|
Pasturing Pointers
By Jeremy W. Singer, Ph.D.
Q: Which is preferable: renovating a tired pasture by reseeding stressed areas or going back to square one with the acreage and establishing brand-new plantings?
A: Both approaches require considerable planning and management if you expect to get good nutrition out of your pastures, and both will improve the productivity of your acreage. Establishing a new pasture is the more expensive option because of the tillage, weed-control and fertilization involved in preparing the seedbed. Of course, you will also be buying a lot more seed if you plant the entire acreage than if you spot renovate. Finally, you will have to allow the renewed area untrampled time to grow its new crop. If you reestablish a pasture, that means the whole field/paddock will be out of service until the new plants can withstand grazing pressures. With spot renovation, you may be able to fence off the renewed areas and continue to use the remainder of the field. Yet sound pasture management is never a matter of finding the quickest fixes: In the long run, a complete makeover of eroded, weed-choked, muddy/dusty fields ultimately produces more nutritious pasturage than partial reseedings. The full treatment also provides a healthier environment for the horses and contributes to soil conservation and ground-water quality.
Q: How long must I wait between seeding a pasture and returning my horses to the area for grazing?
A: Horses are real sod killers; just look around your paddock gates for proof of that fact. Heavy hoof traffic batters the life out of grass and legumes alike. Then there's the murderous effects of their grazing habits: Horses nip plants off down near ground level and may pull fragile plants up by the roots. If you expect your newly established/renovated pasture to withstand the onslaught, the plants have to be well-rooted and mature. The species of pasture plant(s), the growing conditions after seeding and the soil conditions once horses are returned to the area all contribute to the length of the waiting period. The cool-season plants used for pasturage in the greatest part of this country may need the better part of a year to become fully established after planting. One strategy (depending upon your local weather patterns) might be to plant the acreage in the fall when rain and cooler temperatures encourage germination and growth, to keep horses off the area throughout the winter and spring, to harvest a cutting of hay from the young stand the following early summer and finally to reintroduce horses when the now-mature plants had regrown to a height of several inches. If your summers are hot and dry, the recovery for the cool-season plants may not occur until early fall. This seems like a very long time, but if you allow grazing of immature stands, all the expense, time and effort you have put toward renovation will be trampled underfoot.
Q: Are all species of pasture grasses and legumes safe for horses?
A: Cultivated pasture plants are generally safe for horses, but some have undesirable effects under certain circumstances.
- Tall fescue stands that are infected by a specific endophyte (a microscopic parasitic plant) produce alkaloids that cause birth and lactation problems in pregnant mares grazing on them during the last three months of gestation. The druglike alkaloids also depress weight gains in young horses grazing on infected fescue.
- Red clover infected with Rhizoctonia leguminicola contains an alkaloid that can stimulate excess salivation, commonly called "slobbers."
- Alsike clover can trigger photosensitivity--a serious allergic skin reaction to sunlight complicated by liver involvement--in horses; areas of pink skin underlying white hair are especially affected.
- Sorghum, Sudan grass and related hybrids contain high concentrations of prussic acid during periods of rapid growth. Horses can suffer fatal cyanide poisoning within one to three hours of grazing fresh or wilted plants. Chronic poisoning from more mature plants causes hind-limb incoordination and often leads to dangerous urinary-tract infections in horses.
- Grass pollen can trigger respiratory hypersensitivity in susceptible horses who are continually pastured, producing a form of summer heaves.
For the most part, however, the genuine hazards to grazing horses are poisonous weeds and trees allowed to grow within their reach.
Q: How much does the palatability of the species matter in my selection of pasture grasses and legumes?
A: Your horses will eat their favorites first; if those run out, they'll grudgingly eat the rest. This means that the preferred forage species in a mixed pasture is often overgrazed, even as the rest of the roughage grows abundantly into useless overmaturity. If you are able to do so, study your horses' grazing preferences before you establish new pastures or reseed old ones, and give them what they like. Research into the palatability of various forage plants for horses offers conflicting results, but studies generally show a preference for mixed pastures rather than single-species grazing. Kentucky bluegrass and alfalfa usually come out on top of the grass and legume taste tests conducted in this country. If your mixed pasture has areas of less favored grazing, mowing these areas several times during the grazing season keeps the plants from reaching dead-end tasteless maturity.
Q: Why are some forage species more "durable" than others?
A: First, the plants that persist season after season have their species' growing needs well supplied by the environment: the right amount of moisture, congenial temperatures and appropriate soil characteristics. Second, they experience no more grazing stress than they're made to tolerate. Third, they have "coping strategies" for the bad times and propagate readily to regrow in bare areas. Dormancy is a coping strategy used by perennials to get through freezing weather or dry/hot times without dying; during this phase, the plants don't produce any edible growth, but they are not dead, as would be the case with annuals incapable of withstanding freezing temperatures, droughty soil or other adversity. Deep roots, a dense growth habit and low "crowns" are protective characteristics for horse forages because they can withstand trampling and close grazing. Plants that spread by root stolons or rhizomes as well as reproducing by seed are more vigorous in repairing overgrazed and trampled spots. Unfortunately, the most durable forage plants are rarely at the top of horses' palatability lists, although the well-loved Kentucky bluegrass does withstand grazing pressures well.
Q: I'd rather be riding than picking up manure, moving rotation fencing or mowing weeds. Prove to me that it's worth my time and effort to aggressively manage my pastures through rotational grazing, fertilizing, weed control and all that stuff.
A: How do improved yields, superior nutrition, reduced parasite infestation, lower (or no) feed costs, better horse health, safer horse footing, enhanced water and soil quality and upgraded farm aesthetics strike you as payoffs? Perennial forage plants are not just the best food sources for horses, they are guardians of both soil and water quality. Increasingly, states are enacting laws requiring livestock owners to establish nutrient-management plans--in other words, procedures for preventing run-off of animal wastes into surface water--and well-tended pastureland is one of the horseman's primary buffers against pollution. A barren horse lot strewn with manure is a brew of excess phosphorus just waiting to be washed into the nearest stream or pond with the next heavy rain.
Q: If I use portable fencing to subdivide my pastures for rotational grazing, what's the safest arrangement?
A: Electric fencing is an efficient and inexpensive means for creating temporary paddocks in a larger field, and it can be safely set up using wide, white or brightly colored poly tape that is more visible than thin strands of wire. Even then, attach fluttering flags or ribbons to allow horses even greater visibility. When you put up only one tape, string it at a height of approximately 33 inches. For double strands, put one at 20 inches and the other at 36 inches. For triple strands, space them at 16, 28 and 40 inches. Rotational grazing often means that you'll have to arrange the patterns so horses always have access to a common watering and feeding area, which is simplest when this is central to the grazing squares or strips. Be sure this common area is roomy enough for all herd interactions to be carried out without any individuals being trapped or kept away from essential water and nutrient sources.
Q: What's the best way, in terms of effectiveness and safety, to fertilize my pastures?
A: First of all, you have to know what nutrients your soil lacks before you start applying anything. Have soil tests done through your county extension office or a seed/fertilizer supplier, then fertilize according to these recommendations. Legumes require more phosphorus and potash than do grasses, which generally respond well to nitrogen fertilization. Lime may be needed to reduce soil acidity and bring it into the pH range of 6.4 to 6.8 that forage plants find ideal. Liming is best done at the establishment of a pasture and may not be needed again for some time. Fertilization, on the other hand, can encourage hardy regrowth in grazed-down pastures and is more beneficial if applied several times throughout the grazing season than in a single annual application. If you practice rotational grazing, you can lightly fertilize a strip just after you move your horses off for the three-week period of rest. During that time, the nutrients will boost the regrowth and be sufficiently absorbed in the soil so as to pose no hazard to the horses when they return to graze.
Q: Can I realistically expect my pastures alone to provide all my horses' nutritional needs--excepting water and trace-mineral salt, of course?
A: Nature knew what she was doing when she put horses and grasslands together. A mature moderately worked horse can live very well on peak-season pasture alone; all the nutrients he needs are present and perfectly balanced for equine consumption in well-tended forage plants--except for that water and salt and, in some situations, specific trace minerals. Even two-year-olds, who are still growing, have been found to get all they need from most forage species. Younger horses, gestating and lactating mares and horses in hard work, however, may be left short by an all-grass diet. Researchers have determined that a pasture must produce 450 pounds of forage per acre per month to sustain a 1,000-pound horse. Under the ideal growing conditions in the spring, well-tended mixed grass-legume pastures produce 1,100 pounds per acre and all-grass stands produce 1,400 pounds, meaning that there's plenty to spare in peak season and probably enough throughout the rest of the grazing cycle to fill a great portion of your horses' feeding needs.
Jeremy W. Singer, Ph.D., is an extension specialist in field and forage crops at Rutgers University in New Brunswick, New Jersey. This article is from EQUUS Magazine, Issue 270 (April 2000), copyright PRIMEDIA Enthusiast Publications, Inc. All rights reserved.
Related Articles:
Pasture Perfect
Good Grasses, Lush Legumes
Submit Your Question
|
