Date of Award

1984

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Abstract

Solution-phase pH, soluble salts, NH(,4)-N+NO(,3)-N, P and K were compared over a 140-day period in 1982 for five phosphatic sources (0-18-0, 0-46-0, 29-26-0, 18-48-0, 11-55-0) incoporated at three rates in a pine bark-sand medium (4:1 v/v). Treatment effects on visual quality of five ornamental species, media-bound and leaf-tissue nutrient levels (gardenia species) and shoot dry weights (gardenia species) were also investigated. Compared to the check, media amended with each of the P sources were generally lower in pH. Solution-phase nitrogen (NH(,4)-N+NO(,3)-N) levels for the 0-18-0 or 0-46-0 sources were significantly lower than that of the other P sources and the check on day 7. Solution-phase P, media P and leaf-tissue P levels from the five P sources were significantly higher than the check when averaged over sampling days. The 0-18-0 source provided significantly higher media Ca levels and significantly lower media Mg, Na, Zn and Mn levels than the other P sources and check. Leaf-tissue P, K, Cu and Mn levels were significantly and positively correlated with their respective levels in the media. The 1.28 kg/m('3) rate of the 0-18-0 and 0-46-0 sources resulted in significantly lower solution-phase and media pH, significantly higher media P and significantly lower media Mg than the 0.42 kg/m('3) rate. Visual quality ratings of four of the five species grown in media amended with the P sources were superior to that of the check. Higher visual ratings resulted from the 29-26-0 and 18-48-0 sources. The uptake of phosphorus from ('32)P-labeled ordinary superphosphate 0-20-0 by liners and cuttings of Gardenia jasminoides 'Radicans' was monitored over a six-week period in 1983. Phosphorus from 0-20-0 was evident within liners and cuttings by day 4, and its level increased throughout the study. Phosphorus uptake from 0-20-0 increased as application rate of 0-20-0 increased. Upwar mobility of ('32)P within cuttings was not apparent until root initiation had begun. Visual quality ratings of three woody-ornamental species were determined over a 126-day period in 1983 when 0-20-0 and Osmocote 40-0-0 were factorially combined at three rates and incorporated into a pine bark-sand medium and when 0-20-0 and Osmocote 17-7-12 were applied according to two fertilization methods; dibbled and incorporated. Quality of each species at a 1.8 kg/m('3) rate of Osmocote 40-0-0 were superior to those at a 0.9 kg/m('3) rate. The dibbled application of Osmocote 17-7-12 resulted in superior visual ratings for two of the three species. Ordinary superphosphate 0-20-0 had no significant effect on quality of the species studied regardless of application rate or fertilization method.

Pages

195

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