1. Soil and Media

2. 40-50% inorganic solids (rocks, sand, silt, clay) 1-10% organic solids (organic matter, residues, roots, microbes) 20-30% water or soil solution 20-30% air or soil gases Soil

3. Introduction Medium for plant growth Recycles nutrients and organic wastes Habitat for soil organisms Water supply and purification system

4. Objective 1 Measuring the bulk density of –Sand –Soil –Mix (sand + soil) Bulk Volume = V soil + V Air + V water

5. Methods Measure 100ml of soil and sand Mix your samples Tamp the container lightly until your mix is packed Mark the level of the mixture Record the volume Draw a diagram

6. Objective 2 Measuring: –Solid Volume = Vol. of the solid parts –Pore Volume = Vol. occupied by air –Porosity = ( Pore Vol. / Bulk Vol. ) x 100

7. Methods Prepare 100ml of sand, soil and mix Add 100ml of water to each sample Stir each to remove trapped air Record the volume Solid Volume = (Soil Vol. + Water Vol.) – Bulk Vol. Pore Vol. = Bulk Vol. – Solid Vol.

8. Table 1. SandSoilMix Bulk Volume Volume (Water + soil) Solid Volume Pore Volume Porosity (%)

9. Objective 3 Measure: –Aeration pore volume: Drained water volume –Water retention pore volume: Difference between applied and drained water volume. –Total porosity (%)

10. Table 2. SandSoilMix Water Volume Aeration pore volume Aeration Porosity (%) Retention pore volume Retention Porosity (%) Total Porosity (%)

11. Soil Texture