Comparing modelled and observed effects of ash additions on chemistry of a highly acid soil

Soil Research ◽  
1996 ◽  
Vol 34 (6) ◽  
pp. 999 ◽  
Author(s):  
PK Khanna ◽  
B Ludwig ◽  
RJ Raison
Keyword(s):  
Surface Layer ◽  
Acid Soil ◽  
Soil Samples ◽  
Exchangeable Cations ◽  
Fuel Reduction ◽  
Natural Conditions ◽  
Soil Solutions ◽  
Time Required ◽  
Extractable Cations

The chemical composition of soil solutions (field percolates collected in situ and laboratory saturation extracts) and the amount of salt-extractable cations were measured at several microsites (unburnt, moderately burnt, and intensely burnt ashbeds) after a fuel reduction burning in a subalpine Eucalyptus pauciflora forest. Soil samples were collected 1, 58, 375, 745, and 1095 days after the fire, and soil percolates were obtained on 17 occasions during the initial year. A model of coupled equilibria, which includes insoluble salts, multiple cation exchange, and inorganic complexation, was used to describe soil chemical changes after fire and ash addition. The model was able to describe temporal changes in cation concentrations of held percolates and soil exchangeable cations. Measurements of extractable cations using unbuffered salt solution on samples taken immediately after fire suggest immediate changes in exchangeable cations which were related to solubilisation of cations from ash, and not to changes in exchangeable cations in soils. Modelling suggests that under natural conditions the differences in solubility of cations in ash result in slow changes in exchangeable cations extending over a period of 6 years or more. The time required to reacidify the surface layer of ashbed soil was estimated to be 45 years when annual acid input was 0.5 kmol H+/ha.

In situ enzymatic removal of orthophosphate by the nucleoside phosphorylase catalyzed phosphorolysis of nicotinamide riboside

1982 ◽  
Vol 60 (9) ◽  
pp. 917-921 ◽  
Author(s):  
John W. Shriver ◽  
Brian D. Sykes
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nucleoside Phosphorylase ◽  
Nicotinamide Riboside ◽  
Time Required ◽  
Removal System ◽  
Nuclear Magnetic

An enzymatic orthophosphate removal system is described which can be effectively used to continuously remove orthophosphate from biochemical samples. The phosphorolysis of nicotinamide riboside is catalyzed by calf spleen nucleoside phosphorylase to give ribose-1-PO4 and nicotinamide along with a proton. At pH 8 the production of ribose-1-PO4 from orthophosphate is essentially quantitative. This reaction can be monitored optically or by 31P nuclear magnetic resonance (NMR). Equations are given for determining the time required to remove a given amount of phosphate from a typical NMR sample with a known amount of nucleoside phosphorylase. The effects of a competing orthophosphate-producing reaction are considered.

Fate and transport of faecal contamination microbial indicators, pathogenic protozoa and Campylobacter in the artificially recharged fractured aquifer of Salento, Italy

2008 ◽  
Vol 57 (6) ◽  
pp. 849-856 ◽  
Author(s):  
R. La Mantia ◽  
C. Masciopinto ◽  
C. Levantesi ◽  
V. Tandoi
Keyword(s):  
Pathogenic Bacteria ◽  
Fate And Transport ◽  
Fractured Aquifer ◽  
Specific Detection ◽  
Microbial Indicators ◽  
Faecal Contamination ◽  
Time Required ◽  
Indicators Of Faecal Contamination ◽  
Campylobacter Spp

The study investigates the fate and transport of microorganisms introduced by artificial groundwater recharge at the Nardò fractured aquifer in Salento, Italy. Microbial indicators of faecal contamination, parasitic protozoa (Giardia and Cryptosporidium) and pathogenic bacteria (Campylobacter spp.), were monitored into injected water and groundwater to test the efficiency of the “natural disinfection” into the fractured aquifer. A remarkable decrease of microbial indicators and pathogens was observed suggesting that pathogens removal or inactivation may be possible during water flow in fractured aquifer. The recently described PNA probe CJE195 (Lehtola et al. 2005) was utilised for the rapid and specific detection of Campylobacter spp. by fluorescence in situ hybridization (FISH) after enrichment. FISH results were consistent with those of traditional cultural method (ISO 17995) applied in parallel: time required for Campylobacter identification was reduced of 4 days.

In-Situ, Time Resolved, Kinetics of Reactions in Co-Ge thin Films

1991 ◽  
Vol 237 ◽  
Author(s):  
R. M. Walser ◽  
Byung-Hak Lee ◽  
Alaka Valanju ◽  
Winston Win ◽  
M. F. Becker
Keyword(s):  
Depth Profiling ◽  
Laser Interferometry ◽  
Semiconductor Interface ◽  
Time Resolved ◽  
Interface Reactions ◽  
Valuable Adjunct ◽  
Diffusion Controlled ◽  
Sputter Deposited ◽  
Time Required

ABSTRACTWe report the first kinetic study of metal-semiconductor interface reactions using in-situ, time resolved, laser interferometry. Diffusion couples with Co/Ge thicknesses of 1500 Å/1500 Å were sputter deposited on silicon wafers, and vacuum-annealed at temperatures between 300°C-400°C. Under these conditions polycrystalline CoGe was expected to form [1]. Real time laser (HeNe 6328 Å) interferograms for each anneal were recorded in-situ. These data were supplemented by information from AES and X-ray.For temperatures below 400°C the diffusion controlled formation of CoGe was observed. The composition was confirmed by Auger depth profiling that showed uniform Co and Ge concentrations when the reaction went to completion. The well defined interferences fringes were formed by the dissolution of amorphous Ge. The activation energy = 1.6 eV for the formation of CoGe were determined with precision from the temperature dependence of the time required to anneal the fixed λ/4 distance between adjacent minima and maxima of the interferogram. We discuss the evidence for formation of an intermediate Co-rich compound following the initial diffusion of Co into Ge. The results of these experiments indicate that optical interferometry will be a valuable adjunct to other techniques used to study metal-semiconductor interface reactions.

EFFECTS OF LIME ON EXTRACTABLE ALUMINUM AND OTHER SOIL PROPERTIES AND ON BARLEY AND ALFALFA GROWN IN POT TESTS

1972 ◽  
Vol 52 (3) ◽  
pp. 427-438 ◽  
Author(s):  
A. J. MacLEAN ◽  
R. L. HALSTEAD ◽  
B. J. FINN
Keyword(s):  
Plant Growth ◽  
Soil Properties ◽  
Soil Ph ◽  
Acid Soil ◽  
Soil Samples ◽  
Neutral Salt ◽  
Incubation Experiment ◽  
Pot Experiments ◽  
P Content ◽  
Mn Content

Liming of six acid soil samples in an incubation experiment with rates to raise the soil pH to 6.0 or above eliminated Al soluble in 0.01 M CaCl2, reduced soluble Mn and Zn, increased NO3-N markedly, and at the highest pH increased the amounts of NaHCO3-soluble P in some of the soils. In corresponding pot experiments, liming increased the yield of alfalfa and in three of the soils the yield of barley also. Liming reduced the concentrations of the metals in the plants and at the highest pH tended to increase the P content of the plants. Liming to a pH of about 5.3 eliminated or greatly reduced soluble Al and the soils were base saturated as measured by the replacement of Al, Ca, and Mg by a neutral salt. There was some evidence that liming to reduce soluble Al and possibly Mn was beneficial for plant growth. Gypsum increased the concentrations of Al, Mn, and Zn in 0.01 M CaCl2 extracts of the soils whereas phosphate reduced them. The changes in the Mn content of the plants following these treatments were in agreement with the amounts of Mn in the CaCl2 extracts.

EFFECTS OF GROWING SEASON SOIL TEMPERATURE, MOISTURE, AND NH4-N ON SOIL NITROGEN

1974 ◽  
Vol 54 (4) ◽  
pp. 403-412 ◽  
Author(s):  
C. A. CAMPBELL ◽  
D. W. STEWART ◽  
W. NICHOLAICHUK ◽  
V. O. BIEDERBECK
Keyword(s):  
Quantitative Relationship ◽  
Growing Season ◽  
Stepwise Multiple Regression ◽  
Soil N ◽  
N Transformations ◽  
Temperature Changes ◽  
Diurnal Patterns ◽  
Multiple Regression Technique ◽  
Time Required

Wood Mountain loam was wetted with water or (NH4)2SO4 solution to provide a factorial combination among three moisture and three NH4-N levels. Samples in polyethylene bags were incubated at 2.5-cm depths in fallow, and in an incubator that simulated the diurnal patterns of temperature fluctuation recorded in the field. During the growing season, treatments were sampled regularly for moisture, NO3− and exchangeable NH4-N. Similar determinations were made on in situ samples taken in fallow Wood Mountain loam. The incubator simulated the effects of growing season temperatures on soil N transformations satisfactorily. Pronounced increases or decreases in temperature led to flushes in N mineralization. However, in the 1972 growing season, temperature was suboptimal and temperature changes were generally small. Consequently, when a stepwise multiple regression technique was used to analyze the data, neither ammonification nor nitrification showed a quantitative relationship to temperature. Comparison of the nitrification occurring in laboratory-incubated soils with that occurring in situ led to the conclusion that 70 to 90% of the NO3-N produced in surface soil resulted from wetting and drying. Estimates of potentially ammonifiable soil N(No) and its rate of mineralization (k) were derived from cumulative ammonification by assuming that the laws of first-order kinetics were applicable. In the 10, 15, and 20% moisture treatments the average No was 27, 41, and 82 ppm, respectively. Under the conditions of this study, the time required to mineralize half of No was about 7 wk.

scholarly journals Principal Component Gradiometer technique for removal of spacecraft-generated disturbances from magnetic field data

2020 ◽  
Author(s):  
Ovidiu Dragoş Constantinescu ◽  
Hans-Ulrich Auster ◽  
Magda Delva ◽  
Olaf Hillenmaier ◽  
Werner Magnes ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Principal Component ◽  
Field Measurements ◽  
Magnetic Field Data ◽  
Service Oriented ◽  
Sensor Configuration ◽  
Time Required ◽  
First Time ◽  
The Magnetic Field

Abstract. In situ measurement of the magnetic field using space borne instruments requires either a magnetically clean platform and/or a very long boom for accommodating magnetometer sensors at a large distance from the spacecraft body. This significantly drives up the costs and time required to build a spacecraft. Here we present an alternative sensor configuration and an algorithm allowing for ulterior removal of the spacecraft generated disturbances from the magnetic field measurements, thus lessening the need for a magnetic cleanliness program and allowing for shorter boom length. The proposed algorithm is applied to the Service Oriented Spacecraft Magnetometer (SOSMAG) onboard the Korean geostationary satellite GeoKompsat-2A (GK2A) which uses for the first time a multi-sensor configuration for onboard data cleaning. The successful elimination of disturbances originating from several sources validates the proposed cleaning technique.

scholarly journals In situ immobilisation of heavy metals in soils using natural clay minerals

2020 ◽  
Vol 66 (No. 12) ◽  
pp. 632-638
Author(s):  
Senad Murtić ◽  
Emina Sijahović ◽  
Hamdija Čivić ◽  
Mirza Tvica ◽  
Josip Jurković
Keyword(s):  
Heavy Metals ◽  
Ethylenediaminetetraacetic Acid ◽  
Atomic Absorption Spectrophotometry ◽  
Soil Samples ◽  
Natural Clay ◽  
Aqua Regia ◽  
Absorption Spectrophotometry ◽  
Suitable Technique ◽  
Heavy Metals In Soils

This study attempted to evaluate the efficiency of zeolite and pyrophyllite ore materials in reducing the mobility of heavy metals in soil near the lignite mining dumps, and consequently in their availability for plants. Extraction of pseudo-total and available forms of heavy metals from soil samples was performed by using aqua regia and ethylenediaminetetraacetic acid, respectively. Concentrations of heavy metals in soil and plant samples were determined by atomic absorption spectrophotometry. The results of this study illustrate that application of zeolite and pyrophyllite could be a suitable technique to reduce heavy metals availability in soils. Zeolite treatments have been shown to be significantly effective in reducing cadmium (Cd) mobility, as well as pyrophyllite treatments in reducing lead (Pb) mobility in the studied soil, regardless of applied rates. The accumulation of heavy metals in leaves of maize grown on soil plots treated by zeolite and pyrophyllite, was found to be lower compared to the untreated plots. This finding was to be expected, considering the effects of these treatments on heavy metals mobility in the studied soil.

Is it possible to determine formation processes of organic deposits through polysaccharides? Pilot study from the prehistoric site in Brandýs nad Labem, Czech Republic

The Holocene ◽  
2017 ◽  
Vol 27 (9) ◽  
pp. 1273-1280
Author(s):  
Klement Rejšek ◽  
Jan Turek ◽  
Valerie Vranová ◽  
Roman Hadacz ◽  
Lenka Lisá
Keyword(s):  
Czech Republic ◽  
Pilot Study ◽  
Organic Material ◽  
Archaeological Site ◽  
Soil Samples ◽  
Formation Processes ◽  
Cultural Layer ◽  
Different Types ◽  
Organic Deposits

This paper deals with a possible interpretation value of biochemical methods in comparison with the classic tools of geoarchaeology for the evaluation of formation processes. Organic rich layers from the archaeological site Brandýs nad Labem-Vrábí were tested with the aim to determine the origin of several different types of soil organic material by analyzing the content of different sugars. The studied soil body showed signs of cultural layer, redeposited soils, and in situ developed soil. The analysis of different sugars was highlighted: soil samples taken from these layers were analyzed to assess the ratios of mannose + galactose to arabinose + xylose, and of rhamnose + fucose to arabinose + xylose, content of Corg and different nitrates, as well as different rates of absorbance. The results show that the interpretation values of polysaccharides evaluation didn’t bring significant results itself, but in combination with classical tools of geoarchaeology may bring interpretable and new results.

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