Velvet bentgrass (Agrostis canina L.) putting greens require intensive sand topdressing programs for thatch management; however, their high shoot density combined with the low mowing heights make it challenging to maintain smooth, sand-free putting surface when topdressing is applied at high rates. A field trial was initiated to determine the effects of sand size and topdressing rate on a ‘Greenwich’ velvet bentgrass putting green. Treatments were arranged in a 2 × 2 factorial and included a non-topdressed control arranged in a randomized complete block design. The two factors were topdressing sand (medium-coarse sand and medium-fine sand) and topdressing rate (0.15 and 0.3 L m^–2). Topdressing improved turf quality compared to the non-topdressed control. Additionally, velvet bentgrass had better quality when topdressed at the rate of 0.3 L m^–2 compared to 0.15 L m^–2. Increasing topdressing rate from 0.15 to 0.3 L m^–2 notably increased the quantity of unincorporated medium-coarse sand remaining on the putting surface, whereas it often did not increase or only slightly increased the quantity of unincorporated sand with medium-fine sand. Independent of sand size and rate, topdressing treatments maintained the top 0-to-3.8-cm soil profile relatively dry and increased infiltration rate measured with mini disk infiltrometers. The lack of negative effects of medium-fine sand on measured parameters and the minimum disruption to putting surface may encourage superintendents to apply greater quantities of topdressing for improving the performance of velvet bentgrass putting greens.

中文翻译：

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追肥沙粒大小和速率对丝绒翦股颖果岭质量、保水性和渗透率的影响

天鹅绒翦股颖 ( Agrostis canina L.) 果岭需要密集的沙子追肥程序以进行茅草管理；然而，它们的高枝条密度与低割草高度相结合，使得在高速率追肥时保持光滑、无沙的推杆表面具有挑战性。开始进行田间试验以确定沙子大小和追肥率对“格林威治”丝绒翦股颖果岭的影响。处理按 2 × 2 因子排列，包括以随机完整区组设计排列的非追肥对照。这两个因素是追肥砂（中粗砂和中细砂）和追肥量（0.15 和 0.3 L m ^–2）。与未追肥的对照相比，追肥提高了草坪质量。此外，与 0.15 L m ^–2相比，以0.3 L m ^{–2 的}比例追肥时，丝绒翦股颖具有更好的质量。追肥率从 0.15 增加到 0.3 L m ^–2显着增加了推杆面上残留的中粗砂的未掺入量，而中细砂的未掺入砂量往往不增加或仅略有增加。独立于沙子大小和速率，追肥处理保持顶部 0 到 3.8 厘米土壤剖面相对干燥，并增加了用微型盘式渗透计测量的渗透率。中细沙对测量参数没有负面影响，对推杆表面的破坏最小，这可能会鼓励管理者应用更多的追肥，以提高丝绒翦股颖果岭的性能。