Determination of high-risk seeding times for Kentucky bluegrass, tall fescue, and perennial ryegrass when established in autumn at LAT 40 degrees Midwest, USA.

摘要

Autumn, spring, and summer sowing schedules have been recommended for turf re-establishment. Dormant sowing is a practice that is often used when renovating football fields at the end of the playing season. Early sowing in autumn guarantees germination and establishment before the season ends. Very late sowing during autumn usually means no germination; plants do not develop until the following spring. Sowing in the middle of autumn may actually be inefficient due to poor germination and lack of time to develop winter hardiness. An experiment was conducted in Ames, Iowa, USA, during 26 September 2003 and 1 October 2004 to determine high-risk sowing dates of turf grass species for football activities. Three species of turf grass, Kentucky bluegrass (Poa pratensis; KB), perennial ryegrass (Lolium perenne; PR), and tall fescue (Festuca arundinacea; TF) were evaluated. Sowing for year 1 occurred on 26 September, 3 October, 10 October, 17 October, 31 October, 14 November, and 28 November 2003 and 22 April, 13 May, and 3 June 2004. Year 2 sowing dates were 1 October, 8 October, 15 October, 27 October, 15 November, 29 November 2004, and 15 April, 15 May, and 15 June 2005. Sowing rates were 10 g/m2 of KB and 50 g/m2 of PR and TF. Turfgrass cover was evaluated before each sowing date and on 29 June 2004 and 12 July 2005. During the first year, the 17 October sowing date produced the least amount of turf cover by the following summer on 29 June. In the second year, least turf cover in 12 July was produced when TF, PR and KB, were sown on 27 October and 15 and 29 November, respectively. To obtain 50% turf cover by the end of the autumn growing period, KB at 10 g/m2 has to be sown by 31 August, TF at 50 g/m2 has to be sown by 7 September and PR at 50 g/m2 has to be sown by 1 October. A high-risk period when autumn sowing should be avoided could not be determined; however sowing on or before 15 October always yielded over 70% turf cover during the next summer.