High-chilling pear cv. Shinseiki (Pyrus serotina Rehd.) were used to evaluate the cultivation potentiality at warm area via the decrement of supraoptimum temperature damage and the escape from dormancy. Several experimental results were obtained as follows: the media prepared by combination of peat and bark compost (1:1 in volume) inside nonwoven bag was lower in temperature than other media; both of the temperature of leaf surface and media decreased more than 2′C at noon by 25% shading favoring the CO2 exchange in the daytime; the foliage application of Aminofol increased leaf thickness and chlorophyll content; and BA or PP-333 treatment enhanced lateral buds development during the supraoptimum temperature period of summer, etc. An integrated management based on these results helped the 1-year old container-grown Shinseiki pear trees over-summer. The experimental trees were then forced to budbreak and flower by application of cyanamide in October. Eventually, the fruits were harvested in March. These results suggested that the production of high-chilling pears in warm area was technically feasible.
Hsin S. Lin and Chin H. Lin
Mohammed Z. Alam, Calvin Chong, Jennifer Llewellyn, and Glen P. Lumis
To minimize fertilizer and water use, and NO3-N runoff from container culture, growth, and nutrient status of forsythia (Forsythia ×intermedia Zab. ‘Spring Glory’) in No. 2 containers were compared in response to a controlled-release fertilizer (CRF; Nutricote 18-6-8 100-day at rates of 2, 4, and 6 kg·m−3) and placements (incorporation and topdress) under three irrigation strategies [drip-irrigated low (25% or less) leaching fraction (DrLoLF), hand-sprinkled low leaching fraction (HsLoLF), and hand-sprinkled high (50% or less) leaching fraction (HsHiLF)]. In a coexperiment under drip irrigation only, forsythia response was also examined under incorporation, topdress, and dibble fertilizer placements with the same CRF rates applied as single or split dose. Dibble fertilizer placement was superior to both incorporation and topdress in this order. Maximum growth of forsythia occurred at rates of 4.7 kg·m−3 with dibble. With incorporation and topdress, maximum growth was not achieved even at the 6 kg·m−3 maximum rate tested. Forsythia grew better with incorporated than with topdressed CRF with the DrLoLF treatment. The response was reverse with HsHiLF or showed no differences with HsLoLF. Under drip irrigation, greater concentrations of NO3-N generally leached from incorporation and dibbled containers in this order than from topdress. Less nitrate was leached from the topdressed containers because less was released from the CRF prills. At the 6 kg·m−3 CRF rate, total cumulative NO3-N leachings were 76, 85, and 22 kg·ha−1 (45 × 45-cm container spacing) for dibbling, incorporation, and topdress, respectively, under drip irrigation. Split application of CRF greatly reduced NO3-N in leachate, although plant growth also was reduced as a result of less availability of and uptake of nutrients under this strategy.
Mohammed Z. Alam and Calvin Chong
mushroom farm and anaerobic digestion wastewater as supplementary fertilizer sources for container culture of selected nursery plants. The aim of this related investigation was to ascertain if liquid cattle manure (LCM) could be used as the sole nutrient
Osamu Kawabata and Joseph DeFrank
Thomas H. Boyle, Lyle E. Craker, and James E. Simon
Plants of rosemary [Rosmarinus officinalis L. (Lamiaceae)] were grown in pots containing a soilless (1 sphagnum peat:1 perlite) or soil-based (1 sphagnum peat: 1 perlite:1 field soil) growing medium and fertilized with either 12N-5.2P-12.5K controlled-release fertilizer (CRF) at 9.0 g/pot; constant liquid fertilization (LF) with 20N4.3P-16.7K at 150 mg N/liter; constant LF at 150 mg N/liter, plus CRF at 4.5 g/pot; weekly LF at 150 mg N/liter; or weekly LF at 150 mg N/liter, plus CRF at 4.5 g/pot. Constant LF plus CRF generally reduced plant height and depressed shoot fresh weight relative to other fertilizer regimes. Essential oil content was highest in plants receiving weekly LF. Plants grown in the soil-based mix were shorter, shoot fresh and dry weight tended to be lower, and essential oil yield was higher when compared to plants grown in the soilless mix. Satisfactory growth was obtained in both media when rosemary plants were fertilized with 12N-5.2P-12.5K CRF at 9.0 g/pot or weekly LF with 20N<.3P-16.7K at 150 mg N/liter.
Yin-Tung Wang and Lori L. Gregg
The levels of hydration of several hydrophilic polymers (hydrogels) varied greatly. Starch-based polymers had the fastest rate of hydration (<2 hours), followed by a propenoate-propenamide copolymer. Polyacrylamide materials required 4 to 8 hours to become fully hydrated. Maximum water retention in distilled water varied from 400 to 57 g of water per gram of dry material. All hydrogels retained less water in the presence of metal ions or fertilizers in the soaking solution, with substances releasing Fe+2 being the most detrimental. After exposure to fertilizers and ions, the water-holding capacity of a polyacrylamide with a high degree of cross linkage, but not that of hydrogels of the other structures, was fully recovered by subsequently soaking in distilled water. Pots amended with a polyacrylamide polymer but without Micromax (a micronutrient source) reached maximum water retention after six irrigations, while those with Micromax required 10 irrigations to reach peak water retention. The amounts of water being held in pots decreased after repeated fertilization. Medium volume increased with increasing levels of the polyacrylamide Supersorb C (0, 2, 4, or 6 g/pot). Micromax incorporated in medium amended with Supersorb C caused a depression in volume. Medium bulk density, total water retention, and water retention per unit volume of medium were increased by the incorporation of the hydrogel, regardless of the presence of Micromax. Noncapillary porosity measured at container capacity in medium amended with Micromax progressively decreased as the amount of hydrogel increased, but remained unchanged in medium without Micromax. Repeated drying and dehydration of the medium resulted in reduced water retention and increased noncapillary pore space.
William D. Goff and Gary J. Keever
Container-grown pecan [Carya illinoensis (Wangenh.) C. Koch] trees with “mouse-ear” symptoms, characterized by small, rounded, cupped, and slightly wrinkled leaflets, were repotted into two types of media amended with three rates of dolomitic limestone (0, 5.4, or 10.7 kg·m-3). In both media [4 milled pine bark: 1 sand; 1 soil: 1 peat: 1 perlite (by volume)], mouse-ear symptoms in the season following repotting were dramatically reduced at the lower lime application rates. Medium Fe, Ca, Cu, and Mn and foliar Ca, Mg, Mn, Zn, and B were affected by lime rate 10 months after repotting in one or both media. Medium pH increased quadratically as lime rate increased. Greatest plant recovery occurred when no lime was added, resulting in a pH of 3.9 in the bark-sand medium and 4.2 in the soil-peat-perlite medium.
K. Francis Salifu, Michael A. Nicodemus, Douglass F. Jacobs, and Anthony S. Davis
We evaluated suitability of chemical indices of three media formulations or substrates (A, B, and C) consisting of composted pine bark, coconut coir pith, sphagnum peatmoss, processed bark ash, and perlite in varied proportions for growing northern red oak (Quercus rubra L.) seedlings. These substrates were ranked according to their ability to promote seedling growth. The low-yielding substrate (A) was devoid of pine bark and perlite and the medium-yielding substrate (B) contained no peatmoss or processed bark ash. The high-yielding substrate (C) contained all components. Additionally, we tested plant response to high nitrogen (N) fertilization on each substrate. Media EC, pH, and total dissolved solids measured at transplanting explained 68%, 43%, and 66%, respectively, of the variation in plant dry weight and 39%, 54%, and 46%, respectively, of the variation in shoot height. Vector diagnosis effectively ranked nutritional limitations on seedling growth as N > P > K. High N fertilization highlighted element deficiency in seedlings grown on substrate A, but resulted in element toxicity and antagonistic interactions in plants established on substrates B and C, respectively.
David Wees and Danielle Donnelly
Leachates were produced by washing Hydra-fill, a polyurethane ester foam, with water. These leachates decreased radish (Raphanus sativus L.) and tomato (Lycopersicon esculenturn Mill.) seed germination and were phytotoxic to seedlings. Washing the foam for as little as 5 minutes (compared to not washing) before collecting the leachate significantly decreased the mean seed germination time by 0.6 to 1 day. Rinsing the foam with ethanol before collecting the leachate was detrimental to germination. When used as a potting medium component, the foam reduced radish shoot and root dry weights compared to potting media without foam. Washing the foam with tap water before use resulted in increased radish shoot and root dry weights. Hydra-fill generally reduced plant performance when included in potting media. However, radish grew well in fresh 25% Hydra-fill (raw or washed) mixed with loam.