Submitted to: American Society of Horticulture Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 30, 2001
Publication Date: N/A
Technical Abstract: The purpose of this study was to elucidate the effect of CaCl2 presence in urea foliar sprays on growth and N uptake by apple seedlings (Malus domestica Borkh.). In previous work the application of N in conjunction with CaCl2 was more efficient in eliminating N deficiency in field-grown grapefruit trees than when the same rates of N were applied without CaCl2. Greenhouse-grown 'Red Delicious' apple seedlings were pruned to a uniform height of 50 cm and allowed to develop one single shoot. The plants were foliar sprayed 8 times at 10 day intervals with: 10 mM CaCl2 x 2H2O alone or, 83 mM urea with 0, 10, 20, or 40 mM CaCl2 x 2H2O. The control plants were treated with deionized water. All the spray treatments contained Tween 20 surfactant at 0.1% concentration. Compared to the control, sprays with urea alone or in conjunction with CaCl2 x 2H2O increased leaf number, total new leaf area and the area of individual leaves, shoot growth, stem thickness, and leaf and stem dry weights. However, addition of CaCl2 x 2H2O did not improve the effect of urea. In fact some of the growth increases tended to be smaller when urea was used in conjunction with CaCl2 x 2H2O. Sprays with CaCl2 x 2H2O alone tended to increase shoot growth and total leaf area.