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 the centers of the fields and along the sidelines. This data also was taken from the heavily trafficked centers (see Tables 2 and 3). Sur- face hardness was measured using a Clegg Impact soil tester, which is an accelerometer fastened to a 5-pound missile that is dropped from a height of 1 foot with the peak deceleration measured in gravities (Gmax). The higher the Gmax the harder the surface. Traction was measured by a device comprised of a 6-inch steel disc with six soccer studs spaced at intervals around the disc. The disc was weighted with 75 pounds and dropped from a 6-inch height so that the studs fully penetrated the surface. The torque required for the studs to tear the surface was measured in Nm (Newton meters). Penetration resistance was measured using a Penetrometer with a cone point. The cone point was pushed slowly and at a constant rate into the top 2 ½ inches of soil. Twelve readings were taken with each apparatus and then averaged. SOIL SAMPLES Soil samples were collected from each field to determine textural class based upon the USDA-NRCS classification system, soil or- ganic matter content, soil available phosphorus (P) and potassium (K). Particle size for determining textural class was analyzed using the hydrometer method by separating the sand, silt and clay frac- tions. Percent organic matter was determined by weight loss on ig- nition. Soil available P and K were obtained using the modified Morgan extractant. Two intact core samples, 2 inches in diameter by 2 ½ inches in length, were taken from the center of the heavily trafficked area and two taken along the sidelines with a brass cylin- der fitted inside a metal tube for determining bulk density. These results along with bulk density samples taken from the center of the fields are shown in Tables 2 and 3. STATISTICS Correlation coefficients (r) were computed to identify relation- ships between ratings, hours of use, playing quality data, soil prop- erties, maintenance practices and incidence of injury. Correlation is a measure of the strength of the association between two co-vari- ables and is shown in Table 3. A perfect relationship or fit between two co-variables is indicated by an r value of “1” with values less than “1” indicating less than a perfect relationship. A negative sign (-) indicates an inverse relationship between any two co- variables. The degree of statistical significance of the correlation from weak to highly significant is indicated in Table 3 by the level of probability (P value) from weak (P£ 0.10) to highly significant (P£ 0.001). FIELD QUALITY RATINGS AND MAINTENANCE There was a wide range in field ratings for turf density, weed populations, smoothness and overall field conditions ranging from 3 to 9, 1 to 3, 2 to 5, and 1 to 13 respectively, Table 2. Turf density was positively related to smoothness (r = 0.63) and overall field conditions (r = 0.88), and negatively related to weed populations (r = -0.62) in which weed populations increased with progressively greater turf thinning and loss of density (Table 3). Percent weeds in two of the fields were 30% or greater, which also had the lowest scores for overall field quality conditions. Surface smoothness also had a major influence in improving overall field conditions (r = 0.84) Field maintenance had a considerable role in the condition of the fields. Turf density and surface smoothness increased signifi- cantly as maintenance inputs increased (r = 0.69), and (r = 0.74), respectively. Further, as maintenance factors increased, overall field quality increased (r = 0.86) with greater fertilizer nitrogen closely associated with improving overall field condition (r = 0.60). SOIL PROPERTIES The textural classes for the studied soils were classified as seven sandy loams with sand contents ranging from 55.7 to 74.3% sand, three loamy sands ranging from 79.2 to 83.2% sand, and two sand rootzones with 92% and 95% sand. Organic matter content in the 12 soils ranged from 1.0 to 9.1% by weight (Table 2). Bulk density val- ues in the heavily trafficked centers ranged from 1.25 to 1.68 g cm-3 with bulk density increasing as the sand content increased (r = 0.93). Moreover, as the sand content in the soil increased, smoothness of the surface increased (r = 0.88) and the overall field quality in- creased with greater sand content (r = 0.69). Field turf density also improved commensurate with an increase in sand content (Table 3). The improvement in turf density, smoothness, and overall field conditions are likely the result of better wear tolerance and a firmer surface as shown by our previous studies. 10 SportsTurf | May 2011 www.sportsturfonline.com