SOIL SAMPLING AND DETERMINATION OF SOIL PHYSICAL AND HYDRAULIC PROPERTIES OF DIFFERENT SOILS

Abstract

Soil physical and hydraulic properties are fundamental indicators of soil functionality, influencing water movement, nutrient availability, and root growth. Accurate determination of these parameters requires precise sampling and standardized analytical procedures. This study was conducted to develop technical competency in soil sampling and to assess key soil physical and hydraulic properties across different soil types. Both disturbed and undisturbed soil samples were collected from the 0–15 cm depth following standard methods. Disturbed samples, obtained with augers, were used for the determination of soil texture, pH, electrical conductivity, and organic matter, whereas undisturbed core samples (5 cm × 5 cm) were used for the measurement of bulk density, porosity, soil moisture, and hydraulic conductivity. Soil texture was determined by the hydrometer method, and bulk density and particle density were used to calculate total porosity. Soil moisture content was estimated gravimetrically by oven-drying at 105 °C for 24 hours. Saturated hydraulic conductivity was measured using a laboratory permeameter and computed based on Darcy’s Law under constant head conditions. Results revealed textural classes ranging from loam to silt loam, with bulk density values between 1.33 and 1.62 g cm⁻³ and porosity between 39% and 50%. Saturated hydraulic conductivity varied from 0.036 to 0.297 cm hr⁻¹ among soil samples, indicating moderate to high permeability. These findings demonstrate the interrelation between soil structure and hydraulic behavior, providing valuable insights for soil management and sustainable agricultural practices.