Nutrient Management Planning

Nutrient Management Planning for New York State Golf Courses 3 Soil Sampling Proper soil sampling procedures need to be followed to accurately determine the chemical and physical properties that inform a nutrient management strategy. The steps below provide an overview of each step. See the New York BMP website for more detailed information on soil sampling procedures. Step 1: Identify sampling locations. In general, it is a good idea to identify sampling locations in turfgrass management areas with substantially different soil compositions, or areas that have received different fertilizer programs in the past (Soldat, 2009). In general, 10 sampling sites should be identified in each management area. Step 2: Time soil sampling appropriately. Soil samples should be collected when soils are active. Fall is the most common time to collect samples as this allows time to review results and apply lime and nutrients in advance of spring growth. Ideally, soil sampling should not be performed during the two months following fertilization or liming. Consistency in the timing of soil sampling allows comparison of test results from year to year. Step 3: Collect samples. Using a consistent sampling depth (4-6 inches deep, depending on turf management area) and sampling methodology, a representative sample of each different soil or management area identified must be taken. Approximately two cups of soil should be collected, plant material should be removed, and the soil should be thoroughly mixed. Once mixed, the samples should be accurately labeled and dried prior to submission to a laboratory for analysis. Step 4: Laboratory Analysis. Various testing labs and methodologies can be utilized to determine soil chemical and physical properties. Using an accredited laboratory is key to getting reliable results. The Mehlich-3 extraction method is typically recommended and preferred as it gives accurate readings for phosphorus (P), potassium (K), and micronutrients in a wide range of soil types and pH values. Using the same soil testing laboratory provides the basis for year-to-year comparison of soil test results. Using Soil Analysis Results Soil harvesting and testing are only as good as the method of interpretation and the subsequent management practices that address the soil’s chemical and physical properties. For many years, turfgrass managers have had two soil interpretation choices: Base Cation Saturation Ratio (BCSR) and Sufficiency Level of Available Nutrients (SLAN). The BCSR method measures the percentage of basic cations on the soil colloids (Ca%, Mg%, and K%) and assumes an ideal ratio, while SLAN expresses nutrient levels as low, medium, optimum, or excessive (ppm) and the likelihood of a plant response following fertilization. MLSN guidelines identify the minimum amounts of soil nutrients that provide acceptable turfgrass conditions, focusing on reducing inputs and costs, and improving sustainability while maintaining turfgrass performance and health. Minimum Levels of Sustainable Nutrition (MLSN) guidelines. Nutrient MLSN Guideline (ppm) Phosphorus (P) 21 Potassium (K) 37 Calcium (Ca) 331 Magnesium (Mg) 47 Sulfur (S) 7