Estimation of Evapotranspiration andIrrigation Scheduling of Lentilusing CROPWAT 8.0 Model for Anantapur District, Andhra Pradesh, India

Abstract

To achieve effective water allocation and planning, the information about Lentil crop water requirements, irrigation withdrawals, soil types and climate conditions were gathered from the study area i.e. Anantapur district of Andhra Pradesh (A.P). The main objectives of the study area wereto estimate the Lentil crop water requirement (i.e., evapotranspiration) and deciding the proper sowing time in semi-arid agro-climatic conditions.The CROPWAT 8.0 was used to estimate the climatic water deficit, net irrigation requirement (NIR) and gross irrigation requirement (GIR) under different rainfed and irrigated conditions with six different growing dates with aninterval of 10 days.The results showed that the best sowing dates were last week of September to 1st week of October, which gives thebest utilization of rainfall as effective rainfall. The net and gross irrigation requirement(NIR and GIR) varied from a minimum to maximum as 69.7 mm, 110.3 mm, 78.2 mm, 119.4 mm, 114 mm and 165.9 mm; respectively for all sowing dates. Thus by adopting a proper sowing date and irrigation scheduling criteria, it is possible to save 49.7 mm of water as NIR for theearly sown crop.