Nitrogen and phosphorus fertilizer requirements of tall fescue grown on blackland prairie soils

Dal-100 tall fescue (Festuca arundinacea Schreb) was established by seeding into a prepared seedbed during the fall of 1987 at the Texas A&M University Research and Extension Center at Dallas, TX, to determine the nitrogen (N) and phosphorus (P) fertilizer requirements for seed and forage production. Fertilizer treatments consisting of 0, 67, 134, and 201 kg N ha(-1) at 0 or 56 kg P ha(-1) were applied in September of 1988, 1989, and 1990. Dry matter increased with increasing N rate during each year of the study with mean yields of 2,412, 3,756, 4,344, and 4,936 kg ha(-1) for the 0, 67, 134, and 201 kg rates, respectively. No seed was produced in 1989, and N did not increase seed production in 1990. In 1991, the seed produced with ON was less than seed produced in plots having N, but seed production did not differ at 67, 134, and 202 kg N ha(-1). Protein concentration increased with increased N for each harvest, but the greatest difference in protein concentration was due to harvest date. No differences in dry matter production, seed production, or protein content were attributed to P treatments.