Meadow Fescue, Tall Fescue, and Orchardgrass Response to Nitrogen Application Rate
2009
Brink, Geoffrey E. | Casler, Michael D.
Nitrogen has a greater effect on grass growth than any other factor except moisture and temperature. As N costs continue to increase, understanding grass response to nitrogen will help producers determine the most appropriate application rate. Five N rates (0, 60, 120, 180, and 240 lb/acre) were split-applied to meadow fescue, soft-leaf tall fescue, and orchardgrass in three equal applications at two Wisconsin locations in 2005 and 2006. Plots were harvested to a four-inch stubble when sward height reached 10 to 12 inches to represent a typical defoliation scheme for managed grazing. Annual yield and herbage protein concentration of all varieties increased linearly as N application rate increased in all environments. In contrast, N-use efficiency (yield produced per unit of N applied) increased from 15 lb DM/lb N to 20 lb DM/lb N as rate increased from 60 to 120 lb/acre/year, but declined as N rate increased above 120 lb/acre/year. Although meadow fescue varieties produced less annual yield than tall fescue and orchardgrass by the second year, meadow fescue varieties generally had greater cell wall digestibility at each harvest.
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