Estimation of Evapotranspiration for Onion Crop in Semi-Arid Region: Experimental Field Setup Using Lysimeter

摘要

In this work, Blaney-Criddle and Lysimeter method were applied to evaluate the actual evapotranspiration for onion crop in the semi-arid region of Chitradurga district. A reliable and accurate estimation of evapotranspiration are required for proper water balance and to define water-crop requirement. For this purpose, Lysimeter was set up in the field using three different soil layers of specific gravity 2.30. In this research work, an attempt is made to estimate daily evapotranspiration for onion crop, for which 1000ml of water was added on daily basis and corresponding percolation was observed to find the potential water balance deficit and surplus. Onion is a local crop of Chitradurga district having growth rate 90-120 days. For Blaney-Criddle equation, crop coefficient of 0.75 is adopted to estimate the actual evapotranspiration. This method was found to be simple and reliable to estimate the evapotranspiration in semi-arid region.