Seasonal Production, Perloline Content, and Quality of Fescue After N Fertilization1

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Abstract
The already great importance of tall fescue (Festuca arundinacea Schreb.) as a forage grass could be enhanced if its yield and quality during summer, fall, and winter could be increased. The effects of several rates (from 50 to 700 kg/ha) and times (March, May, July, September, October, November—singly or in different combinations) of N fertilizer application on tall fescue seasonality of production and quality were evaluated over a 3‐year period. Herbage was removed at a 5‐cm stubble whenever growth reached 8 to 10 cm. Variables measured included dry matter production in vitro digestible dry matter (IVDDM), and contents of perloline, and total and nitrate N. Nitrogen fertilizer increased yield and total N, NO3‐N and perloline in harvested forage. Season affected IVDDM more than N fertilization, although the higher or more frequent N rates increased IVDDM indirectly. Increases in total N, NO3‐N and perloline were evident in individual harvests soon after N applications, but yield increases were not observed until precipitation occurred. Summer N fertilization to increase yield is therefore questionable unless soil moisture is present, and it may result in higher NO3‐N and perloline contents than are desirable for quality forage. Applying more than 50 kg N/ha in September did not increase appreciably quality and quantity of fall forage. Late fall N fertilization did not increase measurable winter forage production, but it did increase earliness and yield the following spring.