Effects of nitrogen fertilization and cutting schedules on stockpiled tall fescue festuca arundinacea cultivar kentucky 31 1. forage yield
Collins, M.; Balasko, J.A.
Agronomy Journal 73(5): 803-807
ISSN/ISBN: 0002-1962 Accession: 005316425
Two experiments were conducted to study the effects of harvest management and N fertilization rates on spring-summer and autumn-winter production of tall fescue (F. arundinacea Schreb.) forage. Treatments in Exp [experiment] I included 4 N rates; 0, 60, 120 and 180 kg/ha applied as NH4NO3 in split applications of 1/2 in March and 1/2 in Aug.; 3 spring-summer cutting schedules: mid-June only, mid-May and early July, and mid-July; and 3 autumn-winter harvest dates: mid-Dec., mid-Jan., and mid-Feb. The soil was a moderately well-drained Lily loam (Typic Hapludults). Regression analysis indicated that the yield of forage available during winter increased as annual N application increased up to 137 and 126 kg/ha for mid-June stockpiling initiation in 1973-1974 and 1974-1975, respectively. The optimum annual N application rate for forage stockpiled beginning in early-July was calculated to be 197 kg/ha in 1973-1974 and 136 kg/ha in 1974-1975. Stockpiled forage yields decreased from 2.50 to 2.24 metric tons/ha between Dec. and Feb. averaged over the 2 yr of the study. Winter in vitro digestible dry matter yield (IVDDM) decreased during winter. In Exp. II, treatments included 4 N rates: 0, 75, 150 and 225 kg/ha applied as NH4NO3 at the time of the last summer or autumn cutting which occurred in either early Sept., mid-Sept. or early Oct. The soil was a Clarksburg silt loam (member of the fine-loamy, mixed, mesic familty of Typic Fragiudalfs). All forage was harvested in late winter. Forage yields during spring and summer increased up to the highest rate of N applied in both seasons. Any delay in initiation of stockpiling in Exp. II resulted in reduced winter yield. Winter yields increased in response to N application. Cutting date in autumn had little influence on forage yields the following spring, but rate of N fertilization influenced spring yield. Increasing autumn N application from 0 to 225 kg/ha increased spring forage production by an average of 2.40 metric tons/ha.