Our Methods

Soil Testing Instrumentation

We use a variety of instruments to analyze soil samples including:

• atomic absorption spectrometers;
• Inductively Coupled Plasma Spectrometers (ICPs);
• Lachat Flow Injection Analyzer;
• combustion analyzers;
• colorimeters; and
• general laboratory equipment.

Sample Preparation

At the laboratory, each sample is assigned an identification number, transferred to a paper bag, and then placed in a metal tray. Every 12^th sample is a quality control sample, either a check sample of known chemical properties to ensure accuracy or a duplicate sample to evaluate laboratory precision.

Samples are dried rapidly under forced air, at room temperature not exceeding 75^oF.

Dried samples are crushed with a mechanical grinder and passed through a stainless steel 10-mesh, or 2.0-millimeter sieve to remove stones and unwanted debris.

Routine Soil Tests (The Regular Test)

• Estimated soil texture and Organic Matter
• Soil pH (1:1 suspension)
• Lime requirement (Sikora buffer index)
• Extractable phosphorus (Bray-1 extractant, Olsen-sodium bicarbonate extractant)
• Available potassium (ammonium acetate extractant)
• Organic matter (%) (loss on ignition) and estimated texture

Soil Tests Available Upon Request

• Soluble salts (electrical conductance, 1:1 soil suspension, saturation extract)
• Extractable sulfur (calcium phosphate extractant)
• Extractable zinc (DTPA extractant)
• Extractable zinc, copper, iron, and manganese (DTPA extractant)
• Nitrate-nitrogen (0.01 M CaSO₄ extractant)
• Exchangeable magnesium and calcium (ammonium acetate extractant)
• Hot water extractable boron (0.1 % CaCl₂.H₂O)
• Environmental Lead (1 N HNO₃ extractant)
• Nutrient Management Phosphorus (Olsen method)

Florist/Greenhouse Tests

• Spurway
• Saturated Media Extract (SME)

Reference 

Recommended Chemical Soil Test Procedures for the North Central Region. 1988 (revised 2015). North Central Regional Research Publication No. 221 (Missouri Agricultural Experiment Station SB 1001).