Evapotranspiration Estimates for Water Balance Scheduling in the UK

This paper compares the use of different methods for estimating reference evapotranspiration (ETo) for irrigation scheduling in the UK. Methods include use of long-term averages, daily weather data and evaporimeters. The results from a single trial in Silsoe in 1996 suggest that, with careful maintenance and measurement, a modified atmometer such as the ETgage, can give estimates of ETo which are close to those obtained using the Penman-Monteith equation.