Effect of Profile Layering, Root Zone Texture, and Slope on Putting‐Green Drainage Rates

A gravel layer underlying the root zone in a United States Golf Association (USGA) putting green and a typically higher root zone permeability in a University of California green should yield water drainage differences between these construction methods. This study examined effects of soil profile layering, root zone permeability, and slope on water drainage from experimental putting greens. The study employed either one‐tier or two‐tier putting green soil profiles, with each containing root zones having either 530 or 320 mm h−1 water permeabilities. The 1.2‐ by 7.3‐m greens were adjusted to slopes of 0, 2, and 4%, and simulated rain was applied at either 45 or 112 mm h−1. Drainage outflow from the furthest down‐slope drain line was monitored during rainfall and for 48 h after rain stopped. During rain, the two‐tier greens had greater drainage rates, and drainage in these greens did not depend on root zone permeability. In the early drainage period (from 1 to 9 h after rain stopped), profile design and root zone permeability interacted such that the largest drainage rate was from the one‐tier, higher‐permeability green and the smallest drainage rate was from the one‐tier, lower‐permeability green. Later in the drainage period (from 27 to 45 h), increased green slope contributed higher drainage rates for all experimental greens. This research illustrates that both profile design and root zone permeability contribute to the drainage process in putting greens with high sand content.