Investigation of variability in drainage properties of saline soils at village Mudlana in Sonepat district of Haryana

A study was conducted for determining and analyzing depth wise variability in drainable porosity and depth wise and spatial variability in hydraulic conductivity of saline soils. The field data on drain discharge and water table drawdown from at an already installed subsurface drainage system at village Mudlana in Sonepat district of Haryana state were used in this study. The hydraulic conductivity values estimated at multiple locations at the experimental site were also collected. The study revealed that the point measurements of hydraulic conductivity at multiple locations in the experimental area resulted in great variability (0.27–5.30 m day"¹), making it difficult to select field representative value. Hydraulic conductivity as determined from drain discharge and water table drawdown measurements showed depth-wise variability ranging from 0.96 m day near soil surface to 0.39 m day at deeper layer. Similarly, drainable porosity as determined from drain discharge and water table drawdown measurements was also found varying from 5.5% near soil surface to 10.8% at deeper layer. Skaggs (1976) method of determining K/u ratios (ratio of hydraulic conductivity and drainable porosity) has also been presented which resulted in a variation of 17.41 near soil surface to 3.69 at deeper layers. The measurements of the two drainage properties from drain discharge and water table drawdown measurements gave field representative values with lumped effect of soil heterogeneity, non uniformity and anisotropy.