It’s August again! From a forage perspective, August means one thing: stockpiling tall fescue.

If you have tall fescue pastures, you know they produce an abundance of forage in the spring, followed by a second, smaller flush of growth in the fall. By managing that fall growth, we can produce stockpiled forage, essentially standing hay that can be grazed later in the season, reducing the need for stored feed.

The recommended approach is to clip the pasture you plan to stockpile by the end of August. Mowing removes old, mature growth and weeds while encouraging new tillers to produce fresh, leafy forage. After clipping, apply 60 lb of nitrogen (N) per acre [about 130 lb of urea (46-0-0) per acre], ideally just after a rainfall or when rain is in the forecast. Adequate soil moisture is critical because, without it, nitrogen cannot stimulate forage growth.

Nitrogen is typically the most limiting nutrient in our pastures. When moisture is available, applying nitrogen promotes rapid growth, increases forage production, and improves forage quality. So, when everything comes together—late-August clipping, adequate soil moisture, and a timely nitrogen application—you’ve created the ideal conditions for tall fescue to produce high-quality forage that extends the grazing season well into winter.

One question I frequently hear from producers is, “Should I apply more than 60 pounds of nitrogen?”

To answer that question, we conducted on-farm research last fall in Clay, Jefferson, and Knox counties, where three generous Tennessee farmers allowed me to evaluate several nitrogen application rates on their stockpiled tall fescue pastures. The short answer is yes, you can apply more than 60 lb of nitrogen per acre—but from an economic standpoint, it probably isn’t worth it.

Our results showed that increasing the nitrogen rate from 0 to 60 lb N/acre increased forage yield by 48%, from 1,807 to 2,677 lb of dry matter per acre. However, once we exceeded 60 lb N/acre, the return on additional fertilizer declined rapidly.

Applying 90 lb N/acre produced only a modest increase in forage yield (200 lbs) while increasing fertilizer costs by another 33%. Increasing the rate to 120 lb N/acre provided essentially no additional benefit. In fact, it nearly doubled the fertilizer cost compared with a 60 lb N/acre application while producing less than 190 additional pounds of forage per acre (Figure 1).

The bottom line is simple: 60 pounds of nitrogen per acre remains the sweet spot for stockpiling tall fescue in Tennessee. It provides the greatest return on your fertilizer investment and maximizes the value of stockpiled forage. Spending more on nitrogen is unlikely to pay for itself under most conditions, making 60 lb N/acre the most profitable recommendation for extending the grazing season.

This project would not have been possible without the cooperation of three Tennessee cattle producers who volunteered their farms for this research. We greatly appreciate their support and commitment to advancing forage management practices that will benefit producers throughout the state.