Tuesday, November 14, 2006
168-15

Physical and Hydraulic Properties of Rootzone Inorganic Amendments for Turf Putting Green.

Leonard Githinji, Jacob Dane, and Robert Walker. Auburn University, Agronomy and Soils Department, Auburn, AL 36849-5412

            Sports fields are usually constructed on sand-based root zones which provide an ideal medium for turf systems with respect to physical characteristics.  However, sand has low water and nutrient holding capacity. Modification of the root zone by applying amendments provides a potential for enhancing water and nutrient retention. Addition of organic amendments such as peat helps to increase water and nutrient retention, but peat decomposes over time, reducing air-filled porosity. Inorganic amendments offer a number of benefits for improving water and nutrient retention and since an ideal putting green root zone is expensive to build, their resilience also helps to delay reconstruction. However, little information is available on their effects on root zone. We investigated physical, and hydraulic properties of seven inorganic amendments marketed in the southeastern United States. These were zeolites (Clinolite and Ecolite), calcined diatomaceous earth (Isolite and Axis) and fired clays (Moltan plus, Profile, and Pro's choice). The properties analyzed were bulk density (BD), particle density (PD), porosity, particle size distribution (PSD), saturated hydraulic conductivity, water retention (WR) and available water-holding capacity (AWC). The AWC is defined as the difference between the permanent wilting point (PWP) and field capacity (FC). We divided the AWC into easily available water-holding capacity (EAWC), moderately available water-holding capacity (MAWC) and less available water-holding capacity (LAWC). The PD of the amendments ranged from 2.18 to 2.44 g cm-3 which is lower than that of sand (2.67 g cm-3). However, most particle sizes ranged from 0.5 to 2.0 mm, which is comparable to that of coarse sand. The zeolites had the least suitable physical and hydraulic properties, while the calcined diatomaceous earth had the best. Axis showed the best physical and hydraulic characteristics; i.e. highest AWC, and total porosity (0.79 cm3cm-3), and low PD (2.20 g cm-3) and BD (0.47 g cm-3).


Handout (.pdf format, 318.0 kb)