ISHS Acta Horticulturae 594: International Symposium on Foliar Nutrition of Perennial Fruit Plants
INFLUENCE OF FOLIAR AND MICROJET APPLICATION OF SOLUBOR AND CALCIUM ON NUTRIENT CONTENT OF APPLE TREES |
| Authors: | D.E. Deyton, C.E. Sams, C.G. Milne |
| Keywords: | Malus X domestica, fertigation, calcium chloride, boron |
| DOI: | 10.17660/ActaHortic.2002.594.76 |
| Abstract:
Apple growers frequently spray apple (Malus X domestica Borkh.) trees with calcium (Ca) and boron (B) to increase the Ca and B concentrations in fruit and reduce physiological disorders. Also, many growers use low volume irrigation to supply water to apple trees. Research was conducted to determine if calcium chloride [CaCl2 2H2O (27% Ca)] and Solubor [Na2B4O7 (20% B)] could be applied through low volume (microjet) irrigation in addition to calcium chloride (CaCl2) foliar sprays to increase Ca and boron concentrations in fruit. Fertigation treatments were applied through a simulated microjet irrigation system using a compressed carbon dioxide delivery system to supply nutrients on two-week intervals from mid-May until the end of June. Foliar treatments of CaCl2 were sprayed on trees to runoff at the same time interval. The CaCl2 fertigation treatments had no significant effects on foliar, fruit or soil test extractable Ca concentrations. Trees sprayed with 2.4 g/L CaCl2 had apples (309 mg kg-1 dry wt.) with 23% higher Ca concentration than fruit (250 mg kg-1 dry wt.) from unsprayed trees. Fertigation of 0.50 g/day/tree or 1.00 g/day/tree of Solubor increased B concentration in soil and foliage. Boron concentrations in fruit were increased from the 0.20 mg kg-1 in untreated trees to 0.32 mg kg-1 dry wt. and 0.52 mg kg-1 dry wt. in trees receiving 0.50 g/day/tree and 1.00 g/day/tree Solubor, respectively. In summary, the application of CaCl2 at 48 g/day/tree through low volume irrigation did not significantly affect the soil, leaf or fruit Ca concentration. Higher rates of CaCl2 should be evaluated in the future. Foliar applications of CaCl2 increased fruit Ca concentration by approximately 60 mg kg-1 dry wt. Fertigation of 0.5 or 1.0 g/day/tree Solubor through low volume irrigation is a method to increase boron in foliage and apple fruit. | |
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