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Mondher Bouden, Jaaues-Andre Rioux, and Isabelle Duchesne

The agricultural valorization of waste, rich in organic matter and minerals, is one of the best economical and ecological methods of disposal. This study was carried out to evaluate the release of mineral elements restrained in fresh bio-filters, composted sewage sludges, and composted de-inking sludges, and their effects on growth of Physocarpus opulifolius `Nanus' produced in containers. The physical and chemical analysis of the organic residues proved that the fertilization value of composted sewage sludges was greater than the other residues. Moreover, the granular characteristics of fresh biofilters and composted de-inking sludges were finer than composted sewage sludges. Each organic residue was combined, in proportion of 10%, with peatmoss, composted conifer bark, and fine crushed gravel. The regular leaching of container medium showed that the composted sewage sludges release a higher quantity of major mineral elements. Physocarpus opulifolius `Nanus' plants were larger than those plants grown in the control substrate (without residue). The results obtained in media containing fresh bio-filters or composted de-inking sludges were similar to those obtained in the control substrate.

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Francine Bigras

Spring frosts frequently cause significant damage to conifer seedlings during bud flushing and shoot elongation in forestry nurseries. To ensure adequate protection, levels of frost sensitivity must be known during these stages of development. Eight-month-old, containerized, black spruce seedlings were submitted to freezing temperatures of 0, –4, –6, –8, and –10C for 1, 2, 3, 4, 5, and 6 h at the following stages: 1) nonswollen buds; 2) swollen buds; 3) bud scales bursting, needle tips emerging; and 4) shoot elongation, 1 to 5 cm. After the treatments, seedlings were grown for 90 days in a greenhouse. Seedling survival then was estimated; dead seedlings discarded; and damage to buds, needles, and roots and shoot increment and diameter were measured on the remaining seedlings. Results show that frost sensitivity increases with the developing bud and shoot. A decrease in seedling and bud survival was noted with an increase in time of exposure (stages 2, 3, 4); otherwise, time exposure has no effect. Damage to needles and roots increases and diameter decreases with decreasing temperatures at all stages. Shoot increment was influenced by decreasing temperatures at stages 2 and 3 only.

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Kenneth R. Schroeder and Janet E. Schroeder

According to brain-based learning theory, learning is enhanced by challenge and inhibited by threat. Effective learning occurs when students are immersed in the educational experience, challenged yet not threatened, and encouraged to actively process information. All of these components are part of simulation or role-play games. With these basic concepts in mind, we approached the challenge of enhancing student learning in a plant identification course taught in a large class setting. Considering that plant identification requires some basic detective skills, and the popularity of criminal investigation television programming, we designed a role-play exercise involving case files, investigation zones, and detective teams. As a spin-off from the television shows “CSI: Crime Scene Investigation” and “CSI: Miami,” the exercise was coined “CSI: Manhattan, Conifer Site Investigation in Manhattan, Kansas.” It was designed to fit into a 50-minute class period. Throughout the exercise, detective teams (students) needed to collectively locate and identify plants based on previous knowledge and clues within the case files and at the sites. Upon completion, plant specimens were checked in and identification logs discussed in order to provide immediate feedback and reinforcement of learning. Students enjoyed the exercise, offering positive feedback and conversations about the exercise throughout the balance of the semester. Six months later, while walking past one of the investigation sites, students remembered the site, exercises performed, and the plant name. The exercise includes both interactive and experiential learning components. This session will discuss the “CSI” exercise and its value in linking action to information.

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Karen E. Burr and Rudy M. King

Cold hardiness testing is an important tool used at US Forest Service nurseries for evaluating the physiological quality of conifer stock. Three tests were compared. A whole-plant freeze test without root system insulation permitted evaluation of cold injury without complication by drought symptoms if plants were misted. A cutting freeze test underestimated expected field foliar injury due to high humidity used to maintain the cuttings. An electrolyte leakage test failed to detect economically important bud mortality when buds were less hardy than other tissues.

Data from all three testing methods were analyzed with an original software package consisting of standardized input files and a step-by-step series of fortran programs and command files for use with commercially available non-linear modelling programs. Injury (y) versus temperature (x) data were modelled with the versatile, 4-parameter Weibull sigmoid model. Injury estimates at specific temperatures (Ix) or temperature estimates causing specific injury levels (LTy) were calculated with confidence and calibration intervals, respectively. The statistical significance of differences between Ix or LTy estimates was then determined.

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B. Dehgan, F. C. Almira, and T. H. Yeager

Rooted cuttings of Photinia X fraseri and Podocarpus macrophyllus were grown in Metro-mix 500 amended with 0.0, 0.25, 0.50, 0.75, or 1.0% (w/w) Stockosorb 300, a K-based superabsorbent polymer. All 3-liter containers were irrigated with 500 ml of 100, 200, 300, or 400 ppm 20N-8.7P-16.72K Peters fertilizer solution once every 3, 6, 9, or 12 days, respectively. In comparison with the unamended media, P. X fraseri had equal or better growth (shoot and root fresh and dry weights, increased height, and branch and leaf numbers) with 3, 6, and 9 day irrigation in all but the 1 % amended medium. Growth of P. macrophyllus was not noticeably affected by the polymer amendment. This is not unexpected since P. X fraseri is a broad-leaf plant while P. macrophyllus is a slow growing, narrow-leaf conifer. Nitrogen, P, and K tissue levels for Photinia and Podocarpus decreased for the 12 day irrigation treatment regardless of amendment rate. Except for Fe, which was highest at nine day irrigation intervals, micronutrients remained more or less constant in both species. The amended media had a greater water holding capacity at termination of the project (144 and 192 days for Photinia and Podocarpus, respectively) than at the start. Thus, K-based superabsorbents may be used successfully to reduce irrigation frequency.

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Mondher Bouden and Jacques-Andre Rioux

Large spaces are required to eliminate waste by burying and this method is very costly. The horticulture use of waste seems to be one of the best optional methods of disposal. This study was performed to evaluate the effects of fresh bio-filters (FBF), composted sewage sludges (CSS), and composted de-inked sludges (CDS) on growth of three woody ornamental species (Spiraea japonica `Little Princess', Spiraea nipponica `Snowmound', and Physocarpus opulifolius `Nanus') produced in containers. Three fertilization regimes (N at 200, 400, and 600 mg·L–1 in the form of soluble fertilizer 20–20–20) were applied weekly onto containers during 3.5 months. Plants were potted in 10 substrates. The control substrate contained 4 peatmoss: 5 composted conifer bark: 1 fine crushed gravel (by volume). In the other nine substrates, peatmoss was partially substituted by one of the three organic residues (10%, 20%, or 30% of FBF, CSS, or CDS). The experimental design was a split-split-plot with four replicates and two samples by treatment. Chemical analysis of the organic residues proved that the fertilization value of CSS was greater than the other residues and heavy metals are below the undesirable limits for the three residues. The amount of available major mineral elements in these residues is too low to satisfy the mineral nutrient needs of plants. In addition, there is a linear effect of the fertilization on plant growth. The CDS required a high dose of the fertilizer (600 mg·L–1) which may be due to the immobilization of N. The 10% proportion of FBF and CDS, combined with the other materials, was the most adequate proportion and did not reduce the growth of plants (height, aerial, and root dry matter). However, CSS can be used with a high proportion (20%) especially for Spiraea japonica `Little Princess'.

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Mondher Bouden and Jacques-Andre Rioux

The richness of the organic residues in certain fertilizing elements justifies their valorization in horticulture. However, their contents in pathogenic and toxic elements can restrict their use. In this context, this study was conducted in order to evaluate the effect of three organic residues on the environmental medium and the risks of water contamination by the release of heavy metals. Physocarpus opulifolius `Nanus' was transplanted into four substrates. The control substrate contained 4 peatmoss: 5 composted conifer bark: 1 fine crushed gravel (by volume). The three other substrates (25% of peatmoss was substituted by organic residue) contained 10% of fresh bio-filters (FBF), 10% of composted sewage sludges (CSS), or 10% of de-inking sludges (CDS). The pots (5l) were placed in plastic vats and the drainage water was recovered in vessels (17l). The experimental design was in complete blocks with six replications. Samples of the drainage water were collected every 2 weeks for analysis. The pots were fertilized every week (400 mg/Ll of N) and growth parameters were statistically analyzed by ANOVA. The chemical analysis of the residues proves that they contain weak concentrations in organic contaminants. There is an accumulation of \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{3}^{-}\) \end{document} in drainage water following the fertilization; the same applies to sulfates and potassium. On the other hand, heavy metals are not released in important concentrations and so the lead, zinc, manganese, and copper contents do not exceed the desirable limits. Moreover, the Physocarpus plants produced in CSS substrates had a growth significantly larger than those plants produced in FBF or CDS substrates. The three organic residues do not constitute a risk of pollution for the environment.

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Robert R. Tripepi and Mary W. George

Seedlings of several conifer species can be difficult to transplant, with the problem often related to poor root regeneration. The objective of this study was to determine if corkbark fir (Abies lasiocarpa arizonica) seedlings or pinyon pine (Pinus edulis) seedlings would produce more root growth when grown in a Missouri gravel bed growing system compared to field soil. The 3–0 fir seedlings and 4–0 pine seedlings were planted in a gravel bed in mid-April. The gravel bed was 3 m × 3.7 m and was filled with a mixture of 60% pea gravel (1 cm minus), 30% Turface®, and 10% silica sand (by volume). A field bed 3 m × 3.7 m in size was also prepared. Fir seedlings were harvested in September and October, but pinyon pine seedlings were harvested only in October due to their poor transplant survival. Plant heights, stem diameters, and root volumes, as well as root and shoot dry weights, were determined at harvest. Of all the measured growth parameters for both species, only root dry weights and root volumes were significantly different. In particular, fir seedlings grown in the gravel bed produced at least 30% more root dry weight and 74% more root volume than those planted in field soil whether plants were harvested in September or October. Likewise, pine seedlings grown in gravel produced at least 37% more root dry weight and 86% more root volume than those grown in soil. In addition, only 10.6% of the pine seedlings planted in soil survived transplanting, but 23.3% of those grown in the gravel bed survived. This study demonstrated that corkbark fir and pinyon pine seedlings grown in a gravel bed produced larger root systems than those planted into field soil, and the gravel bed also improved pinyon pine seedling survival after transplanting.

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Robert R. Tripepi, Mary W. George, and John E. Lloyd

Field-grown conifers are usually discarded if their root balls break during digging, but using an alternative holding system until the root systems recover could reduce production losses. The objective of this study was to determine if a gravel bed could be used as a holding treatment for 1.5- to 1.8-m-tall Colorado spruce (Picea pungens) trees that had soil removed from their root systems in the spring. Root systems from 12 trees were washed free from pine bark mulch and soil before the trees were randomly assigned to a gravel bed. One bed held a mixture of 88% pea gravel (1-cm minus), 2% Turface®, and 10% silica sand (by volume). The other bed contained a mixture of 90% basalt gravel (1.2-cm) and 10% sand. Trees were grown in the gravel beds for 5 or 6 months before height increases were determined. If the terminal leader died on the tree, the next highest lateral branch was measured for its increase in length. All trees survived and actually grew a little during the summer after removing all the soil from their root systems. Several trees suffered slight needle burning at the ends of random branches, but the damage appeared minimal. Tips of several small branches randomly located around the canopies on several trees died back, and up to 10 cm of the terminal leaders on about half the trees died back. Height increases were similar among the different trees grown in the two types of gravel, with the mean increase in height being 8.9 cm. The trees regenerated many roots in both types of gravel. In fact, new roots formed all over the root systems and encased large amounts of gravel, making its removal difficult. This study demonstrated that gravel beds can be used to help 1.8-m tall Colorado spruce trees recover from severe root losses.

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Larry A. Rupp, William A. Varga, and Roger Kjelgren

Bigtoothmaple(Acer grandidentatum Nutt.) is of interest for its fall color and potential use in water-conserving landscapes. Clonal propagation of desirable selections would be beneficial. Since bigtooth maple commonly self-propagates by layering, we explored mound layering as a means of vegetative propagation. A stool bed was established in 1999 with seedlings grown from northern Utah seed. Beginning in 2001, seedlings were dormant pruned to their base and shoots allowed to grow until early July, when treatments were applied. At the time of treatment application for the reported experiments, shoot bases were girdled with 24-gauge copper wire, covered with conifer wood shavings, and kept moist during the growing season. The effects of rooting hormones and enclosure of the rooting environment on rooting were examined. On 7 July 2002, 32 trees were randomly selected and the four tallest shoots within each tree were treated with either 0, 1:5, 1:10, or 1:20 (v/v) solutions of Dip-N-Gro© rooting hormone (1% IBA, 0.5% NAA, boron). There was no significant difference in rooted shoots between treatments and 81% of the trees had at least one rooted shoot. On 9 July 2004, 39 trees were selected and two shoots per tree were girdled. One-half of the stool bed area was treated by underlaying the shavings with BioBarrier© (17.5% trifluralin a.i.). Measurements on 12 Nov. 2004 showed no apparent treatment effect on rooting and 90% of the trees had at least one rooted shoot. This research demonstrates that mound layering is an effective means of rooting shoots of juvenile bigtooth maples. Further research will examine the effectiveness of the technique in propagating mature clones.