scholarly journals Physical Properties of and Plant Growth in Peat-based Root Substrates Containing Glass-based Aggregate, Perlite, and Parboiled Fresh Rice Hulls

2011 ◽  
Vol 21 (1) ◽  
pp. 30-34 ◽  
Author(s):  
Michael R. Evans
Keyword(s):  
Plant Growth ◽  
Physical Properties ◽  
Bulk Density ◽  
Catharanthus Roseus ◽  
Pore Space ◽  
Santa Fe ◽  
Rice Hulls ◽  
Sphagnum Peat ◽  
Impatiens Walleriana ◽  
Water Holding

Aggregates produced from finely ground waste glass [Growstones (GS); Earthstone Corp., Santa Fe, NM] have been proposed to adjust the physical properties of peat-based substrates. The GS had a total pore space (TPS) of 87.4% (by volume), which was higher than that of sphagnum peat and perlite but was similar to that of parboiled fresh rice hulls (PBH). The GS had an air-filled pore space (AFP) of 53.1%, which was higher than that of sphagnum peat and perlite but lower than that of PBH. At 34.3%, GS had a lower water-holding capacity (WHC) than sphagnum peat but a higher WHC than either perlite or PBH. The bulk density of GS was 0.19 g·cm−3 and was not different from that of the perlite but was higher than that of sphagnum peat and PBH. The addition of at least 15% GS to sphagnum peat increased the AFP of the resulting peat-based substrate. Substrates containing 25% or 30% GS had a higher AFP than substrates containing equivalent amounts of perlite but a lower AFP than substrates containing equivalent PBH. Substrates containing 20% or more GS had a higher WHC than equivalent perlite- or PBH-containing substrates. Growth of ‘Cooler Grape’ vinca (Catharanthus roseus), ‘Dazzler Lilac Splash’ impatiens (Impatiens walleriana), and ‘Score Red’ geranium (Pelargonium ×hortorum) was similar for plants grown in GS-containing substrates and those grown in equivalent perlite- and PBH-containing substrates.

scholarly journals Physical Properties of Whole Fresh-ground Parboiled Rice Hulls for Use as a Horticultural Root Substrate

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 979B-979
Author(s):  
Johann S. Buck ◽  
Michael R. Evans ◽  
Paolo Sambo
Keyword(s):  
Plant Growth ◽  
Physical Properties ◽  
Bulk Density ◽  
Pore Space ◽  
Water Holding Capacity ◽  
Rice Hull ◽  
Particle Sizes ◽  
Parboiled Rice ◽  
Rice Hulls ◽  
Water Holding

Horticultural root substrates are designed to provide the optimal physical properties for plant growth. These properties include bulk density (g·cm-3), air-filled pore space (% v/v), total pore space (% v/v), water-filled pore space (% v/v), water-holding capacity (% v/v and w/w), and wettability. Whole, fresh parboiled rice hulls were ground to produce four grades with varying particle size distributions. Particle sizes for the four grades ranged from <0.25 to >2.80 mm. Additionally, discrete particle sizes of <0.25, 0.50, 1.00, 2.00, 2.80, and >2.80 mm were produced. For all grade distributions and particle point sizes, physical properties were determined and contrasted against Canadian sphagnum peat. As the proportion of smaller particle sizes in the distributions increased or as the particle point sizes decreased, total pore space (% v/v) and air-filled pore space (% v/v) decreased, while, bulk density (g·cm-3) and water-holding capacity (% v/v and w/w) increased. Additionally, as the proportion of particle sizes from <0.25–0.50 mm increased, the wettabilty of the whole fresh parboiled rice hull material decreased. Particle sizes ranging from 1.00–2.80 mm possessed the physical properties most suitable for plant growth in containerized greenhouse crop production and were most similar to peat.

scholarly journals Physical Properties of Sphagnum Peat-based Root Substrates Amended with Perlite or Parboiled Fresh Rice Hulls

2007 ◽  
Vol 17 (3) ◽  
pp. 312-315 ◽  
Author(s):  
Michael R. Evans ◽  
Mary M. Gachukia
Keyword(s):  
Physical Properties ◽  
Pore Space ◽  
Water Holding Capacity ◽  
Practical Significance ◽  
Equivalent Amount ◽  
Rice Hulls ◽  
Sphagnum Peat ◽  
Rate Of Increase ◽  
Water Holding

Ten substrates were formulated by blending perlite or parboiled fresh rice hulls (PBH) to produce root substrates (substrates) that contained either 20%, 30%, 40%, 50%, or 60% (by volume) perlite or PBH, with the remainder being sphagnum peatmoss. All substrates containing PBH had higher total pore space than substrates containing an equivalent amount of perlite. As the percentage perlite increased from 20% to 60%, the total pore space decreased. The total pore space increased as the amount of PBH increased to 50% and then decreased as the amount of PBH increased from 50% to 60%. The air-filled pore space was not different between substrates containing 20% perlite or PBH. However, the air-filled pore space was higher in PBH-containing substrates than in equivalent perlite-containing substrates when the amount of PBH or perlite was at least 40%. As the amount of perlite or PBH was increased, the air-filled pore space increased, but the rate of increase was higher for PBH-containing substrates. The 20% PBH-containing substrate had a higher water-holding capacity than the 20% perlite-containing substrate. However, at 30% or higher PBH, the PBH-containing root substrates had a lower water-holding capacity than equivalent perlite-containing substrates. As the percentage perlite or PBH was increased, the water-holding capacity decreased, but at a higher rate in PBH-containing substrates than in perlite-containing substrates. For all substrates except those containing 40% PBH or perlite, substrates containing PBH had lower bulk densities than equivalent perlite-containing substrates. The differences in bulk densities were not great enough to be of practical significance. Inclusion of PBH in the substrate provided for drainage and air-filled pore space as did perlite. However, less PBH would be required in a substrate to provide the same air-filled pore space as perlite when more than 20% perlite or PBH is used.

scholarly journals Physical Properties of Processed Poultry Feather Fiber-containing Greenhouse Root Substrates

2007 ◽  
Vol 17 (3) ◽  
pp. 301-304 ◽  
Author(s):  
Michael R. Evans ◽  
Leisha Vance
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Pore Space ◽  
Water Holding Capacity ◽  
Pine Bark ◽  
Sphagnum Peat ◽  
The Difference ◽  
Poultry Feather ◽  
Feather Fiber ◽  
Water Holding

A series of soilless root substrates was formulated to contain either 20% composted pine bark or perlite and 0%, 10%, 20%, or 30% feather fiber, with the remainder being sphagnum peat. The substrates containing bark or perlite with 0% feather fiber served as the controls for the bark- and perlite-containing substrates respectively. For root substrates containing perlite, the inclusion of feather fiber increased the total pore space compared with the control substrate. For substrates containing bark, the inclusion of 10% or 20% feather fiber increased total pore space, but the inclusion of 30% feather fiber reduced total pore space. For substrates containing perlite, the inclusion of feather fiber increased the air-filled pore space compared with the control, and as the percentage feather fiber increased, air-filled pore space increased. For substrates containing bark, the inclusion of 10% or 20% feather fiber increased air-filled pore space, but air-filled pore space of the substrate containing 30% feather fiber was not different from the control. For all substrates, the inclusion of feather fiber reduced the water-holding capacity, but water-holding capacities for all substrates remained within recommended ranges. The bulk density of feather fiber-containing substrates was not different from the control except for the substrate containing 30% feather fiber with bark, which had a higher bulk density than its control without feather fiber. The difference in physical properties of the 30% feather fiber substrate with bark from its control substrate was attributed to the aggregation of the feather fiber when formulated with composted bark. Aggregation of feather fiber when blended into substrates at levels of 30% or higher would create difficulties in achieving uniform substrates.

scholarly journals Efficacy of Cork Granulates as a Top Coat Substrate Component for Seed Germination as Compared to Vermiculite

2013 ◽  
Vol 23 (1) ◽  
pp. 114-118 ◽  
Author(s):  
Arianna Bozzolo ◽  
Michael R. Evans
Keyword(s):  
Seed Germination ◽  
Bulk Density ◽  
Solanum Lycopersicum ◽  
Capsicum Annuum ◽  
Catharanthus Roseus ◽  
Pore Space ◽  
Water Holding Capacity ◽  
Impatiens Walleriana ◽  
Water Holding ◽  
Number Of Seeds

A top coat is a lightweight substrate component used in seed germination. The seeds are typically placed on a substrate such as peat and then the seeds are covered with a layer of the top coating substrate. The top coat serves to maintain adequate moisture around the seeds and to exclude light. Vermiculite and cork granulates (1 mm) were used as top coat substrates for seed germination to determine if cork granulates could be successfully used as an alternative to vermiculite. The cork granulates had a bulk density of 0.16 g·cm−3, which was higher than that of vermiculite that had a bulk density of 0.12 g·cm−3. Cork granulates had an air-filled pore space of 22.7% (v/v), which was higher than vermiculite which was 13.2%. The water-holding capacity of vermiculite was 63.4% (v/v), which was higher than that of cork granulates that was 35.1%. Seeds of ‘Rutgers Select’ tomato (Solanum lycopersicum), ‘Dazzler Lilac Splash’ impatiens (Impatiens walleriana), ‘Orbital Cardinal Red’ geranium (Pelargonium ×hortorum), ‘Better Belle’ pepper (Capsicum annuum), and ‘Cooler Grape’ vinca (Catharanthus roseus) were placed on top of peat and covered with a 4-mm top coating of either vermiculite or cork granulates. For tomato, impatiens, and vinca, days to germination were similar between seeds germinated using vermiculite and granulated cork as a top coat. Days to germination of geranium and pepper were significantly different with geranium and pepper seeds coated with cork granulates germinating 0.7 and 1.5 days earlier than those coated with vermiculite. For tomato, impatiens, and geranium, the number of seeds germinating per plug tray was similar between the top coats. Number of seeds germinating per tray for pepper and vinca were significantly different. Pepper had an average of 2.8 more seeds germinating per tray, and vinca had an average of 2.4 more seeds germinating per tray if seeds were germinated using granulated cork vs. vermiculite. For all species, dry shoot and dry root weights were similar for seedlings germinated using cork and vermiculite top coats.

Growth of Container-grown Plants With and Without Azomite Soil Amendment

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 492c-492
Author(s):  
Chris Ely ◽  
Mark A. Hubbard
Keyword(s):  
Plant Growth ◽  
Physical Properties ◽  
Bulk Density ◽  
Soil Amendment ◽  
Extended Period ◽  
Mineral Elements ◽  
Field Soil ◽  
Rooted Cuttings ◽  
Sodium Calcium ◽  
Water Holding

Azomite is a mined, commercially available, hydrated sodium calcium aluminosiliclate soil amendment reported to act as a source of mineral elements. To determine its effect on plant growth, Dendranthema `Connie' rooted cuttings, Malus seedlings, and Citrus seedlings were grown in containers in one of two growing media: ProMix BX or ProMix BX with Azomite (1:1, v:v). Plant height was monitored weekly and after 6 weeks of growth, fresh and dry plant weights of roots and shoots were determined. There was no difference in any of the parameters measured as a result of the addition of Azomite. Any nutritional influence of the Azomite may only be evident in different conditions, e.g., field soil, or over an extended period of time. The Azomite altered the medium's physical properties and therefore bulk density and water-holding capacity of the Azomite were determined for consideration.

scholarly journals Physical Properties of Ground Fresh Rice Hulls and Sphagnum Peat Used for Greenhouse Root Substrates

2008 ◽  
Vol 18 (3) ◽  
pp. 384-388 ◽  
Author(s):  
Paolo Sambo ◽  
Franco Sannazzaro ◽  
Michael R. Evans
Keyword(s):  
Oryza Sativa ◽  
Physical Properties ◽  
Water Content ◽  
Pore Space ◽  
Rice Hull ◽  
Water Release ◽  
Rice Hulls ◽  
Available Water ◽  
Available Water Content ◽  
Water Holding

Ground fresh rice (Oryza sativa) hull materials were produced by grinding whole fresh rice hulls and passing the resulting product through a 1-, 2-, 4- or 6-mm-diameter screen to produce a total of four ground rice products (RH1, RH2, RH4, and RH6, respectively). The physical properties and water release characteristics of sphagnum peatmoss (peat) and the four ground rice hull products were evaluated. All of the ground rice hull products had a higher bulk density (Bd) than peat, and as the grind size of the rice hull particle decreased, Bd increased. Peat had a higher total pore space (TPS) than all of the ground rice hull products except for RH6. As grind size decreased, the TPS decreased. Peat had a lower air-filled pore space (AFP) than all of the ground rice hull products and as the grind size of the rice hull products decreased, AFP decreased. Peat had a higher water holding capacity (WHC) than all of the ground rice hull products. Grind sizes RH4 and RH6 had similar WHC, whereas RH1 and RH2 had a higher WHC than RH4 and RH6. Peat, RH4, and RH6 had similar available water content (AVW), whereas RH2 had higher AVW than these materials and RH1 had the highest AVW. However, peat had the lowest AVW and easily available water (EAW) as a percentage of the WHC. The ground rice hull products RH1 and RH2 had the highest AVW and EAW of the components tested. Peat had the highest water content at container capacity. As pressure was increased from 1 to 5 kPa, peat released water more slowly than any of the ground rice hull products. The RH1 and RH2 ground hull products released water at a significantly higher rate than peat, but RH4 and RH6 released the most water over these pressures. For all rice hull products, most water was released between 1 and 2 kPa pressure. The rice hull products RH1 and RH2 had physical properties that were within recommended ranges and were most similar to those of peat.

scholarly journals Fresh Parboiled Rice Hulls Serve as an Alternative to Perlite in Greenhouse Crop Substrates

HortScience ◽  
2004 ◽  
Vol 39 (2) ◽  
pp. 232-235 ◽  
Author(s):  
Michael R. Evans ◽  
Maryanne Gachukia
Keyword(s):  
Lycopersicon Esculentum ◽  
Catharanthus Roseus ◽  
Tagetes Patula ◽  
Tomato Plants ◽  
Parboiled Rice ◽  
Rice Hulls ◽  
Sphagnum Peat ◽  
Significant Difference ◽  
Weed Seeds ◽  
Impatiens Walleriana

Ten substrates were formulated by blending perlite or parboiled fresh rice hulls (PFH) at 20%, 30%, 40%, 50%, or 60% (v/v) with sphagnum peat. After 6 weeks, NH4+ concentrations were not significantly different among substrates containing perlite and those containing equivalent amounts of PFH. Nitrate concentrations were significantly higher in the 40% perlite substrate than in the 40% PFH substrate, but there were no significant differences in NO3- concentrations among the remaining substrates containing equivalent amounts of PFH or perlite. When tomato (Lycopersicon esculentum Mill.) was grown in the substrates for 5 weeks, tissue N concentrations were not significantly different between equivalent perlite and PFH-containing substrates. Non-parboiled fresh rice hulls produced organically contained a higher number of viable weed seeds than non-parboiled fresh rice hulls produced conventionally. No weed seeds germinated in the PFH. `Better Boy' tomato, `Bonanza Yellow' marigold (Tagetes patula L. French M.), `Orbit Cardinal' geranium (Pelargonium ×hortorum L.H. Bailey), `Cooler Blush' vinca (Catharanthus roseus L.G. Don), `Dazzler Rose Star' impatiens (Impatiens walleriana Hook. f.), and `Bingo Azure' pansy (Viola ×wittrockiana Gams) were grown in sphagnum peat-based substrates containing perlite or PFH at 10%, 15%, 20%, 25%, 30%, 35%, or 40% (v/v). Dry root weights of vinca and geranium were not significantly different among plants grown in the substrates. Tomato plants grown in 10%, 15%, 25%, 30%, and 35% PFH had significantly higher dry root weights than those grown in equivalent perlite-containing substrates. Impatiens grown in 35% PFH had higher dry root weights than those grown in 35% perlite. Marigold grown in 20% perlite had higher dry root weights than those grown in 20% PFH. However, there were no significant differences in impatiens or marigold dry root weights among the remaining substrates containing equivalent amounts of PFH or perlite. Dry root weights of pansy grown in 10%, 20% 25%, 35%, and 40% perlite were not significantly different from those grown in equivalent PFH-containing substrates. Across substrates, root dry weights of impatiens, marigold, and pansy grown in perlite-containing substrates were not significantly different from those grown in PFH-containing substrates. No significant difference in dry shoot weights of vinca, geranium, impatiens, and marigold occurred between equivalent perlite and PFH-containing substrates. Tomato plants grown in 20% to 40% perlite had significantly higher dry shoot weights than those grown in equivalent PFH-containing substrates. However, dry shoot weights of tomato grown in 10% to 15% perlite were not significantly different from those grown in equivalent PFH-containing substrates. Dry shoot weights of pansy grown in 10%, 25%, 30%, 35%, and 40% perlite were not significantly different from those grown in equivalent PFH substrates.

scholarly journals 483 PB 134 PHYSICAL ANALYSIS OF FRESH AND AGED RICE HULLS USED AS A PEAT MOSS SUBSTITUTE IN GREENHOUSE MEDIA

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 501c-501 ◽  
Author(s):  
Shelly D. Dueitt ◽  
Steven E. Newman
Keyword(s):  
Bulk Density ◽  
Crop Production ◽  
Pore Space ◽  
Peat Moss ◽  
Production Cycle ◽  
Physical Analysis ◽  
Rice Hulls ◽  
Sphagnum Peat ◽  
Sphagnum Peat Moss ◽  
Rice Milling

Rice hulls, a by-product of the rice milling process, were used at various rates to substitute sphagnum peat moss in greenhouse media. Previous studies demonstrated that media containing rice hulls replacing the vermiculite fraction grew plants equal to or better than traditional peat vermiculite blends. The objective of this study was to determine if rice hulls can replace sphagnum peat moss in a greenhouse medium. Physical properties, including bulk density, total pore space, and water retention were determined in media blended with fresh or aged rice hulls, sphagnum peat moss, and vermiculite. The bulk density of the media increased with increasing levels of fresh rice hulls. The pore space in media containing both fresh and aged rice hulls decreased over time during the crop production cycle and the pH increased.

scholarly journals Physical Properties of Ground Parboiled Fresh Rice Hulls Used as a Horticultural Root Substrate

HortScience ◽  
2010 ◽  
Vol 45 (4) ◽  
pp. 643-649 ◽  
Author(s):  
Johann S. Buck ◽  
Michael R. Evans
Keyword(s):  
Physical Properties ◽  
Particle Density ◽  
Pore Space ◽  
Pine Bark ◽  
Rice Hull ◽  
Hammer Mill ◽  
Parboiled Rice ◽  
Greenhouse Crops ◽  
Rice Hulls ◽  
Water Holding

Fresh parboiled rice hulls ground in a hammer mill and screened through a 1.18-mm screen and collected on a 0.18-mm screen (RH3) and particles with a specific diameter of 0.5 to 1.0 mm had total pore space (TPS), air-filled pore space (AFP), and water-holding capacity (WHC) similar to that of Canadian sphagnum peat (peat). However, RH3 had more available water, a higher bulk density (BD), and a higher particle density (PD) than peat. When blended with 20% to 40% perlite or 1 cm aged pine bark, RH3-based substrates had lower TPS, similar AFP, and lower WHC than equivalent peat-based substrates. The RH3-containing substrates had higher BD and average PD than equivalent peat-based substrates. When blended with parboiled rice hulls (PBH), RH3-based substrates had lower TPS than equivalent peat-based substrates. When blended with 20% to 40% PBH, RH3-based substrates had lower AFP than equivalent peat-based substrates. RH3-based substrates containing up to 20% PBH had lower WHC than equivalent peat-based substrates. RH3-based substrates containing 40% PBH had a higher WHC than equivalent peat-based substrates. When blended with PBH, all RH3-based substrates had higher BD and average PD than equivalent peat-based substrates. The addition of 40% RH3 to a peat-based substrate containing 20% perlite decreased substrate TPS, whereas the addition of 10% to 40% decreased AFP. The addition of 10% to 30% RH3 increased WHC. The addition of 30% RH3 to a peat-based substrate containing 20% 1 cm aged pine bark decreased substrate TPS and the addition of 20% to 40% RH3 decreased AFP. The addition of 10% RH3 increased WHC, but the addition of 20% or more RH3 did not affect WHC. The addition of 30% RH3 increased the BD, but the addition of RH3 had no effect on average PD. The addition of 20% or more and 30% or more RH3 to a peat-based substrate containing 20% PBH decreased substrate TPS and AFP, respectively. The addition 20% RH3 decreased WHC. The addition of 10% to 40% RH3 increased BD. Overall, RH3 was the ground rice hull product that had physical properties most similar to peat. Peat-based substrates in which up to 40% of the peat was replaced with RH3 had physical properties that, although different from peat controls, were within commonly recommended ranges for substrates used to grow greenhouse crops.

scholarly journals Growth of Bedding Plants in Sphagnum Peat and Coir Dust-Based Substrates

1996 ◽  
Vol 14 (4) ◽  
pp. 187-190 ◽  
Author(s):  
Michael R. Evans ◽  
Robert H. Stamps
Keyword(s):  
Bulk Density ◽  
Pore Space ◽  
Fresh Weight ◽  
Axillary Shoots ◽  
Bedding Plants ◽  
Sphagnum Peat ◽  
Bright Yellow ◽  
Water Filled Pore Space ◽  
Coir Dust ◽  
Water Holding

Abstract Water-holding capacity of substrates increased as the proportion of sphagnum peat and coir increased, and coir-based substrates had greater water-holding capacities than comparable peat-based substrates. There were no significant differences between coir and peat-based substrates with respect to bulk density, percent pore space and percent solids. Air-filled pore space and water-filled pore space decreased and increased, respectively, as the proportion of peat and coir increased. ‘Pink Elite’ geranium plants grown in coir-based substrates had greater root fresh weights than those grown in sphagnum-peat based substrates. Greatest root fresh weight occurred in an 80% coir and 20% perlite substrate. Days to flower, height, shoot fresh weight and number of axillary shoots were not significantly different between substrates. ‘Janie Bright Yellow’ marigold and ‘Blue Lace Carpet’ petunia plants had increased heights and shoot fresh weights when grown in coir-based substrates as compared with sphagnum peat-based substrates. Greatest heights and shoot fresh weights of petunia and marigold occurred in an 80% coir and 20% perlite substrate. Days to flower were reduced for marigold plants grown in coir-based substrates.

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