CSS 210 Lecture 5: Bulk Density and Soil Weight (5).txt
10 Feb 2014
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Bulk density: mass per unit volume of oven dried soil. The mass is always expressed on an oven dried basis, where the soil weight remains constant and contains no water. Bd = mass of soil particles/volume of soil. Bulk density is most commonly expressed in grams per cubic centimeter, but may also be written as pounds per cubic foot, pund per acre furrowslice or kilograms per hectare layer. Bulk density samples are obtained by driving a metal core ring into the ground. It must be undisturbed and uniform of the typical area. Soil is dried for 10 hrs at 105 to 110 degrees centigrade. Bd (g/cc) = oven dried soil (g) - core ring (g)/core ring cc. The higher the pororsity, lower the bulk density. Structureless soils, like dune sand, often have a bulk density from 1. 6-1. 7. A horizon ith loam soil would usually be about 1. 3. As bulk density increases, percent total pore space decreases.
