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Calculation Help - 9. Weigh the pan + dry soil and record...

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Soil Chemistry 8/20/2010 Method for Soil Moisture Content Soil moisture content is one of the most basic and commonly made measurements in any soil laboratory. The final calculation is based on the definition of water content: Wet soil weight (g) - Dry soil weight (g) Soil moisture % = * 100 Dry soil weight (g) - Pan weight (g) 1. Label a pan with your sample number. 2. Weigh out the empty pan (do NOT tare the pan's weight on the balance). 3. Record the weight of the empty pan in the notebook. 4. Add 10 - 50 g of moist or wet soil to the pan. 5. Weigh the pan + wet soil and record the weight in your notebook. 6. Transfer to oven set at 105 C 5 C. (put a note on the oven with your name and phone number) 7. Allow samples to dry overnight. 8. Turn oven off and allow samples to cool to room temperature or if the humidity is high and soils are clayey, place samples in desiccator to cool.
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Unformatted text preview: 9. Weigh the pan + dry soil and record the weight in the notebook. 10. Dispose of soil in soil waste bucket (not the trash can). Oven-dried soil is NOT appropriate for most soil chemical, physical or biological analyses. One exception is the acid digestion method for total elemental analysis (EPA methods 3051 and 3051A) 11. Clean or dispose of pan (they can be reused indefinitely). 12. Calculate the water content using the equation above. Excel spreadsheet example: 1 A B C D E F G 2 Sample # pan wt. pan + wet wt. pan + dry wt. % moisture sample wet wt O.D. wt 3 alpha or num (g) (g) (g) [=(C D)/(D B)*100] (g) [=F/(1+(E/100))] 4 1A 10.1 36.8 32.2 20.8 5.2 4.3 (calculated) (calculated) except for calculations in cells E and G, all other data or formulas are entered manually...
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This note was uploaded on 10/20/2010 for the course SOIL 479 taught by Professor Ulery during the Spring '10 term at NMSU.

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