Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: February 18, 2006
Publication Date: March 1, 2007
Citation: Krueger, R. 2007. Nutritional dynamics of date palm (phoenix dactylifera l.). Acta Horticulturae. Interpretive Summary: There has been little work on fertilization of date palms in the US since the 1960s despite changes in fertilization and other cultural practices. In particular, there has been no work devoted towards development of nutritional diagnostic standards. As a first step in this area, seasonal variations in most major and minor elements were studied in a commercial 'Deglet Noor' date garden in Thermal, California. There were gradients from older to younger leaves, with most elements showing higher concentrations in the younger leaves. In addition, there was a gradient along with leaf axis, with most elements showing higher concentrations in the distal portion of the leaf. Concentrations in the US have generally been lower than reported from other countries; the reason for this is not known at this time. Seasonal changes in nutrient concentrations varied among the elements. However, most of the macro-elements exhibited their lowest concentrations in the summer or early fall. Patterns among the micro-nutrients were more variable. The results suggest that the most appropriate time for sampling for nutrient diagnosis would be in the late summer, with leaf samples being taken from the middle portions of leaves in the intermediate portion of the canopy. It remains to relate concentrations to yield and other horticulturally important parameters. Current levels of fertilization appear to be adequate to replace N lost from the leaves and fruit, but more attention needs to be paid to the efficiency of N application.
Technical Abstract: Leaves and fruit of date palms (Phoenix dactylifera L.) cv. 'Deglet Noor' grown under commercial conditions were assessed during the course of an entire growing season for nutrient levels of most macro- and micro-nutrients. The different nutrients showed various patterns in the different organs throughout the year. Implications of these patterns for nutritional analysis are discussed. Since nutritional studies on date palms in the USA have shown varied results over the decades, a comparison is made with results from other countries, particularly Egypt.