– Chris Teutsch, UK Research and Education Center at Princeton
Stockpiling tall fescue is one the cheapest and best ways to provide winter grazing for livestock in the Commonwealth. In good years, tall fescue pastures top-dressed with 60-80 lb nitrogen/A in mid August can produce 1-2 ton/A hay equivalent. The question in drought years is does this recommendation work? No pasture will respond to nitrogen until it rains. In addition, pastures that have been overgrazed during a drought have the least potential for fall growth. Applications of nitrogen for stockpiling should target pastures where the “gates were closed” and overgrazing was prevented!
The next question is when and how much nitrogen to apply. Ideally nitrogen for stockpiling should be applied in mid-August at a rate of 60 to 80 lb/A. In a drought year there are several approaches to stockpiling. The first is to apply nitrogen in mid-August at normal rates and then pray for rain. The second is to delay applications until rain looks like a sure thing. This option requires more planning since nitrogen needs to be applied prior to the impending rain. As the application date becomes later, decrease the amount of nitrogen since the grass will have less time to grow before frost and cool temperatures set in.
Research conducted in Virginia has shown that not all nitrogen sources are created equal when it comes to stockpiling. Three years of data found that the most effective nitrogen sources for stockpiling in late summer were ammonium nitrate and ammonium sulfate. Using urea or urea ammonium nitrate (30% solution) resulted in significantly lower yields. If you are using these products, treat them with a urease inhibitor containing the active ingredient NBPT. This ingredient has been tested extensively and proven to prevent volatilization. Organic nitrogen sources such as broiler can be used for stockpiling but they tend to yield lower because not all the nitrogen is immediately available to the plant at application.
The last option is to stockpile with no nitrogen. In well managed grazing systems, a strong nitrogen cycle and higher levels of soil organic matter can be developed, making these pastures less responsive to nitrogen applications. I would suggest testing this approach before applying it across large acreages. To accomplish this, apply nitrogen as you would normally, but leave some no nitrogen strips out for comparison. This will give you an indication of the difference that the nitrogen application made in both yield and quality.
In drought years, winterfeed is often tight, so maximizing the utilization of stockpiled grass is essential. Strip grazing stockpiled fescue can increase grazing days by 30 to 40%. Starting at your water source, allocate only enough pasture for 2-3 days of grazing. This is easily accomplished by using a forward temporary electric fence. No back fence is required since plants are dormant. During wet periods feed hay in a sacrifice area to avoid wasting stockpiled grass and damaging pasture sod.