Growing media, feeding schedules, and container coating for Eucalyptus globulus Labill. container stock production

Abstract

Present day container nursery systems for the production of Eucalyptus Dill, are reviewed and documented from the results of a comprehensive questionnaire distributed to 30 major Eucalyptus producing countries. The results of the survey showed that 41 Eucalyptus species were under production in 1990. Most of these species were grown in containers that varied in diameter, depth, diameter to depth ratio, and volume. The growing media, fertilizer types, fertilizer formulation, and the morphological standards used for the production of Eucalyptus stock for outplanting varied considerably. Two separate experiments were conducted with Eucalyptus globulus nursery stock. 1) The media and feeding schedule study tested the merits of Sphagnum peat, Vermiculite, and Perlite in various proportions as growing media under the exponential and replacement feeding schedules. Seedling height (cm), root collar diameter (mm), top dry weight (mg) and root dry weight (mg) were measured to study growth of the seedlings. 2) The media and container coating study tested the merits of radiata pine bark. Sphagnum peat, Vermiculite, and Perlite in various proportions as growing media in coated and uncoated containers. It also evaluated the effects of container coating on root growth potential and root form. In addition to the morphological attributes measured in the media and feeding schedule study, root number, and root elongation were measured. Both studies were subjected to Analyses of Variance to determine the significance of differences in growth attributes. Both studies showed that seedling height and root collar diameter are not appropriate morphological characteristics to determine or compare the size and quality of finished Eucalyptus globulus stock. A response surface showed that the highest seedling dry weight range lies between 60 to 67% Sphagnum peat, 33 to 40% Vermiculite and 0 to 3% Perlite in the experimental region. The highest predicted seedling dry weight was found at 62% Sphagnum peat and 38% Vermiculite. In each growing medium, seedlings grown under the exponential feeding schedule had a more rapid seedling dry weight gain and higher Dickson's Seedling Quality Index than those grown under the replacement feeding schedule. Eucalyptus globulus seedlings grown in coated Ventblock containers filled with various proportions of radiata pine bark. Sphagnum peat, Vermiculite, and Perlite were physiologically and morphologically superior to their counter parts grown in uncoated containers.