2.4.3. Soil physical properties
Standard core method was used to calculate bulk density (ρb) using mass per unit volume of soil. Particle size analysis was performed by adding 25 ml of 5% hydrogen peroxide to remove organic matter, followed by addition of sodium hexamata phosphate to disperse soil and size of the soil particles were investigated by standard hydrometer techniques. Total porosity (ρt) was calculated from the measured values of bulk density (ρb) and standard soil particle density (ρp) of 2.65 g/cm3 and was expressed as percent as follows: