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Soil Testing & Plant Analysis Lab

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Procedures

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Procedures Used at the Laboratory Procedures used for tests offered by the LSU AgCenter Soil Testing and Plant Analysis Laboratory (STPAL) Please select a test procedure from the links provided below: Soil Tests Plant Tissue Tests Water Tests Soil Tests Analysis Sample Size Procedure pH 10 g Add 10 ml deionized water, equilibrate 2 hr, read on pH meter. Lime req. 10 g Add 25 ml deionized water and 2.5 ml saturated Ca(OH)2 for each ton of lime, shake 15 min every 3 hr for 16 hr, read on pH meter. Sulfur req. 10 g     Add 25 ml deionized water and 3.125 ml  0.1N of H2SO4  for each 1000 pounds of sulfur, shake 15 min every 3 hr for 16 hr, read on pH meter.   ROUTINE Phosphorus, Potassium, Calcium, Magnesium, Sodium, Sulfur, Copper, Zinc 2 g Add 20 ml of Mehlich 3 extractant solution, shake 5 min on fast speed, read on ICP. Organic matter 1 g Add 10 ml 1 N K2Cr2O7 and 20 ml concentrated sulfuric acid (wait 2 hr) then add 90 ml water, equilibrate 16 hr, read on colorimeter. Boron 10 g Add 20 ml deionized water, reflux on 100 oC hot plate, read on ICP. DTPA Copper, Iron, Manganese, Zinc 10 g Add 20 ml pH 7.3 0.005 M DTPA solution, shake 2 hrs, read on ICP. HCL Arsenic, Lead, Cadmium, Nickel, Zinc 2 g Add 20 ml 0.1 M HCl solution, shake15 min, read on ICP. Soluble salts 20 g Add 50 ml deionized water, shake 30 min, equilibrate 16 hr, read on conductivity meter. Sulfur 10 g Add 25 ml 0.5 M NH4OAc and 0.25 M HOAc, shake 30 min, read on ICP. Aluminum 2 g Add 20 ml of 0.1 M BaCl2 and NH4Cl solution, shake 15 min, read on ICP. Oil 50 g Add 125 ml petroleum ether, shake 30 min, weigh and calculate. Texture 5 g Add water and empirically determine. Nitrogen 0.4 g Dry Combustion by Leco CN Analyzer Carbon 0.4 g Dry Combustion by Leco CN Analyzer Plant Tissue Tests Analysis Sample Size Procedure Phosphorus, Potassium, Calcium, Magnesium, Sulfur, Boron, Copper, Iron, Zinc, Molybdenum, Aluminum, Sodium, Lead, Cadmium, Arsenic, Nickel, Chromium, Cobalt, selenium 0.5 g Add 5 ml concentrated HNO3 (wait 50 min then 3 ml H2O2, digest for 2.75 hr on heat block, cool, dilute and read on ICP. Nitrogen 0.1 g Dry combustion by Leco CN analyzer. Carbon 0.1 g Dry combustion by Leco CN analyzer. Water Tests Analysis Sample Size Procedure pH 25 ml Direct read on pH meter. Alkalinity 25 ml Titrate to pH 4.5 using HCI and calculate. Conductivity 25 ml Direct read on conductivity meter. Sodium, Calcium, Magnesium, Potassium ,Iron, Maganese, Sulfate, Chloride 15 ml Direct read on ICP. Nitrate 10 ml Direct read on pH meter with ion-selective electrode (after ISA adjustment).

Posted on: 5/4/2005 12:10:02 AM