Hydrological water balance modelling for assessing productivity and irrigation planning

Abstract

The physically based distributed modelling system, MIKE SHE, is used to simulate the hydrological water balance of Belura watershed with the objective of developing the irrigation plan and assessing productivity.The existing cropping system was replaced with the cropping system planned using qualitative land evaluation i.e. land capability and suitability classification for soils of the watershed.The hydrological water balance was simulated using calibrated model for Belura watershed.The actual yield of the sorghum, cotton and pigeonpea from watershed area was estimated by Food and Agriculture Organisation (FAO) model, using simulated hydrological water balance.Yield of sorghum, cotton and pigeonpea is estimated to be 32, 48 and 55% of the potential yield at downstream side and 28, 41 and 46% at upstream side, respectively.Considering the water requirement to obtain potential yields, these crops suffered soil moisture deficit of 61, 68 and 151mm at upstream; and 57, 65 and 157mm at downstream sides of the watershed, respectively.If irrigation is provided as and when water content in the root zone goes below allowable limit at different crop growth stages using hydrological water balance, it is possible to obtain sustainable crop yields.The overall results illustrate the applicability of MIKE SHE comprehensive hydrological modelling system for the management of water resources for sustainable agricultural productivity in a watershed.