N, P, and K Fertilization for Newly Established Tall Fescue.

Tall fescue is the major cool-season grass in southeastern Kansas; however, meadows and pastures are often under-fertilized. The objective of this study was to determine whether N, P, and K fertilization improves yields during the early years of a stand.  The experimental design was a split-plot arrangement of a randomized complete block. The six whole plots were select combinations of P and K fertilizer levels.  Subplots were four levels of N fertilization.  The experiment was established on two adjacent sites in fall 2012 (Site 1) and fall 2013 (Site 2). First-year production of tall fescue at both sites was affected by N and P but not K fertilization. At the R5 hay harvest at Site 1, yields were high at nearly 7 Mg/ha with no P and approximately 10 Mg/ha with P additions of 12 to 49 kg/ha.  In contrast, increasing N rates tended to decrease yield at R5. For the first year at Site 2, increasing N and P rates increased measured yield at the R4 hay harvest. Second-year production of tall fescue was affected by N and P but not K at Site 1, and mainly by N at Site 2. At the R4 hay harvest at Site 1, yields were low at less than 3 Mg/ha with no P and approximately 4.5 Mg/ha with P additions of 24 kg/ha.  Yield was increased up to, but not above the 112 kg N/ha rate. For the second year production at Site 2, R4 yield was mainly affected by increasing N rates.