Effects of N Fertilization and Cutting Schedules on Stockpiled Tall Fescue. II. Forage Quality1

Abstract

AbstractTall fescue (Festuca arundinacea Schreb.) is the coolseason grass used most frequently to extend the grazing season in mid‐latitude states of the midwestern and eastern United States. Insufficient information is available regarding the influence of fertilization and harvest management on the quality of stockpiled tall fescue forage available during winter. Results of two field experiments dealing with the influence of cutting and N fertilization management on stockpiled tall fescue quality and chemical composition are reported.In Exp. I, treatments consisted of four N rates: 0, 60, 120, and 180 kg/ha applied as split applications of one‐half in March and one‐half in August; three dates when stockpiling began (1) mid‐June, (2) early July, and (3) mid‐July; and three autumn and winter harvest dates (1) mid‐December, (2) mid‐January, and (3) mid‐February. The soil used in Exp. I was a well‐drained loam (Typic Hapludults) with high levels of P and K. The treatment with the greatest influence on in vitro dry matter disappearance (IVDMD) was winter harvest date. Forage IVDMD decreased from 47.3% hi mid‐December to 41.1% by mid‐February. Crude protein (CP) concentration increased from 7.4% at 0 N to 10.4% at the 180 kg/ha N rate averaged over all other treatments and 2 years. Forage P and Mg concentrations were below minimum requirements for dry beef cows by late whiter.In Exp. II, conducted on a silt loam soil (Typic Fragiudalfs), treatments included four N rates: 0, 75, 150, and 225 kg/ha applied at the last summer or autumn cutting which occurred in either early September, mid‐September, or early October. In this experiment, all accumulated forage was harvested in late winter. Nitrogen fertilization increased forage IVDMD and CP, water soluble carbohydrate, K, and Mg concentrations in the stockpiled forage. Data from the two experiments Indicate that supplementation of energy, P, and Mg may be necessary in utilizing stockpiled tall fescue during January and February.