RATE OF PYROPHOSPHATE HYDROLYSIS IN ORGANIC SOILS

1985 ◽  
Vol 65 (3) ◽  
pp. 497-506 ◽  
Author(s):  
L. E. PARENT ◽  
A. F. MacKENZIE
Keyword(s):  
Half Life ◽  
Organic Soil ◽  
Ash Content ◽  
Enzymatic Activities ◽  
Organic Soils ◽  
Pyrophosphatase Activity ◽  
Life Values ◽  
Highly Correlated ◽  
Pyrophosphate Hydrolysis ◽  
Humic Soil

Twenty-four organic soil materials were selected in order to study pyrophosphatase activity and pyrophosphate retention and hydrolysis. The activation energy of pyrophosphate hydrolysis was 22 kJ∙mol−1 for virgin fibric soil materials and 33 kJ∙mol−1 for cultivated humic soil materials. Phosphatase and pyrophosphatase activities were highly correlated (r = 0.947**) and were promoted apparently by non-specific enzymes. Enzymatic activities varied from 11.6 to 148.1 mmol∙kg−1∙(2 h)−1, and were higher in virgin than in cultivated soil materials. Soil retention increased with an increase in ash content (r = 0.876**) and was apparently weak, as noted by complete pyrophosphate hydrolysis after 4–8 days of incubation. Half-life values of pyrophosphate incubated at room temperture varied from 0.1 to 3.7 days, and were highly correlated with enzymatic activities and levels of nonretained pyrophosphate. A regression model, involving an interaction between pyrophosphatase activity and level of nonretained pyrophosphate, accounted for 77% of the variation in log of half-life values of pyrophosphate in organic soil materials. Key words: Pyrophosphatase, phosphatase, pyrophosphate, half-life values, pyrophosphate retention

RATE OF P UPTAKE BY ONIONS COMPARED WITH RATE OF PYROPHOSPHATE HYDROLYSIS IN ORGANIC SOILS

1985 ◽  
Vol 65 (4) ◽  
pp. 1091-1095 ◽  
Author(s):  
L. E. PARENT ◽  
A. F. MACKENZIE ◽  
Y. PERRON
Keyword(s):  
Half Life ◽  
Dry Matter ◽  
Phosphorus Uptake ◽  
P Uptake ◽  
Organic Soils ◽  
Matter Production ◽  
Allium Cepa L ◽  
Pyrophosphatase Activity ◽  
Pyrophosphate Hydrolysis ◽  
Humic Soil

The rate of phosphorus uptake by onions was compared to the rate of pyrophosphate hydrolysis in mesic (MSM) and humic soil materials (HSM). Dry matter production and P uptake were very small from seeding to leek stage but increased considerably toward bulb maturity. Pyrophosphate half-life was 2 days in the HSM and 4 wk in the MSM, since addition of Ca(OH)2 markedly decreased pyrophosphatase activity and amounts of non-retained pyrophosphate in the MSM. By the time of high P demand by the crop, pyrophosphate was completely hydrolyzed in the HSM and most of it was already hydrolyzed in the MSM. These results suggest comparable availability of orthophosphate and pyrophosphate for onions grown in organic soils.Key words: Allium cepa L., onion growth, polyphosphates, Histosol, pyrophosphatase activity

scholarly journals Annual variations of the 214Po, 213Po and 212Po half-life values

2020 ◽  
Vol 1690 ◽  
pp. 012029
Author(s):  
E N Alexeev ◽  
A M Gangapshev ◽  
Yu M Gavrilyuk ◽  
A M Gezhaev ◽  
V V Kazalov ◽  
...  
Keyword(s):  
Half Life ◽  
Annual Variations ◽  
Life Values

Half-lives of spherical proton emitters within the framework of fractional calculus

2014 ◽  
Vol 23 (09) ◽  
pp. 1450044 ◽  
Author(s):  
Abdullah Engin Çalik ◽  
Hüseyin Şirin ◽  
Hüseyin Ertik ◽  
Buket Öder ◽  
Mürsel Şen
Keyword(s):  
Fractional Calculus ◽  
Fractional Derivative ◽  
Nuclear Structure ◽  
Caputo Fractional Derivative ◽  
Half Life ◽  
Nuclear Decay ◽  
Life Values ◽  
Derivative Order

In this paper, the half-life values of spherical proton emitters such as Sb , Tm , Lu , Ta , Re , Ir , Au , Tl and Bi have been calculated within the framework of fractional calculus. Nuclear decay equation, related to this phenomenon, has been resolved by using Caputo fractional derivative. The order of fractional derivative μ being considered is 0 < μ ≤ 1, and characterizes the fractality of time. Half-life values have been calculated equivalent with empirical ones. The dependence of fractional derivative order μ on the nuclear structure has also been investigated.

RELATIONSHIPS BETWEEN SOME PROPERTIES OF ORGANIC SOILS FROM THE SOUTHERN CANADIAN SHIELD

1990 ◽  
Vol 70 (3) ◽  
pp. 363-377 ◽  
Author(s):  
D. ANN BROWN ◽  
S. P. MATHUR ◽  
ANTON BROWN ◽  
D. J. KUSHNER
Keyword(s):  
Principal Component Analysis ◽  
Acid Leaching ◽  
Principal Component ◽  
Organic Soil ◽  
Component Analysis ◽  
Soil Types ◽  
Organic Soils ◽  
Mining Districts ◽  
Two Populations ◽  
Inorganic Components

Different numerical methods used to distinguish between organic soil types are evaluated. The research was initiated by the suggestion that acid leaching from mining wastes could be prevented by capping the tailings with a self-renewing methane-producing muskeg bog, in order to prevent the penetration of oxygen to the wastes. Thirty organic soils from bogs in the mining districts of Elliot Lake, Sudbury, and Timmins, Ontario, and Noranda, Quebec, were sampled and 28 soil characteristics were measured. These characteristics, whose values are normally or lognormally distributed, were analyzed by several different statistical methods. Some characteristics indicate the existence of two populations, and others are bivariantly correlated. Canonical discriminant analysis was more successful than cluster analysis in separating the bogs into well-defined geographical groups. However, principal component analysis proved best at grouping the organic soils according to their organic and inorganic components, and we suggest that this is a suitable method for the general discrimination of organic soil types. Methane was present in all the 17 bogs tested for it, and in two very wet bogs more than 2 mmol of methane per liter were extracted. Key words: Muskeg bog, organic soils, soil characterization, principal component analysis

scholarly journals A Novel Approach to the Analysis of the Soil Consolidation Problem by Using Non-Classical Rheological Schemes

2021 ◽  
Vol 11 (5) ◽  
pp. 1980
Author(s):  
Kazimierz Józefiak ◽  
Artur Zbiciak ◽  
Karol Brzeziński ◽  
Maciej Maślakowski
Keyword(s):  
Constitutive Models ◽  
Organic Soil ◽  
Organic Soils ◽  
Soil Consolidation ◽  
Flexible Tool ◽  
One Dimensional ◽  
Novel Approach ◽  
Soil Skeleton ◽  
The One ◽  
The Relationship

The paper presents classical and non-classical rheological schemes used to formulate constitutive models of the one-dimensional consolidation problem. The authors paid special attention to the secondary consolidation effects in organic soils as well as the soil over-consolidation phenomenon. The systems of partial differential equations were formulated for every model and solved numerically to obtain settlement curves. Selected numerical results were compared with standard oedometer laboratory test data carried out by the authors on organic soil samples. Additionally, plasticity phenomenon and non-classical rheological elements were included in order to take into account soil over-consolidation behaviour in the one-dimensional settlement model. A new way of formulating constitutive equations for the soil skeleton and predicting the relationship between the effective stress and strain or void ratio was presented. Rheological structures provide a flexible tool for creating complex constitutive relationships of soil.

scholarly journals A fertile peatland forest does not constitute a major greenhouse gas sink

2013 ◽  
Vol 10 (11) ◽  
pp. 7739-7758 ◽  
Author(s):  
A. Meyer ◽  
L. Tarvainen ◽  
A. Nousratpour ◽  
R. G. Björk ◽  
M. Ernfors ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Eddy Covariance ◽  
Organic Matter Content ◽  
C Sequestration ◽  
Organic Soil ◽  
Organic Soils ◽  
Indirect Approach ◽  
Short Period ◽  
N2o Fluxes ◽  
C Assimilation

Abstract. Afforestation has been proposed as a strategy to mitigate the often high greenhouse gas (GHG) emissions from agricultural soils with high organic matter content. However, the carbon dioxide (CO2) and nitrous oxide (N2O) fluxes after afforestation can be considerable, depending predominantly on site drainage and nutrient availability. Studies on the full GHG budget of afforested organic soils are scarce and hampered by the uncertainties associated with methodology. In this study we determined the GHG budget of a spruce-dominated forest on a drained organic soil with an agricultural history. Two different approaches for determining the net ecosystem CO2 exchange (NEE) were applied, for the year 2008, one direct (eddy covariance) and the other indirect (analyzing the different components of the GHG budget), so that uncertainties in each method could be evaluated. The annual tree production in 2008 was 8.3 ± 3.9 t C ha−1 yr−1 due to the high levels of soil nutrients, the favorable climatic conditions and the fact that the forest was probably in its phase of maximum C assimilation or shortly past it. The N2O fluxes were determined by the closed-chamber technique and amounted to 0.9 ± 0.8 t Ceq ha−1 yr−1. According to the direct measurements from the eddy covariance technique, the site acts as a minor GHG sink of −1.2 ± 0.8 t Ceq ha−1 yr−1. This contrasts with the NEE estimate derived from the indirect approach which suggests that the site is a net GHG emitter of 0.6 ± 4.5 t Ceq ha−1 yr−1. Irrespective of the approach applied, the soil CO2 effluxes counter large amounts of the C sequestration by trees. Due to accumulated uncertainties involved in the indirect approach, the direct approach is considered the more reliable tool. As the rate of C sequestration will likely decrease with forest age, the site will probably become a GHG source once again as the trees do not compensate for the soil C and N losses. Also forests in younger age stages have been shown to have lower C assimilation rates; thus, the overall GHG sink potential of this afforested nutrient-rich organic soil is probably limited to the short period of maximum C assimilation.

Surfactant metabolism of newborn lamb lungs studied in vivo

1980 ◽  
Vol 49 (6) ◽  
pp. 1091-1098 ◽  
Author(s):  
A. Jobe ◽  
M. Ikegami ◽  
I. Sarton-Miller ◽  
L. Barajas
Keyword(s):  
Palmitic Acid ◽  
Intravenous Injection ◽  
Half Life ◽  
Lamellar Body ◽  
Lung Parenchyma ◽  
Newborn Lamb ◽  
Specific Activities ◽  
Life Values ◽  
Surfactant Metabolism

Surfactant, microsomal, and lamellar body fractions were isolated from the lungs of 5-day-old lambs 0.21-55 h after the intravenous injection of radiolabeled palmitic acid. The specific activities as cpm/mumol phospholipid phosphate of phosphatidylcholine, saturated phosphatidylcholine, phosphatidylglycerol, and phosphatidylethanolamine were measured. The palmitate-labeled phospholipids disappeared from the lung parenchyma with a half-life of approximately 50 h. The radiolabel disappeared from phosphatidylcholine, saturated phosphatidylcholine, phosphatidylglycerol, and phosphatidylethanolamine of microsomal fractions with initial half-life values of 4.5, 4.6, 1.9, and 23.9 h, respectively. The labeled phospholipids rapidly appeared in the lamellar body fraction and accumulated in the surfactant of the lambs in a linear fashion for 35 h. The curves for the labeling of surfactant with radiolabeled saturated phosphatidylcholine, phosphatidylglycerol, and phosphatidylethanolamine were similar to the curve for phosphatidylcholine.

scholarly journals A fertile peatland forest does not constitute a major greenhouse gas sink

2013 ◽  
Vol 10 (3) ◽  
pp. 5107-5148 ◽  
Author(s):  
A. Meyer ◽  
L. Tarvainen ◽  
A. Nousratpour ◽  
R. G. Björk ◽  
M. Ernfors ◽  
...  
Keyword(s):  
Greenhouse Gas ◽  
Eddy Covariance ◽  
Organic Matter Content ◽  
C Sequestration ◽  
Organic Soil ◽  
Organic Soils ◽  
Optimum Growth ◽  
Indirect Approach ◽  
Short Period ◽  
N2o Fluxes

Abstract. Afforestation has been proposed as a strategy to mitigate the often high greenhouse gas (GHG) emissions from agricultural soils with a high organic matter content. However, the carbon dioxide (CO2) and nitrous oxide (N2O) fluxes after afforestation can be considerable, depending predominantly on site drainage and nutrient availability. Studies on the full GHG budget of afforested organic soils are scarce and hampered by the uncertainties associated with methodology. In this study we determined the GHG budget of a spruce-dominated forest on a drained organic soil with an agricultural history. Two different approaches for determining the net ecosystem CO2 exchange (NEE) were applied: for the year 2008, direct (eddy covariance) and an indirect (analyzing the different components of the GHG budget), so that uncertainties in each method could be evaluated. The annual tree production in 2008 was 8.2 (± 1.7)t C ha–1yr–1 due to the high levels of soil nutrients, the favorable climatic conditions and the fact that the forest was in its optimum growth phase. N2O fluxes were determined by the closed chamber technique and amounted to 3.3 (± 2.4) t CO2eq ha–1 yr–1. According to the direct measurements from the eddy covariance technique, the site acts as a minor GHG sink of −4.1 (± 2.6) t CO2eq ha–1 yr–1. This contrasts with the NEE estimate derived from the indirect approach which suggests that the site is a net GHG emitter of 3.3 (± 10.1)t CO2eq ha–1 yr–1. Irrespective of the approach applied, the soil CO2 effluxes counter large amounts of the C sequestration by trees. Due to major uncertainties involved in the indirect approach, the direct approach is considered the more reliable tool. As the site was in its optimum growth stage, i.e. the rate of C sequestration was at its maximum and will decrease with forest age, it will probably become a GHG source once again as the trees mature. Since forests in their younger stages are usually GHG sources or have no effect on GHGs, the overall sink potential of this afforested nutrient-rich organic soil is probably limited to only a short period.

scholarly journals Water repellency of clay, sand and organic soils in Finland

2008 ◽  
Vol 16 (3) ◽  
pp. 267 ◽  
Author(s):  
K. RASA ◽  
R. HORN ◽  
M. RÄTY
Keyword(s):  
Preferential Flow ◽  
Management Practice ◽  
Soil Surface ◽  
Water Repellency ◽  
Organic Soil ◽  
Water Infiltration ◽  
Organic Soils ◽  
Water Repellent ◽  
Moisture Regime ◽  
Wetting Process

Water repellency (WR) delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95) at the time of sampling. WR increased as follows: sand (R = 1.8-5.0) < clay (R = 2.4-10.3) < organic (R = 7.9-undefined). At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr.), where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;

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