scholarly journals Desorption Kinetics of Legacy Soil Phosphorus: Implications for Non-Point Transport and Plant Uptake

Soil Systems ◽  
2022 ◽  
Vol 6 (1) ◽  
pp. 6
Author(s):  
Chad J. Penn ◽  
Mark R. Williams ◽  
James Camberato ◽  
Nicholas Wenos ◽  
Hope Wason
Keyword(s):  
Plant Uptake ◽  
Soil Phosphorus ◽  
Desorption Kinetics ◽  
Flow Rates ◽  
Soil P ◽  
First Order Kinetics ◽  
Flow Through ◽  
Kinetics Of ◽  
P Desorption ◽  
Solution Volume

Soil phosphorus (P) solubility and kinetics partly control dissolved P losses to surface water and uptake by plants. While previous studies have focused on batch techniques for measuring soil P desorption kinetics, flow-through techniques are more realistic because they simulate P removal from the system, akin to runoff, leaching, and plant uptake. The objectives were to measure soil P desorption by a flow-through technique at two flow rates and several batch methods, and utilize both for understanding how flow rate impacts the thermodynamics and kinetics of soil P desorption. Desorption obeyed first-order kinetics in two different phases: an initial rapid desorption phase followed by a gradual release. Desorption was limited by equilibrium and the kinetics of physical processes as demonstrated by an interruption test. Dilution-promoted desorption occurred with increasing cumulative volume, which increased desorption rate via first-order kinetics. The batch tests that simulated cumulative solution volume and time of flow-through were similar to the flow-through results; however, the batch methods overestimated the desorption rates due to less limitations to diffusion. Fast flow rates desorbed less P, but at a greater speed than slow flow rates. The differences were due to contact time, cumulative time, and solution volume, which ultimately controlled the potential for chemical reactions to be realized through physical processes. The interaction between these processes will control the quantity and rate of desorption that buffer P in non-point drainage losses and plant uptake.

EFFECTS OF SOIL TEMPERATURE ON PHOSPHORUS EXTRACTABILITY. II. SOIL PHOSPHORUS IN SIX CARBONATED AND SIX NON-CARBONATED SOILS

1984 ◽  
Vol 64 (2) ◽  
pp. 255-263 ◽  
Author(s):  
S. C. SHEPPARD ◽  
G. J. RACZ
Keyword(s):  
Root Growth ◽  
Soil Temperature ◽  
Plant Uptake ◽  
Soil Phosphorus ◽  
P Uptake ◽  
Effect Of Temperature ◽  
Soil P ◽  
Desorption Curve ◽  
Labile Pool ◽  
Response To Temperature

The change in the extractability of soil phosphorus (P) in response to temperature was examined in 12 Manitoba soils. These soils varied in carbonate and P contents. The soil P was labelled with 32P to facilitate measurements. Sodium bicarbonate extractions, anion exchange resin extractions, P desorption curves and short-term plant uptake using wheat were used to measure P extractability. An increase in soil temperature increased the extractability of P. This was apparent for P extracted by NaHCO3 only in soils low in P. The P extracted by resin appeared to respond similarly but was quite variable. Effects of temperature on the desorption curve parameters were significant only in soils high in P. The latter may reflect the detection limits for P using the desorption curve extraction system. Plant uptake was closely correlated to root growth. Both increased markedly as temperature increased. However, in certain soils the increase in P uptake due to temperature was far greater than the corresponding increase in root growth. The estimates of the labile pool accessed by plants increased as temperature increased. The principle hypothesis, that the effect of temperature on P extractability changed from soil to soil, was confirmed. The only controlling soil factor that could be identified was the basic soil P content. Key words: Temperature, soil phosphorus, carbonated, non-carbonated, plant uptake, wheat

Comparison of H2 Desorption Kinetics from Si(111)7×7 and Si(100)2×l

1990 ◽  
Vol 204 ◽  
Author(s):  
M. L. Wise ◽  
B. G. Koehler ◽  
P. Gupta ◽  
P. A. Coon ◽  
S. M. George
Keyword(s):  
Activation Energy ◽  
Preexponential Factor ◽  
Desorption Kinetics ◽  
Bond Energies ◽  
First Order ◽  
First Order Kinetics ◽  
Upper Limits ◽  
Desorption Activation Energy ◽  
Temperature Programmed ◽  
Kinetics Of

ABSTRACTThe desorption kinetics of hydrogen from the β1 H2 -TPD state on Si(111)7×7 and Si(100)2×l were studied using laser-induced thermal desorption (LITD) and temperature programmed desorption (TPD) techniques. Isothermal LITD studies of H2 desorption from Si(111)7×7 revealed second-order kinetics with a desorption activation energy of Ed = 62 ±4 kcal/mol and a preexponential factor of Vd = 92 ±10 cm2 /s. In contrast, H2 desorption from Si(100)2×l revealed first-order kinetics with an activation energy of Ed = 58 ±2 kcal/mol and a preexponential factor of Vd = 5.5 ±0.5 × 1015 s−1. The desorption kinetics yield similar upper limits for the Si-H bond energies but different desorption mechanisms on Si(lll)7×7 and Si(100)2×l.

Competitive Pairing and the Chemistry of Coadsorbed Hydrogen and Halogens on Ge(100)

1992 ◽  
Vol 282 ◽  
Author(s):  
Yuemei L. Yang ◽  
Stephen M. Cohen ◽  
Mark P. D'Evelyn
Keyword(s):  
Epitaxial Growth ◽  
Atomic Layer ◽  
Temperature Programmed Desorption ◽  
Model System ◽  
Atomic Layer Epitaxy ◽  
Desorption Kinetics ◽  
First Order ◽  
First Order Kinetics ◽  
Temperature Programmed ◽  
Kinetics Of

ABSTRACTThe chemistry of coadsorbed H and X (X=C1, Br) on semiconductor surfaces is important in epitaxial growth of silicon from chlorosilanes and of SixGe1−x alloys, in hydrogenating/ halogenating cycles in atomic layer epitaxy, and also provides an interesting model system, yet has received little attention to date. We have investigated the interaction of HC1 and HBr with Ge(100) by temperature-programmed desorption, and find that H2, HCl and HBr each desorb with near-first-order kinetics near 570–590 K and that GeCl2 and GeBr2 desorb with near-second-order kinetics near 675 K and 710 K, respectively. Analysis of the desorption kinetics of H2 and HX provides evidence that adsorbed H and X atoms pair preferentially in a qualitatively similar way as H atoms adsorbed alone on Ge(100)2×1 or Si(100)2×1 and that pairing of H+X occurs in competition with pairing of H+H.

Kinetics of E-glass Fibres Leaching in Borate Solution and Distilled Water

2008 ◽  
Vol 39-40 ◽  
pp. 355-358 ◽  
Author(s):  
Lucia Mišíková ◽  
Marek Liška
Keyword(s):  
Activation Energies ◽  
Distilled Water ◽  
Flow Rates ◽  
Potassium Borate ◽  
Glass Fibres ◽  
Time Dependencies ◽  
Leaching Experiments ◽  
Flow Through ◽  
Kinetics Of ◽  
Borate Solution

Flow – through leaching experiments have been conducted on E – glass fibres in distilled water and buffered potassium borate solution at temperatures 50, 70 and 90°C and at flow rates 8, 16 and 32 ml/hour. Time dependencies of normalized amount of leached elements in corrosive solutions have been determined. Values of stationary leaching rates were calculated and values of activation energies were found.

Improved Plant Diversity as a Strategy to Increase Available Soil Phosphorus

2019 ◽  
Vol 103 (1) ◽  
pp. 43-45 ◽  
Author(s):  
Carlos Crusciol ◽  
João Rigon ◽  
Juliano Calonego ◽  
Rogério Soratto
Keyword(s):  
Crop Yields ◽  
Soil Phosphorus ◽  
Cropping System ◽  
P Availability ◽  
P Fractions ◽  
Crop Species ◽  
Soil P ◽  
Residue Decomposition ◽  
Available Soil Phosphorus ◽  
Crop Residue Decomposition

Some crop species could be used inside a cropping system as part of a strategy to increase soil P availability due to their capacity to recycle P and shift the equilibrium between soil P fractions to benefit the main crop. The release of P by crop residue decomposition, and mobilization and uptake of otherwise recalcitrant P are important mechanisms capable of increasing P availability and crop yields.

Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methyl Orange ◽  
Solution Ph ◽  
Vanadium Concentration ◽  
Limiting Behavior ◽  
First Order ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetic Pattern ◽  
Triton X ◽  
Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH < 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

Desorption Kinetics of Cadmium and Lead from Goethite

2002 ◽  
Vol 66 (3) ◽  
pp. 797 ◽  
Author(s):  
Leslie J. Glover ◽  
Matthew J. Eick ◽  
Patrick V. Brady
Keyword(s):  
Desorption Kinetics ◽  
Cadmium And Lead ◽  
Kinetics Of

Evaluation of DGT and DGT-PROFS modeling approach to estimate desorption kinetics of Cs in soils

2021 ◽  
Vol 235-236 ◽  
pp. 106646
Author(s):  
P. Ciffroy ◽  
L. Carasco ◽  
D. Orjollet ◽  
C. Simonucci ◽  
L. Février
Keyword(s):  
Desorption Kinetics ◽  
Modeling Approach ◽  
Kinetics Of

scholarly journals Analysis of Performance of the Wind-Driven Pulverizing Aerator Based on Average Wind Speeds in the Conditions of Góreckie Lake

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2796
Author(s):  
Andrzej Osuch ◽  
Ewa Osuch ◽  
Stanisław Podsiadłowski ◽  
Piotr Rybacki
Keyword(s):  
Mathematical Model ◽  
Wind Speed ◽  
Water Pump ◽  
Average Wind Speed ◽  
Flow Rates ◽  
Wind Speeds ◽  
Average Wind ◽  
Flow Through ◽  
Analysis Of Performance ◽  
Research Period

In the introduction to this paper, the characteristics of Góreckie lake and the construction and operation of the wind-driven pulverizing aerator are presented. The purpose of this manuscript is to determine the efficiency of the pulverizing aerator unit in the windy conditions of Góreckie Lake. The efficiency of the pulverization aerator depends on the wind conditions at the lake. It was necessary to conduct thorough research to determine the efficiency of water flow through the pulverization segment (water pump). It was necessary to determine the rotational speed of the paddle wheel, which depended on the average wind speed. Throughout the research period, measurements of hourly average wind speed were carried out. It was possible to determine the efficiency of the machine by developing a dedicated mathematical model. The latest method was used in the research, consisting of determining the theoretical volumetric flow rates of water in the pulverizing aerator unit, based on average hourly wind speeds. Pulverization efficiency under the conditions of Góreckie Lake was determined based on 6600 average wind speeds for spring, summer and autumn, 2018. Based on the model, the theoretical efficiency of the machine was calculated, which, under the conditions of Góreckie Lake, amounted to 75,000 m3 per year.

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