Performance Evaluation of Subsurface Drainage System under Waterlogged Saline Vertisols for Sugarcane Crop in Ukai Kakrapar Canal Command, Gujarat

Abstract

Crop productivity in canal command areas of India is declining due to waterlogging and soil salinization problems, and it is posing a big threat to livelihood security of small and marginal farmers. Subsurface drainage (SSD) technology, which restores favourable condition in the crop root zone by reclaiming waterlogged saline soils, can be one of the options to restore the crop productivity in such areas. The SSD system was installed at Mulad village in the Ukai Kakrapar canal command area, Gujarat, in the year 2012 to address the problem of drastic yield reduction of sugarcane due to twin problems of waterlogging and soil salinity in Vertisols. It was found that the SSD helped in desalination of soil profile as soil electrical conductivity was reduced to a range of 0.42 to 3.90 dS.m-1 from its initial range of 1.2 to 7.3 dS.m-1. Electrical conductivity of drained water was in the range of 1.3 to 4.4 dS.m-1. Further, there was reduction in waterlogging condition, both surface and sub-surface, as water table lowered below crop root zone depth (depth of 0.6 m) and surface water ponding duration reduced to 6-8 days from earlier 25-30 days during peak monsoon days. Overall performance of SSD system was satisfactory as average sugarcane yield in the study area increased significantly from 39.29 to 97.29 t.ha-1 as result of reduction in soil salinity and waterlogging in drainage area. Economic analysis also indicated 114% increase in benefit-cost ratio after SSD installation. Thus, large scale installation of SSD system for reclamation of waterlogged saline Vertisols is economically viable in the state of Gujarat.