Soil and Media

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

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

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

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

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

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.

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

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

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

Soil Texture