Effect of Porous Rootzone Materials Underlined with Plastic on the Growth of Creeping Bentgrass (Agrostis palustris Huds)1

Abstract

AbstractRecent developments in plastic barrier placement under compacted sand for regulated availability and retention of water (PURR‐WICK Rootzone) raises questions of duration of availability. Creeping bentgrass (Agrostis palustris Huds) was studied under putting green conditions when grown on replicated 1‐m2 plastic‐lined plots containing dune sand, mortar sand, calcined clay, diatomaceous earth, and peat. Soil was not included in any of the rootzone mixtures because of its inherent structural instability. In 1968 and 1969, some infiltration rates exceeded 150 cm/hr and all were greater than 7 cm/hr, therefore, water movement was considered ample.The relative ability of the material in plots to retain moisture was measured by allowing the plots to dry‐down for 15 days between rains during August 1968 and for 17 days during July 1969. No irrigation was added to any plot until turf showed severe wilt. Bentgrass on plots containing the finer fractions of the dune sand, diatomaceous earth, various mixtures of sand, calcined aggregates, and peat did not require water for either period.Comparison of the dune sand treatments with and without subsurface irrigation showed that a constant moisture level could be maintained in the subirrigated plots. Depth ranged from 20 to 50 cm with 40 cm proving ample.