Preliminary Investigations of a Porous Ceramic Soil Amendment for Golf Green Use

Grady Miller
University of Florida, Gainesville
Institute of Food and Agricultural Sciences

Many claims are being made that various soil amendments will help regulate the moisture content of greens. Organic materials have historically been used in sand-based root zones of sports turfs to increase moisture and nutrient retention. Internally porous inorganic amendments may also increase the water holding capacity of high sand content rootzone mixes. An increase in water retention may delay drought damage of grasses grown in sand with high percolation rates and low water retention capacity. Field and Envirotron studies have been initiated to assess moisture and nutrient holding capacity of an inorganic amendment. Specific objectives were (i) to determine if a porous ceramic reduces incidence, or improves recovery from localized dry spot on a high sand content golf green and (ii) to determine water retention properties of sand-porous ceramic soil amendment mixtures supporting dwarf bermudagrass growth. Studies were conducted on a Gainesville golf course and in the Turfgrass Envirotron's greenhouses.

In this study, addition of a porous ceramic soil amendments reduced soil and surface temperatures on a sand based golf green compared to addition of 50:50 mixture of porous ceramic and sand, or spraying with a wetting agent. Addition of porous ceramic also had a positive influence on reducing localized dry spot and increased overall turfgrass quality. An unexpected response was plots treated with 100% sand generally responded similarly to those treated with porous ceramic. In the greenhouse study, bulk density of sand decreased with increasing amounts of porous ceramic amendment. There was essentially no influence in non-capillary pore space but there was an increase in capillary pore space with increasing amendment levels. With increasing capillary pore space there were increases in water retention. [NOTE: Sand used in this study was a coarse sand (68.9%). Since this sand has only 2.6% fine sand particles, it has an unusually high hydraulic conductivity and low water retention.] Increased porous ceramic levels in media resulted in increased time before plants showed signs of water stress. Plants grown in 50% sand:50% porous ceramic maintained turgor 13% longer than those grown in 100% sand. Adding 10% porous ceramic increased dry-down cycles nearly 6% over a 100% sand growing medium.

RLD was generally inversely related to amendment levels. During establishment phase of this study, lower moisture levels in well drained sand might have promoted vigorous root growth; whereas, mediums that maintained higher moisture levels may not have needed similar rooting development to provide water to growing plants. Dry-down data indicates that this extra root growth was not as efficient in sustaining plant turgor as the increased moisture provided by porous ceramic.

Tissue analysis indicated that K supply increased with increasing concentrations of porous ceramic in growing media. The K concentration was very low in sand medium, most likely due to leaching. Increase in tissue K concentration had a quadratic response to increasing porous ceramic levels. There was very little, if any change in Ca, Mg, or P concentrations due to addition of porous ceramic. Results from this study indicated that under some conditions, porous ceramic may improve water status and K supply to dwarf bermudagrass grown in a sand, resulting in a higher quality turf.