Pine Bark Research Articles

Influence of extraction solvent on the biological properties of maritime pine bark (Pinus pinaster)

Maritime pine bark (Pinus pinaster Aiton subsp. atlantica) is rich in polyphenols with known bioactive properties which are beneficial for human health. However, biological activities of bark extracts depend on the type of polyphenols extracted and the characteristics of these extractives depend on several factors such as the type of solvents used. The influence of the extraction solvent on the composition and consequently on the properties of the extracts has been poorly described. Thus, in this study the influence of the extraction solvent (water, ethanol and ethanol-water (50/50 v/v%)) on the antibacterial and anticancer properties of P. pinaster bark samples were evaluated. LC-DAD-MS profiling of the different extracts was also carried out to study their polyphenol composition. Results show that extraction solvent must be carefully chosen with respect to foreseeing use of bark extracts, since ethanolic and hydroethanolic extracts displayed the greatest antibacterial activity whereas water extracts showed increased anticancer properties.

The Inhibitory Effects of New Zealand Pine Bark (Enzogenol®) on α-Amylase, α-Glucosidase, and Dipeptidyl Peptidase-4 (DPP-4) Enzymes.

The New Zealand pine bark extract (Enzogenol®) has previously been shown to elicit acute hypoglycaemic effects in humans. The present study investigated the underlying mechanisms of Enzogenol® in reducing postprandial glucose in humans. The potential inhibitory action of Enzogenol® against digestive enzymes: α-amylase and α-glucosidase, and dipeptidyl peptidase-4 (DPP-4) enzyme was determined. Enzogenol® demonstrated the ability to inhibit all three enzymes: α-amylase enzyme activity (IC50 3.98 ± 0.11 mg/mL), α-glucosidase enzyme activity (IC50 13.02 ± 0.28 μg/mL), and DPP-4 enzyme activity (IC50 2.51 ± 0.04 mg/mL). The present findings indicate the potential for Enzogenol® to improve postprandial glycaemia by delaying carbohydrate digestion via the inhibition of digestive enzymes (α-amylase and α-glucosidase), and enhancing the incretin effect via inhibiting the dipeptidyl-peptidase-4 enzyme. The inhibitory actions of Enzogenol® on enzymes should therefore be further validated in humans for its potential use in type 2 diabetes mellitus prevention and management.

Removal of selected pollutants from landfill leachate in constructed wetlands with different filling

Constructed wetlands (CW) with vertical flow were used to treat leachate from municipal landfills (active and closed, at different concentrations) using a combination of substrates, i.e., gravel, sand and an exchangeable layer, depending on a variant: organic substrate (pine bark) or mineral substrate (zeolite, expanded clay). The systems were planted with Phragmites australis. The aim of this study was to compare the efficiency of removal of selected pollutants from landfill leachate in CW using different types of filling. For most parameters, the best reductions were obtained on zeolite substrates. In the investigated CW, reductions were achieved at the levels of: AN 96%-99%; TKN 75%-88.5%; TN 62.5%-70%, TP 84–88% and heavy metals (Zn, Ni, Cu, Cr) 41%-56%.

Production and characterization of cost-effective magnetic pine bark biochar and its application to remove tetracycline from water.

Low-cost adsorbent, pine bark biochar (PBB) from the forest residue, was produced and applied to remove tetracycline (TC) from aqueous solution via adsorption pathway. The PBB, hence obtained, was modified using aqueous ferric and ferrous ion solutions to obtain magnetic pine bark biochar (M-PBB). Batch adsorption experiments were conducted to examine the adsorption of TC by PBB and M-PBB in the variation of pH, contact time, dosage, and temperature. The adsorbents were characterized by SEM/EDX, TGA, and pHpzc. The adsorption mechanism was evaluated by fitting Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich (D-R) isotherms model. Also, the experimental data were analyzed by kinetics models (pseudo-first-order, pseudo-second-order, intra-particle diffusion, and Elovich) and thermodynamics. The maximum adsorption capacity (qm) of M-PBB was 15.3mg/g from the experiment at pH 6. A high correlation coefficient (R2 ≈ 0.9) of Freundlich isotherm postulated multi-layer adsorption of TC on M-PBB at pH 6. The kinetic studies showed that the pseudo-first-order was more suitable for representing the adsorption of TC molecules on the surface. The thermodynamic analysis was showed that the adsorption process is favorable, spontaneous, and endothermic at studied temperatures. M-PBB demonstrated a potential for removal of TC from water as a low-cost and convenient adsorbent.

Properties of Boards Prepared from Mixture of Mineral Adducts with Bark and Cone of Calabrian Pine (Pinus brutia)

Olivine and dolomite addition with some formulations clearly retarded the water absorption change in both bark (Type 1 boards) and cone (Type 2 boards) based experimental panels. However, the lowest water absorption value of 15.20% was found in dolomite contain (40:60, dolomite-bark chip, w/w, %) sample which show approximately 169.6% lower than olivine contain sample at similar proportions. However, it is important to note that Type 1 boards show considerably lower water absorption than Type 2 boards at similar experimental conditions. The boards which produced with 10-, 20-, and 30% dolomite and 90-, 80-, 70% bark chips (XBI, XBII and XBIII) proportions, show higher thickness swelling (TS, %) than control (B0) while rest of show lower TS than control samples, regardless of type of mineral or experimental conditions. The highest TS improvement of -79.1% was found with sample of YBV which produced with equally (1:1, w/w) proportions olivine and pine cone chips in matrix. It is noticeable that dolomite addition to Type 1 boards are usually effects higher IB values than olivine added samples while the highest IB value of 0.72 MPa was found with sample of XBV. Moreover, only sample of XBII (20% dolomite and 80% pine bark chip in boards proportions, w/w) show higher MOR strength value (4.42 MPa) than control (B0: 3.63 MPa), regardless of mineral content. In Type 2 boards, all experimental panels that prepared with two different mineral addition at five loading levels show lower MOR values than control (C0: 6.59 Mpa). It is also realized that both Type 1 and 2 type experimental panels show lower elastic property (MOE) than control samples (B0: 1129.3 MPa: C0: 820.1).

Exploring the feasibility of substituting mimosa tannin for pine bark powder. A LCA perspective

The use of vegetable tannins is a bio-based alternative to chrome tanning. The most used vegetable extracts are Mimosa and Quebracho. To improve the sustainability of the tanning process, a chemically unmodified pine bark could be used as a natural source of tannins. The present study was aimed to evaluate the environmental impact of the use of pine bark powder to obtain vegetable leather through a life cycle assessment. Specifically, the life cycle impact evaluation was performed for both: i) pine bark powder tannin and the atomized mimosa extract production as raw material; and ii) the production process of a tanned leather with pine bark tannin versus a tanned leather with mimosa extract. An eco-friendly and cleaner production method for obtaining pine bark powder was developed. This new production method allows to obtain a reduction in 83% in the “climate change” impact category. However, when this tannin is applied to obtain a tanned leather, the tanning process shows an increase in all studied impact categories compared with the use of the atomized mimosa extract.

Trap Type Affects Catches of Bark and Woodboring Beetles in a Southern Pine Stand

AbstractIn 2012, we tested the relative efficacy of four commercial types of insect traps (panel; standard multiple-funnel; modified multiple-funnel; and sea, land, and air Malaise [SLAM]) for capturing bark and woodboring beetles (Coleoptera) in a pine stand in northcentral Georgia. All traps were baited with ethanol, α-pinene, ipsenol, and ipsdienol lures. The SLAM trap outperformed the panel trap for diversity and abundance of Cerambycidae. Mean catches of Asemum striatum (L.) in SLAM traps were greater than those in all other traps. SLAM traps caught more Acanthocinus obsoletus (LeConte) and Xylotrechus sagittatus (Germar) than standard multiple-funnel funnel and panel traps. The greatest numbers of Monochamus titillator (F.) were in SLAM and modified multiple-funnel traps. In contrast, SLAM traps were inferior to all other trap types in trapping bark beetles (Curculionidae: Scolytinae). More Dendroctonus terebrans (Olivier), Hylastes porculus Erichson, and Hylastes salebrosus Eichhoff were captured in panel traps than the other types of traps. Catches of Ips avulsus (Eichhoff), Ips calligraphus (Germar), Orthotomicus caelatus (Eichhoff), and Pityophthorus spp. were the same in panel, standard multiple-funnel, and modified multiple-funnel traps. Our data suggest that combinations of trap types should be considered in maximizing the effectiveness of detection programs for pine bark and woodboring beetles.

Traditional sports and games among the S\xe1mi people in Northern Fennoscandia (S\xe1pmi): an ethnobiological perspective

IntroductionModern sports equipment is nowadays manufactured industrially according to globally accepted and standardized models, but traditionally tools for play and games were prepared from materials found in the local environment. The objective of this article is to investigate various aspects of Sámi local knowledge about organisms used for their material culture of traditional sports and games in northern Fennoscandia (Sápmi). What functions did the surrounding biota have in the production of equipment used in sports and games?MethodsA qualitative method was used; the ethnographic literature and travel narratives have been analyzed particularly for descriptions and notes on traditional games, toys, and sports.ResultsBefore the turn of the twentieth century, bats, balls, and skis were seldom produced in factories, but by children and adults who utilized available materials from the surrounding environment. The manufacture of tools for play and games was characterized by a rich creativity in the use of various biological and natural resources. A wide range of such resources is presented in this article, among them the bracket fungus Fomitopsis betulina, used for making balls, reindeer antlers utilized for lassoing contests, and pine bark painted with reindeer blood, prepared for playing cards. We also highlight how tools usually associated with means of transport could switch functions and serve playful and competitive purposes, such as skis made of compression pine or walking sticks of birch: The former were used in skiing races, and the latter appeared in fencing competitions.ConclusionThe industrialization of the material culture of sports has been contributed to a loss of local knowledge and familiarity with locally available organic stuffs for producing equipment for play and games. By reconnecting with previous knowledge of traditional games, we discover a potentially new direction for modern sports and games, shifting from globalization to environmentalization. Such an environmentalization could permit the local environmental context define the content, meaning and structure of sports, and simultaneously enrich both sports and outdoor life.

Properties of biomass powders resulting from the fine comminution of lignocellulosic feedstocks by three types of ball-mill set-up.

Background: Lignocellulosic biomass has many functionalities that hold huge potential for material, energy or chemistry applications. To support advanced applications, the biomass must be milled into ultrafine powder to increase reactivity. This milling unit operation needs to be fully mastered to deliver high-quality standard end-products. Here we studied the relationship between the characteristics of the starting lignocellulosic plant material and the properties of the resulting ultrafine powder in different ball-mill process routes. Methods: Two lignocellulosic biomasses (pine bark and wheat straw) with contrasted compositional and mechanical properties were milled using three ball-mill set-ups delivering different balances of impact force and attrition force. The resulting powders were analysed for particle characteristics (size, agglomeration extent, shape) and powder flow properties (compressibility, cohesion) using a dynamic powder rheometer. Results: Pine bark is more amenable to a fast particle size reduction than the fibrous wheat straw. The resulting pine bark powders appear less compressible but much more cohesive than the straw powders due to particle shape, density and composition factors. The mill set-up working by attrition as dominant mechanical force (vibratory ball mill) produced a mix of large, elongated particles and higher amounts of fines as it acts mainly by erosion, the resulting powder being more prone to agglomerate due to the abundance of fines. The mill set-up working by impact as dominant mechanical force (rotary ball mill) produced more evenly distributed particle sizes and shapes. The resulting powder is less prone to agglomerate due to a preferential fragmentation mechanism. Conclusions: The attrition-dominant mill yields powders with dispersed particle sizes and shapes and the poorest flow properties, while the impact-dominant mill yields more agglomeration-prone powders. The mill set-up working with impact and attrition as concomitant mechanical forces (stirred ball mill) produces powders with better reactivity and flow properties compared to rotary and vibratory mills.

Effect of Dietary Polyphenols on Osteoarthritis-Molecular Mechanisms.

Osteoarthritis is a common crippling and degenerative disease resulting in irreversible functional changes due to damage of the cartilage and other tissues of the joint. With limited safe and effective pharmaceutical treatments, the demand and use for alternative therapeutic approaches with symptomatic relief for OA patients have increased. Clinical, pre-clinical, and in vitro studies have demonstrated that polyphenols can exert pain-relieving symptoms coupled with increased functional capacity in OA models. This review will highlight studies carried out in the last five years to define the efficacies and underlying mechanisms in polyphenols such as quercetin, resveratrol, curcumin, epigallocatechin-3-gallate, rosmarinic acid, genistein, ginger, berries, silver fir, pine bark, and Boswellia. Most of these studies indicate that polyphenols exhibit their beneficial roles through regulating changes at the biochemical and molecular levels, inducing or inhibiting various signaling pathways related to inflammation and oxidative stress. Polyphenols have also been implicated in modulating microRNA at the posttranscriptional level to counteract OA pathogenesis.

Particle Densities of Horticultural Substrates

The heterogeneity of horticultural substrates makes basic physical characteristics, such as total porosity and particle density, difficult to estimate. Due to the material source, inclusion of occluded pores, and hydrophobicity, particle density values reported from using liquid pyknometry, vary widely. Gas pycnometry was used to determine the particle density of coir, peat, perlite, pine bark, and wood substrates. Further precision was examined by gas species and separation by particle size. The calculated particle densities for each material determined by He, N2, and air were relatively constant and varied little despite the species of gas used. Particle size affected the measured particle density of perlite and pine bark but was minimal with coir, peat, and wood. Reducing the particle size removed more occluded pores and the measured particle density increased. Given the small variability, the use of particle density values obtained by gas pycnometry provides repeatable, precise measurements of substrate material total porosity.

Evaluating Stratified Substrates Effect on Containerized Crop Growth under Varied Irrigation Strategies

Growers rely on soilless substrates to provide sufficient water and nutrients to containerized crops. Traditional bark-based substrates are engineered to have relatively low water-holding capabilities, which can lead to nonuniform rewetting patterns and inefficient usage of water resources. Engineering substrates to redistribute water dynamics and maximize aeration within the container may improve water resource efficiencies. The goal of this study was to evaluate whether more efficient irrigation schedules can be used when stratifying unique substrates within a container for added crop water and nutrient efficiency. Loropetalum chinense ‘Ruby’ liners were planted and grown in a conventional pine bark substrate or one of three stratified substrate treatments, including a bark:peat, bark:coir, or fine bark layered on top of a coarse bark. The crops were grown under four different irrigation schedules, including single daily application, single application at deficit levels, cyclic application, or cyclic at deficit schedules. Stratified substrates improved crop growth, quality, and yield when compared with plants grown in conventional bark in the single application irrigation treatment. Measured at final harvest, substrates positively influenced plant growth index (P < 0.0001), whereas irrigation scheduling alone had no effect (P = 0.6321). There was a strong interaction between substrate and irrigation schedules on Δ growth index (P = 0.0141). There were strong substrate effects on shoot dry weight (P = 0.0060), root dry weight (P = 0.0342), and growth index (P = 0.0040). The stratified bark:coir treatment outgrew all other substrate treatments. In addition, within all irrigation treatments, plants grown with the stratified bark:coir substrate had the highest survival ratings among the other substrate treatments, whereas the conventional bark had the lowest survival rates. Substrate and irrigation had an effect on nitrogen and potassium leachate concentrations levels (P = 0.0107 and P = 0.0004, respectively). Evaluation of microbial communities showed that substrate (P = 0.0010) and the stratified layer (P = 0.0010) had strong influences on the type of community present and the relative abundance in the treatments used herein this study. Specifically, within cyclic scheduling, bark:peat actinomycete populations were significantly greater than other substrate treatments. Furthermore, under deficit irrigation, stratified substrate systems were able to mitigate crop water stress. The results indicate that when crops such as the Loropetalum are grown in the stratified system, crop growth can be sustained when drought conditions are present. This is possible by providing adequate water availability even under low water inputs until subsequent irrigations during the fragile establishment period, when compared with using traditional bark-based substrates.

The results of the introduction of twisted pine (Pinus contorta) in Bolshoy Solovetsky Island

Abstract In the central part of the Bolshoy Solovetsky Island, in the same type of growing conditions, two plots were created in 1988: the first consisted of twisted pine (Pinus contorta Loud. var. latifolia S. Wats) crops and the second one was of Scots pine (Pinus sylvestris L.). The aim of the study was to establish the morphological parameters of the twisted pine and its growth in the conditions of the Bolshoy Solovetsky Island in comparison with the native species P. sylvestris L. Also, we aimed to identify the features of P. contorta var. latifolia and determine the possibility and necessity of further introduction of the species. The preservation of the twisted pine and scots pine cultures was determined. Accounting trees were selected (62 and 31 trees, respectively), in which morphometric indicators were measured. Wood samples (cores) were taken from them with an age drill to measure radial growth. The radial increment was measured using the MBS-9 microscope and the Lintab device. To measure the increase in height, six medium-sized model trees were cut down. According to the taxation indicators, the two types differed slightly and the differences were most often unreliable. The average height of the twisted pine trees was significantly higher compared to that of Scots pine. The thickness of the bark varied; on average, at the age of 18, it was 1.35 ± 0.038 mm for twisted pine and 1.86 ± 0.095 for Scots pine, that is, the native pine bark was 38% thicker. Typical for twisted pine were a significant number of pathologies noted in 22% of the studied trees. Twisted pine was distinguished by a stronger development of the assimilation apparatus: the number of branches of the first order, the number of branches in the whorl, the life span of needles. An increase in radius (the width of the annual ring) was observed at 14–15 years, and then with age, the value decreased in twisted pine and remained at a consistently high level in Scots pine. The width of the late zone of the annual ring was 12% in Scots pine and 14% in twisted pine; but at a young age, the late wood in twisted pine was very small. The increase in height of the twisted pine was on average less than that of Scots pine. The dependence of the trunk volume on the diameter was almost identical in both species.

Determination of Antioxidant Activity of Different Extracts From Bark of Pinus spp. grown in Giresun (Turkey) Province – Phenolic analysis by RP-HPLC-DAD

This study aimed to investigate the phenolic compounds, total phenolic content, and antioxidant activities of Pinus sylvestris L. var hamata Steven, Pinus pinaster Aiton subsp. pinaster, and Pinus pinea L. bark extracts prepared with hot water. The phenolic composition and total phenolic content (TPC) of extracts were determined by Reversed Phase-High Performance Liquid Chromatography-Diode Array Detector (RP-HPLC-DAD) and Folin–Ciocâlteu method, respectively. The antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging and ferric ion (III) reducing / antioxidant power (FRAP) assays. Besides, the highest total phenolic content was detected in P. pinea bark extract [984.46±4.08 μg mL-1 gallic acid equivalent (GAE) and 1163.33±4.04 μg mL-1 catechin equivalent (CE)] and the lowest result was detected in P. sylvestris bark extract (361.53±3.52 μg mL-1 GAE and 427.26±4.17 μg mL-1 CE). Among the tested materials, the most abundant phenolic compounds in P. pinea bark extract were catechin (3.586±0.114 mg g-1) and taxifolin (1.866±0.096 mg g-1). According to the antioxidant results, P. pinea bark extract exhibited remarkable antioxidant activity than standard BHT and Trolox [SC50: 1.64310±0.00003 µg mL-1 for DPPH and 1428.75±5.62 µM Trolox Equivalent Antioxidant Capacity (TEAC) for FRAP]. The obtained results indicated that pine bark extracts can be used as an easily obtainable natural source of antioxidants for the food and pharmaceutical industry.

Pine bark valorization by activated carbons production to be used as VOCs adsorbents

The exploitation of pine bark, a byproduct of timber industry, as biochar or activated carbons has been demonstrated. It can be successfully charred, and further activated, either by physical and chemical activation. The biochar yield and quality (amount of carbon) is mainly determined by the maximum temperature. Temperatures above 300°C were required to convert pine bark into biochar (by means of cracking and volatiles release), and yield stabilized at 32% at the maximum temperature tested (850°C). With uniform heating, the heating rate and the particle size did not affect significantly the biochar yield.The carbon loss in biochar activation was found to be dramatic with steam at 850°C, while chemical activation significantly reduced it, preserving most of the biochar. The activated carbons obtained have been tested for adsorption of CO2 (at 90%) and toluene (a model VOC, between 500ppm and 2.5%). Significant differences in VOC loading capacity have been measured and explained with the different microstructure of the activated carbons produced. BET specific surface up to 3342m2/g has been measured, in carbons activated with H3PO4, and 1499m2/g with K2CO3, and total pores volume up to 2.57cm3/g.The chemically activated carbons were found very effective in VOC capture, up to 50% (5.5mmol/g) of the original solid mass. Among them, the one activated by K2CO3 shows the highest loading capacity (32%, or 3.5mmol/g) even at quite low toluene concentration (500ppm), thanks to its largest share of micropores.

Determination of phenylbutazone, sulfamethazine, carbendazim and linuron using a novel pine bark biosorbent for solid-phase extraction (SPE) with high-performance liquid chromatography (HPLC)

The paper presents a novel pine bark based biosorbent for solid-phase extraction (SPE). The morphology and composition of the pine bark were characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The biosorbent was used for the preparation of wastewater for the determination of phenylbutazone, sulfamethazine, carbendazim, and linuron by high performance liquid chromatography with ultraviolet detection (HPLC-UV). The SPE conditions were optimized with respect to elution solvent, sample volume, and extraction pH. The results showed that developed sorbent provides good repeatability. The relative standard deviation (n = 3), was between 0.3 and 2.2%. The limits of detection (LOD) were between 0.11 and 0.4 µg.L−1. The developed method was used for determination of the analytes in effluent from a wastewater treatment plant.

Vermicompost Amended With Rock Phosphate as a Climate Smart Technology for Production of Organic Swiss Chard (Beta vulgaris subsp. vulgaris)

Vermicomposting is being promoted as climate-smart agriculture (CSA) technology for developing organic nutrient sources that can be adopted by smallholder farmers. The amendment of soils with cost-effective and available inorganic fertilizers like rock phosphate (RP) and phosphorus-solubilizing microorganisms should also be promoted. Our study investigated the seedling and maturity growth of Swiss chard. The crop maturity study investigated the effect of amending an Oxisol soil with three phosphorus (P) sources applied at three different rates (0, 25, and 50 mg P kg−1 soil), cow and pig manures, and P-solubilizing bacteria resulting in the following treatments: control (soil), soil + RP alone, soil + RP-enriched cow manure vermicompost (VC) with phosphorus-solubilizing bacteria (PSB), and soil + RP-enriched pig manure vermicompost (VP) with PSB. The study investigated the growth performance and accumulation of copper (Cu), zinc (Zn), chromium (Cr), and lead (Pb) in the edible parts of Swiss chard (Beta vulgaris subsp. valgaris var. Cicla). The seedlings were grown using pine bark compost and the three P sources (VC, VP, and RP) at five different application rates (0, 25, 50, 75, and 100%). The results revealed that the use of 50 mg P kg−1 as VP gave the highest fresh weight of 39.78 g, leaf area of 240.41 cm2, and a total P in tissues of 326.91 mg kg−1 at 8 weeks after transplanting. The 50 mg P kg−1 application as VC resulted in a higher Zn content of 8.50 mg kg−1, which was above the permissible level. These results suggest that the best treatment mixture for establishing fully matured Swiss chard was the 50 mg P kg−1 as VP. Therefore, pig manure vermicompost that has been inoculated with phosphorus-solubilizing microorganisms is a promising CSA technology that can improve organic vegetable production by smallholder farmers.

Seasonal changes in water absorbability of some litterfall compoSeasonal changes in water absorbability of some litterfall components in Scots pine stands differing in agenents in Scots pine stands differing in age

Understanding the water-holding capacity of the litter layer is of interest when constructing forest hydrology models, where the presence of litter affects soil moisture content and fire behavior. However, to understand the process of water storage in the litter layer it is not only important to know (i) how much water the litter layer can store, but also (ii) how much water particular litter components can store. Little is known about the role of organic matter chemistry in water absorption and saturation of its internal capillarity. We hypothesized that water absorption of freshly fallen organic matter changes with stand age and during the year, i.e. the term when organic matter falls (month of the year or season) affects its water absorbability. Thus, we determined seasonal changes in water absorption time, carbon and nitrogen contents, and the C/N ratio of bark and needles taken from Scots pine stands of different ages during laboratory tests. Pine needles and bark were collected every month for one year in five stands in north-western Poland. The time of water absorption for bark was about 30% shorter than that of needles. The age of the stand did not affect the time of water absorption in the litterfall components. We observed that the term when litter falls (month of the year or season) significantly affected the water absorption time. It indicates that organic matter reaching the forest floor and forming the litter layer is characterized by different output properties affecting the water storage capacity of the litter layer.

Effect of Mulch Type and Depth on Rooting of Stem Cuttings and Weed Control in Containers

Weeds are a major problem in cutting propagation and compete with the main crop for water, sunlight, and nutrients, thus reducing growth and marketable quality of rooted cuttings. Due to the high labor cost of hand weeding, mulches can be an alternative method for weed control in the propagation environment. The objective of this research was to determine the effect of mulches (coarse vermiculite, rice hulls, paper pellets, and pine pellets) on rooting of stem cuttings and weed control when applied at 0.5- and 1-inch depths. Cuttings of three plant species [‘Nanho Blue’ butterfly bush (Buddleja davidii), ‘Catawba’ crape myrtle (Lagerstroemia indica), ‘Phantom’ hydrangea (Hydrangea paniculata)] were stuck in 2.5-inch-diameter containers filled with pine bark substrate and treated with mulch. In a separate study, seeds of four weed species [creeping woodsorrel (Oxalis corniculata), hairy bittercress (Cardamine hirsuta), large crabgrass (Digitaria sanguinalis), mulberry weed (Fatoua villosa)] were sown onto the mulch surface. Rooting percentage was unaffected by mulch type or depth for any of the three crop species (‘Nanho Blue’ butterfly bush, ‘Catawba’ crape myrtle, ‘Phantom’ hydrangea). Pine pellets did not affect root dry weight of any crop species, but root length and volume of ‘Catawba’ crape myrtle was reduced by pine pellets at 1-inch depth. Rice hulls slightly reduced the root length and volume of ‘Catawba’ crape myrtle, but the reduction was less than 50%. Pine pellets and paper pellets (both depths) reduced growth of all four weed species. Even though weed seeds germinated in pine and paper pellets, seedlings did not grow large enough to potentially affect crop rooting. In conclusion, pine pellets and paper pellets at 0.5-inch depth can be effective in suppressing weed populations with minimal effect on rooting.

Evaluation of Peat Blended with Pine Wood Components for Effects on Substrate Physical Properties, Nitrogen Immobilization, and Growth of Petunia (Petunia ×hybrida Vilm.-Andr.)

The first objective was to evaluate wood components for differences in nitrogen (N) immobilization and effects on substrate physical properties. The second objective was to evaluate peat substrates amended with pine wood components for effects on plant growth, shoot tissue N, and fertigation practices during production. Substrates consisted of a coarse sphagnum peat blended with four types of processed pine wood at rates of 15%, 30%, 45%, and 60% (by volume). For comparison, peat was also blended with an aged pine bark, perlite, and coconut coir. Nitrogen immobilization was measured for individual components, except perlite. Individual components and blended substrates were evaluated for particle size distribution, total air porosity, container capacity, and dry bulk density. In a greenhouse experiment, petunia (Petunia × hybrida Vilm.-Andr.) were grown in hanging basket containers with each substrate blend as well as 100% peat, which served as a nonblended control substrate, and fertilized at each irrigation with 200 mg·L−1 N. Blended component and blend percent interacted in effects on all measured substrate physical properties; however, physical properties of all substrate blends were considered adequate for horticultural purposes. In the laboratory, pine bark immobilized 9% of total N supplied, whereas the remaining pine wood components immobilized <5% of total N. In the greenhouse experiment, blend component influenced shoot growth and flowering, which were greatest for petunia grown in 100% peat. Increasing the blend percent of all components decreased shoot growth and flowering with all blended components. Blended substrates had minimal effects on number of fertigation events, and substrate treatments differed by a maximum of three fertigation events per container over a 56-d period. This study illustrates the challenges of measuring N immobilization because results from the laboratory were not consistent with plant performance in the greenhouse. Increasing blends of each substrate (including perlite) were also observed to interact with fertigation practices and therefore applied N, tissue N, shoot dry weight, and total N uptake. As a practical conclusion from this study, peat incorporated with 60% wood fiber increased the risk of reduced plant growth and N uptake, but this risk was lower as the blend percentage decreased. In addition, other analytical methods to test N immobilization, such as microbial respiration, should be further explored.