to be permitted for tomato production, but to provide some unbiased

data that should be helpful to water management officials and

tomato growers in negotiating irrigation use permits.

 METHODS AND MATERIALS

 Experiment #1: Field plots were transplanted with tomato

plants of the Walter cultivar on 19 March during a relatively dry

growing season. Plant rows (six feet apart) were located on beds

three feet wide covered with black plastic mulch. Spacing between

plants was two feet with wood stakes driven into the ground between

plants with twine attached to prevent plants from falling over. A

fumigant was applied just before the plastic mulch to control

pests. Soil type was Tifton loamy fine sand (fine, loamy,

siliceous, thermic, Plinthic Kandiudult).

 There were three irrigation treatments: sprinkler (SI),

automatic drip (ADI), and manual drip (MDI). All treatments were

scheduled for irrigation with tensiometers (one per plot) placed

six inches from plants with the sensor at the six-inch depth.

Therefore, plant demand for water determined the amount of

irrigation used in each treatment. Irrigation was turned on for

each treatment when the reading reached 20 centibars (cb). One bar

is equal to 14.5 lbs/square-inch of negative pressure or suction;

20 cb = 0.2 bar or 2.9 Ibs/square-inch of suction. Treatments SI

and MDI were irrigated with one-inch and 0.2 inches of irrigation

at each application, respectively. Treatment ADI had a switching

tensiometer connected to a solenoid that turned the irrigation on

above 20 cb and off below 20 cb. A municipal type water meter was