Seeding rates that maximize turf cover when sown during traffic

Sports turf managers seed at rates that often exceed the recommended range by a factor of two and sometimes three. The upper range for seeding rates is not clearly understood when traffic is applied during the seed establishment period. Our objective was to determine if higher than normal seeding rates and seeding schedules can be used to improve turf cover. An important part of our study evaluated the ability of the overseeded grass species to establish when sowing and traffic occurred at the same time. Kentucky bluegrass KB (Poa pratensis L.) and perennial ryegrass PR (Lolium perenne L.) were established at the Horticulture Research Farm in Ames, Iowa USA, on 3 Sep 2003 and 1 2 Sep 2004. Treatments consisted of 7 seeding rates: 5, 10, 15, 20, 25, 30, and 35 g.m(-2) for KB and 25, 50, 75, 100, 125, 150 and 175 g.m(-2) for PR; and 2 seeding regimes (single vs. multiple). Traffic was applied immediately after the first seeding, with a GA-SCW simulator with cleated rollers and a differential slip action, and thereafter weekly for a total of 40 passes during the traffic period. Turf cover was evaluated monthly during the autumn traffic and spring recovery periods. The influence of seeding rate on turf cover was more noticeable for PR than KB. Sowing perennial ryegrass in early autumn produced more turf cover than spreading the same amount of total seed among multiple applications through out the playing season. Under the traffic intensity of this study, perennial ryegrass cover increased as seeding rate increased up to 150 g.m(-2). At the end of the recovery period, Kentucky bluegrass 2 turf cover increased from 29 to 65% as the seeding rate increased from 5 to 35 g m(-2). Applying higher than normal seeding rates during traffic seems appropriate when sport field managers are trying to improve turf cover. At no time did higher than normal seeding rates result in reduced wear tolerance as shown based on percentage turf cover.