VARIATION IN SOIL-PH AND CALCIUM STATUS INFLUENCED BY MICROSPRINKLER WETTING PATTERN FOR YOUNG CITRUS TREES

Deep aquifer water, which contains high levels of bicarbonate and Ca, is used predominantly for citrus irrigation. Changes in soil pH and Me hlich 1 extractable Ca concentrations were examined inside and outside the microsprinkler-wetted zone in 3- to 5-year-old citrus groves on t hree soils. Soil pH at 0 to 15 cm inside the wetted zone was 0.4, 0.9, and 1.3 pH units higher than that outside the wetted zone in Immokale e, Myakka, and Holopaw sands, respectively. This pH increase was due t o the addition of bicarbonate in the irrigation water. Extractable Ca concentrations were also about two-fold higher inside compared to thos e outside the wetted zone at depths of 0 to 15 and 15 to 30 cm. With y oung trees, a majority of the roots are within the microsprinkler-wett ed zone; therefore, soil samples should be taken inside the wetted zon e for measuring soil pH and status of plant nutrients.