Aeration and Black Sand Topdressing to Enhance Putting Green Recovery.

Golf course superintendents in the intermountain Pacific Northwest are aerating putting greens at the extreme ends of the growing season to minimize disruption to play. The objectives of this study were to determine the time of year that results in the fastest recovery from aeration and if black colored sand topdressing (BS) can speed recovery compared to tan colored sand topdressing (TS). The BS was an organically dyed sand (BLACK SAND^®, Grass Roots Agronomics, Emmet,ID) and the TS was a locally available topdressing sand. A ‘T-1’ creeping bentgrass (Agrostis stolonifera L.) research green at Pullman, WA was aerated with 1.25-cm hollow tines every two weeks from 15 April to 1 November 2008 and 2009. TS or BS, with comparable particle size, was applied (39,059 kg ha^-1) after aeration and brushed into aeration holes. Numerically, fastest recovery from aeration was 10 d in 2008 with the 15 August BS or TS treatments; however, they were not different from several other treatments. Fastest recovery in 2009 was 14 d with the 15 September BS treatment, but it was not different from the 1 September BS or 1 August TS treatments. BS resulted in faster recovery at one date in 2008 (1 October) and five of fourteen dates in 2009 (15 April, 1 and 15 June, and1 and 15 September). Late fall treatments (after 1 October 2008 and 15 September 2009) did not fully recover. Average temperature for BS was 16.3 °C at a 7.5 cm soil depth in 2008 and 23.2 °C at a 2.5 cm depth in 2009 and was 0.3 and 0.5 °C greater than TS in 2008 and 2009, respectively. Since BS did not always result in faster recovery it was concluded that the time of year had a greater effect on the days to recover than sand color.