When a 200 ppm N solution as (NH4)2SO4 was percolated through a wet pine bark medium, 6 times the medium volume of the N solution was required to reach an equilibrium of N in the bark. Once equilibrium was reached, the water added, leaching of the ammonium ion was rapid. When twice the medium volume of water was passed through the medium, 85% of the ammonium ions were leached. After analysis of the leachate indicated no N being leached from the bark, 60 ppm of N remained in the bark.
Various barks, aged and composted to different degrees, are used in potting mixes. These differences have different effects on plant growth. It was observed that electrical conductivities (ECs) of the bark mixes that reduced plant growth were lower when compared to the ECs of the mixes that did not reduce growth, despite the same fertilization. This difference in EC diminished over time, differently for different barks. The decrease in EC was mainly due to a decrease in N. Apparently, nutrients were adsorbed or immobilized, which decreased their availability to the plants. This observation may be used to assess the suitability of a bark. The relative decrease in EC or N of similarly fertilized bark mix vs. no bark, peat mix (that does not reduce EC) may indicate the relative unsuitability of the bark, as related to nutrition. The amount of decrease in EC may also indicate the amount of additional fertilization to be provided to the bark mix during its use. The same method may also be applicable to other wood wastes, such as kenaf, sawdust, etc.
Urban soils are often not ideal planting sites due to removal of native topsoil or the mixing of topsoil and subsoil at the site. Adding pine bark based soil amendments to a clay soil altered soil bulk density and soil compaction which resulted in improved plant growth. Addition of nitrogen (N) or cotton gin waste to pine bark resulted in improved plant growth compared to pine bark alone. Growth of pansies (Viola × wittrockiana) during the 1999-2000 winter growing season was enhanced by the addition of pine bark plus nitrogen at 3- and 6-inch (7.6- and 15.2-cm) application rates (PBN3 and PBN6) and pine bark plus cotton gin waste at the 6 inch rate (CGW6). Plant size and flower production of vinca (Catharanthus roseus) were reduced by pine bark amendments applied at 3- or 6-inch rates (PB3 or PB6). Crapemyrtle (Lagerstroemia indica) grown in plots amended with 3 or 6 inches of pine bark plus cotton gin waste (CGW3 or CGW6) and pine bark plus nitrogen at 3- or 6-inch rates (PBN3 or PBN6) produced greater shoot growth than other amendment treatments. In some instances PB3 treatments suppressed growth. High levels of N and soluble salts derived from CGW and PBN soil amendments incorporated into the soil probably contributed to the improved plant growth observed in this experiment.
Formulations of superior oil applied to the developing buds and bark of ‘Delicious’ apple trees in the greenhouse inhibited bud break and growth. Bud break was significantly affected by oil concn, viscosity, and unsulfonated residue (UR). Total fresh wt of shoots was adversely affected by increasing concn and decreasing UR. Severity of bark injury increased with decreasing viscosities and increasing concn.
Growth of Chrysanthemum morifolium Ramat was evaluated in ground pine bark:sand mixes; a soil:peat:perlite mix; and commercially mixed media. Flowering stem:dry weight of plants grown in barkrsand (3:1 or 2:1, by volume) were comparable to commercial mixes but 100% pine bark or soil:peat:perlite significantly reduced plant height and flowering stem dry weight.
Experiments were conducted to evaluate the effect of fresh and aged conifer barks on galling by the root-knot nematode [Meloidogyne incognita (Kofoid and White) (Chitwood)] on tomato (Lycopersicon esculentum Mill.) roots. Fresh bark (stored at sawmill) exhibited significant nematicidal activity (reduced galling) when used as a medium component [50% or 75% with sand (v/v)]. Galling on tomatoes grown in aged bark (used as a culturing medium for tomatoes for 5 years) was extensive. When 10% or 20% fresh conifer bark was mixed into beds, galling was less extensive on tomato roots than on roots from tomatoes grown in an unamended medium. The nematicidal property of conifer bark diminished during long-term use. Increases in medium pH, which occurred during continuous cropping, could have contributed to the reduced nematicidal activity with time.
Mung bean (Phaseolus aureus Roxb.) cuttings and cucumber (Cucumis sativus L. cv. Marketer) seedlings were cultured in water extracts of bark from silver maple (Acer saccharinum L.) hackberry (Celtis occidentalis L.), sycamore (Platanus occidentalis L.) and cottonwood (Populus deltoides Marsh.). Extracts of fresh silver maple bark inhibited root elongation of cucumbers and the adventitious rooting of mung bean. Composting the silver maple bark for 30 days prior to preparing the water extracts reduced inhibition. Pretreatment of fresh silver maple bark extracts with insoluble polyvinylpyrrolidone (PVP) reduced inhibition and indicated that the inhibitory compound was phenolic in nature. Chromatography and spectral analysis of common phenolic compounds and silver maple bark extracts revealed the toxic substance was similar to tannic acid.
The objective of this study was to determine the effect of micronutrient fertilization on seedling growth in pine bark with pH ranging from 4.0 to 5.5. Koelreuteria paniculata (Laxm.) was container-grown from seed in pine bark amended (preplant) with 0, 1.2, 2.4, or 3.6 kg/m3 dolomitic limestone and 0 or 0.9 kg/m3 sulfate-based micronutrient fertilizer (Micromax ®). Initial pine bark pH for each lime rate was 4.0, 4.5, 5.0, and 5.5, respectively. Final pH (week 10) ranged from 4.7 to 6.4. Ca and Mg supply in irrigation water was 10.2 and 4.2 mg·L–1. Seedlings were harvested 10 weeks after planting, and shoot dry weight and height were determined. Pine bark solution was extracted using the pour-through method at 3, 7, and 10 weeks after planting. Solution pH was measured, and solutions were analyzed for Ca, Mg, Fe, Mn, Cu, and Zn. Shoot dry weight and height were higher in micronutrient-amended bark than in bark without added micronutrients. Lime (1.2 kg·
Leachates were collected at 3-month intervals over 12 months to determine the influence of bark, controlled-release fertilizer, and dolomitic lime sources and dolomitic lime application rates on pH of nursery media. The randomized complete-block design was arranged as a factorial and included three bark sources (pinebark, hardwood, and pinebark + hardwood), two fertilizer sources (Nutricote 17-7-8 and SierraBlen 18-7-10), and two dolomitic lime sources (microencapsulated granular and pulverized). Dolomitic lime application rates were 0, 5, 10, and 15 pounds per cubic yard. Leachate pH was influenced over the one-year evaluation period by fertilizer source, bark source, and application rate of dolomitic lime. Dolomitic lime source was not a significant factor in adjustment of leachate pH. Pinebark medium had lower leachate pHs than hardwood medium and the medium containing hardwood and pinebark. Dolomitic lime influenced leachate pH of pinebark medium more than the other bark sources. SierraBlen was more acid-forming than Nutricote.
Dendranthema×grandiflorum (Ramat.) were grown in either a peat-based or pine bark—based medium and drenched with growth retardants at a range of concentrations to generate dose : response curves. The effect of ancymidol, paclobutrazol, and uniconazole on stem elongation was less in the pine bark—based than in the peat-based medium. Generally, the concentrations required to achieve the same response were 3- to 4-fold as high in the pine bark—based medium as in the peat-based medium. However, chlormequat was slightly more active in the pine bark—based medium than in the peat-based medium. Chemical names used: α-cyclopropyl-α—(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); (±)-(R*,R*)-β-[(4-chlorophenyl)methyl]-α-(1,1-di methyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol); (E)-(RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)pent -l-en-3-ol (uniconazole); 2-chloroethyltrimethylammonium chloride (chlormequat).