Search Results

You are looking at 51 - 60 of 1,672 items for :

  • Refine by Access: All x
Clear All
Open access

W.J. Foster, R.D. Wright, M.M. Alley, and T.H. Yeager

Abstract

Pine bark was shown to adsorb 1.5 mg of N/g of bark when NH4 solutions were leached through the bark. Increasing pH of bark increased adsorbed NH4. At pH 3.3, only NH4 was adsorbed to bark particles when a fertilizer solution containing NH4, Ca, K, and Mg was applied. However, adsorption of NH4 and other cations increased as pH was increased from 3.8 to 5.8. These data indicate that 2 types of sites exist for the adsorption of NH4 to pine bark. One site is effective at lower pH; the other is active as pH increases. Daily application of 2.5 cm of water containing 50 ppm NH4 required 20 days for equilibration to occur so as to satisfy all binding sites. Thus, incorporation of NH4 into a pine-bark medium prior to planting may be advisable to prevent low N levels from occurring in the container solution due to NH4 binding when plants are first planted and fertilized.

Open access

D. F. Wagner and J. C. Neal

Abstract

Coal cinders with pine bark were evaluated as containerized plant growing medium. Rhododendron obtusum Lindl. ‘Hinodegiri’ liners were grown in several combinations of media composed of pine bark mixed with an aged and a recently combusted source of cinders. Measurements of media pH, soluble salts, NO3 –N, NH4 + –N, and 19 extractable nutrient and metallic ions were obtained. Leaf tissue samples were analyzed for 19 elements. Top dry weight, visual growth and chlorosis ratings, and root visual ratings constituted the plant growth parameters measured. Satisfactory growth was generated in pine bark amended with up to 50% cinders from either source.

Open access

Richard Ogden and Harry Mills

Abstract

Initial availability of NO3, NH4, and urea applied to limed or unlimed pine bark as well as the form of N available over a period of 21 days was determined. Nitrate was not present in significant amounts when N was supplied as either urea or NH4, and the extractable amounts of both urea and NH4 declined significantly over the course of the experiment. Urea was the least effective of the N forms in supplying N in an extractable form. With NO3 as the N source, addition of lime to pine bark resulted in significant reductions in extractable NO3. Applications of NH4 gave relatively equal amounts of extractable N as NH4 from limed and unlimed pine bark after 21 days. It was concluded that N interaction and N transformations with these N forms in pine bark would influence total available N as well as the form of N available for plant growth.

Free access

Zoran Jeknic and Tony H. H. Chen

The development of bud dormancy in poplar plants is initiated by short-day photoperiods (SD). During the development of bud dormancy, there was a gradual increase in the force required to peel off the bark from the stems. We measured the force required for bark peeling and investigated the cellular changes associated with this phenomenon. Stem samples were collected from plants which had been grown under SD for different period of time up to 10 weeks. At each sampling date, the forces required to peel off the bark were measured by a tensiometer. At the same time, samples were fixed to examine ultrastructural changes by transmission electron microscopy. We have observed that there was a significant increase in the force (in Newtons) required to peel off bark from poplar stems when the development of dormancy was initiated by SD treatment. Many ultrastructural changes were observed, including the accumulation of bark storage proteins, the break down of the central vacuole to form many small vacuoles, thickened cell walls, etc. Efforts have been made to relate ultrastructural alterations to changes in the force required for bark peeling.

Free access

Graham J. Wright and Irwin E. Smith

Composted pine bark is one of the most important substrates used in the seedling industry today. Previous work suggested the availability of inherent Potassium (K) in the bark. This research confirmed the availability of K and indicated that little or no K is needed for seedling production when pine bark is used as a substrate. Pre-enrichment rates ranged from 0 to 460 g.K.m-3, with a supplemental solution application of 0 to 200 mg.K.l-1. No evidence of K deficiencies or toxicities were detected. Three K sources, KCl, KNO3, and K2SO4 were used in the pre-enrichment of the bark. No differences were noted for top fresh mass, seedling height, root dry mass, root to shoot ratio and percentage moisture. Seedlings grown in treatments without and supplementary K showed tissue contents of 162.5 mg.K.kg-1. This research suggests the possibility of reducing the levels of-K applied to seedlings grown in a composted pine bark substrate.

Free access

Alexander X. Niemiera

Amending soilless media with micronutrients is a routine nursery practice. The objective of this research was to determine the micronutrient status of pine bark amended with two sulfate micronutrient sources and a control (unmended). Limed pine bark was unamended, amended with Ironite (1 and 2 g/l), or Micromax (1g/l). Bark was irrigated with distilled water in amounts equivalent to 30, 60, 90, and 120 irrigations (.63 cm per irrigation). Following irrigations, Cu, Fe, Mn, and Zn were extracted with a modified saturated media extract method using .001M DPTA as the extractant. Irrigation amount had no effect on Cu and Mn concentrations which were greater in the Micromax treatment than the Ironite or control treatments. A micronutrient source × irrigation interaction existed for Fe and Zn concentrations requiring regression analysis. In general, slope values indicating the decrease in micronutrient values with increasing irrigations were quite low (≤ .001) for each source. Regardless of irrigation amount, Fe and Zn concentrations were similar for amended and unamended bark.

Open access

R. A. Backhaus, R. M. Sachs, and H. Z. Hield

Abstract

Morphactins, mixed with non-phytotoxic paraffinic, low molecular weight oil, were applied as bark bands and tested for growth inhibition of trees growing under field conditions. Three species were tested: Monterey pine (Pinus radiata D. Don.), olive (Olea europaea L. cv. Manzanillo) and eucalyptus (Eucalyptus globulus Labill). Shoot elongation was inhibited in all three species, but sensitivity to the treatment varied.

Free access

Jeffrey G. Williamson and E. Paul Miller

Bearing `Misty' and `Star' southern highbush blueberries were grown on pine bark beds and fertilized at three rates using granular and liquid fertilizers with a 3–1–2 (1N–0.83K–0.88P) ratio. Granular fertilizer was applied 8 times per year at 4-week intervals beginning in April and continuing through October. Liquid fertilizer was applied with low volume irrigation 16 times per year at 2-week intervals during the same period. During the growing season, irrigation was applied at 2- to 3-day intervals in the absence of rain. A 2 cultivar × 2 fertilizer type × 3 fertilizer rate factorial arrangement of treatments was replicated 8 times in a randomized complete-block design. All fruits were harvested from single-plant plots at 3- to 4-day intervals. Canopy volume was not affected by fertilizer type, but fruit yield was slightly greater for granular than for liquid fertilizer treatments. In 2003, fruit yield of 2.5-year-old `Misty' and `Star' plants increased with increasing fertilizer rates up to the highest rate tested (50 g N/plant/year). Similarly, in 2004, fruit yields increased with increasing fertilizer rates up to the highest rate (81 g N/plant/year). Root distribution was limited to the 12-cm-deep layer of pine bark with very few roots penetrating into the underlying soil. The positive growth responses of blueberry plants to high fertilizer rates in pine bark beds suggests that soluble fertilizer was leached through the pine bark layer into the soil below the root zone. More frequent, lighter applications of soluble fertilizers, use of slow-release or controlled-release fertilizers, and careful irrigation management may improve fertilizer use efficiency of blueberry plantings on pine bark beds.

Open access

Timothy E. Crocker and A. L. Kenworthy

Abstract

In 4 experiments conducted to study internal bark necrosis (IBN) in apple, ‘Delicious’ trees were treated with Mn, Fe, Cu, and Al (100 and 200 ppm in nutrient solution), Mn, Fe, Cu, plus Al (50 ppm each) and a minus B treatment. Only trees receiving Mn and minus B developed IBN symptoms. Trees grown under normal and low levels of Ca and receiving variable concentrations of Mn (0, 25, 50, 75, and 100 ppm) developed IBN in proportion to Mn concentration. Spur-type and standard ‘Delicious’ trees did not differ in IBN severity. Bark samples with IBN symptoms, when analyzed on the electron microprobe x-ray analyzer, had greater Mn and Ca concentrations in necrotic tissue areas than in non-necrotic areas. IBN lesions induced with minus B had a higher Ca concentration in necrotic areas than in healthy tissue

Free access

Hannah M. Mathers and Michele M. Bigger

Many nurseries within Ohio and northeastern, southeastern, and western United States, and Canada have reported severe bark splitting and scald-type problems in 2005. The amount and severity of damage seen in 2005 has been unlike anything seen before. At Ohio State University, samples from across the state started appearing in 2003–04 and increased in incidence in 2005. Growers' reports of exceeding losses of 5% of their inventory or 3000 to 4000 trees per nursery are not uncommon. At an average cost of $125 per tree and with the number of nurseries reporting problems, the stock losses in Ohio have been staggering, in excess of several million dollars. The trees that we have seen problems on in 2005 have been callery pears, yoshino cherry, kwanzan cherry, crab apples, sycamore, serviceberry, hawthorn, mountain ash, black gum, paper bark maple, japanese maples, norway maple `Emerald Queen', red maples, kousa dogwood, magnolia `Elizabeth' and the yellow magnolias such as `Butterflies', `Sawada's Cream', `Yellow Bird', and `Yellow Lantern'. It has long been observed that the actual cause of a bark crack was “preset” by a wound such as the improper removal of a basal sprout, herbicide, leaving of a branch stub, or lack of cold hardiness. Cold and frost may be contributing to the increase in bark splitting across the United States; however, new research results at Ohio State University regarding the effects of DNA preemergent herbicides in the reduction of root hardiness and regrowth potential, sprout removal and other mechanical injuries, and postemergent herbicide application will reveal these are more the causal agents.