Evaluating mini pan evaporimeter for on-farm irrigation scheduling

In the scenario of water scarcity, it is imperative to utilize and conserve available irrigation water effectively to improve water productivity and in this context, scientific irrigation scheduling assists the farmers for effective utilization of the water resources. In this study, an attempt has been made to develop and standardize a small size pan evaporimeter which is low cost and easy to interpret and maintain at farm level for irrigation scheduling purpose. Mini pan evaporimeters made up of galvanized iron and PVC with different diameters (30 cm, 20 cm and 10 cm) and height of 25 cm. Observations were taken on daily basis as well once in 3-days, 5-days and 7-days. Regression analysis indicated that GI mini pan with 30 cm and 20 cm diameter had closest relation with USWB class A pan compared to other pans. From t test, it is seen that significant difference was noticed between evaporation measured at 5, 7-days interval and daily evaporation cumulated for the same days but not for 3-days interval. It may be concluded from the present experiment that 30 cm and 20 cm diameter GI mini pans can be used for on-farm irrigation scheduling purpose.