The Feasibility of Controlled Subsurface Drainage in Saline Vertisols: A Case Study of the TBP Command Area

As the drain discharge water from various places or facilities will vary in their quality characteristics, surface and subsurface drainage discharge water from irrigated agriculture field is often variable compared with the quality of the canal water supply. As a result, in order to reuse drainage discharge in crop production, feasibility studies or quality assessments of the discharge must be conducted for both the short- and long-term adoption of conventional and controlled SSD under different drain spacing. In the TBP command area, there are no such feasibility studies on the characterization of drain discharge from various subsurface drainage systems. Therefore, it is suggested that this experiment be done. At the Agricultural Research Station, Gangavati (Karnataka), a plot experiment was carried out in rabi 2021 to investigate the characterisation of drain discharge water for its reuse as irrigation water. An established and controlled subsurface drainage system (SSD) was used for the experiment. According to the treatments, drain discharge under traditional subsurface drainage systems (SSD) ranged from 3.66 to 0.63 compared to 1.38 to 0.42 mm/day under controlled subsurface drainage systems, according to water samples obtained from six different sampling locations. Drain discharge water's electrical conductivity under normal SSD ranged from 3.89 to 1.24 dS/m, whereas it ranged from 1.01 to 0.81 dS/m under controlled SSD. While salt output under conventional conditions ranged from 29.0 to 11.0 kg/ha, it was 16.5 to 2.5 kg/ha under. Finally, the subsurface drainage system drain water samples were not suitable for reuse as irrigation water to paddy in the R/S season as per the classification of irrigation water quality particularly for poorly drained black soils in the TBP command area.