Reducing the risk of N loss when stockpiling fescue

News
Nov 8, 2013
by WLJ

After feeding corn stalks in the fall, probably the lowest cost way to feed cattle is to stockpile forages for fall and winter grazing. Stockpiling means to make the last harvest by clipping or grazing of a hay field or pasture and then let it grow for grazing later; in this situation, in the fall or winter. While most predominantly grass-based fields will work, fescue works the best as it maintains quality into and throughout the winter better.

Many studies have demonstrated that adding nitrogen (N) to the fields will increase quality and quantity of the grass. Urea is the most common form of N used for stockpiling in Ohio, but the biggest risk is applying the urea, then not getting a rain allowing much of the nitrogen to be lost through volatilization.

One product available locally to reduce nitrogen loss is Agrotain, a urease inhibitor. Several universities have done research on urease inhibitors and the University of Kentucky has an excellent factsheet on nitrogen inhibitors (http://www2.ca.uky.edu/ agc/pubs/agr/agr185/agr185. pdf).

In southeast Ohio, a study is underway to evaluate quality and quantity of stockpiling fescue with no nitrogen (control), 100 pounds of urea (46 pounds N), and 100 pounds of urea with Agrotain at a rate of five quarts of the product applied per ton of urea. There are lower rates that can be used but we chose the high rate that would provide up to 14 days of protection. Stockpiling began on Aug. 5 and there was not a soaking rain for 17 days (there were three days of .05 to .15 inches of rain); then there was 1.5 inches of rain on Aug. 22.

On Oct. 14, initial samples were harvested from a set of plots and the control plot had 2,003 pounds per dry matter (DM) acre, the 46 pounds of N had 2,904 pounds of DM per acre, and the 46 pounds of N with Agrotain had 4,141 pounds of DM per acre. The cost of the urea was $465 per ton or $23.25 per acre and the Agrotain cost $112.44 per ton or $5.62 per acre. We had good initial responses from the urea alone and even better with the urea and Agrotain. We have over an extra ton of dry matter so far for less than $30 per ton. All of the plots will be harvested later this month for quality and quantity, so I expect the yields to be even better.

If we can minimize the risk of N loss, maybe more of us can stockpile for fall and winter grazing. It is nice to not have to feed my cattle right now and in fact, they are probably grazing better feed than the hay I have in the barn. We had a couple farmers in Morgan County last year make it into March before they had to start feeding hay. This week, cattle are grazing for a third day on a stockpiled field. The field was grazed three times in March and April, then had two cuttings of hay, followed by stockpiling since early August. If we can minimize the amount of hay we need to feed, maybe we can make it as easy as raising chickens! — Chris Penrose, OSU Extension

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