Evaluation of Movement of Wetting Front under Surface Point Source of Drip Irrigation in Vertisols

The knowledge of wetted width, depth and maximum wetted width beneath the surface of soil is required in design and management of an efficient drip irrigation system, which can largely be controlled by emitter discharge and time of irrigation. Temporal movement of wetting in horizontal and vertical directions under surface point source was studied in acrylic tank at 0.5 l.h⁻¹, 1.0 l.h⁻¹, 2.0 l.h⁻¹ and 4.0 l.h⁻¹ emitter discharges in vertisols. However, a constant volume was applied in each run. Power equation based models were developed using results obtained for temporal changes in parameters of wetting geometry like the horizontal surface wetting width (B_s), maximum wetting depth (d), maximum horizontal wetting width (B) at high value of correlation. The maximum wetted radius at the soil surface as well as beneath the soil surface increased with the increase in emitter discharge rate. The maximum wetting radius at soil surface was found to be 113 mm, 115 mm, 132 mm and 134 mm at discharge rate of 0.5 l.h⁻¹, 1.0 l.h⁻¹, 2.0 l.h⁻¹ and 4.0 l.h⁻¹, respectively. The maximum wetted depth did not increase with increase in emitter discharge rate. It covered distance of 133 mm, 119 mm, 119 mm and 119 mm with emitter discharge rates of 0.5 l.h⁻¹, 1.0 l.h⁻¹, 2.0 l.h⁻¹ and 4.0 l.h⁻¹, respectively.