Kentucky Ag News

Will late-summer nitrogen applications to pastures pay off in 2013?


University of Kentucky College of Agriculture, Food and Environment

We are close to the point where some livestock farmers would normally start to apply nitrogen to tall fescue pastures to boost production levels and stockpile for fall and winter grazing. Since there are many factors that will impact the profitability of this practice, the question at hand is: Under what set of conditions will applying nitrogen to pastures pay this year?


Given the excellent early and mid-summer rains throughout most of the state, we generally have good soil moisture conditions this year going into late July. Areas with good soil moisture will typically have the best response to nitrogen applications. On the other hand, we are also having good hay yields, so the “cost” of hay will likely be a bit lower than normal this year.

The price of nitrogen was evaluated on an elemental basis between 55-75 cents per unit ($370-500 per ton ammonium nitrate and $505-690 per ton urea with urease inhibitor), with application rates of 40 and 80 units/acre. Three response rates (low, medium, and high) were evaluated corresponding to various soil moisture and fertility conditions.

Farm size and management practices were assumed to be typical Kentucky conditions: 30-cow herd with late winter/early spring calving. Waste rates were estimated at 25 percent for both hay feeding and grazing. Forage quality was estimated at 55 percent TDN for hay and 65 percent for stockpiled fescue. Machinery and labor costs were estimated at 9 cents and 25 cents per cow-day for grazing and hay feeding, respectively. P and K from the hay were assumed to be recycled back into pastures at a 50 percent rate at 50 cents per pound for P2O5 and 50 cents per pound for K2O.

A range of hay prices were evaluated to determine which prices, if any, would result in profitable nitrogen applications this year. In general, there appear to be considerable opportunities for profitable nitrogen applications this year, mostly in fescue stands with a low clover content (less than 15 percent). Assuming a medium response rate and nitrogen priced at 65 cents per unit ($600/ton urea with urease inhibitor), hay prices at or above $60/ton generated moderate to high cost savings. Even with the low response rate, these stands generated low to moderate costs savings with hay priced above $60/ton. With a high response rate, these stands generated high cost savings with just about all combinations of nitrogen and hay prices.

Cost savings occurred less frequently in the mixed fescue-clover stands. With a medium response rate, hay prices needed to be at or above $100/ton to generate even low cost savings. With the high response rate, hay prices needed to be at least $80/ton to generate low cost savings. Additionally, any potential savings in the fescue-clover stands need to be balanced against the potential loss of clover due to N applications. As a consequence, it is advised to target pastures with the highest fescue content before considering nitrogen applications to these mixed fescue-clover stands.

As noted above, hay quality was assumed to be medium-quality, mixed hay with a 55 percent TDN. There is a lot of hay put up in Kentucky that has a much lower feed value. For each 5 percent reduction in TND, add $6-9/acre in cost savings for 40 unit applications and $10-15/acre for 80 unit applications. Use the lower part of this range for the medium response rate and the higher part of this range for the high response rate.

For more detailed results, consult the publication “Profitability of Nitrogen Applications for Stockpiling Tall Fescue Pastures – 2013 Guide” that can be found at:

This article was written by Greg Halich, professor of farm management economics in the University of Kentucky College of Agriculture, Food and Environment. The article first appeared in the July 30 edition of Economic and Policy Update.