Increasing Irrigation Efficiency
Water Use and Management
Updated Crop Evapotranspiration (ET) & Salinity Management
Cantaloupe
Cantaloups has a long history of production in Arizona. Both spring and fall production occurred. Fall production has declined over the past two decades due to competition for land in the fall from the leafy vegetable industries, and risk of cucurbits to white fly insect pressure in the early fall. Today most spring cantaloupes fallow fall-winter leafy vegetables. Approximately 13,000 acres of cantaloupes produced in 2021 had a value of 91.5 million dollars.
Cantaloupes and other melons were traditionally produced by furrow irrigation. However, buried drip irrigation, with and without plastic mulch, has become more common in recent years. Using eddy covariance (Figure 1), we have measured seasonal ETc of 472 mm (18.6 acre-inches) for cantaloupes produced on bare soil. However, when grown with plastic mulch ETc averages about 202 mm (7.9 acre-inches) due to marked reduced soil evaporation.
The growth periods as tracked by growing degree days (GDD) and satellite derived normalized vegetable indices (NDVI) and crop coefficients for each period are shown in Table 1. Salinity generally increases during the cantaloupe production cycle (Figure 2) and a pre-irrigation is usually required to restore salt balance before fall vegetable production.
Table 1. Cantaloupe heat units, NDVI, Kc vs. growth stages.
Stage | GDD (C-Day) | GDD (F-Day) | NDVI | Kc |
---|---|---|---|---|
INI | 0.078 | 0.575 | ||
INI/DEV | 509.2 | 948.6 | 0.119 | |
DEV/MID | 1014.5 | 1858.1 | 0.558 | 0.983 |
MID/END | 1408.7 | 2567.7 | 0.558 | |
END | 1713.2 | 3115.8 | 0.339 |
GDD based on minimum and maximum thresholds of 5 C (41 F) and 30 C (86 F), respectively.
Figure 1
Eddy Covariance system in cantaloupe field in the Yuma area.
Figure 2
Salinity increases through 90 cm soil depth during spring cantaloupe production within the Yuma County Water Users Association.