Estimation of long-term reference evapotranspiration using limited weather data in sugar beet plantation area from Middle Anatolian, Turkey

The Konya basin, Middle Anatolian region, is one of the most important agricultural area in Turkey. The region is in a semi-arid area with average annual rainfall ranging from 280 to 500 mm. Sugar beet is the vital commercial crop in this area that is the largest producer of Turkey. Water requirement of the sugar beet and evapotranspiration is very high during the growing season in the basin. The Food and Agricultural Organization of United Nations Penman-Monteith (FAO56-PM) equation requires accurate weather data like air temperature, relative humidity, solar radiation and wind speed. Unfortunately, not all these input data are possible to reach easily. Therefore, FAO56 suggested another equation that is Hargreaves – Samani (HS) equation when sufficient weather data are not available to estimate FAO56-PM. This study estimates ETo using by HS equation. For this purpose, daily maximum and minimum temperature data collected along the period 1986-2015 from sugar beet plantation area located in Konya basin. Finally, this study estimates long-term reference evapotranspiration to give the idea of water loss in a semi-arid area