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Soil, Plant and Water Reference Methods for the Western Region1 SOIL, PLANT AND WATER REFERENCE METHODS FOR THE WESTERN REGION 1 2005 3rd Edition Dr. Ray Gavlak Dr. Donald Horneck Dr. Robert O. Miller 1 From: Plant, Soil and Water Reference Methods for the Western Region. 1994. R. G. Gavlak, D. A. Horneck, and R. O. Miller. WREP 125. PREFACE This manual has been developed as a guide of standard analytical methods for agricultural laboratories for use in the Western Region, byt the Western Coordinating Committee on Nutrient Management. This publication an update of Plant, Soil and Water Reference Methods for the Western Region , 1994, (WREP 125) written by Dr. Ray Gavlak formerly of the University of Alaska, Dr. Donald Horneck of Oregon State University, and Dr. Robert O. Miller of Colorado State University. These represent accepted methods for the analysis of soil and plant samples and were selected for the express purpose of identifying common methods on which a group of agricultural laboratories analytical results can be statistically evaluated. We would like to thank all those individuals who have contributed to this manual. The specific soil, plant and water analytical methods listed represent those analytical procedures that are recommended for use in the current North American Proficiency Testing Program organized by the Soil Science Society of America. We encourage all suggestions and comments from participating laboratories for improving this manual for future publication. The authors would like to thank Dr. Byron Vaughan of MDS Harris Laboratory Services, Dr. Kelly Belden of the University of Wyoming for reviewing this publication. WREP-125, 3 rd Edition TABLE OF CONTENTS Page Quality Assurance in the Agricultural Laboratory ...................................... 5 Analysis Calculations and Error ................................................. 12 Soil Analytical Methods Saturation Paste Analysis Saturation Percentage, S - 1.00 . .............................. 17 Saturation Paste Soil pH, S - 1.10 . ................................ 20 Saturation Paste - Soluble Salts, S - 1.20 . .................................. 21 Saturation Paste Extract - Alkalinity: Bicarbonate and Carbonate, S - 1.30 . 24 Saturation Paste Extract - Chloride, S - 1.40 . ................................. 26 Saturation Paste Extract - Boron, S - 1.50 . ................................. 28 Saturation Paste Extract - Calcium, Magnesium, Sodium and SAR, S - 1.60 . 31 2- Saturation Paste Extract Soluble Sulfate (SO 4 ), S - 1.70 ........................... 33 - Saturation Paste Extract Soluble Nitrate (NO 3 ), S - 1.80 ............................ 35 Soil pH and Electrical Conductivity Soil pH (1:2), S - 2.10 . .............................. 37 Soil pH (1:2) CaCl 2, S - 2.11 ....................................... ............ 39 Soil pH (1:1), S - 2.20 . .............................. 41 Soil pH (1:1) CaCl 2, S - 2.22 ....................................... ............ 43 Soil EC (1:1), S - 2.30 . ............................ 45 Soil EC (1:2), S - 2.40 . ............................ .. 47 Soil Buffer pH, Lime Requirement SMP Single Buffer pH, S - 2.50 . .............................. 50 Woodruff - Modified, S - 2.60 . .............................. 53 Adams and Evans Buffer pH, S - 2.70 . ............................. 55 Mehlich Buffer pH, S - 2.80 . .............................. 57 Soil Nitrate Nitrogen, NO 3-N Cadmium Reduction, S - 3.10 . ......................... 59 NO 3-N Ion Selective Electrode, S - 3.20 . ............................. 61 NO 3-N Chromotropic Acid Method, S - 3.30 . ............................ 63 Soil Ammonium Nitrogen, S - 3.50 . ................................. 65 Soil Nitrogen Mineralization Potential, S - 3.60 ........................................ 67 Extractable Phosphorus and Soil Bases Bicarbonate, S - 4.10 . ............................. 69 Bray P-1, S - 4.20 ............................... ............................ 72 Mehlich 1 (Multiple Nutrients), S - 4.31 . .................................. 75 Mehlich 3 (Multiple Nutrients), S - 4.33 . .................................. 78 AB-DTPA (Multiple Nutrients), S - 4.40 . ................................ 80 Modified Morgan (Multiple Nutrients), S - 4.50 . .................................. 84 Modified Kewlona Extractable P (Multiple Nutrients), S - 4.60 ......................... 87 Soil P Sorption (Environmental Test), S - 4.70 . .................................. 90 NH 4oAc Extractable Potassium, Calcium, Magnesium, and Sodium, pH 7.0, S - 5.10 . 94 NH 4oAc Extractable Potassium, Calcium, Magnesium, and Sodium, pH 8.5, S - 5.11 . 96 Potassium Fixation, S - 5.20 . ..................................... 98 WREP-125, 3 rd Edition Micronutrients DTPA Extractable Zinc, Manganese, Iron and Copper, S - 6.10 . 100 DTPA-Sorbitol Extractable Zinc, Manganese, Iron, Copper & Boron, S - 6.12 . 102 HCl Extractable Zinc, S - 6.20 . .............................. 105 Extractable Soil Boron, Hot Water, S - 7.10 . ................................. 107 Soil Organic Matter Soil Kjeldahl Nitrogen, S - 8.10 . ............................... 109 Walkley - Black, Titration, S - 9.10 . ................................ 111 Loss on Ignition, S - 9.20 . .............................. 114 Total Organic Carbon and Nitrogen (TOC and TN), S - 9.30 ......................... 116 Soil Cation Exchange Capacity Ammonium Replacement Method, S - 10.10 . .......................... 119 Barium Replacement Method, S - 10.20 . ............................ 121 Extractable Soil Sulfate-Sulfur, S - 11.10 . .................................... 123 Soil Chloride, S - 12.10 . ................................ 126 Inorganic Carbon Carbonate Qualitative Test, S - 13.05 . ............................... 128 Gravimetric Determination, S - 13.10 . .............................. 129 Volumetric CO 2-C Determination, S - 13.30 . ............... 131 Particle Size Analysis, Hydrometer Method, S - 14.10 . ........................... 133 Modified Pipette Method, S - 14.20 . ............................. 137 Extractable Aluminum - KCl, S - 15.10 . ................................ 140 Acid Recoverable Metals, EPA 3050A, S - 16.10 . ......................... 142 EPA 3051A, S - 16.20 . ......................... 145 Botanical Analytical Methods Dry Matter Content, Gravimetric, B - 1.10 . .................................. 149 Nitrogen and Sulfur Total Kjeldahl Nitrogen, B - 2.10 . ............................. 150 Total Nitrogen, Automated Combustion, B - 2.20 . ............................. 153 Total Sulfur, Automated Combustion, B - 2.30 . .............................. 155 Extractable Potassium, Nitrate, Ammonium, Ortho-Phosphate and Chloride, B - 3.10 . 157 Extractable ISE Nitrate, B - 3.20 . ................................. 160 Extractable Sulfate-Sulfur, B - 3.40 . .................................. 162 Total analysis: P, K, S, Ca, Mg, Na, B, Zn, Mn, Fe, Cu and Mo Dry Ashing, B - 4.10 .............................. .......................... 164 Nitric/Perchloric Acid Digest, B - 4.20 . ............................... 167 Nitric Hydrogen Peroxide, B - 4.25 . ............................. 170 Microwave Digestion, B - 4.30 . ........................... 173 Total Selenium in Botanical Materials, B - 6.10 . .................................... 176 WREP-125, 3 rd Edition Water Analysis Methods pH, W - 1.10 ...................................... ............................ 179 Electrical Conductivity - Soluble Salts, W - 1.20 . ...................................... 180 Alkalinity: Bicarbonate and Carbonate, W - 1.30 . .................................... 183 Chloride, W - 1.40 ................................ .............................. .185 Boron, W - 1.50 .................................... ............................ 187 Calcium, Magnesium, Sodium and SAR, W - 1.60 . ............................... 189 Sulfate, W - 1.70 ................................. .............................. .191 Nitrate, W - 1.80 ................................. .............................. 193 Nitrogen, TKN, W - 1.90 . .............................. 195 Phosphorus Total, W - 2.0 . .............................. .197 Appendix Appendix A, ICP-AES Wavelengths . ............................. 199 Appendix B, Standard Element Solutions . ................................ 200 Appendix C, Reference Botanical Material Sources .................................. 202 Appendix D, U.S. Standard Testing Sieve Sizes . .................................. 203 Appendix E, Soil Textural Triangle . ................................. 204 Appendix F, Preparation of QCR Soils . ................................ 205 WREP-125, 3 rd Edition QUALITY ASSURANCE IN THE AGRICULTURAL LABORATORY A Quality Assurance (QA) program Quality Control (QC) is essential for demonstrating long term performance of accuracy and precision to the laboratory clientele. By developing and implementing a QC program that not only monitors the process but provides a mechanism for improvement, the agricultural laboratory can only enhance its credibility and that of the industry. Quality Assurance is a set of operating principles when strictly followed in the analytical laboratory will produce analytical results of known and defensible quality. It is composed of two main sub groups quality control and quality assessment. Quality control (QC) consists of analytical appraisal tools which the laboratory utilizes to verify the analytical process. A few of these are: use of control samples, recovery of known additions, analysis of external standards, use of
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