YIELD AND DIGESTIBILITY OF CRESTED WHEATGRASS AND RUSSIAN AND ALTAI WILD RYEGRASSES AS INFLUENCED BY N FERTILIZATION AND DATE OF FIRST CUTTING

Abstract

The effects of three rates of N fertilizer and nine dates of initial harvest on the dry matter (DM) yield, recovery, organic matter digestibility (OMD), and yield of digestible organic matter (DOM) of crested wheatgrass (Agropyron desertorum (Fisch.) Schult.), Russian wild ryegrass (Elymus junceus Fisch.), and Altai wild ryegrass (Elymus angustus Trin.) were studied on irrigated land for 2 yr. Russian wild ryegrass produced the highest yield in May, while the yield of crested wheatgrass equalled that of Russian wild ryegrass in June. Altai wild ryegrass yielded more dry matter than either Russian wild ryegrass or crested wheatgrass in July and August. Altai wild ryegrass showed the best recovery after cutting and produced the highest total DM yield. Crested wheatgrass had the lowest and Altai wild ryegrass the highest OMD. Nitrogen fertilizer application resulted in increased DM yield, increased OMD, and higher yield of DOM.