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.

There are many factors that will impact the profitability of this practice. Under what set of conditions will applying nitrogen to pastures pay this year in Kentucky?

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 summer. 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 cents and 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 per 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 per 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 was evaluated to determine which prices, if any, would result in profitable nitrogen applications this year.

In general, there appears to be considerable opportunity for profitable nitrogen applications this year, mostly in fescue stands with low clover content, or one with less than 15 percent.

Assuming a medium response rate and nitrogen priced at 65 cents per unit ($600 per ton urea with urease inhibitor), hay prices at or above $60 per 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 per ton.

With a high response rate, these stands generated high cost savings with just about all combinations of nitrogen and hay prices.

For more details to see if that late-season nitrogen can help your pastures, click here.