Spring Establishment of Turf-Type Tall Fescue Seed Crops with Cereal Companion Crops

Spring plantings of tall fescue (Festuca arundinacea Schreb.) for seed production are common in the Pacific Northwest, but seed yields are negligible in the year of planting. Planting tall fescue seed crops with cereal companion crops could increase the profitability of seed production. The purpose of this study was to determine the competitive effects of spring cereals on growth, seed yield, and economic return of turf-type tall fescue. ‘Bonanza’ tall fescue was interplanted iin 45-cm rows with ‘Waverly’ spring wheat (Triticum aestivum L.), ‘Steptoe’ spring barley (Hordeum vulgare L.), and ‘Cayuse’ spring oats [Avena fatua var. sativa (L.) Haussk.] in 15- and 30-cm rows. Experiments were initiated in March 1985 near Corvallis, OR, and repeated in 1986. Cereals reduced the photosynthetic photon flux density (PPFD) available for tall fescue seedlings, which caused transient increases in chlorophyll content and reduced soil temperature by 1.8 °C. Soil water content was decreased by competition from cereals, causing greater stomatal resistance and lower transpiration rate. Reduction in PPFD and soil water by cereals was responsible for low tall fescue tiller and dry matter production. Following cereal harvest, tall fescue regrowth and new tiller initiation were delayed until spring as a consequence of competition with cereals, resulting in fewer fertile tillers and a 61% reduction in firstyear (after planting) seed yield compared with no companion crop. Tall fescue growth and seed yield were similar with all cereals, row spacings, and combinations of row spacings and cereals. Second-year (after planting) seed yield was 15% greater when fescue was established with cereals than when no companion crop was used. Dry conditions caused low grain yield and increased competition by cereals, and was partly responsible for poor economic returns; however, fescue planted with spring oats earned $139.00 ha⁻¹ more than monoculture over a 3-yr period because of compensatory increases in second-year seed yield. This suggests that turf-type tall fescue establishment with cereals could be more profitable in spring with irrigation or in fall when water is not limiting. Contribution of the Oregon Agric. Exp. Stn., Corvallis. Tech. Paper No. 8477.