Reaction of Tall Fescue to Frequent Summer Nitrogen Applications1

Abstract

AbstractThe postulation that tall fescue (Festuca arundinacea L. var. ‘Ky. 31’) might tolerate and respond more favorably to higher rates of N in summer if applied frequently in small increments was studied at Holland, Va. from 1966 to 1970. Weekly N applications of up to 56 kg/ha, May through August each year, and one application of 168 kg/ha each March, totalling 1,120 kg/ha by September 1, thinned stands of tall rescue by only 30%. Rates of N up to 22.4 kg/ha per week increased density of stands.Annual dry matter yields increased from 41 to 110 q/ha as N rates increased up to 39.2 kg/ha per week. Yields from the May harvests were highest with generally lower yields in successive cuttings taken every 4 to 6 weeks through September. Nitrogen content was lower in the May cuttings than in succeeding cuttings. Generally, protein concentrations increased in the summer cuttings as the rate of N increased to 22.4 kg/ha per week, above which no increase occurred. Nitrogen uptake by fescue increased from 90 to 375 kg/ha as weekly N rates increased from 0 to 56 kg/ha. The proportion of N removed in rescue forage relative to that applied was highest (61%) from 5.6 kg/ha per week of N and lowest (33%) from 56.0 kg/ha per week of N.Use of tall rescue may be feasible as a vegetative cover for disposal of high N waste if applied frequently in small increments.Soluble carbohydrate concentrations in the stubble probably were not low enough (7%) to influence regrowth and stand survival appreciably.