Inorganic Soil Amendment Effects on Sand‐Based Sports Turf Media

Inorganic soil amendments have been suggested for use in turf to alleviate soil compaction, increase water retention and hydraulic conductivity, and improve many other soil physical properties. The objectives of this study were to determine the effects of ceramic, porous ceramic clay (PCC), calcined diatomaceous earth (CDE), and polymer coated clay (PC) on the physical characteristics of sand-based media and to determine the effects of these amendments on bulk density following freeze-thaw treatments. Inorganic materials were added to a sand-based golf green at 10% on a volumetric basis during construction in 1996. Data collected from the field included saturated hydraulic conductivity (K sat ), water retention, water release curves, bulk density and total porosity on compacted samples collected at construction, and undisturbed samples collected from the treated plots 1 and 2 yr after establishment. The PCC treatment had an 8 and 7% higher cation-exchange capacity (CEC) than the control in 1997 and 1998, respectively. The PCC increased the K sat by 26 and 20% in the compacted and undisturbed samples, respectively, in 1998. The CDE increased water retention by 13% in both compacted and undisturbed samples. Saturated hydraulic conductivity of the sand-inorganic mixtures decreased in the 2 yr, although some increases in K sat were observed each spring. The K sat of plots receiving all inorganic amendments was reduced by 75% in November of 1998. The K sat values in the spring of 1999 increased from the low levels of 1998 by 19% (PC), 44% (control), 59% (ceramic), 72% (PCC), and 82% (CDE). The changes of K sat over the winter may have been induced by freezing and thawing. These changes may not necessarily be caused by total porosity increases; instead they may be caused by increases in macropores. This hypothesis was further tested in the laboratory in a freeze-thaw study conducted in 1999. The PC, control, CDE, and PCC decreased bulk density by 10.7, 7.2, 2.5, and 2.2%, respectively, following a freeze-thaw cycle.