Evaluation of soil phosphate buffering indices

Soil Research ◽  
1979 ◽  
Vol 17 (3) ◽  
pp. 495 ◽  
Author(s):  
ICR Holford
Keyword(s):  
Phosphorus Uptake ◽  
Equilibrium Concentration ◽  
Solution Concentration ◽  
Parent Material ◽  
Heterogeneous Group ◽  
Homogeneous Group ◽  
Soil Phosphate ◽  
Simple Index ◽  
Natural Solution ◽  
Additional Variance

Seven phosphate buffering indices were evaluated by determining the additional variance accounted for when each index was added to a regression of plant phosphorus uptake on labile soil phosphate. The study was done on two groups of soils: one relatively homogeneous group of 24 soils all formed on the same parent material, and a heterogeneous group of 30 soils formed on a variety of parent materials. A separate pot experiment was done on each group, ryegrass being grown on the homogeneous soils and white clover on the heterogeneous soils. Only two indices did not account for a large and significant increase in variance in phosphate uptake. The extra variance accounted for was much greater in the heterogeneous group than in the homogeneous group, although the total variance accounted for by both variables was greater in the homogeneous group. The much smaller volume of soil used in the ryegrass experiment may explain the smaller buffering effect in the homogeneous soils. The three most effective and consistent indices were a simple index of the maximum buffer capacity, determined from the Langmuir isotherm over a standard range of equilibrium solution concentrations, the slope of the isotherm at the natural solution concentration, and the amount of adsorption at a standard equilibrium concentration of 0.3 pg phosphorus/ml.

P5612In vivo histological and clinical evaluation of layered culprit plaque by optical coherence tomography in stable angina patients

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
H Okamoto ◽  
T Kume ◽  
R Yamada ◽  
Y Neishi ◽  
S Uemura
Keyword(s):  
Clinical Study ◽  
Stable Angina ◽  
Histological Study ◽  
Heterogeneous Group ◽  
Homogeneous Group ◽  
Histological Evaluation ◽  
Plaque Progression ◽  
Culprit Lesion ◽  
Histological Features ◽  
Layered Pattern

Abstract Background In patients with stable angina pectoris (SAP), exact mechanism of plaque progression overtime is still unclear due to lack of histological evaluation. Directional coronary atherectomy (DCA) allows for the differential cutting of atherosclerotic lesions and for the histological examination. Purpose The aims of this study were to compare the histological features obtained by DCA and layered pattern (LP) by OCT, and to establish the prevalence and clinical characteristics of LP in culprit lesion form SAP patients. Methods SAP patients who underwent OCT imaging guide PCI in our medical school hospital between June 2016 and June 2018 were included into this study. This was two-fold histological and clinical studies. In a histological study, we evaluated histological features of 42 specimens from 18 patients who underwent DCA and compare OCT findings. Lesions were classified into the following categories based on the OCT finding before DCA cutting; homogeneous or heterogeneous group. Furthermore, lesions in heterogeneous group were classified into 2 categories; LP or non-LP group. In a clinical study, 205 target lesions form 205 patients were categorized as shown above at minimum lumen area (MLA) sites. Plaque characteristics were compared among these groups. Results In the histological study, 9 (21.4%) specimens were classified in homogeneous group and 33 (78.6%) in heterogeneous group. In 33 heterogeneous group, LP group were observed in 12 specimens (36.3%). Of 12 LP group, 10 LP group consisted of intramural thrombosis. In clinical study, 39 (19.0%) lesion were classified in homogeneous group and 166 (81.0%) in heterogeneous group. In 166 heterogeneous group, LP group were observed in 75 lesions (45.2%). Of heterogeneous group, LP group had significantly smaller MLA (1.5±0.9 mm2 vs 1.9±1.0 mm2, p<0.05) and higher rate of microchannels (57.3% vs 15.4%, p<0.05) than non-LP group. A representative layered pattern case Conclusions LP in culprit lesion with SAP was significantly associated with intramural thrombosis. MLA sites in LP was significantly smaller than in non-LP group. These data suggest that thrombus formation and subsequent their organization overtime might contribute to the plaque progression even in SAP patients.

An assessment of the depletion technique for comparative measurement of phosphorus uptake in plants

1987 ◽  
Vol 38 (2) ◽  
pp. 263 ◽  
Author(s):  
KD McLachlan ◽  
YH Kuang ◽  
WJ Muller
Keyword(s):  
Kinetic Parameters ◽  
Initial Rate ◽  
Phase 1 ◽  
Phosphorus Uptake ◽  
Subterranean Clover ◽  
Solution Concentration ◽  
Rate Of Change ◽  
Plant Performance ◽  
Depletion Curve ◽  
Kinetics Of

This paper examines the depletion of a standard 32P solution by 221 plants, either cereals or clovers, as a means of determining the recognized parameters, Vmax, Km and Cmin, in the kinetics of phosphorus uptake, and attempts to relate them to comparative phosphorus uptake by the plants, with a view to recognizing the more efficient ones.No single depletion curve was found. The data were grouped into six distinct curve types, based on the change in solution concentration (C) with time (t) and the rate of change in concentration (dC/dt) with concentration. The six types were part of one general curve which could be separated into 3 phases.In Phase 1, solution concentration was non-limiting, and plant performance was the principal determinant in depleting the solution. In the second and third phases, plant performance became progressively less dominant and the solution concentration more dominant in determining the concentration of the remaining solution.For comparative phosphorus uptake purposes, it is suggested that only the initial rate of uptake (Phase 1) is worth measuring and that this has attendant difficulties; the issue whether these kinetic parameters are real, or measurements of the model selected, is raised and discussed.No relation was found between these kinetic parameters and the efficiency of phosphorus use by subterranean clover plants grown in soil. Despite these practical shortcomings, variability in uptake capability between individual plants, even of the same line, was demonstrated. This plant variability offers a new area of plant nutrition for exploitation.

scholarly journals 256 Evaluation of Phosphate Desorption Characteristics of Clay Minerals for Soilless Root Media

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 486C-486
Author(s):  
Young-Mi Oh ◽  
Paul V. Nelson ◽  
Dean L. Hesterberg
Keyword(s):  
Clay Minerals ◽  
Soil Solution ◽  
Equilibrium Concentration ◽  
Solution Concentration ◽  
Reaction Chamber ◽  
Maximum Adsorption Capacity ◽  
Commercial Alumina ◽  
Root Media ◽  
Phosphate Leaching ◽  
Phosphate Desorption

Soilless root media retain very little phosphate. This characteristic necessitates continual application of phosphate, which leads to excessive application and leaching. The phosphate desorption characteristics of synthetic hematite (a-Fe2O3), goethite (a-FeOOH), allophane (Si3Al4O12*nH2O), and a commercial alumina (Al2O3), previously determined for their maximum adsorption capacities, were evaluated to determine their potential for providing a low, constant soil solution phosphate supply with low phosphate leaching from soilless root media. The desorption isotherms of the clay minerals were obtained by introducing 10 mM KCl solution at 0.2 ml/min flow rate into a stirred flow reaction chamber loaded with clay adsorbed with phosphate at maximum adsorption capacity. The suspension in the reaction chamber was held at pH 6.4 during desorption. Effluent solutions were collected for phosphorus analysis until the equilibrium concentration of phosphorus in solution reached 0.05 mg•L-1. Adsorbed phosphorus at 0.05 mg•L-1 equilibrium concentration in solution was in the order allophane (19 mg•g-1) > alumina™ goethite (8 mg•g-1) > hematite (1.3 mg•g-1). The equilibrium concentration of phosphorus in solution over time showed that allophane releases phosphate for a longer time than the other clay minerals at a desirable soil solution concentration for plants, less than 5 mg•L-1. Among the clay minerals tested, allophane showed the most favorable potential to supply phosphate to plants in soilless root media.

Effects of lime on the residual effectiveness of phosphate in acid soils

Soil Research ◽  
1989 ◽  
Vol 27 (2) ◽  
pp. 425
Keyword(s):  
Detrimental Effect ◽  
Phosphorus Uptake ◽  
Acid Soils ◽  
The Other ◽  
Soluble Phosphate ◽  
Acidic Soils ◽  
Soil Phosphate ◽  
Native Soil ◽  
Induced Changes ◽  
Residual Effectiveness

The effectiveness of phosphate, applied 9 months previously, was compared with that of freshly applied phosphate in relation to lime-induced changes in several phosphate characteristics of 14 phosphate-deficient, acidic soils. Effectiveness was measured in terms of the yield and phosphorus uptake of white clover herbage in a glasshouse experiment. Lime increased yields on the majority of soils, whether phosphate was applied or not. These were accompanied by increases in uptake of soil phosphate, which were usually associated with higher levels of exchangeable and soluble phosphate but not of sodium bicarbonate-extractable phosphate. On the other hand, lime had much more variable effects on the apparent uptake of fertilizer phosphate which were unrelated to lime-induced changes in soil phosphate sorptivity. Lime increased the uptake of previously applied phosphate in all but two soils, and it had a more beneficial or less detrimental effect on the uptake of old phosphate than of fresh phosphate in 9 of the 14 soils. Because lime usually increases the uptake of soil phosphate but often depresses the uptake and effectiveness of fertilizer phosphate, the more beneficial effect of lime on phosphate residues is consistent with their partial transformation into compositions resembling native soil phosphates.

Urban and Community Fisheries Programs: Development, Management, and Evaluation

2008 ◽  
Keyword(s):  
Urban Areas ◽  
Human Dimensions ◽  
Heterogeneous Group ◽  
Homogeneous Group ◽  
Recreational Activities ◽  
Development Management ◽  
Community Fisheries ◽  
Demographic Patterns

<em>Abstract.—</em>Fisheries managers may be better equipped to meet angler satisfaction if they understand why people fish and, more importantly, their expectations of the fishing experience. It is important to recognize that the angling population is not comprised of a single, homogeneous group, but is rather a heterogeneous group made up of numerous subgroups. Motivational characteristics of angler subgroups should not be used to generalize to the entire angling population. Experiences that anglers seek from fishing can be divided into those that are activity-specific (unique to fishing) and activity-general (common to all outdoor recreational activities). Fisheries managers have emphasized activity-specific over activity-general elements. A perception that agencies have limited control over activity-general elements may result from limited training in human dimensions, or because most managers feel catch-oriented elements are more important than noncatch, activity-general elements. In urban areas, fisheries managers are adapting to changing cultural and demographic patterns, which shape angler motivations and preferences.

Sorbed phosphate at standard supernatant concentration as an estimate of the phosphate needs of soils

1965 ◽  
Vol 5 (16) ◽  
pp. 52 ◽  
Author(s):  
RS Beckwith
Keyword(s):  
Sorption Capacity ◽  
Surface Soil ◽  
Equilibrium Concentration ◽  
Solution Concentration ◽  
Small Field ◽  
Surface Soils ◽  
Phosphate Sorption ◽  
Surface Horizon ◽  
Supernatant Solution

Phosphate sorption capacity of soils has meaning only if the equilibrium supernatant solution concentration is specified. Measurements have been made, on a variety of Queensland soils, at an equilibrium concentration of 0.2 p.p.m. P ; reasons for this choice of cencentration are discussed. Phosphate sorption values measured in this way appear to parallel the phosphate needs of legumes growing on a number of the soils examined in the laboratory. The approach is put forward for testing by others on present and future phosphate rate trials. Present phosphate sorption measurements are interpreted as indicating (1) that even where native phosphate is inadequate, or has been depleted by cropping, heavy-textured grey and brown soils of the brigalow lands will only require small field applications of superphosphate. (This statement may not apply to soils containing free carbonate in the surface). (2) that phosphate requirements of krasnozems vary considerably but may exceed 1 ton of superphosphate an acre in some areas. Loss of the surface horizon by erosion, or mixing the subsoil With surface soil, could increase the phosphate requirement of some of these soils. (3) that the phosphate status of soils formed from phyllite in the Gympie district is intermediate between these extremes. Here also the subsoils must be expected to have larger phosphate requirements than the surface soils.

Parliamentary Representation in Six European Right-Wing Sovereignist Parties: Resemblance or Innovation?

2021 ◽  
Author(s):  
Rossella Borri ◽  
Luca Verzichelli
Keyword(s):  
The Netherlands ◽  
Heterogeneous Group ◽  
Homogeneous Group ◽  
Right Wing ◽  
Extreme Right ◽  
National Sovereignty ◽  
The People ◽  
Extreme Right Parties

Abstract The appeal to the re-appropriation of national sovereignty has recently become the unifying trait of a heterogeneous group of right-wing parties. The underlying reasoning behind this claim is that globalised elites ignore the needs of the people—defined as a restricted and ethnically homogeneous group of natives—they are supposed to represent. After defining the perimeter of this party cluster, including populist, national conservatives and extreme-right parties, this article explores the extent to which the adoption of similar political platforms might also be reflected in a convergence of parliamentary party articulations. A qualitative account of the evolution of parliamentary representation in a few right-wing parties from Italy, Hungary and the Netherlands shows that a two-way street of institutionalisation might be at play in the complex balance between uncompromising grassroots components and a more pragmatic institutional component.

scholarly journals PHOSPHORUS UPTAKE BY SIX POTATO CULTIVARS

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 614d-614
Author(s):  
William B. Evans ◽  
Darryl D. Warncke
Keyword(s):  
Uptake Rate ◽  
Unit Length ◽  
Phosphorus Uptake ◽  
Solution Concentration ◽  
P Uptake ◽  
Solution Culture ◽  
Russet Burbank ◽  
Potato Cultivars ◽  
General Nature ◽  
P Concentration

Six potato cultivars (Atlantic, Sebago, Onaway, Russet Burbank, Lemhi Russet,and Norland) were evaluated for phosphorus uptake efficiency in solution culture. Individual rooted cuttings of each cultivar were transferred from a standard 1/5 Hoagland's solution into solutions containing one of six P concentrations (0.05,0.1,0.22,0.5,1.1 and 2.3mg/l). After a 24h adjustment period P uptake was followed over a 6h period by collecting solution aliquots every two hours. All cultivars depleted the two lowest initial P concentrations to similar stable P concentration. The P uptake rate per unit length of root showed a sigmoidal relationship to the initial P solution concentration. The general nature of the P uptake relation to solution P concentration was similar among the cultivars, although the actual values varied. In general, P uptake rate increased from 5.0 × 10-4 at the lowest concentration to 7.0 × 10-2μg·cm-1·h-1 at the highest P solution concentration.

scholarly journals DEPOSITIONAL BEHAVIOR OF FINE SEDIMENT IN A TURBULENT FLUID MOTION

1966 ◽  
Vol 1 (10) ◽  
pp. 40 ◽  
Author(s):  
Emmanuel Partheniadis ◽  
John F. Kennedy
Keyword(s):  
Initial Period ◽  
Fluid Motion ◽  
Particle Diameter ◽  
Equilibrium Concentration ◽  
Annular Channel ◽  
Sediment Concentration ◽  
Parent Material ◽  
Silty Clay ◽  
Initial Concentration ◽  
Average Shear

An experimental investigation, utilizing an apparatus consisting of a counterrotating annular channel and ring, of the depositional characteristics of fine, cohesive sediment revealed that after an initial period of rapid deposition, the sediment concentration approaches asymptotically an equilibrium value. The ratio of this equilibrium concentration to the initial concentration is nearly independent of initial concentration and for a given sediment and environment depends only on the flow conditions. For the three water depths investigated, the ratio of equilibrium to initial concentration was found to he a single function of an average shear stress around the channel-section perimeter. A comparison of the size distributions of the parent material with the material retained in suspension when equilibrium was achieved indicated that the greatest losses occur in the clay-size fractions, suggesting that the deposition is controlled predominantly by flocculation, and that the strength and size of the floes exert a stronger influence on the deposition than does the particle weight. A silty-clay sediment with a mean particle diameter of 0.0009 mm was used in all experiments.

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