Irrigation scheduling and cantaloupe yield model for the Jordan Valley

Abstract

A crop yield and soil water management simulation model (CRPSM) developed at Utah State University was modified and calibrated using data from a trickle irrigation experiment with different mulched treatments on cantaloupe ( Cucumis melo L.) in the Jordan Valley. The soil water budget model was adapted to the field conditions through input describing rooting depth, field capacity, wilting point and wet soil surface air-drying characteristics. Observed field crop growth progress was used for the model's phenology clock. Calibration of the yield model was accomplished by adjusting model parameters to obtain a reasonable match between model and field yields. Simulated possible irrigation schedules were tested using different options provided by the model. By using 1.5 cm per irrigation for a total of 44 to 47 irrigations and starting the first instead of the last of April, simulated yields were about double what was actually obtained in the field. This indicates that the date of first irrigation as well as total water applied is important for maximizing yield. Plants in the field were apparently subjected to water stress prior to late April when irrigation was initiated. The use of the CRPSM model could reduce the number of plots needed in further field experimentation since the less successful possibilities could be identified by simulation. Thus, field efforts can be concentrated on treatments most likely to provide higher yields with improved irrigation management.