Estimating the Volume of Subsurface Drainage Water under Different Crops

Abstract

Large-scale subsurface drainage projects are being implemented in different states of India for reclamation of waterlogged saline soils. Various options for management of saline drainage water like disposal into stream or river, reuse for cropping or agro-forestry and evaporation ponds have been tried on pilot scale field studies with different degrees of success. Information on expected rate and volume of drainage water from subsurface drainage projects would be useful for comparative evaluation of different disposal/management options and to design structures for conveyance or storage of drainage water. The parameters of De Zeeuw-Hellinga equations, appropriate for simulation of watertable depth and drain discharge in homogenous soils were modified in this study to be applicable for two layered stratified soils. The simulated results compared favourably with field observations of an experimental subsurface drainage site at Hisar. (Haryana) during the recession phase of drainage. Peak discharge rate and volume of drainage water were simulated based on 10 years meteorological and irrigation data for different kharif (cotton, sorghum and bajra) and rabi (wheat, berseem, barley, mustard and oat) crops at the experimental site. Due to occurrence of high intensity rain during rainy season, peak rate of drainage was higher in kharif crops than in rabi crops. Berseem, cotton, sorghum and wheat generated considerably larger drainage volumes than the remaining kharif and rabi crops