Impact of Distillery Effluent and Salts on Hydraulic Conductivity of a Sandy Loam Soil

Irrigation with distillery effluent, besides influencing crop yield, may have considerable impact on physical properties of soil because of its high salt and organic carbon contents. This experimental study was conducted to evaluate the effect of distillery effluent on hydraulic conductivity of a sandy loam alluvial soil and compare the effect of inorganic salts of potassium (K) with that of distillery effluent on hydraulic conductivity of soil. The treatments consisted of 4 sources of K: potassium chloride, potassium sulphate, post methantion distillery effluent (PME) and oxidized PME (PME minus organic carbon) at 4 levels equivalent to 10, 20, 40 and 100% of the K concentration in the PME. There were 4 replications for each treatment. Soils, collected from the upper 15 cm of a farm were crushed, passed through a 2-mm sieve and packed in 6.5 cm diameter and 50 cm long columns. Each of the solutions was applied 4 times at the interval of 20 days to the soil column, which were subsequently flushed with distilled water and saturated hydraulic conductivity of soil was measured using the constant head technique. Application of PME and salts increased the hydraulic conductivity of soil to 3 to 4 fold as compared to that of the untreated soil. With the increasing levels of salt concentration, the rate of increase in hydraulic conductivity initially decreased, but at 100% salt level soil hydraulic conductivity increased sharply. The oxidized PME, which contained only the inorganic salts present in the PME, had highest hydraulic conductivity at 100% salt level followed by PME and inorganic salts. The exchangeable K content of soil (x) and hydraulic conductivity (y) showed a polynomial relationship (y = 15.28 – 1.61x 0.05x2). The study showed that application of PME has significant impacts on soil hydraulic conductivity suggesting that impact assessment of PME application on physical properties of soil be recommended to find an optimum application rate before the practice is adopted.