Prince William Soil & Water Conservation District
By Kate Norris
Finally, the grazing season is in sight! If you want to help a thinning pasture you have a couple a weeks left to overseed and fertilize. According to the agronomy experts at Virginia Tech, the optimal time for spring seeding of cool season perennial grasses (i.e., fescue, orchardgrass, bluegrass) is March 1st - April 15th.
Rules of (Green) Thumb to Graze By
How do you know when it's time to let the horses start grazing new spring growth? One important point to remember is that grass root length is generally equal to the grass height. The more closely a pasture is grazed or mowed the shorter the root system will get. Short roots will have difficulty reaching water and nutrients in the soil. By allowing the new growth to reach a height of 6-8+ inches you will greatly reduce the likelihood that over-anxious equines will graze and pull up your new seedlings-root and all!Start to graze your pastures when the grasses reach 6-8 inches. It's best to start with short periods of time to allow your horses' digestive system to become acclimated to the new food source (consult your vet for more information). Continue grazing until the grass is grazed down to about 4 inches. This height is an absolute minimum for orchardgrass. Orchardgrass stores its energy reserves higher up on the plant than fescue and bluegrass. Once the pastures have been grazed to 4 inches it's time to rotate the horses to a new pasture with taller grasses or if necessary into a sacrifice area paddock.
If you overgraze your grasses it's harmful to the plant in two main ways. First, the plant stores it's energy reserve in the base of its stem. Grazing into this storage area will deplete the plant's reserves making it weak and eventually killing it. Second, the plant needs a few inches of leaf-area to gather sunlight for the process of photosynthesis. Removing the plant's "solar panels" reduce it's ability to convert sunlight into food. Graze your pastures with management that balances the needs of both the horse and the plant for the best results.
After you have finished grazing a pasture it's a good idea to use a chain harrow or"drag" to break up the manure piles. The harrow will help distribute this fertilizer over a wider area and it will also help to kill parasite eggs by exposing them to sunlight. You will also probably notice that there will be taller grass in the horses'"restroom" areas (aka "roughs") and also taller weeds that the horses won't eat. Mowing the remaining grasses and weeds to a uniform height of 4 inches will keep your weeds from going to seed and it will encourage new more tender and palatable growth in all areas of the field. This type of management along with using interior fencing to create smaller pastures will promote more even grazing and less waste.
The most important rule to remember is that you have to watch your pastures closely to determine when and for how long the horses should graze them. The grass growth will be dependent upon the weather (rainfall and temperature), the type of grasses, the soil nutrient levels and pH, and your management. Don't try to follow a rotational schedule of moving the horses every "X" days or weeks. Watch the height of the grasses and only graze on dry days. Use your sacrifice area paddock as needed and enjoy great grazing in the weeks ahead.