SportsTurf provides current, practical and technical content on issues relevant to sports turf managers, including facilities managers. Most readers are athletic field managers from the professional level through parks and recreation, universities.
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FieldScience contact. Smooth a rough uneven surface. Two common materials used to modify a rootzone are organic materials (in the form of compost) and sand. Caution must be practiced with either material. Sand is sometimes used to improve the drainage characteristics of a heavy textured, clayey soil. A heavy textured soil should reach approximately 85% sand by weight to have a positive effect on hydraulic conductivity. Medium to coarse size sand should be used for this purpose. A steady supply of a uniform material, which conforms to very specific guidelines, should be consistently available. Variations in material uniformity can void the success of the most well planned program. An agronomist can best prescribe these specifications. Leaf compost is being used more and more to topdress athletic fields. Production by private and public recycling plants alike has made it a widely available material. It is sometimes blended with sand and sold as organic topsoil. The benefit to incorporating compost into the rootzone is realized through the addition of or- ganic matter. hydraulic conductivity, root penetration and even air and gas ex- change characteristics of the soil. Before you can determine the proper topdressing material to use, it is important to determine why you are topdressing. A few reasons for topdressing are: Modification of existing rootzone. • Increase water conductivity • Increase organic matter content • Increase tilth (soil structure) • Increase cation exchange capacity (CEC) Increase success rate of renovation thru improved soil seed The addition of organic matter can decrease the compactive tendencies of a soil and over time help to improve the soil struc- ture (tilth) of a heavy textured soil. Tilth can be associated with the soft, fluffy texture of a well-maintained garden soil. A lack of tilth can be associated with the hard clumpy soil of a goalmouth. The benefits of organic matter can be realized in all areas of an athletic field but more noticeably in high traffic areas where exist- ing soil structure has been destroyed. Once soil structure is destroyed the ability of the soil to drain and maintain turf cover is severely compromised. The result is a weed-infested area of high compaction. A major cause of this de- struction is playing games in wet water logged conditions where the soil is actually smeared under the stress of heavy foot traffic. Similar materials to leaf compost are biosolids such as sewage sludge and spent mushroom compost. These materials are much the same as leaf compost in that they have high organic content but many have the added benefit of higher nutrient availability and therefore the potential for a greater "fertilizer effect." As with any topdressing material, care must be taken when ac- quiring and applying compost. A quality compost material should be adequately aged before purchase and be properly screened to eliminate all twigs and debris. It should show no resemblance to its original components and have a clean earthy odor. The results of a compost analysis report should be requested fits. In a light, sandy soil, organic matter can be of benefit by in- creasing the ability of the soil to retain moisture. This increase can combat compaction and maximize irrigation efficiency. The incorporation of organic matter into a soil adds essential plant nutrients. Depending on the source of the organic matter, this "fertilizer effect" can be substantial and could replace one or more applications in a fertilization program. Organic matter can also in- crease CEC or the ability of a soil to retain nutrients. This increase in not usually necessary with heavy textured clay soils but may be of benefit in sandy soils. Note that it takes a tremendous amount of organic matter to increase soil CEC. Thus in most situations the benefit of incorporating organic matter is more a result of increase water retention and nutrient addition than increase in CEC. The addition of organic matter can provide a number of bene- before purchase. These results should supply a minimum of pH, percent of organic matter, soluble salt levels, heavy metal levels and the carbon:nitrogen (C:N) ratio. Included with these test re- sults should also be a reference made to the acceptable levels of soluble salts and heavy metals. If the compost is a blended mate- rial it should also carry a physical (sand, silt, clay) analysis and have a texture classification such as loamy sand, sandy loam etc. A chemical analysis is also useful in determining the potential "fertilizer effect" of a topdressing material. The C:N ratio is used as a barometer to measure the level of decomposition and should be less than 30:1. Higher C:N ratios can cause nitrogen supplies in the soil to become temporarily un- available to the turf until the C:N ratio is reduced through fur- ther decomposition. This can have a negative effect on turf quality. With compost materials as with any other topdressing mate- rial, care must be taken to provide adequate cultivation in con- junction with the topdressing procedure. The more a topdressing material differs from the existing rootzone, the more cultivation is necessary to blend the two materials. This is done to minimize the effects of layering. Applying highly organic compost to a As with any topdressing material, care must be taken when acquiring and applying compost. A quality compost material should be adequately aged before purchase and be properly screened to eliminate all twigs and debris. It should show no resemblance to its original components and have a clean earthy odor. 18 SportsTurf | June 2012 www.sportsturfonline.com