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  • Author or Editor: R. B. Reed x
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Abstract

Dwarf Burford holly (Ilex cornuta Lindl. & Paxt. ‘Burfordii Nana’), dwarf Japanese euonymus (Euonymus japonica Thunb. ‘Microphylla’), and ‘Hershey’s Red’ azalea (Rhododendron x sp.) were grown in containers in all combinations of 3 diameters (10.2, 15.2, and 20.3 cm) and 3 depths (7.6, 15.2, and 30.5 cm). Top growth of Burford holly, a species with coarse, lateral, and deep roots, increased as pot depth and width increased; root growth was increased in deep pots. Euonymus, a species with a densely branched, medium fine root system, increased in top growth as pot depth and width increased, although the response to pot depth was less than to width. Top growth of azalea, a fibrous and shallow-rooted species, increased as pot width increased but was not affected by pot depth. Root density of euonymus and azalea decreased as pot depth and width increased, whereas relative root depth of azalea was reduced in deep pots.

Open Access

Growth of pawpaw (Asimina triloba) seedlings in containers was examined in a factorial greenhouse experiment with four treatment levels of the slow-release fertilizer, Osmocote 14-14-14 (14N- 6.1P-11.6K), incorporated in Pro-Mix BX potting substrate at 0, 0.13, 0.26 or 0.81 kg·m-3 (0, 0.22, 0.44, or 1.37 lb/yard3) and three treatment levels of liquid-feed fertilizer of Peters 20-20-20 (20N-8.7P-16.6K) water-soluble fertilizer at 0, 250, or 500 mg·L-1 (ppm). When plants were harvested 18 weeks after sowing, seedlings subjected to the highest rate of Osmocote 14-14-14 at 0.81 kg·m-3 and liquid-feed at 500 mg·L-1 had the greatest total biomass, about 3-fold greater than nonfertilized plants. In a separate greenhouse experiment, growth of seedlings was examined with Osmocote 14-14-14 as the sole fertilizer source at six treatment levels of: 0, 0.81, 2.22, 4.43, 8.86, or 17.7 kg·m-3 (0, 1.37, 3.74, 7.47, 14.9, or 29.9 lb/yard3). Early seedling growth was hastened in the 2.22 kg·m-3 treatment rate, but delayed in 17.7 kg·m-3 treatment rate, when compared to nonfertilized control plants. When seedlings were harvested 17 weeks after sowing, plants had the greatest shoot, root, and total dry weight with Osmocote 14-14-14 at a rate of 2.22 kg·m-3. Root:shoot ratio decreased from about 1.5 without Osmocote 14-14-14, to about 0.65 at rates of 2.22 kg·m-3 or greater. Based on the results of this study, the slow-release fertilizer, Osmocote 14-14-14, can be used effectively as a sole fertilizer source when incorporated into potting substrate at a rate of 2.22 kg·m-3 or at a reduced rate of 0.81 kg·m-3 when supplemented with weekly applications of liquid-feed fertilizer at a rate of 500 mg·L-1 of Peters 20-20-20, to enhance production of container-grown pawpaw seedlings.

Full access

The effects of overhead pulse irrigation versus conventional overhead irrigation on growth of Ageratum houstonianum `Blue Puff' in 2 media, container leachate volumes and leachate NO3-N and NH4-N levels were evaluated. Container leachate volumes, and NO3-N and NH4-N levels were higher with pinebark:sand medium. Container leachate volumes tended to be lower with pulse irrigation compared to conventional irrigation. Shoot dry weights of plants grown in pinebark:peat were greater under conventional irrigation compared to pulse irrigation; however, growth indices, flower number, and NO3-N and NH4-N levels were not affected by irrigation method in either medium.

Free access

A sprayable formulation of 1-methylcyclopropene (1-MCP; AgroFresh, Spring House, PA) was applied to ‘Scarletspur Delicious’ and ‘Cameo’ apples in the orchard 1 to 3 weeks before harvest and compared in different postharvest studies with the commercial postharvest 1-MCP fruit treatment (SmartFresh; AgroFresh) and with aminoethoxyvinylglycine (AVG; ReTain; Valent BioSciences, Walnut Creek, CA). Treated apples were held in air storage for 50 to 60 d or in controlled-atmosphere storage for 120 to 125 or 215 to 225 d. With increased concentration, sprayable 1-MCP treatments were effective at controlling flesh firmness loss and internal ethylene concentration (IEC) up to 225 d of storage as well as during a 7-d poststorage shelf life simulation at room temperature. Application closer to harvest improved the effect of sprayable 1-MCP on control of flesh firmness loss and IEC. Concentrations of sprayable 1-MCP above 90 mg a.i./L produced similar fruit effects to 1-MCP. Treatment with 1-MCP showed little effect on soluble solids concentration (SSC), titratable acidity (TA), or skin or flesh color in ‘Delicious’ but slightly increased SSC and TA in ‘Cameo’ apples. AVG applied 4 weeks before commercial harvest controlled IEC nearly as well as either sprayable 1-MCP or 1-MCP during storage, but AVG-treated fruit allowed to ripen for 7 d at room temperature after storage lost much more flesh firmness regardless of storage regime. Sprayable 1-MCP also reduced starch hydrolysis, IEC and fruit drop at harvest. Sprayable 1-MCP may offer new opportunities for effective preharvest management of apple fruit condition, storability, and poststorage fruit quality.

Free access