Soil testing : enhancing land productivity, nutrient use efficiency & environmental quality

When shipping several types of agronomic samples, package each type separately. For example, place soil samples in one package, nematode assay samples in another package, and plant/waste/solution samples in yet another package. Make sure each package is addressed to the appropriate laboratory. Look for your soil test report(s) online. Just select "Find Your Report” from the left navigation bar on the Agronomic Division’s home page www.ncagr.com/ agronomi. You will also receive a copy of the report in the mail. For help interpreting reports, contact your NCDA&CS regional agronomist. For additional information, contact NCDA&CS Agronomic Division Soil Testing Section Physical Address: 4300 REEDY CREEK RD RALEIGH NC 27607-6465 Mailing Address: 1040 MAIL SERVICE CENTER RALEIGH NC 27699-1040 Phone: (919) 733-2655 Web site: www.ncagr.com/agronomi Prepared by David H. Hardy, Jeana Myers & Catherine Stokes revised August 2006 Colleen M. Hu dak- Wise, Director NCDA&CS Agronomic Division Steve Troxler, Commissioner of Agriculture Agronomic Division Soil Testing Enhancing Land Productivity, Nutrient Use Efficiency & Environmental Quality 3.(XI() copies of this public document were printed at a cost of $300.99 or SO. 10 per copy. N.C. Dept, of Agriculture & Consumer Services Reasons for Soil Testing In North Carolina, most soils are naturally acidic and low in nutrients. Both lime and fertilizer are required for good plant growth and yield (Fig. 1 ). Soil testing is the best way to find out how much lime and fertilizer to apply based on the crop and existing field conditions. ] A Strategy for Collecting Samples Improperly collected soil samples are the weak link in the soil testing process. For test results to be useful, the sample must accurately reflect the variability and conditions in the field. A sample from a single spot cannot do this. Without soil testing, managing crop nutrients is difficult due to the complex nature of their interactions with the soil. Acid soils, for example, can limit root growth and cause certain nutrients to be unavailable for plants. Unless soil acidity and pH are corrected through liming, applying fertilizer may cause additional problems rather than enhance yield. Soil testing measures the soil’s nutrient-holding capacity and provides a basis for sound land management decisions. The lime and fertilizer recommendations given on the soil test report are cost effective and help optimize crop yield. Following these recommendations also protects the environment by safeguarding against excess fertilizer application. Types of Soil Tests The Agronomic Division of the N.C. Department of Agriculture and Consumer Services conducts soil tests free of charge for all state residents. The tests can be either predictive or diagnostic. Predictive (or routine) soil tests estimate the nutrient requirements of the plants to be grown. Samples for this kind of analysis are usually taken before the growing season. The report provides site-specific lime and fertilizer recommendations based on soil class, pH, levels of nutrients in the soil, and crop requirements. Diagnostic (or problem) soil tests identify nutrient- related problems that occur during the growing season. They are like predictive soil tests, except that soluble salt levels are also measured. Test results are reviewed by a staff agronomist who makes recommendations for adjustments in fertilization based on site-specific circumstances. Before sampling, make a detailed map of your land. Forsmall areas, simply draw adiagram. For large tracts, aerial photographs may be helpful. Divide the map into individual sample areas of 20 acres or less. Assign a short, permanent sample identification name to each area that will help you remember its location. Keep in mind that the sample ID space on the soil test box is limited to five characters. Each sample area should consist of only one general soil type or condition. If a field varies in slope, color, drainage or texture and if those areas can be fertilized separately, submit a separate sample for each area (Fig. 2). If the field being sampled has been divided into sections for various crops, submit a sample for each section — even if you now plan to grow the same crop across the entire field. Areas where liming or fertilizing patterns have differed from the rest of the field should also be sampled separately. Figure 1 . Nutrient management is critical for optimum crop production.