ISHS Acta Horticulturae 586: IV International Symposium on Olive Growing
NITROGEN, BORON, AND POTASSIUM DYNAMIC IN "ON" VS "OFF" CROPPED MANZANILLO OLIVE TREES IN CALIFORNIA, USA |
| Authors: | G.S. Sibbett, L. Ferguson |
| Abstract:
Leaf nitrogen (N), boron (B), and potassium (K) were measured during the 1998 growing season bi-weekly from un-fertilized mature Manzanillo trees that were fully cropped (“on” trees) and where the crop had been chemically reduced during bloom with naphthalene acetic acid (“off” trees). Similar analyses were taken bi-weekly from these same, un-fertilized trees during the growing season of 1999 when crop yields had reversed from their respective 1998 levels. In 1998, crop levels were 75.8 kg/tree for “on” cropped trees and 12.9 kg/tree for “off” cropped trees. In 1999, “on” cropped trees (“off” crop in 1998) yielded 111.6 kg/tree whereas “off” cropped trees (“on” crop in 1998) yielded 23.6 kg/tree. In 1998, “on” cropped trees had significantly higher N levels than “off” cropped trees only as fruit began the maturation process, mid-September and October. That year “off” cropped trees had significantly higher K and B levels than “on” cropped trees during the same period. No significant differences in these elements occurred previously in the growing season due to crop level. In 1999, no significant difference in N or B occurred due to crop level on any sampling date. Trees that were “off” crop in 1998, with significantly elevated K leaf levels at the end of that season, emerged in 1999 with significantly higher leaf K than previously “on” cropped trees, remaining so until mid-June, following anthesis. These “on” cropped trees had significantly reduced leaf K by mid-October in 1999. | |
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