scholarly journals Effect of drainage layers on water retention of potting media in containers.

2021 ◽  
Author(s):  
Avery Rowe
Keyword(s):  
Water Retention ◽  
Coarse Sand ◽  
Organic Media ◽  
Particle Sizes ◽  
Drainage Layer ◽  
Drainage Layers ◽  
Potting Media ◽  
Effective Drainage ◽  
Almost All ◽  
Reduced Water

Abstract Excess water retention in the potting medium is a significant problem for plants grown in containers due to the volume of saturated medium which forms above the drainage hole. Adding a layer of coarse material like gravel or sand at the bottom is a common practice among gardeners with the aim of improving drainage, but some researchers have argued that such layers will raise the saturated area and in fact worsen drainage. Two different depths and four different materials of drainage layer were tested with three different potting media to determine the water retention in the container after saturating and draining freely. For loamless organic media, almost all types of drainage layer reduced overall water retention in the container compared to controls. For loam-based media, most drainage layers had no effect on the overall water retention. Two simple models were also used to estimate the water retention in the media alone, excluding the drainage layer itself. All drainage layers reduced water retention of loamless organic media, according to both models. There was disagreement between the two models applied to loam-based media, and further study is required to determine the most accurate. Both models showed that some drainage layers with smaller particle sizes reduced water retention in loam-based media, but disagreed on the effect of drainage layers with larger particle sizes. Overall, any drainage layer was likely to reduce water retention of any medium, and almost never increased it. Thicker drainage layers were more effective than thinner layers, with the most effective substrate depending on the potting media used. A 60 mm layer of coarse sand was the most universally-effective drainage layer with all potting media tested.

scholarly journals Wetting Characteristics of Different Peat and Peat: Bark-based Potting Media: Influence of Wetting Agents in Improving Wetting and Rewetting Performance

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 583f-584
Author(s):  
Santakumari Mane ◽  
James A. Turner
Keyword(s):  
Water Retention ◽  
Unit Volume ◽  
Initial Moisture Content ◽  
Wetting Agent ◽  
Media Composition ◽  
Potting Media ◽  
The Media ◽  
Wetting Agents ◽  
Reduced Water ◽  
Agent Treatment

Eight different peat-based or peat: bark-based potting media were evaluated for their wetting performance when treated with the media wetting agent AquaGro 2000 (2–5 oz/yd3). Upon initial irrigation, no differences in wetting uniformity were observed in seven of the eight test media regardless of their media wetting agent treatments. In four media, water retention was reduced by media wetting agent treatment, however, uniform distribution of water was achieved. AquaGro 2000 improved uniformity of initial wetting in one medium in which the initial moisture content was 6.5%. Uniformity of wetting and water retention improved with increasing wetting agent rate. All media were allowed to air dry and then were re-irrigated. Wetting agent-treated media rewet uniformly, while rewetting varied greatly in untreated media (7.5%–82.5%). Less than 50% of the mass of untreated media wet subsequent to drying. Those portions of the untreated media that did wet retained up to three times more water per unit volume compared to AquaGro 2000-treated media. AquaGro 2000 enhanced uniformity of rewetting, reduced water logging, and improved drainage at all rates (2–5 oz/yd3) tested. Media composition (peat vs. peat: bark did not affect wetting agent efficacy.

Detection of oomycide-insensitive Phytophthora isolates in Maryland ornamental nurseries and Mid-Atlantic landscapes provide data for reconsidering management strategies

2021 ◽  
Author(s):  
Justine Beaulieu ◽  
Johanna Del Castillo Munera ◽  
Yilmaz Balci
Keyword(s):  
Growth Rate ◽  
Mycelial Growth ◽  
Management Strategies ◽  
Resistance Management ◽  
Phytophthora Species ◽  
Oak Forests ◽  
Relative Growth ◽  
Off Label ◽  
Potting Media ◽  
Almost All

Five Phytophthora species comprising a total of 243 isolates (77 P. cinnamomi, 23 P. citrophthora, 18 P. multivora, 18 P. pini, and 107 P. plurivora) were screened for sensitivity to mefenoxam, fosetyl-Al, dimethomorph, dimethomorph + ametoctradin and fluoxastrobin using amended agar assays. Mefenoxam-insensitive isolates were detected within P. cinnamomi (4%), P. multivora (11%), and P. plurivora (12%) even at approximately 2.5x the recommended label rate. These isolates were also insensitive to higher (off-label) concentrations of fluoxastrobin. Concentrations of dimethomorph (400 g/mL) and dimethomorph + ametoctradin (100 g/mL) were mostly effective in mycelial growth inhibition, but two P. plurivora isolates were insensitive, suggesting that resistance management is required. All mefenoxam-insensitive isolates were sensitive to fosetyl-Al at the label rate. Surprisingly, the populations of P. cinnamomi from mid-Atlantic oak forests included insensitive isolates. With almost all species, isolates recovered from asymptomatic hosts (e.g., soil/potting media collected of randomly selected asymptomatic hosts) had a significantly greater relative growth rate when compared to isolates recovered from symptomatic hosts (e.g., isolates recovered from lesions or wilted plants). These findings suggest that mefenoxam should no longer be used to manage oomycetes in Maryland ornamental nurseries and that the use of fluoxastrobin should be limited.

scholarly journals The Characteristics of Swelling Pressure for Superabsorbent Polymer and Soil Mixtures

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5071
Author(s):  
Jakub Misiewicz ◽  
Arkadiusz Głogowski ◽  
Krzysztof Lejcuś ◽  
Daria Marczak
Keyword(s):  
Soil Structure ◽  
Water Retention ◽  
Swelling Pressure ◽  
Coarse Sand ◽  
Loamy Sand ◽  
Superabsorbent Polymer ◽  
Soil Water Retention ◽  
Proposed Model ◽  
Soil Mixtures ◽  
Time Required

Superabsorbent polymers (SAPs) are used in agriculture and environmental engineering to increase soil water retention. Under such conditions, the swelling pressure of the SAP in soil affects water absorption by SAP, and soil structure. The paper presents the results of swelling pressure of three cross-linked copolymers of acrylamide and potassium acrylate mixed at the ratios of 0.3%, 0.5% and 1.0% with coarse sand and loamy sand. The highest values of swelling pressure were obtained for the 1% proportion, for coarse sand (79.53 kPa) and loamy sand (78.23 kPa). The time required to reach 90% of swelling pressure for each type of SAP differs. Samples of coarse sand mixed with SAP K2 in all concentrations reached 90% of total swelling pressure in 100 min, while the loamy sand mixtures needed only about 60 min. The results were the basis for developing a model for swelling pressure of the superabsorbent and soil mixtures, which is a fully stochastic model. The conducted research demonstrated that the course of pressure increase depends on the available pore capacity and the grain size distribution of SAPs. The obtained results and the proposed model may be applied everywhere where mixtures of SAPs and soils are used to improve plant vegetation conditions.

Design of a hierarchically structured hybrid material via in situ assembly of a silica aerogel into a wood cellular structure

RSC Advances ◽  
2016 ◽  
Vol 6 (67) ◽  
pp. 62825-62832 ◽  
Author(s):  
M. Sedighi Gilani ◽  
S. Zhao ◽  
S. Gaan ◽  
M. M. Koebel ◽  
T. Zimmermann
Keyword(s):  
Thermal Conductivity ◽  
Hybrid Material ◽  
Dimensional Stability ◽  
Silica Aerogel ◽  
Cellular Structure ◽  
Water Retention ◽  
Heat Of Combustion ◽  
Structure Modification ◽  
Reduced Water

We present a route for incorporation of silica aerogel into wood cellular structure. Modification results in an improved dimensional stability and reduced water retention of the material, with lower thermal conductivity and total heat of combustion.

scholarly journals Study on drainage layer strategy for improving performance of glass fibrous coalescing filter

2020 ◽  
Author(s):  
chengwei xu ◽  
chenglong xiao ◽  
Yan yu ◽  
xiaodong si
Keyword(s):  
Pressure Drop ◽  
Pore Size ◽  
High Efficiency ◽  
Size Difference ◽  
Drainage Layer ◽  
Filtration Performance ◽  
Fibrous Filters ◽  
Drainage Layers ◽  
Commercial Glass ◽  
Positive Effect

The drainage layer strategy is a common method for improving filtration performance of coalescing filter. In this study, using the commercial glass fibrous filters, the influence of sub-high efficiency drainage layers on high efficiency coalescing filters were investigated experimentally. The efficiency of coalescing filter slight increases, whereas the total wet pressure drop reduces 0.32 kPa after assembling drainage layer. In addition, the influence of pore size, thickness and wettability on performance were evaluated. While the pore size of drainage layer decrease, the wet pressure drop reduces and quality factor increase. Likewise, the thickness of drainage layer also has positive effect on filtration performance. By contrast, the wettability has a weak affect on the filtration performance. As different coalescing filter with the same drainage layer, the improvement in the filtration performance increase with the decrease of pore size difference between the coalescing and drainage layers.

scholarly journals Clinical study of necrotizing fasciitis and its management

2017 ◽  
Vol 4 (6) ◽  
pp. 1964
Author(s):  
Archana Shukla ◽  
Ashish Sharma
Keyword(s):  
Necrotizing Fasciitis ◽  
Successful Management ◽  
Predisposing Factor ◽  
E Coli ◽  
Medical College ◽  
Short Period ◽  
Skin Erythema ◽  
Effective Drainage ◽  
Gandhi Medical College ◽  
Almost All

Background: Necrotizing fasciitis is a severe flesh-eating disease of soft tissue infection. It is characterized by widespread infection of the fascia with necrosis. It may lead to MODS and shock in a very short period of time. In this study we have evaluated the predisposing factors, clinical manifestation and different modalities of investigation which helps in management of this near fatal disease.Methods: This study was conducted in Department of Surgery, Gandhi Medical College, Bhopal, Madhya Pradesh, India for 3 years (October 2013-September 2016). A total of 107 patients having necrotising fasciitis were admitted in this period. The diagnosis was confirmed by detailed history and physical examination followed by haematological, microbiological and radiological investigations priority wise. After initial resuscitation patients were taken to OT where debridement of dead necrotic tissue was done, laying open of deeper planes with proper and effective drainage of pus. Most of the dressings used were silver sulfadiazine or iodine depending upon the sensitivity to sulpha group.Results: Diabetes mellitus was the most common predisposing factor (65.4%) followed by trauma (28%). Perineum and thigh were the most commonly affected site (70%). Most of the patients (84%) presented with skin erythema and blistering. Fever and tachycardia were seen in almost all the patients (95%). Leukocytosis and neutrophilia were seen in 91.5%. Most common organisms isolated were E. coli and proteus. Mortality rate was 24.29%.Conclusions: Necrotizing fasciitis is a flesh eating, highly lethal disease. Early diagnosis, early and radical surgical debridement supported by appropriate antibiotic and correction of metabolic disorder are the cornerstones of successful management.

scholarly journals Assessment methodology of backwash in pressurized sand filters

2016 ◽  
Vol 20 (7) ◽  
pp. 600-605 ◽  
Author(s):  
Fábio P. de Deus ◽  
Roberto Testezlaf ◽  
Marcio Mesquita
Keyword(s):  
Coarse Sand ◽  
Sand Particle ◽  
Particle Sizes ◽  
Assessment Methodology ◽  
Cleaning Efficiency ◽  
Sand Filters ◽  
Bed Height ◽  
Practical Tool ◽  
Filter Bed

ABSTRACT The objective of this study was to apply a methodology based on sampling sand from contaminated filter beds, to evaluate the performance of the backwash process in pressurized sand filters used in irrigation. Backwash trials were conducted in an experimental module with three new sand filters of the same commercial model. The evaluations were conducted after filtration processes performed using four filtration rates and three separate sand particle sizes (fine - 0.55 mm; medium - 0.77 mm, and coarse sand - 1.04 mm diameter), repeated in three subsequent cycles. After reaching a fixed expansion of 25% of the filter bed height, the backwash processes were performed for 15 min. Backwash cleaning efficiency was evaluated in all trials based on the mass of removed solids for different filter bed layers and throughout the entire filter bed. The backwash assessment methodology is effective and has potential to be a practical tool for farmers in the evaluation of the performance of pressurized sand filters used in irrigation.

scholarly journals Seepage Analysis of a Multilayer Waste Slope considering the Spatial and Temporal Domains of Permeability

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Rong Yang ◽  
Zengguang Xu ◽  
Junrui Chai
Keyword(s):  
Distribution Curve ◽  
Numerical Models ◽  
Vertical Direction ◽  
Seepage Analysis ◽  
Drainage Layer ◽  
Finite Element Software ◽  
Pore Pressures ◽  
Two Factors ◽  
Drainage Layers ◽  
Waste Degradation

Landfilled municipal solid waste has evident heterogeneity, and clogging of the drainage layer can easily happen during operation of the landfill. These two factors significantly influence the distribution of leachate in a landfill. Herein, the distribution of waste permeability in the spatial and temporal domains was analyzed. Then, changes to the drainage-layer permeability in the temporal domain were fitted to these data. A simple model of multilayer waste slope was established combining the finite element software and a user subroutine. Herewith, changes of permeability in the waste and drainage layers were simulated, such that the heterogeneity of waste and the process of clogging of the drainage layer could be simulated. Then, the leachate distributions and transport conditions of nine schemes for landfill were analyzed. The results indicated that the distribution curve of waste-saturated permeability follows a logarithmic relation in the vertical direction, and the distribution curve of fresh-waste-saturated permeability follows a polynomial relation in time. After each landfill is worked for a few years, the drainage layer always encounters clogging problems of some kind and its permeability decreases by one to five orders of magnitude. Through numerical models, the simulation results of the permeability distribution in the spatial and temporal domains were found satisfactory. When the permeability distributions were layered in the buried depth, pore pressures and leachate levels are smaller than the logarithmic distributions. During the process of degradation, the pore pressures and leachate levels are increased slightly under the consideration of the polynomial distribution of waste permeability in time. With clogging of the permeability of the drainage layer, the pore pressures and leachate levels of landfill were found to be increasing gradually. To obtain results closer to that of actual situations, corresponding models should be established and analyzed based on a range of permeability, waste degradation rate, and degree of clogging.

The Relationship Between Colliery-waste Particle Sizes and Plant Growth

1974 ◽  
Vol 1 (4) ◽  
pp. 281-284 ◽  
Author(s):  
Christopher G. Down
Keyword(s):  
Particle Size ◽  
Plant Growth ◽  
Water Retention ◽  
Size Range ◽  
Growth Period ◽  
Dry Weight ◽  
Particle Sizes ◽  
Small Particles ◽  
The Relationship ◽  
Water Holding

Seed germination and dry-weight production in Lolium perenne were examined in relation to growth on 12-years-old colliery waste separated into seven size-fractions. The size-range was from more than 4,000 μ to less than 125 μ, and the growth period was up to 30 days. Germination percentages after 6 days generally increased with decreasing particle-size, as did dry-weight. Shoot : root ratios also showed an inverse relationship with particle size.After 30 days there was no distinction between dryweights on different particle sizes, except that on the largest fractions it had been found impossible to keep the plants alive. Problems of water-holding capacity are discussed, and the significance of soil particle-size in revegetation work is examined, it being concluded that an admixture of small particles is important for water retention and plant growth.

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