Evaporation Pan: A Tool for Irrigation Scheduling

Agriculture is the major consumer of water in Pakistan. However, water application and water useefficiencies are very low. The main reason for low efficiency is the over irrigation by the farmers. Farmersnormally over irrigate the field due to lack of proper knowledge about irrigation scheduling. Significant quantitiesof water could be saved by adopting irrigation scheduling. Irrigation scheduling is the procedure used todetermine the time and depth of water application for each irrigation. However, it is not easy for commonfarmers to adopt proper irrigation scheduling practices due to difficulties in soil moisture measurement.Nevertheless, an evaporation pan may help the farmers to devise irrigation scheduling. In this investigation, anevaporation pan attached with a Marriott bottle was used for irrigation scheduling purposes. The evaporationpan predicted the soil moisture close to that predicted by the gravimetric method. For wheat crop, irrigationscheduling saved about 50% irrigation water irrespective of irrigation method used with out affecting crop yield.