Figures (3)  Tables (2)

    • Figure 1. 

      Soil cores from an annual bluegrass putting green were evaluated from the zone below the green leaf canopy to the distinct interface between the thatch and sand layer indicated by the red arrow.

    • Figure 2. 

      Relating organic matter of an annual bluegrass putting green to the cumulative quantities (L·m–2) of sand applied as topdressing over three years. Data from all four replications were used for regression analysis. (a) Mat layer depth increases linearly with sand quantity. (b) Organic matter content based on loss-on-ignition method has a quadratic relationship with sand quantity. (c) Organic matter accumulation per unit area does not have a strong relationship with sand quantity.

    • Figure 3. 

      Layering observed from 2.4 L·m–2·yr–1 autumn and spring only treatments at the conclusion of a three-year sand topdressing study on an annual bluegrass turf mowed at 2.8 mm.

    • 1 L·m–2 equals ab
      3.28 ft3·1,000 ft–2
      24.5 gal·1,000 ft–2
      1.54 kg·m–2
      0.122 yd3·1,000 ft–2
      328 lbs·1,000 ft–2
      7.15 tons·acre–1
      16.0 tonnes·ha–1
      0.0394 depth (inch)
      0.100 depth (cm)
      10.0 m3·ha–1
      a All conversions from volume to weight are made under the assumption that one cubic foot of sand weighs 100 lbs. b All conversions from volume to depth are made under the assumption that one liter of dry sand spread across one square meter is 0.1 cm in depth.

      Table 1. 

      Sand topdressing rate unit conversions.

    • Source of variation Organic matter accumulation
      Replication ***
      Autumn topdressing (AU) NSa
      Linear NS
      Quadratic NS
      Spring topdressing (SP) ***
      Linear ***
      Quadratic NS
      Summer topdressing (SU) ***
      Linear ***
      Quadratic NS
      AU × SP NS
      AU × SU NS
      SP × SU NS
      AU × SP × SU NS
      CV, % 5.0
      Main effects kg·m–2
      Autumn topdressingb
      0 L·m–2·yr–1 6.5
      1.2 L·m–2·yr–1 6.6
      2.4 L·m–2·yr–1 6.5
      Spring topdressingc
      0 L·m–2·yr–1 6.4
      1.2 L·m–2·yr–1 6.5
      2.4 L·m–2·yr–1 6.7
      Summer topdressingd
      0 L·m–2·yr–1 6.4
      0.6 L·m–2·yr–1 6.6
      1.2 L·m–2·yr–1 6.7
      *** Significant at the 0.001 probability level. a NS, nonsignificant. b The total autumn topdressing was applied as two split applications on 22 Oct., 9 Nov. 2010; 21 Oct., 4 Nov. 2011; and 18 Oct., 6 Nov. 2012. Data for means were pooled across other factor levels. c The total spring topdressing was applied as two split applications on 21 Apr., 5 May 2011; 20 Apr., 4 May 2012; and 20 Apr., 3 May 2013. Data for means were pooled across other factor levels. d Summer topdressing was applied at 0, 0.075, and 0.15 L·m–2 every two weeks from 7 June to 13 Sept. 2011, 8 June to 14 Sept. 2012, and 12 June to 13 Sept. 2013. Data for means were pooled across other factor levels.

      Table 2. 

      Organic matter accumulation response to the main effects of autumn, spring, and summer topdressing rate measured at the conclusion of the three-year study on an annual bluegrass turf mowed at 2.8 mm in North Brunswick, NJ, USA.