Nitrogen Rate and Source Effects on Biomass Yield of Teff Grown for Livestock Feed in the Mid-Atlantic Region
Teff (Erogrostis tef (Zucc.)), an annual warm-season grass from Ethiopia, has potential to provide forage during periods when cool-season grass growth is limited by high temperatures. An experiment was conducted at three Virginia locations in 2009 and 2010 to determine the effect of nitrogen (N) fertilization rate and source on the yield, nutritive value, and nitrate content of teff. Nitrogen (N) was applied at 0, 45, 90, and 135 kg plant available N ha-1 as a single application of either ammonium nitrate (AN) or broiler litter (BL) at seeding. The experimental design was a randomized complete block with a two-factor factorial treatment design (N rate and source) and four replications. Biomass yield typically peaked at the 90 kg N ha-1 rate, but rarely showed an increase beyond the 45 kg N ha-1 rate. Yield ranged from 2325 to 7542, 1477 to 6151, and 1805 to 8875 kg DM ha-1 for the Blacksburg, Southern Piedmont, and Shenandoah Valley locations, respectively. Crude protein and total digestible nutrients ranged from 70 to 240 g kg-1 and 460 to 700 g kg-1, respectively. Nitrate concentrations increased with increase in N fertilization but source had no effect on nitrate concentration. Typically, nitrates only posed a health risk for ruminant livestock at N rates above 90 kg N ha-1, but dangerous levels were present occasionally at the 0 and 45 kg N ha-1 rates. The results from this study indicate that teff responds to moderate rates of N and could provide summer forage for grazing livestock in the mid-Atlantic region.