Submitted to: World Wide Web
Publication Type: Other
Publication Acceptance Date: July 21, 2008
Publication Date: August 1, 2008
Repository URL: http://www.cias.wisc.edu/wp-content/uploads/2008/08/grassclippings808.pdf
Citation: Brink, G.E., Casler, M.D. 2008. Orchargrass, Tall Fescue, and Meadow Fescue Response to Nitrogen Rate. Grass Clippings [electronic newsletter]. 3(2). Available: http://www.cias.wisc.edu/wp-content/uploads/2008/08/grassclippings808.pdf Technical Abstract: Nitrogen has a greater effect on pasture grass growth than any other input except moisture, but the cost of fertilizing pastures with N has risen significantly. Although seeding legumes or applying manure can increase pasture productivity, a producer may be unable or unwilling to grow legumes, lack sufficient manure, or feel that N fertilizer produces more dependable growth. Understanding the relationship between yield and N application rate would help producers determine an appropriate rate to meet their production requirements. Five rates of nitrogen (0, 60, 120, 180, 240 lb/acre) were applied in three equal applications to three meadow fescue varieties and one variety of soft-leaf tall fescue and orchardgrass at two Wisconsin locations in 2005 and 2006. Plots were harvested on a grazing schedule, or whenever grass reached 10 to 12 inches height. At both locations, annual yield of all varieties increased linearly as N application rate increased. Nitrogen use efficiency (yield produced for each unit of N applied) increased from 15 to 18 lb DM/lb N as rate increased from 60 to 120 lb N/acre/year, but declined as N rate increased above 120 lb N/acre/year. Producers should also consider the timing of application and potential N recycling. Response to N application is greatest in spring, but also is a time when forage production exceeds demand. In addition, some N is returned to the pasture by the grazing animal in manure and in senescing leaves and roots, which should be accounted for when planning N fertilization.