Estimation of crop water requirement based on Penman-Monteith approach under micro-irrigation system.

摘要

A study was carried out to estimate crop evapotranspiration (ETc) for different crops growing under surface (SI) and microirrigation (MI) methods in the command area of Mula Irrigation Project in Maharashtra, India. A spreadsheet-based computer model was developed to estimate the ETc values and compute the water requirement. The climatological data obtained from the meteorological observatory located at All India Co-ordinated Research Project on Water Management, Rahuri (Maharashtra), from 1975 to 2005 was used. The crop water requirement under MI methods was less than that under SI methods. The saving in water for MI method was maximum under pomegranate and lime (88%) and minimum for summer groundnut (38%) when compared to the SI method. Similar saving in water was also observed for other crops under MI methods. The percentage saving in MI methods was 75, 62, 64, 73, 68, 61, 43, 51, 65, 48, 53, 70, 63, 65, 63, 40, 52 and 63% for pawpaw, banana, sugarcane, grapes, kharif soyabean, rabi tomato, kharif groundnut, rabi onion, cotton, gram, potato, kharif brinjal [aubergine], cabbage, summer brinjal, summer cucumber, summer onion, summer okra and summer chilli, respectively, when compared to the water requirement under SI method. Thus, there is a saving of at least 50% of water if drip irrigation method is used instead of SI method. This indicates that in the case of water scarcity there is possibility of bringing additional area under irrigation by using the saved amount of water.