A study by the University of Wyoming helps to answer the question of how lubricants affect soil test results. The study included five commonly used lubricants, two (motor oil and dish washing liquid) wiped on and three (WD-40, vegetable oil spray, and silicone) sprayed on the soil probe. Chemical composition of the lubricants is shown in Table 1.
|Table 1. Chemical Composition of Five Commonly Used Soil Probe Lubricants|
|“PAM” Vegetable oil spray||>70||9||34||1200||2.9||0.2||1.4||0.3|
|“Dove” dish washing liquid||30||205||44||2||0.2||<0.1||<0.1||<0.1|
|Synthetic motor oil||48||11||33||5||0.8||0.1||460||0.6|
Data shown in Table 1 indicates that lubricants can pose potential contamination problems. Their effects on test results for samples in the Wyoming study are shown in Table 2, and may be summarized as follows:
|Table 2. Effects of Soil Probe Lubricants on Soil Test Results|
|Control (no lubricant)||1.7||1||14||249||11.4||1.5||0.8||1.7|
|“PAM” Vegetable oil spray||1.7||2||16||263||13.5||3.8||1.1||2.3|
|“Dove” dish washing liquid||1.7||3||14||280||10.1||1.3||0.7||1.2|
|Synthetic motor oil||1.6||2||16||265||12.5||1.4||0.9||2.0|
Reference: Alan D. Blaylock, Lyle R. Bjornstead, and Joseph G Lauer, University of Wyoming. Taken from The Soil-Plant Council Analyst, The Soil and Plant Analysis Council, Inc. March 1996.