Effects of N Fertilization and Cutting Schedules on Stockpiled Tall Fescue. I. Forage Yield1
- Michael Collins and
- J. A. Balasko2
Forage stockpiled in situ for winter use provides pasturage during a period of low forage production in midlatitude states of the midwestern and eastern United States. 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 (Festuca urundinacea Schreb.) forage. Treatments in Exp. I included four N rates; 0, 60, 120, and 180 kg/ha applied as NH4NO3 in split applications of one-half in March and one-half in August; three spring-summer cutting schedules (1) mid-June only, (2) mid-May and early July, and (3) early June and mid-July; and three autumnwinter harvest dates (1) mid-December, (2) mid-January, and (3) mid-February. The soil was a moderately welldrained Lily loam (Typic Hapludults). Regression analysis indicated that the yield of forage available during winter increased as annual N application increased up to 137 kg/ha and 126 kg/ha for mid-June stockpiling initiation in 1973–1974 and 1974–1975, respectively. The optimum annual N application rate for forage stockniled beginning in earlffuly was calculated to 6e 197 kg/ha in 1973–1974 and 136 kg/ha in 1974–1975.
Stockpiled forage yields decreased from 2.50 metric tonslhd to 2.24 metric tons/ha between December and February averaged over the 2 years of the study. Winter in vitro digestible dry matter yield (IVDDM) decreased during winter.
In Exp. II, treatments included four N rates: 0, 75, 150, and 225 kg/ha applied as NH4NO2 at the time of the last summer or autumn cutting which occurred in either early September, mid-September, or early October. The soil was a Clarksburg silt loam (member of the fine-loamy, mixed, mesic family 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 did influence 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.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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