Broccoli is a crop produced during the fall-winter-spring season in the lower Colorado River region near Yuma, Arizona. Approximately 12,500 acres of broccoli are planted between September and December each year and has an economic value of approximately 129 million dollars.

Broccoli is germinated with solid set sprinklers. After the stand is established, all subsequent water requirements are met by furrow irrigation. Using eddy covariance (Figure 1), measured seasonal ETc ranges between308 to 406 mm (12 to 16 acre-inches). Like the other cool season crops, days from first irrigation to harvest vary, meaning that growth and water use can be more accurately tracked using growing degree days (GDD) and satellite imagery. The calculated crop coefficients (Kc) by growing period are shown below.

Because broccoli, like other cool season vegetable crops, generally receives efficient irrigation applications, there is a potential for salt accumulation in season and during the summer rotational crop (Figure 2). The required leaching is typically achieved in a pre-irrigation off-season in the late summer months.