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).

Last Updated: 4/28/2009 7:44:53 AM

Procedures Used at the Laboratory

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