Irrigation Scheduling to Maximize Water Utilization of the Crop Rotation

Abstract

There are some evidences indicate increasing trends in evapotranspiration (ETo) values in the past 30 years in Egypt. Due to unavailability of daily weather elements in many parts of Egypt, there is a need to determine the length of time interval of previous weather data and consequently ETo values, with less variability that can be used to properly schedule irrigation in the five agro-climatic zones of Egypt. Daily values of maximum, minimum and dew point temperatures, as well as solar radiation, and wind speed were collected for 10 years (2007–2016). Statistical analysis was applied to study the spatial and temporal variability of weather elements, as well as ETo values (annual, winter, and summer). The analysis revealed that in the first agro-climatic zone, the interval between 2013 and 2016 is suitable to be used to schedule irrigation for both winter and summer crops. In the second and third agro-climatic zones, the interval between 2012 and 2016 is suitable for winter crops and the interval between 2013 and 2016 is suitable for summer crops. For the fourth agro-climatic zone, the interval between 2013 and 2016 is suitable for winter between 2014 and 2016 is suitable for summer crops. Whereas, in the fifth agro-climatic zone, interval between 2013 and 2016 is suitable for winter crops and summer crops. Using the developed ETo time intervals in calculating water requirements for the prevailing crop rotations saved 1–3% of the applied water to these rotations using 2016 weather data. Thus, the above results implied the suitability of the developed ETo time intervals in irrigation scheduling in for crops to improve irrigation water management on field level. This approach could result in efficient use of irrigation water in agriculture to reduce unnecessary losses.