An Experimental Center-Pivot Irrigation System for Reduced Energy Crop Production Studies

AN experimental 52.6 ha center-pivot irrigation system for studies of reduced energy crop production systems is described. The system consists of high pressure impact sprinklers, low pressure impact sprinklers, and low pressure spray nozzles that are automatically turned on or off at preselected locations in the field. The control procedures ofthe system operation are described. The system also has the capability of applying different depths of water per irrigation as a function of position radially outward from the pivot point. Four years of data indicate that the system controls function properly and the design irrigation depths are being met. The concept of rotational uniformity or the spiking of water application as the pivot rotates is presented. Field measurements of water distribution of the different sprinkler packages indicate that rotational uniformity appears to be a problem only on the spray nozzle system and only for those systems applying relatively small application depths. The low pressure spray nozzles have the lowest uniformities while the high pressure impact and low pressure impact sprinklers have nearly identical uniformities.