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Cation exchange properties of pine bark growing media
... Nash and Pokorny (1990) reported a value of 96.6 meq/L for a milled pine bark, and Rideout and Tripepi (2011) reported a CEC of 81.9 meq/L for 90% pine bark amended with 10% sand. The most thorough analysis of pine bark CEC to date is work by Daniels and Wright (1988); however, they only provided CEC on a weight basis, which is less informative for container substrates than CEC on a volumetric basis (Biernbaum, 1992). Furthermore, the CEC values provided by Daniels and Wright (1988) are the weighted sums of CEC for several pine bark particle size fractions, which may provide inaccurate estimates of composite CEC since nesting and settling of particles was not taken into account (Nash and Pokorny, 1990). ...
... The most thorough analysis of pine bark CEC to date is work by Daniels and Wright (1988); however, they only provided CEC on a weight basis, which is less informative for container substrates than CEC on a volumetric basis (Biernbaum, 1992). Furthermore, the CEC values provided by Daniels and Wright (1988) are the weighted sums of CEC for several pine bark particle size fractions, which may provide inaccurate estimates of composite CEC since nesting and settling of particles was not taken into account (Nash and Pokorny, 1990). ...
... Bulk density also decreased with increasing particle size, further exacerbating the differences in volumetric CEC between the three particle size classes. Daniels and Wright (1988) reported that particle size of pine bark had little effect on weight-based CEC over the range of 0.05 to 2.38 mm, although they provided no statistical analysis to support their findings. However, they did report a ''significant drop'' in CEC among particles greater than 2.38 mm (Daniels and Wright, 1988), which is in general agreement with our data. ...
Cation exchange capacity (CEC) describes the maximum quantity of cations a soil or substrate can hold while being exchangeable with the soil solution. Although CEC has been studied for peatmoss-based substrates, relatively little work has documented factors that affect CEC of pine bark substrates. The objective of this research was to determine the variability of CEC in different batches of pine bark and determine the influence of particle size, substrate pH, and peat amendment on pine bark CEC. Four batches of nursery-grade pine bark were collected from two nurseries, and a single source of sphagnum moss was obtained, separated in to several particle size classes, and measured for CEC. Pine bark was also amended with varying rates of elemental sulfur and dolomitic limestone to generate varying levels of substrate pH. The CEC varied with pine bark batch. Part of this variation is attributed to differences in particle size of the bark batches. Pine bark and peatmoss CEC increased with decreasing particle size, although the change in CEC from coarse to fine particles was greater with pine bark than peatmoss. Substrate pH from 4.02 to 6.37 had no effect on pine bark CEC. The pine bark batch with the highest CEC had similar CEC to sphagnum peat. Amending this batch of pine bark with sphagnum peat had no effect on composite CEC.
... Brown and Pokorny (1977) reported that soluble potassium applied to the top of a pine bark-filled column resulted in K + adsorption to the bark and that the distribution of that adsorbed K + was uneven throughout the column with most retained in the upper portion of the substrate profile. Furthermore, they demonstrated that an increase in pH led to an increase in the amount of adsorbed K + , indicating the presence of pHdependent functional groups, which has been confirmed in several subsequent studies (Daniels and Wright, 1988;Foster et al., 1983). Foster et al. (1983) applied deionized (DI) water to pine bark-filled columns that had been pre-treated with a ammonium nitrate (NH 4 NO 3 ) solution and found that the majority of both ammonium (NH 4 + ) and nitrate ions were leached with 120 mL of DI water, which was slightly less than the total column volume (170 mL). ...
... This finding alone warrants further research into a functional quantification of the cation exchange that occurs under varying conditions (i.e., ion species, residence times, pH, and moisture content) that are likely to occur in a production scenario such as during fertilizer application or between irrigation events. Daniels and Wright (1988) found surprisingly few differences between the CEC of various pine bark particle size fractions and hypothesized that the internal porosity of pine bark may account for a significant portion of the overall CEC. Mohammadi et al. (2009) discussed an immobile fraction of the soil solution that, when accounted for in prediction models, allowed for a fairly accurate prediction of solute breakthrough. ...
... An unexpected observation while conducting both the cation and anion transport experiment was that during the pre-experiment DI flush (Step 1), the effluent was consistently cloudy and had a light brown color that became clear when fertilizer solution was applied (Step 2). It became cloudy again when DI water was re-applied in Step 3. A similar effect was observed in previous CEC studies ( Daniels and Wright, 1988), where the washing of bark with distilled water after ion displacement produced a cloudy solution. Their observations and ours may suggest an interaction between soluble organic materials and applied fertilizer ions. ...
An understanding of how dissolved mineral nutrient ions (solutes) move through pine bark substrates during the application of irrigation water is vital to better understand nutrient transport and leaching from containerized crops during an irrigation event. However, current theories on solute transport processes in soilless systems are largely based on research in mineral soils and thus do not necessarily explain solute transport in soilless substrates. A study was conducted to characterize solute transport through a 9 pine bark:1 sand (by volume) substrate by developing and analyzing breakthrough curves (BTCs). Columns filled with pine bark substrate were subjected to the application of a nutrient solution (tracer) and deionized water under saturated and unsaturated conditions. Effluent drained from the columns during these applications was collected and analyzed to determine the effluent concentration
... The CEC of common organic substrates such as peat, pine bark or composts is generally high (80-160 cmol kg −1 ) and is pH dependent (Brown and Pokorny, 1975;Puustjarvi, 1977;Ogden et al., 1987;Daniels and Wright, 1988). The charge is derived mainly from ionization of COOH groups and, to a lesser extent, from phenolic OH (Stevenson, 1994). ...
... The charge is derived mainly from ionization of COOH groups and, to a lesser extent, from phenolic OH (Stevenson, 1994). The pH effect on CEC of organic material was found to be more pronounced than that of soil inorganic materials (Hallsworth and Wilkinson, 1958;Helling et al., 1964;Ogden et al., 1987;Daniels and Wright, 1988;Stevenson, 1994). The contribution of a unit pH increase to the CEC of soil organic material was found to be 51 cmol kg −1 of organic C ( Fig. 6.4A). ...
... The charge characteristics of composts were found to be dependent on composting time (Harada and Inoko, 1980;Inbar, 1989;Inbar et al., 1989Inbar et al., , 1991Iglesias-Jimenez and Perez-Garcia, 1992;Saharinen, 1996;Jokova et al., 1997), mainly because of transformations of organic constituents such as C/N ratio, humic material and lignin Helling et al. (1964), with kind permission from the Soil Science Society of America Journal; (B) several particle size fraction of pine bark growing media. Based on Daniels and Wright, (1988). ...
This chapter deals with the chemical properties of soilless media. Tuff is a volcanic material used as a substrate for horticultural crops in Italy, Spain, France, Turkey, and Israel and had been the subject of considerable research with respect to chemical properties as a horticultural substrate. This chapter uses tuff as model for illustration and elucidation of the chemical processes taking place in soilless media systems. The first category of chemical property described is that related to charge characteristics. This includes cation exchange capacity, anion exchange capacity, and pH titration analysis. Following this, the study discusses specific adsorption and interactions between cations/anions and substrate solids. The solubility and the interactions of nutritional elements with the substrate solids are associated with ion characteristics such as valence, size, and hydration status. Furthermore, it deals with plant-induced changes in the rhizosphere. Under this, it considers the effects on chemical properties of surfaces of substrate solids. Plant growth may affect the chemical properties of the substrate solids through three main mechanisms: changes of the surface charge and chemical properties of the solids through the addition of specifically adsorbed ions, addition of new solid materials, and accumulation of root exudates and decomposition products. Finally, this chapter explains nutrient release from inorganic and organic substrates.
... This can cause "lime-induced chlorosis" (Mengel and Kirkby, 1987). An increase in pH can reduce nutrient availability by precipitating micronutrient cations, as well as increasing adsorption of cations to the substrate particle as a result of higher cation exchange capacity (Brady, 1990;Daniels and Wright, 1988). The micronutrient × lime interaction in Expt. 2 (Fig. 1B) indicated that adding micronutrients to bark, regardless of lime treatment, increased growth; however, the increase was greater when lime was added. ...
The objective of this study was to determine the effects of lime and micronutrient amendments on growth of seedlings of nine container-grown landscape tree species in two pine bark substrates with different pHs. Acer palmatum Thunb. (Japanese maple), Acer saccharum Marsh. (sugar maple), Cercis canadensis L. (redbud), Cornus florida L. (flowering dogwood), Cornus kousa Hance. (kousa dogwood), Koelreuteria paniculata Laxm. (golden-rain tree), Magnolia × soulangiana Soul.-Bod. `Lennei' (magnolia), Nyssa sylvatica Marsh. (blackgum), and Quercus palustris Müenchh. (pin oak) were grown from seed in two pine bark substrates with different pHs (pH 4.7 and 5.1) (Expt. 1). Preplant amendment treatments for each of two pine ( Pinus taeda L.) bark sources were: with and without dolomitic limestone (3.6 kg·m –3 ) and with and without micronutrients (0.9 kg·m –3 ), and with and without micronutrients (0.9 kg·m –3 ), supplied as Micromax. Seedlings were harvested 12 and 19 weeks after seeds were planted, and shoot dry weight and tree height were determined. The same experiment was repeated using two of the nine species from Expt. 1 and pine bark substrates at pH 5.1 and 5.8 (Expt. 2). Seedling shoot dry weight and height were measured 11 weeks after planting. For both experiments, pine bark solutions were extracted using the pour-through method and analyzed for Ca, Mg, Fe, Mn, Cu, and Zn. Growth of all species in both experiments was greater in micronutrient-amended than in lime-amended bark. In general, adding micronutrients increased nutrient concentrations in the pine bark solution, while adding lime decreased them. Effect of bark type on growth in Expt. 1 was variable; however, in Expt. 2, growth was greater in the low pH bark than in the high pH bark. In general, nutrient concentrations in bark solutions were higher in low pH bark than in high pH bark for both experiments. Under the pH conditions of this experiment, micronutrient additions stimulated growth whereas a lime amendment did not.
... Coir has a lower CEC than peat, with values ranging from 35 to 95 cmol c kg −1 (approximately 70-150 meq L −1 ) reported (Abad et al., 2002;Handreck and Black, 2010). Pine bark has a similar CEC, reported as between 58 and 74 cmol c kg −1 (Daniels and Wright, 1988), which translates to 120 to 200 meq L −1 . Composted bark is reported to have a higher CEC than fresh bark (Handreck and Black, 2010). ...
Organic growing media are essentially bulk products. Availability in large quantity allied to its excellent air and water retention, low pH and salinity, and freedom from pests and diseases has led to peat being the dominant organic constituent of growing media in many parts of the world for the last 50 yr. The unique microporous properties of Sphagnum peat and its resistance to degradation are matched by few other growing media constituents. Nevertheless, local scarcity of Sphagnum peat and the expense of transport has led to the use of other materials in growing media. Notable among these is coir, which unlike peat, a CO2 sink, is widely regarded as a rapidly renewable resource. Indeed, advances in processing and quality control in situ have led to a huge upsurge in the export and use of coir in growing media, particularly in Europe but also in the western United States. Locally available organic materials such as bark, composted materials including green (yard) wastes, municipal solid wastes, and even sewage sludge are also used in growing media. While possessing advantages such as the high air content of bark and nutrient supply of many composted materials, these media components may have disadvantages, from limited supplies due to bioenergy pulls and N lock-up in bark, to physical, chemical, and microbial contaminants in composts. Current innovative approaches involve increasing use of wood fiber in Europe, whole pine-tree thinnings in the United States, and realizing the use and transformation of composted wastes as next-generation constituents of growing media.
... This can cause "lime-induced chlorosis" (Mengel and Kirkby, 1987). An increase in pH can reduce nutrient availability by precipitating micronutrient cations, as well as increasing adsorption of cations to the substrate particle as a result of higher cation exchange capacity (Brady, 1990;Daniels and Wright, 1988). The micronutrient × lime interaction in Expt. 2 (Fig. 1B) indicated that adding micronutrients to bark, regardless of lime treatment, increased growth; however, the increase was greater when lime was added. ...
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/m ³ dolomitic limestone and 0 or 0.9 kg/m ³ 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· \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{m}^{-_{3}}\) \end{document} ) increased growth only in the absence of micronutrient additions. In general, adding micronutrients increased pine bark solution Ca, Mg, and micronutrient concentrations. Adding lime increased pine bark solution pH and Mg concentration and either had no effect on or decreased solution Ca and micronutrient concentrations. Regardless of pine bark pH, micronutrient additions resulted in improved growth and adding lime was not necessary.
... Chemically, the smaller the particles the more exchange sites exist for reaction. Daniels and Wright (1988), stated that, unexpectedly, pinebark particles decreasing from <2.38 to <0.05mm only slightly increased CEC, but CEC increased at 20 meq/100 g per pH unit increase. ...
... The pH for PL and PTS-50P did not reach the desired pH in some cases, which could be the result of low water alkalinity (36 mgÁL -1 ) and the acidic reaction of the fertilizer (200 g acidity/kg fertilizer). The apparent low buffering capacity of PTS observed in this study is in contrast to peatmoss and PB substrates that have been shown to have high buffering capacities (Daniels and Wright, 1988;Nash et al., 1983). ...
This work was conducted to evaluate the effect of limestone additions to pine
tree substrate (PTS) and PTS amended with peatmoss on pH and plant growth. ‘Inca
Gold’ marigold (Tagetes erecta L.) and ‘Rocky Mountain White’ geranium (Pelargonium
·hortorum L.H. Bailey) were grown in three PTSs—100% PTS, PTS plus 25% peatmoss
(v/v), and PTS plus 50% peatmoss (v/v)—made from freshly harvested loblolly pine trees
(Pinus taeda L.) chipped and hammermilled through a 4.76-mm screen and a peatmoss/
perlite (4:1 v/v; PL) control. Each substrate was amended with various rates of dolomitic
limestone and used to grow marigolds in 10-cm square (l-L) plastic containers and
geraniums in round 15-cm (1.25-L) plastic containers in a glasshouse. Regardless of
limestone rate, pH was highest in 100% PTS and decreased with peat additions with PL
having the lowest pH. As percent peat increased from 25% to 50%, more limestone was
required to adjust pH to a particular level showing that PTS is more weakly buffered
against pH change than peatmoss. Adding limestone did not increase the growth of
marigold in 100% PTS, but additions of limestone did increase growth of marigold when
grown in PTS containing peatmoss or in PL. Geranium growth was higher in PTS
containing peatmoss (25% or 50%) and PL than in 100% PTS at all limestone rates. This
research demonstrates that PTS produced from freshly harvested pine trees has an
inherently higher pH than PL, and the additions of peatmoss to PTS require pH
adjustment of the substrate for optimal plant growth.
... Liming would be needed in all cases to raise the pH to a more desirable range for improving plant growth. Daniels and Wright (1988) showed that increasing media pH results in high cation exchange capacity of pine bark, which could hold more exchangeable cations in the media and potentially reduce nutrient leaching. Foster et al (1983) showed that substantial amounts of NH were bound by pine bark and that the cation adsorption preferences (in comparison to other cations) increased with pH. ...
Physical and chemical properties of container media are important factors in controlling the supply and movement of water and nutrients for nursery plant growth. The objectives of this study were to evaluate the physical and chemical properties and quality of media formulated with systematic substitution of composted pine bark (bark) for sphagnum peat (peat) in the presence of sand. Ten formulations were prepared that contained 40-90% bark, 0-50% peat, and 10 or 20% sand by volume. Increasing the percentage of bark increased the percentage of coarse particles, and linearly decreased the medium-sized particles in media in either 10% or 20% sand. Increasing the percentage of bark in the media significantly decreased water holding capacity, whereas bulk and particle densities and total porosity were influenced by the interaction of bark x peat x sand. Increasing the percentage of bark increased electrical conductivity and total C, P, K, Ca, Fe, Cu and Zn. Availability of nutrients were also increased by increasing percentages of bark. Substitution of bark for peat did not influence the pH of the formulated media. Our results suggest that formulated media with 70 to 80% composted pine bark and 10 to 20% peat (V/V) exhibited physical and chemical properties considered optimum for the growth of container nursery plant crops.
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