Shrinkage of Selected Two-component Container Media

Nash, Mark A.; Pokorny, F. A.

doi:10.21273/hortsci.25.8.930

Cited by 18 publications

(7 citation statements)

References 5 publications

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“…Shrinkage after 70 weeks was highest in fallow PTS at both fertilizer rates (22.3% and 24.4%), but shrinkage in PTS that contained plants was equal to PB with plants (Table 2). Shrinkage results from particle size breakdown (microbial decomposition) and sub-strate settling (finer particles fit between larger particles) caused by gravity and water movement through the substrate during irrigations (Bilderback and Lorscheider, 1995;Bures et al, 1993;Nash and Pokorny, 1990). Substrate shrinkage causes a decrease in AS and an increase in CC over time as observed in this study (Table 2) and reported in other works (Bohne and Gunther, 1997;Prasad and Chualain, 2005).…”

Section: Resultssupporting

confidence: 77%

Changes in Chemical and Physical Properties of Pine Tree Substrate and Pine Bark During Long-term Nursery Crop Production

Jackson¹,

Wright²,

Seiler³

2009

horts

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The objective of this study was to evaluate a pine tree substrate (PTS) for decomposition, changes in physical and chemical properties, and substrate carbon dioxide (CO2) efflux (microbial activity) during a long-term production cycle under outdoor nursery conditions. Substrates used in this study were PTS constructed using a 4.76-mm hammer mill screen and aged pine bark (PB). Plastic nursery containers were filled with each substrate and amended with either 4.2 or 8.4 kg·m−3 Osmocote Plus fertilizer and planted with Cotoneaster horizontalis or left fallow. Substrate solution chemical properties and nutrient concentrations were determined each month during the summers of 2006 and 2007 in addition to measuring substrate CO2 efflux (μmol CO2/m−2·s−1) as an assessment of microbial activity. Substrate breakdown (decomposition) was determined with particle size analysis and physical property determination on substrates at the conclusion of the study (70 weeks). Substrate solution pH was higher in PTS than in PB at both fertilizer rates in 2006, but pH levels decreased over time and were lower in PTS at both fertilizer rates in 2007. Substrate solution electrical conductivity levels, nitrate, phosphorus, and potassium concentrations were all generally higher in PB than in PTS at both fertilizer rates through both years. Pine tree substrate decomposition was higher when plants were present in the containers [evident by an increase in fine substrate particles (less than 0.5 mm) after 70 weeks], but breakdown was equal at both fertilizer rates. Shrinkage of PTS in the presence of plants was equal to the shrinkage observed in PB with plants, but shrinkage was higher in fallow PTS containers than PTS with plants. Substrate air apace (AS) was highest in PTS and container capacity (CC) was equal in PB and PTS at potting. Substrate AS decreased and CC increased in both substrates after 70 weeks but remained in acceptable ranges for container substrates. Substrate CO2 efflux rates were higher in PTS compared with PB at both fertilizer rates indicating higher microbial activity, thereby increasing the potential for nutrient immobilization and substrate breakdown. This work provides evidence that PTS decomposition is unaffected by fertilizer rate and that substrate shrinkage in containers with plants is similar to PB after two growing seasons (70 weeks), which addresses two major concerns about the use and performance of PTS for long-term nursery crop production. This work also shows that the higher microbial activity in PTS increases the potential of microbial nutrient immobilization, which is likely the reason for the lower substrate nutrient levels reported for PTS compared with PB over 70 weeks.

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Section: Resultssupporting

confidence: 77%

Changes in Chemical and Physical Properties of Pine Tree Substrate and Pine Bark During Long-term Nursery Crop Production

Jackson¹,

Wright²,

Seiler³

2009

horts

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“…Media containing high proportion of kenaf core fiber (T 5 ) have a higher rate of water absorption (b = 0.798) and ended-up with a significantly higher moisture content than the medium with 70% cocopeat and 30 kenaf core fiber (T 4 , b = 0.401). High water absorption by this medium may be due the settling effect upon wetting which reduces column height and changes the distribution between the capillary and noncapillary pores [15] . In the process, small particles settle into large non-capillary pores located between the larger particles.…”

Section: Resultsmentioning

confidence: 99%

Chemical and Physical Characteristics of Cocopeat-Based Media Mixtures and Their Effects on the Growth and Development of <i>Celosia cristata</i>

Awang¹

2009

American Journal of Agricultural and Biological Sciences

129

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Problem statement: Cocopeat is considered as a good growing media component with acceptable pH, electrical conductivity and other chemical attributes but it has been recognized to have high water holding capacity which causes poor air-water relationship, leading to low aeration within the medium, thus affecting the oxygen diffusion to the roots. Incorporation of coarser materials into cocopeat could improve the aeration status of the media. Approach: Selected chemical and physical characteristics of five types of growing media comprising of (v/v) 100% cocopeat, 70% cocopeat: 30% burnt rice hull, 70% cocopeat: 30% perlite, 70% cocopeat: 30% kenaf core fiber and 40% cocopeat: 60% kenaf core fiber were determined and their suitability as growing media was tested using Celosia cristata. Data on pH, Electrical Conductivity (EC) and various aspects of air-water relationships of the media, as well on growth and flowering of test plant and leaf nutrient contents were collected. Results: Initial pH for 100% cocopeat and 70% cocopeat: 30% kenaf core fiber was higher than the other media but the values were eventually similar by the end of the study. The bulk density and EC of media containing burnt rice hull was markedly higher than the other media (0.12 g cm³ and 0.48 mS cm^-1, respectively). Media comprising of 70% cocopeat: 30% burnt rice hull and 70% cocopeat: 30% perlite contained higher air content. The former held the highest volume of available water. Incorporation of burnt rice hull and perlite into cocopeat increased water absorption ability of the media which reached saturation earlier than the other media. Addition of burnt rice hull (30%), perlite (30%) and kenaf core fiber (30%) to cocopeat elevated the Air-Filled Porosity (AFP) of the media. The growth and flowering of Celosia cristata were the greatest when grown in a mixture of 70% cocopeat: 30% burnt rice hull and perhaps linked with a good balance in the aeration and moisture relationship of the media. Conclusion: Results of this study indicated that certain chemical and physical properties of cocopeat can be improved through incorporation of burnt rice hull and its positive effect was clearly reflected in the growth and development of Celosia cristata

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“…settling and compression caused by gravity and water movement through the substrate during irrigations (Fonteno et al, 1981;Meinken and Fischer, 1997). When particles of different sizes are mixed, shrinkage of the final volume occurs, because small particles fill the pores located between the large particles (Bures et al, 1993;Nash and Pokorny, 1990). Effects on poinsettia growth, floral quality, and postproduction time to wilting.…”

Section: Resultsmentioning

confidence: 99%

Pine Tree Substrate, Nitrogen Rate, Particle Size, and Peat Amendment Affect Poinsettia Growth and Substrate Physical Properties

Jackson¹,

Wright²,

Barnes³

2008

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‘Prestige’ poinsettias (Euphorbia pulcherrima Willd. Ex Klotzsch) were grown at different fertilizer rates in three pine tree substrates (PTS) made from loblolly pine trees (Pinus taeda L.) and a peat-based control. Pine tree substrates were produced from pine trees that were chipped and hammer-milled to a desired particle size. Substrates used in this study included peat-lite (PL), PTS produced with a 2.38-mm screen (PTS1), PTS produced with a 4.76-mm screen (PTS2), and PTS produced with a 4.76-mm screen and amended with 25% peatmoss (v/v) (PTS3). Initial and final substrate physical properties and substrate shrinkage were determined to evaluate changes over the production period. Poinsettias were grown in 1.7-L containers in the fall of 2007 and fertilized at each irrigation with 100, 200, 300, or 400 mg·L−1 nitrogen (N). Shoot dry weight and growth index were higher in PL at 100 mg·L−1 N but similar for all substrates at 300 mg·L−1 N. Bract length was generally the same or longer in all PTS-grown plants compared with plants grown in PL at each fertilizer rate. Postproduction time to wilting was the same for poinsettias grown in PL, PTS1, and PTS3. Initial and final air space was higher in all PTSs compared with PL and container capacity (CC) of PTS1 was equal to PL initially and at the end of the experiment. The initial and final CC of PTS2 was lower than PL. The incorporation of 25% peat (PTS3) increased shoot dry weight and bract length at lower fertilizer rates compared with 4.76 mm PTS alone (PTS2). Substrate shrinkage was not different between PL and PTS1 but greater than shrinkage with the coarser PTS2. This study demonstrates that poinsettia can be successfully grown in a PTS with small particles (2.38-mm screen) or a PTS with large particles (4.76-mm screen) when amended with 25% peatmoss, which results in physical properties (CC and air space) similar to those of PL.

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Shrinkage of Selected Two-component Container Media

Cited by 18 publications

References 5 publications

Changes in Chemical and Physical Properties of Pine Tree Substrate and Pine Bark During Long-term Nursery Crop Production

Changes in Chemical and Physical Properties of Pine Tree Substrate and Pine Bark During Long-term Nursery Crop Production

Chemical and Physical Characteristics of Cocopeat-Based Media Mixtures and Their Effects on the Growth and Development of <i>Celosia cristata</i>

Pine Tree Substrate, Nitrogen Rate, Particle Size, and Peat Amendment Affect Poinsettia Growth and Substrate Physical Properties

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