SOME ASPECTS OF SELENIUM RELATIONSHIPS IN EASTERN CANADIAN SOILS AND PLANTS

1974 ◽  
Vol 54 (2) ◽  
pp. 205-214 ◽  
Author(s):  
M. LÉVESQUE
Keyword(s):  
Organic Matter ◽  
Root Zone ◽  
Practical Method ◽  
Water Soluble ◽  
Humic Compounds ◽  
Eastern Zone ◽  
The Status ◽  
Corn Plants ◽  
P Addition ◽  
Soil Constituents

The status of native and applied selenium (Se) in various soils and plants was assessed while the level of phosphorus (P) and humic compounds varied in the growth medium. The addition of 1.5 ppm of selenite-Se was found adequate to maintain a suitable Se content in alfalfa plants grown on a loam and a clay soil. Under greenhouse conditions, the lasting effect of the treatment would extend much beyond a 15-mo period of cropping. Although the incorporation of fulvic acid (FA) into the soil increased the water-soluble fraction of total Se, FA had a depressing effect on the Se content of the alfalfa plants. The effect of P addition on the uptake of native Se by alfalfa and corn plants was generally positive; for lettuce, however, P reduced the uptake markedly. The water-soluble Se was found to be of doubtful value as an index of Se availability for Se-deficient soils; but it was a useful criterion for assessing the behavior of Se applied to soil. Se in soils was closely assocated with organic matter and/or with organic matter-iron complexes; this association influenced the behavior of Se in the root zone, and its uptake by plants. It was concluded that, in the temperate eastern zone of North America, Se addition to Se-deficient soils would be a practical method of correcting Se deficiency. Se adequacy in plants grown on certain soils could be obtained through ordinary fertilization; but it is necessary, for a better control of Se in plants and soils, to clarify further the interactions of Se with P, organic matter, and other soil constituents.

ORGANIC COMPOUNDS FORMED BY THE HYDROGEN PEROXIDE XIDATION OF SOILS

1977 ◽  
Vol 57 (3) ◽  
pp. 223-231 ◽  
Author(s):  
S. M. GRIFFITH ◽  
M. SCHNITZER
Keyword(s):  
Hydrogen Peroxide ◽  
Fatty Acids ◽  
Organic Matter ◽  
Aromatic Compounds ◽  
Water Soluble ◽  
Mineralogical Analysis ◽  
Two Samples ◽  
Subsurface Soil ◽  
Phenolic Extraction ◽  
Soil Constituents

Two samples taken from tropical volcanic surface soils and one sample from a Canadian Podzol subsurface soil were oxidized with H2O2 under conditions usually employed for the removal of organic matter from soils prior to mineralogical analyses. Between 65 and 82% of the C but only between 23 and 36% of the N in the initial organic matter in the three soils was oxidized to volatile and water-soluble products. Among the latter, small amounts of about 40 different aliphatic and aromatic compounds were identified, most of which were phenolic. Extraction with organic solvents removed n-alkanes and n-fatty acids from H2O2-resistant organic matter, but most of the latter consisted of humic substances strongly bonded to or absorbed on inorganic soil constituents. H2O2-resistant fractions accounted in the case of two soils, initially rich in organic matter, for 12.0 and 7.5% of the air-dry weights of peroxidized soils. The presence of such substantial amounts of H2O2-resistant organic matter may interfere with the dispersion and mineralogical analysis of peroxidized soils, especially those with high initial organic matter contents.

scholarly journals Depth-wise Distribution of boron in Relation to Soil Properties in South-West Punjab

Agropedology ◽  
2019 ◽  
Vol 27 (2) ◽  
Author(s):  
A.K. Boparai ◽  
◽  
J.S. Manchanda ◽  
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Properties ◽  
Root Zone ◽  
Water Soluble ◽  
Hot Water ◽  
Soil Types ◽  
South West ◽  
Positive Correlations

The soils of Punjab are coarse textured and low in organic matter, therefore leaching of boron (B) beyond the root zone is more likely to occur in these soils. To study the depth-wise B availability in different soil types , samples were collected (0-15 cm, 15-30 cm, 30-60 cm and 60-90 cm) depth from soils representing Ustic Torripsamments, Typic Ustipsamments and Ustochreptic Camborthids. The highest (3.94 mg kg-1 soil) of hot water soluble boron (HWS-B) was observed in Ustochreptic Camborthids followed by Typic Ustipsamments (2.40 mg kg-1 soil) and Ustic Torripsamments (2.03 mg kg-1 soil). In general, hot water soluble B decreased with depth to the tune of 41.8, 35.4 and 36.4 per cent in Ustic Torripsamments, 16.2, 15.0 and 31.2 per cent in Typic Ustipsamments and 17.2, 29.1 and 39.1 per cent in Ustochreptic Camborthids, respectively. Significant positive correlations of HWS-B were observed with pH, organic carbon of soil and negative with CaCO3.

Mobility of soil water-soluble organic matter during rice cultivation

2012 ◽  
Vol 38 (1) ◽  
pp. 40-42 ◽  
Author(s):  
O. A. Gutorova ◽  
A. Kh. Sheudzhen ◽  
A. G. Ladatko
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Rice Cultivation ◽  
Water Soluble ◽  
Soluble Organic Matter

Utilization of grass-silage nitrogen by growing sheep

1983 ◽  
Vol 100 (1) ◽  
pp. 43-62 ◽  
Author(s):  
Elisabeth Grenet
Keyword(s):  
Organic Matter ◽  
Formic Acid ◽  
Nitrogen Balance ◽  
Crude Protein ◽  
Nitrogen Loss ◽  
Nitrogen Retention ◽  
Protein Digestibility ◽  
Water Soluble ◽  
Nitrogen Intake ◽  
Green Fodder

SUMMARYThe digestibility, the voluntary intake and the nitrogen balance of 108 diets corresponding to 94 silages prepared from 20 fresh crops were measured in growing sheep. Series of silages were made from the same fresh forage. Each series included two controls: a direct-cut silage without additive and a direct-cut silage with formic acid, with a variable number of experimental silages with different additives.Rumen ammonia concentration, measured on rumen-fistulated sheep, decreased when an additive was used. It increased with nitrogen intake and was inversely related to the organic-matter digestibility and the crude-fibre digestibility. It varied with the silage composition.The crude-protein digestibility of direct-cut silages without additives was similar to or slightly higher than the crude-protein digestibility of the fresh crops. The addition of formic acid depressed the digestibility, but the addition of formaldehyde decreased it even more. The urinary nitrogen loss was higher for silages without additive than for the fresh crops and was decreased by the addition of formic acid. The addition of formaldehyde to formic acid had an additive effect.Retained nitrogen was lower in silages without additives (12% of nitrogen intake) than in parent crops (15·7%). It increased when formic acid (15·8%) was added. The addition of formaldehyde at a low rate (1·5 l/t green fodder) to the formic acid did not increase the nitrogen retention whether expressed in g/day or as percentage of nitrogen intake, but the addition of formaldehyde at a high rate (3·5 l/t green fodder) to formic acid decreased nitrogen retention. The other additives based on cereals or whey did not improve the nitrogen balance compared with formic acid. Nitrogen retention differed according to plant species.Retained nitrogen increased with digestible organic-matter intake and nitrogen intake. It increased with the silage water-soluble carbohydrate content. The higher the silage fermentation product content (ammonia, lactic acid, propionic acid), the lower the retained nitrogen. It appears that the nitrogen value of silages can be high provided that the silages are well preserved and that excessive protein breakdown is avoided.

scholarly journals Explicit modeling of volatile organic compounds partitioning in the atmospheric aqueous phase

2013 ◽  
Vol 13 (2) ◽  
pp. 1023-1037 ◽  
Author(s):  
C. Mouchel-Vallon ◽  
P. Bräuer ◽  
M. Camredon ◽  
R. Valorso ◽  
S. Madronich ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Water Content ◽  
Gas Phase ◽  
Aqueous Phase ◽  
Water Soluble ◽  
Chemical Mechanism ◽  
Organic Species ◽  
Cloud Water Content ◽  
Isoprene Oxidation

Abstract. The gas phase oxidation of organic species is a multigenerational process involving a large number of secondary compounds. Most secondary organic species are water-soluble multifunctional oxygenated molecules. The fully explicit chemical mechanism GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere) is used to describe the oxidation of organics in the gas phase and their mass transfer to the aqueous phase. The oxidation of three hydrocarbons of atmospheric interest (isoprene, octane and α-pinene) is investigated for various NOx conditions. The simulated oxidative trajectories are examined in a new two dimensional space defined by the mean oxidation state and the solubility. The amount of dissolved organic matter was found to be very low (yield less than 2% on carbon atom basis) under a water content typical of deliquescent aerosols. For cloud water content, 50% (isoprene oxidation) to 70% (octane oxidation) of the carbon atoms are found in the aqueous phase after the removal of the parent hydrocarbons for low NOx conditions. For high NOx conditions, this ratio is only 5% in the isoprene oxidation case, but remains large for α-pinene and octane oxidation cases (40% and 60%, respectively). Although the model does not yet include chemical reactions in the aqueous phase, much of this dissolved organic matter should be processed in cloud drops and modify both oxidation rates and the speciation of organic species.

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