EVAPOTRANSPIRATION BY YOUNG FLORIDA FLATWOODS CITRUS TREES

Twenty-one drainage lysimeters were installed in 1988 to measure water balance parameters for citrus trees. The lysimeters were designed to simulate the high water-table conditions that exist for the more than 150,000 ha of citrus grown in the Florida Flatwoods. The lysimeters were constructed from 3.5-m diameter by 1.0-m deep polyethylene tanks. Young trees were transplanted into the lysimeters in 1988. Four experimental treatments consisting of constant water tables at depths of 0.61 m, 0.76 m, and 0.91 m plus a fluctuating water-table treatment were included in the study. Trees were watered with a microirrigation system and all irrigation and drainage water was metered. Water-table levels were maintained by float-controlled pumps. Annual evapotranspiration (ET) averaged 16.030 L tree-1 for March 1989 to March 1990 and 11,733 L tree-1 for March 1990 to March 1991. ET rates were not significantly different among water-table treatments. Tree growth, yield, and juice quality were not affected (p = 0,05) by the water-table treatments.