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Bill Urbanowicz

From Soil Report To Solution

Soil Report
Previously, Bill Urbanowicz, chief agronomist at Spectrum Analytic, Inc., demystified the numbers in a soil test report. In this article, he breaks down those numbers into real-world fertilizer selection and application. (Spectrum Analytic, is not able to recommend specific fertilizers brands, since they vary by area.) Prior to making fertilizer and lime applications, the amount of area to be fertilized must be calculated so the correct amount of nutrients is applied to the soil. Google Maps can be used to get a somewhat accurate area. Or Spectrum’s website library has a paper containing a variety of lawn sizes and shapes a landscaper may encounter when calculating area. What’s In A Grade? As most know, fertilizer is identified by the percent of each nutrient contained in the product. While each fertilizer might contain any combination of up to 13 nutrients, the majority have a three number identification referring to the major nutrients: Nitrogen (N), phosphate (P2O5), and potash (K2O) in that order. P2O5 is the fertilizer form of Phosphorus (P), and K2O is the fertilizer form of Potassium (K). These three numbers are called the fertilizer analysis or “Grade.” Fertilizer products that contain some amount of all three major nutrients are often called “complete” fertilizers. Soil test nutrient recommendations are made in the same units (N, P2O5 and K2O). But once you have those recommendations, you need to determine how much fertilizer will supply those nutrient amounts. This requires some basic arithmetic, presented in Formula #1. For example, if the recommendation ...