Soil physical properties of aging golf course putting greens.

United States Golf Association (USGA) specifi cation putting greens are designed to limit excess soil water and compaction; but these soil properties change over time. Objectives were to defi ne soil physical properties of sand- amended rootzones as affected by (i) rootzone mixture, (ii) establishment treatment, and (iii) putting green age. The USGA specifi cation rootzones were built and established with Agrostis stolonifera L. in four sequential years. Rootzone treatments were 80:20 (v:v) sand and sphagnum peat and an 80:15:5 (v:v) sand, sphagnum peat, and soil. An accelerated establishment treatment applied 2.5, 3, and 2.5 times N, P, and K, levels, respectively, than the control treatment. Data were collected on rootzone particle size distribution and saturated hydraulic conductivity (K sat ), bulk density, total, air-fi lled and capillary porosity for 8 yr, infi ltration rate for 10 yr. All soil physical properties changed with age, but were not infl uenced by establishment treatment. Infi ltration declined 73% but remained adequate (≥0.15 m h –1 ) for location precipitation. Capillary porosity and bulk density increased 32 and 7%, respectively, while air-fi lled porosity decreased 38%. Capillary and air-fi lled porosity still met USGA specifi cation after 8 yr. Addition of soil to the sand-based rootzone mixture had no negative effect on soil physical properties. Fine sand from topdressing and surface organic matter accumulation were thought to account for these changes.