An overview of organic and inorganic amendments for sand rootzones - with reference to their properties and potential to enhance performance

Sand-dominant rootzones alleviate the difficulties in providing good quality playing conditions for sport on natural turf in adverse weather - especially wet weather. However sand is inherently a poor growing medium because plant nutrients are retained and cycled inadequately and available water is released over a narrow range of moisture tension. Furthermore sands are unstable to physical displacement when unbound by turfgrass roots. Organic and/or inorganic amendments mixed into rootzone sand can help overcome shortcomings without compromising beneficial physical properties. Moss peat has been used for many years in a range of sports situations to provide, in particular, improved water retention/release characteristics that are especially valuable during the early establishment period. Progressively more stringent environmental protection programs will make moss peat virtually unavailable in the future. Composts are a potential replacement and since they provide a valuable route for the use of recycled wastes, increased production will create pressure to expand their range and extent of use. However composts are very variable and turfgrass science should focus on establishing criteria for suitability for different uses and on quality control. Sandy soils are suitable amendments for some rootzones but good quality sources are becoming unavailable. Zeolite is the main inorganic amendment that is increasing in use and potential benefits and limitations are explained. Polypropylene fibers have greatly increased in use as an amendment for sand rootzones for sports where tearing-type wear is inflicted. Whilst there are variations in the types of fine fibers produced they are generally unobtrusive and have no substantial direct effect on the physical properties of rootzone sands other than increasing wear tolerance and resistance to shear. Amendments that are less widely used including lignite, calcined clay, diatomaceous silica and rubber crumb are commented upon.