Tall Fescue and Smooth Bromegrass. I. Nitrogen and Water Requirements¹

Abstract

Irrigated cool‐season grasses are needed in the Southern High Plains to extend grazing provided by winter wheat (Triticum aestivum L.) pasture and native range. Little information is available concerning their N requirements in relation to irrigation water application. The main objective of this study was to determine the N and water requirements for sustained high production of tall fescue (Festuca arundinacea Schreb.) and smooth bromegrass (Bromus inermis Leyss.). ‘Fawn’ tall fescue and ‘Southland’ smooth bromegrass were grown on Pullman clay loam (fine mixed thermic, Torrertic Paleustoll) under fertilizer N rates of 0, 168, 336, 504, and 672 kg ha‐1year‐1 on three water regimes. The N source was NH4NO3 except in a companion study in which feedlot manure was used. In one year of the 3‐year study when all irrigation treatments could be compared, adequately watered (W‐2) and fertilized (672 kg N/ha) tall fescue yielded 15.2 metric tons/ha, whereas similarly treated smooth bromegrass yielded 12.0 metric tons/ha. With moderate water (W‐I) and adequate N, however, smooth bromegrass yielded 6.9 and tall fescue yielded 5.2 metric tons/ha. With moderate water distributed for cool‐season forage production (W‐3), respective yields of similarly fertilized tall fescue and smooth bromegrass were 11.9 and 10.9 metric tons/ha. Also in 1976, first cuttings produced 77, 62, and 82% of total seasonal yields on W‐l, W‐2, and W‐3 plots, respectively. Over the 3‐year period, yield increases were almost directly proportional to the amount of N applied through 336 kg/ha. Yield increases per kg of applied N (to 336 kg/ha) were 12.1, 24.1, and 17.9 kg on W‐l, W‐2, and W‐3 plots, respectively. Feedlot waste, at N rates equivalent to those applied as‐ NH4NO3, was about one‐half as efficient as NH4NO3 in increasing yields. In the Southern High Plains, the most efficient irrigation management for tall fescue and smooth bromegrass is for early spring production with subsistence irrigation for the rest of the year.

Nitrogen Timing, Placement, and Rate to Improve Tall Fescue Yield and Quality

“…This result may have been a response of the fescue to the two passes of the application knives (once in fall and once in late winter); however, Moyer and Sweeney (1990) found no enhancement in final yield from knife-only passage without fertilizer N. Regardless, overall forage production above that obtained with the no-N control averaged 30 lb forage/lb fertilizer N at the 75 lb N acre −1 rate but was reduced to 23 lb forage/lb fertilizer N at the higher 150 kg N ha −1 rate. These values and the decline in efficiency of N conversion to dry matter with increasing N rate are similar to values reported by Phillips et al (1993) and Eck et al (1981), even though N rates and fescue management differed from our study. The CP, NDF, and IVDMD quality parameters measured for fescue harvested for hay was affected by the N placement method and to a lesser extent by N fertilizer timing and rate (Table 3).…”

Irrigation and Nitrogen Effects on Tall Wheatgrass Yield in the Southern High Plains

“…T all wheatgrass is well adapted to the Southern High Plains (Schuster and Garcia, 1973) and the Middle Rio Grande Valley of the USA (Jones and Hooks, 1976). It is widely used in year‐round grazing systems during the early spring and fall when small‐grains pastures are not available and before and after warm‐season species are productive (Eck et al, 1981; Schuster and Garcia, 1973; Undersander and Naylor, 1987). Tall wheatgrass is also used throughout the summer in lieu of warm‐season pastures.…”

“…There is considerable information about N fertility of other perennial cool‐season grasses in the literature (Black, 1968; Campbell et al, 1986; Collins, 1991; Cooper and Hyder, 1959; Eck et al, 1981; Frame, 1991; Frank and Bauer, 1991; Power, 1980). Power (1980), however, mentioned that one of the more important factors affecting the response to N fertility was grass species.…”

Nitrogen Management for Forage Production from Endophyte‐Free Tall Fescue Grown on Claypan Soil

“…Across years, increasing N rate lowered overall agronomic N use efficiency at both the R4 and stubble hay harvests from near 26 lb dry matter/lb N with 50 lb N/acre to ~15 lb dry matter/lb N at 200 lb N/acre (data not shown). As in this study, commonly occurring, nonlinear yield responses of tall fescue to increasing N rates have resulted in reduced agronomic N use efficiency with increasing N fertilization (Eck et al, 1981;Phillips et al, 1993;Sweeney and Moyer, 2014).…”