grazed for a complete year. The new grass will also need cutting to stimulate root growth and make thicker, stronger top growth.
Overseeding is the next best option. To achieve the best results, old manure needs to be distributed and the soil aerated to allow the “good guys,” worms and insects, to get to work. Aerating can be done by discing, harrowing, or using an aerator. Any implement which can scarify and open up the soil to let in oxygen and moisture is a good step towards better grass.
New pasture seed can then be broadcast over the field. Timothys, orchard grasses, and endophyte-free fescues are good species with which to overseed. Kentucky Blue grass is a later maturing grass but will hold the pasture together. Check with pasture and seed management experts who will be able to advise you on the species of pasture mixes which will do well in your area. Some grasses do better on wetter land, some on dry. Pasture seed can be custom mixed for particular geographic and soil conditions.
Temporary electric fencing is a good way to section off your pasture to rotate horses and avoid overgrazing.
Nitrogen is second to moisture in importance for maximum plant growth. However, it’s very important to wait until the new seed has taken a hold before fertilizing as any existing growth will tend to crowd out the weaker young grass if you fertilize too early.
One still has to keep livestock off the field to give the seed the chance to root and grow. Cutting or mowing should be done to achieve the thickening process and fertilizing, liming, and adding minerals such as manganese, boron, etc. may be needed where these elements are not naturally occurring. Do not lime and apply manure at the same time; there should be about six weeks between applications as lime causes manure to give off ammonia.
After liming or fertilizing, you will need irrigation or rain to wash the powders or pellets into the ground effectively so that the nutrients are available quickly. In dry spells and the summer months, irrigation is a huge help to keep grass growing. If you know rain is coming, time fertilization accordingly; the moisture from the rain helps organisms work and organic matter will break down to soil much faster.
When the grass has been grazed down to four inches in height, animals should be moved off, and the grass should be rested and allowed to regenerate until it is at least eight inches high.
Once you have achieved that beautiful and bountiful green pasture, keep it that way by being disciplined about frequently rotating your livestock. The rule of thumb is that when the grass is down to four inches in height, it is time to move the animals off and let the grass regenerate until it is back to at least eight inches tall. During the resting period, check and treat any deficiencies in the soil.
Plan your pastures so that you can easily divide them with temporary fencing that can be moved around as needed. Electric fencing is the easiest route to go as it is lightweight and does not require heavy permanent line posts. Use proper electric fence reels to wind in and out the wires so that storage in the winter time is very neat and easy. Plan to run the temporary electric wires from permanent posts at the edges of the pasture with the correct strainers and tensioners so that you can keep the temporary fence looking and working well. This will also allow for a convenient temporary gateway setup. A well organized system can be worked in minutes, and planning ahead saves time and money.
Happy horses in a healthy pasture.
All your efforts will result in your horses being well nourished and happy in a natural environment; you will save on feed costs and your property will give you the joy and beauty of green and bountiful pastures.
Author John Ferris and his wife Lesley have operated Ferris Fencing for more than 20 years, specializing in equine, general farm, horticulture, and vineyard applications, complete electric systems, and electric nets. As farmers, horse owners, and engineers, they are experts in the technical aspects of installation and application of fencing systems. For more information, visit www.ferrisfencing.com.
This article originally appeared in the June 2009 issue of Pacific & Prairie Horse Journal.