Bulk density from Calculation: Soil porosity Sample site 2 1 - (soil bulk density ÷ (percent) (grams/cm3) 2.65)* Example 1.2 1 - (1.2 ÷ 2.65) 54.7 *The default value of 2.65 is used as a rule of thumb based on the average bulk density of rock. Table 5.—Water-filled pore space *Percent of Water content Calculation: Sample Soil porosity pore space from table 3 (water content ÷ soil site from table 4 filled with (grams/cm3) porosity) x 100 water (0.3108 gr/cm3 ÷ 0.547) Example 0.3108 0.547 56.8 x 100 Figure 11.—Example soil core dimensions, Figure 9.—Soil porosity volume, and weight, by component. Figure 10.—Example soil core volume, by component (volume = 321 cm3). Were results of bulk density and porosity expected? Why or why not?
Sample site Bulk density from 2 (grams/cm3) Calculation: 1 - (soil bulk density ÷ 2.65)* Soil porosity (percent) Example 1.2 1 - (1.2 ÷ 2.65) 54.7 *The default value of 2.65 is used as a rule of thumb based on the average bulk density of rock. Table 5.—Water-filled pore space Sample site Water content from table 3 (grams/cm3) Soil porosity from table 4 Calculation: (water content ÷ soil porosity) x 100 *Percent of pore space filled with water Example 0.3108 0.547 (0.3108 gr/cm3 ÷ 0.547) x 100 56.8 Figure 9.—Soil porosity Figure 10.—Example soil core volume, by component (volume = 321 cm3). Figure 11.—Example soil core dimensions, volume, and weight, by component. Were results of bulk density and porosity expected? Why or why not?
USDA_NRCS_bulk_density_guide.docx