Turfgrass quality, growth rates, and annual bluegrass contamination as affected by seasonal fertilizer distribution on red fescue putting greens

Abstract Red fescue ( Festuca rubra L.) is the preferred turfgrass species for low‐input golf course putting greens in Northern Europe. While it is well recognized that fescue requires less fertilizer than bentgrasses ( Agrostis spp.) or annual bluegrass ( Poa annua L.), the optimal fertilizer distribution throughout the growing season has not been investigated. Our objective was to determine the effects of three seasonal fertilizer distributions on turfgrass quality, seasonal growth rates, root development, and competition from annual bluegrass on a sand‐based red fescue putting green at the NIBIO (Norwegian Institute of Bioeconomy Research) Turfgrass Research Center, Landvik, Norway (58° N). All fertilizer treatments comprised weekly inputs of a complete, liquid fertilizer solution for a total of 11 g N m −2  year −1 , but the inputs were distributed with (1) the highest weekly rates from early May to mid‐summer (SPRING+), (2) equal weekly rate from early May through late September (FLAT), or (3) the highest weekly rates from mid‐August to late September (FALL+). SPRING+ fertilization resulted in higher turfgrass quality, deeper roots, and, in the second experimental year, less annual bluegrass than FALL+ fertilization. The advantage of FALL+ fertilization was faster green‐up and enhanced growth in September, October, and April, but this came at the expense of more annual bluegrass. Results are discussed in light of previously published data on temperature and fertilizer requirements for the growth of red fescue versus annual bluegrass.