weight of oven-dry soil Example— (e - g) ÷ (g) (34 gr 27 gr) = 0.259 gr of of soil – 27 gr Dry weight of soil core based on water content of subsample (gr): Dry wt of soil core = [wt of moist soil + bag (gr) - wt of bag (gr)] [1 + soil water content (gr/gr)] Example— Dry wt of soil core = [(a - b) ÷ (1 + h)] = (490 gr - 5 gr) = 385 gr (1 + 0.259) Bulk density calculation (gr/cm3): Dry wt of soil core ÷ volume of soil core Example— 385 gr ÷ 321 cm3 = 1.20 gr/cm3 Soil water content and porosity calculations: 3.—Total soil water content Soil content (by Bulk density Total inches of weight) Sample Water content from table 2 water/foot of soil (grams/gram) site (grams/cm3)* (grams/cm3) depth** (h in 2) Example 0.259 1.2 0.3108 3.7 *Water content (gr/cm3) = soil water content (gr/gr) x bulk density (gr/cm3); 1 gram of water (by volume) = 1 cm3/cm3 **Total inches of water/foot of soil depth = water content x 12 inches (1 foot) Table 4.—Soil porosity
weight of oven-dry soil Example— (e - g) ÷ (g) (34 gr – 27 gr) = 0.259 gr of of soil 27 gr Dry weight of soil core based on water content of subsample (gr): Dry wt of soil core = [wt of moist soil + bag (gr) - wt of bag (gr)] [1 + soil water content (gr/gr)] Example— Dry wt of soil core = [(a - b) ÷ (1 + h)] = (490 gr - 5 gr) = 385 gr (1 + 0.259) Bulk density calculation (gr/cm3): Dry wt of soil core ÷ volume of soil core Example— 385 gr ÷ 321 cm3 = 1.20 gr/cm3 Soil water content and porosity calculations: 3.—Total soil water content Sample site Soil content (by weight) (grams/gram) (h in 2) Bulk density from table 2 (grams/cm3) Water content (grams/cm3)* Total inches of water/foot of soil depth** Example 0.259 1.2 0.3108 3.7 *Water content (gr/cm3) = soil water content (gr/gr) x bulk density (gr/cm3); 1 gram of water (by volume) = 1 cm3/cm3 **Total inches of water/foot of soil depth = water content x 12 inches (1 foot) Table 4.—Soil porosity
USDA_NRCS_bulk_density_guide.docx