Laboratory Operations:   The Turf Diagnostics & Design (TDD)  laboratory follows the test methods of the American Society of Agronomy (ASA), American Society for Testing & Materials (ASTM) and the USGA laboratory protocol from the 1993 Putting Green Construction Recommendations.  The laboratory is accredited by the American Association for Laboratory Accreditation [A2LA] for testing of sand based turf systems in accordance with the 2004 USGA Recommendations for Putting Green Construction.

 TDD Inc. is licensed by the United States Department of Agriculture as a plant protection and quarantine laboratory. [Import #S-51438].  The company's laboratory facilities are listed by the United States Golf Association.

 A former NASA physicist fabricated our USGA test equipment to our exact specifications.  TDD Inc. is the only physical evaluation laboratory in the commercial sports turf industry that is equipped to offer soil moisture release data.  These innovative tests offer additional information that can not be obtained by using the USGA procedures alone.  They are very useful for diagnosing problems, non-traditional rootzone designs, and the evaluation of fairway soils.

•  Particle Size Analysis:  Particle Size Analysis (PSA) is one of the most descriptive analyses performed on soil materials.  The PSA analysis includes a determination of the clay content using a pipette method and a sand grain distribution. Parameters such as the diameter 15 (D15) and uniformity coefficient (Cu) are reported. A textural classification based on the United States Department of Agriculture (USDA) will also be provided.  Sands for use in sand based turf systems and sand traps for golf courses will have a shape of sand particle provided according to United States Golf Association (USGA) - Green Section requirements.  The PSA analysis is composed of two distinct phases.

1. One phase of the PSA is the textural analysis of a soil and is defined by the sand, silt, and clay content.  The USDA classification criteria define sand as the material retained on a 270 mesh (0.05mm) sieve.

2.  Another phase of the PSA is the sand grain distribution analysis.  TDD offers two types of sand grain distributions.  One sand grain distribution is based on the USDA sand distribution definition. The other sand distribution analysis offered is tailored for the USGA Green Section specifications.  All sand grain distributions are determined on the sand component that has had all the silt and clay removed.  The results of the PSA are useful in estimating the physical and chemical performance of a sand or soil.

TDD offers flexibility in service and will determine the particle size distribution or textural analysis as independent tests.

•  Physical Performance Evaluation:  The physical performance evaluation (PE) provides information concerning the infiltration rate, bulk density, and porosity characteristics of a proposed rootzone material.  The methods used for determining the parameters are based on standard agronomic test methods and the USGA protocol.  Conceptually, the method involves compacting a sample at field capacity and determining the listed parameters.  The USGA protocol requires a particle density determination for every sample.  The samples are compacted using a 14.3 ft-lbs /in² force.  Infiltration rates are determined using a constant head saturated hydraulic conductivity (K-SAT).  The infiltration rates (K-SAT) are adjusted to a rate equivalent to 20^oC water temperature for consistency of reporting.

The PE analysis is a useful risk assessment tool in determining the suitability of submitted materials for use in gravity drained perched sand turf systems such as the USGA putting green system.  Important parameters that aid in risk assessment are the K-SAT and capillary porosity values.  The PE is performed on a compacted sample and represents a worse possible case scenario in regards to the rootzone performance.  The USGA offers guides for selecting or designing acceptable rootzones.  TDD offers two different PE analysis packages.

1. One package uses submitted components to make a mix in the lab and perform the PE analysis.  The mix preparation and analyses are tailored to design agronomically acceptable rootzones for sand based systems.  The bulk weights and moisture contents of each component are defined and reported with the PE results.  Organic amendment bulk weights are usually based on the manufacturer criteria, while the bulk weights of sand and other amendment are determined in the lab.  Since most mixes are defined as a volume ratio, TDD offers definition of the volume to provide an objective analysis.  To offer a guide as to
   how much of each component is necessary to make the mix, an "Estimated Yield Report" is provided.  The actual yields of components may vary according to moisture contents of the respective materials on-site.

2.  There are times that rootzone mixes are already available and a determination of the physical performance is required.  In this case, the PE analysis involves the determination of a submitted rootzone mix for suitability in perched sand based turf systems.  Since TDD is not preparing the mixes and defining the mix ratios, analysis of a submitted mix is offered at lower price.  If desired only the infiltration rate (K-SAT) will be provided.

 To provide criteria for future quality control of construction programs, the organic matter content of the mix is determined in conjunction with the PE analysis.  The organic matter content and particle size analysis (PSA) are required to properly check the integrity of the rootzone as it is produced.  The two analyses offer a quick, reliable, and affordable method of providing quality control for rootzone mixes.  The USGA protocol also requires an organic matter content to be determined.

•  Organic Matter Determination:  Two methods are used to determine organic matter (OM) depending on the sample type submitted. Materials that contain more than 4% organic matter (dry weight basis) are analyzed using a combustion method.  The sample is combusted at 750^o C and the results are reported on a dry weight basis.  Composts, peats, and organic soils are analyzed using a combustion method.

 Soils and rootzone mixes usually contain less than 2% organic matter by weight, and the OM is determined using a wet oxidation method known as the Walkley-Black technique.  The Walkley-Black method is a chemical oxidation method that can be performed in a short amount of time and is adaptable for use in the field.  The USGA has adopted this technique to define and provide benchmark data for the quality control of construction of sand based rootzones.  TDD reports the OM on mixes made in the lab as well as submitted mixes to compare to USGA suggested levels and to help interpret the physical evaluation data.  The performance of the mix is directly related to the particle size analysis and the organic matter by weight.

•  Particle Density:  Particle density is necessary for determining the total porosity of a soil core.  The USGA protocol requires that each sample have the particle density determined.  Desiccators and pycnometers are used for particle density determination.  A pycnometer is a specific gravity bottle capable of being filled accurately with a definite amount of liquid without any air space.  Oven dry weight and volume of the sample are determined.  Particle density, which equals the oven dry weight divided by the volume, is important in the calculation of total pore space.

•  Water Release Characterization:  Used for moisture release and retention evaluation.  Testing can be performed on undisturbed soil cores or laboratory compacted samples.  Our lab is capable of producing a range of soil tensions from 15 bars (permanent wilt point), to 1/3 bar pressure (field capacity for continuous soil profile), or any range of soil tensions points between 15 bars to less than 1/3 bar.  A series of moisture release points can be plotted to determine at which pressures a soil or amendment product releases moisture.  The laboratory is also equipped with Tempe cells for low soil tension evaluation from 10 centimeters to 1000 centimeters.

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