the root zone. Peat is a common root zone additive used, but other organic and inorganic additives can also be used. Peat has the ability to increase water and nutrient holding capacity and decrease bulk density. A common ratio of sand to peat ranges from 9.5:5 to 8:2. These ratios will allow a water holding capacity of 15 to 26% and increase nutrient holding capacity greatly. 100% sand root zones are used often and are more cost effective from a construction standpoint. Selection of the type of sand is very crucial, as there are variations in particle size and shape. One main type being rounded sands, that provide efficient filtration for water and other aqueous solutions, enabling the turf to take more rainfall. The downside of rounded sands is that their shape prohibits them from forming a firm seedbed. This makes the turf less durable which can be problematic for high trafficked areas during sporting seasons. Another type is angular sands, that are able to provide this firm seed bed, thus establishing durable turf. Angular sands achieve this firmness as they are able to settle and form together more efficiently than rounded sands. However, because of this firmness, angular sands do have the potential to cut into roots, thus inhibiting water and nutrient uptake and leaving the turf susceptible to plant pathogens. Both types of sands have potential pros and cons, but in the end, it is up to the turf manager to determine which type of sand will be most beneficial to the turf. Once a sand is selected and it is determined if a soil conditioner will be used, the layout of the root zone profile must be determined. In the United States, common specifications for constructing a sand-based system are laid out by the United States Golf Association (USGA) and by ASTM International (American Society of Testing and Materials, ASTM F2396 Standard Guide for Construction of High Performance Sand-Based Rootzones for Athletic Fields). The USGA specifications used for a sand-based athletic field are the same as what is typically used for USGA golf greens. These specifications consist of a 12 to 16 inch sand root zone. The choice of sand type and the addition of an amendment depend on the designer. When an amendment is used, it must be thoroughly incorporated with the sand. The sand overlays a 4-inch gravel layer. This creates a perched water table