scholarly journals Theoretical Approach of the Adsorption of Herbicide Amitrole on the Soil using DFT Method

2018 ◽  
Vol 34 (3) ◽  
pp. 1240-1248
Author(s):  
Rabia Tazi ◽  
Hamza El Hadki ◽  
Mohammed Salah ◽  
Abdallah Zrineh ◽  
Mohammed El Azzouzi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Quantum Chemical ◽  
Dft Method ◽  
Aqueous Environment ◽  
Water As Solvent ◽  
Structural Configurations ◽  
Main Components ◽  
Global And Local

Quantum chemical calculations were performed on amitrole used as herbicide in agriculture to investigate its interaction with humic substances which are the main components of soil organic matter. They contain carboxylic, phenolic, amine and quinonic groups as well as specific structural configurations. Global and local reactivity have been studied to predict reactive centers and to determine the favorable site for interaction with surface. The results suggest us that hydrogen bonds are formed between this compound and the amino acids of soil organic matter. The effect of water as solvent is considered since adsorption of pesticide commonly occurs in aqueous environment.

Effect of crop rotations and fertilization on soil organic matter and some biochemical properties of a thick Black Chernozem

1991 ◽  
Vol 71 (3) ◽  
pp. 377-387 ◽  
Author(s):  
C. A. Campbell ◽  
R. P. Zentner ◽  
K. E. Bowren ◽  
L. Townley-Smith ◽  
M. Schnitzer
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Crop Residues ◽  
Cultural Practices ◽  
Organic Matter Content ◽  
Biochemical Properties ◽  
Matter Content ◽  
Organic C ◽  
Cropping Frequency

The effects of crop rotation and various cultural practices on soil organic matter and some biochemical characteristics of a heavy-textured, Orthic Black Chernozem with a thick A horizon were determined after 31 yr at Melfort, Saskatchewan. Treatments investigated included: fertilization, cropping frequency, green manuring, and inclusion of grass-legume hay crops in predominantly spring wheat (Triticum aestivum L.) systems. The results showed that neither soil organic C nor N in the top 15 cm of soil, nor hydrolyzable amino acids, nor C mineralized in 14 d at 20 °C were influenced by fertilization. However, the relative molar distribution (RMD) of the amino acids reflected the influence of fertilization and the phase (Rot-yr) of the legume green manure rotation sampled. Some characteristics assessed increased marginally with increasing cropping frequency but differences were less marked than results obtained earlier in a heavy-textured Black Chernozem with a thin A horizon at Indian Head, Saskatchewan. The relationship between soil organic matter or C mineralization versus estimated crop residues, residue C, or residue N returned to the land over the 31-yr period, were not significant in the Melfort soil. This contrasts with our findings for the thin Black soil. We speculate that the lack of soil organic matter response in the Melfort soil was due to its very high organic matter content (about 64 t ha−1C and 6.5 t ha−1N in the top 15 cm). We also hypothesized that the amino acid RMD results, which differed from most of those reported in the literature, may be reflecting the more recent cropping history of the soil. This aspect requires further research into the composition and distribution of the humic materials in this soil. Key words: Amino acids, relative molar distribution, C respiration, green manures, fertilization

Effect of crop rotations and rotation phase on characteristics of soil organic matter in a Dark Brown Chernozemic soil

1992 ◽  
Vol 72 (4) ◽  
pp. 403-416 ◽  
Author(s):  
C. A. Campbell ◽  
V. O. Biederbeck ◽  
R. P. Zentner ◽  
S. A. Brandt ◽  
M. Schnitzer
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Biomass ◽  
Respiratory Activity ◽  
Carbon Mineralization ◽  
Crop Rotations ◽  
Organic N ◽  
Microbial Biomass C ◽  
Rotation Phase

The influence of five crop rotations and the rotation phases (i.e., rotation-yr) on some soil organic matter characteristics was investigated in a long-term (23 yr) study carried out on an Orthic Dark Brown Chernozemic soil at Scott, Saskatchewan. The cropping systems included different cropping frequencies and crop types (cereals, oilseeds, and legume-hay). Soil samples were taken from the 0- to 7.5- and 7.5- to 15-cm depths in mid-September 1988, 2 wk after harvest of the grain crops (i.e., 2 mo after hay harvest and plowdown). Most effects of rotations, and rotation phases, on soil biological characteristics assessed, were significant primarily in the top 7.5-cm soil depth. Increasing the cropping frequency did not increase soil organic matter. Excessive preseeding tillage of stubble plots may have masked any potential advantage provided by frequent cropping. Including alfalfa (Medicago sativa L.) hay crops in rotation with grain crops decreased soil organic matter in the fallow and grain crop rotation phases of rotations. This was likely due to increased moisture stress depressing associated cereal production in this semiarid environment. As expected, rotation phase did not influence soil organic C, but alfalfa under-seeded into barley (Hordeum vulgare L.) increased soil organic nitrogen. We believe this was due to crop residue inputs from the seedling alfalfa. Microbial biomass C and N, C mineralization, the specific respiratory activity (ratio of CO2-C respired/microbial biomass C) and hydrolyzable amino acids were also greater in the rotation phases in which barley was underseeded with alfalfa. Carbon mineralization and specific respiratory activity were directly related to estimated crop residue-C returned to soil, but not residue-N. However, both were increased by including alfalfa in the rotation. Carbon mineralization and specific respiratory activity were more sensitive indexes of soil organic matter quality than biomass C and N per se. Hydrolyzable amino acids and amino sugars responded to the treatments in a manner similar to total soil organic N. Relative molar distribution of amino acids was unaffected by crop rotation or rotation phase. Potentially mineralizable N in this soil was low compared to other Canadian prairie soils, even though the total soil organic N of the Scott soil was relatively high. We concluded that (i) all soil biochemical characteristics studied are useful for assessing soil quality changes; (ii) when studying soil changes, thin (0- to 7.5-cm) soil slices are more likely to reveal treatment effects than thicker slices; (iii) all rotation phases should be analyzed whenever forage legumes are constituents of crop rotations. Key words: C mineralization; microbial biomass, amino acids, N mineralization, specific respiratory activity

ACTION OF PROTEOLYTIC ENZYMES ON SOIL ORGANIC MATTER

1970 ◽  
Vol 50 (2) ◽  
pp. 233-241 ◽  
Author(s):  
F. J. SOWDEN
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Amino Acid ◽  
Soil Organic Matter ◽  
Acid Hydrolysis ◽  
Leucine Aminopeptidase ◽  
Proteolytic Enzymes ◽  
Complexing Agent ◽  
Organic Matter Fractions ◽  
Hydrolysis Of

The amino acids set free by proteolytic enzymes were determined with an amino acid analyzer. Soil and enzyme blanks were subtracted. Pronase released 2 to 10% of the aspartic acid + asparagine, threonine, serine, glutamic acid + glutamine, glycine, lysine and histidine in some fractions of soil organic matter along with 15–35% of the alanine, valine, isoleucine, leucine, tyrosine, phenylalanine and arginine. There was no release of proline, ornithine or ammonia. When the pronase hydrolysate was treated with leucine amino-peptidase, 15% of the proline was released, the yield of glycine was raised from 2 to 14% and the amount of the acidic amino acids was also higher. Acid hydrolysis of the pronase hydrolysate also released more amino acid material but the blanks were much higher than with leucine aminopeptidase. The results suggested that more than half of the aspartic and glutamic acids found on acid hydrolysis were present in the soil organic matter fractions as asparagine and glutamine. The action of pronase on the organic matter of the intact soil was slight, even in the presence of a complexing agent. Papain released very little amino acid material from organic matter fractions, but leucine aminopeptidase or HCl hydrolysis of the papain hydrolysate released about 10% of the amino acid of the fraction, indicating that significant amounts of peptides were formed on papain treatment.

A novel fluxomics approach to decipher the flux partitioning between anabolic and catabolic processes in soil microbial communities

2020 ◽  
Author(s):  
Theresa Böckle ◽  
Yuntao Hu ◽  
Jörg Schnecker ◽  
Wolfgang Wanek
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Microbial Communities ◽  
Metabolic Pathways ◽  
Isotope Labeling ◽  
Soil Microbial Communities ◽  
Microbial Activities ◽  
Soil Microbial ◽  
Wide Range

<p>The activities of soil microorganisms drive soil carbon (C) and nutrient cycling and therefore play an important role in local and global terrestrial C dynamics and nutrient cycles. Unfortunately, soil microbial activities have been defined mostly by measurements of heterotrophic respiration, potential enzyme activities, or net N processes. However, soil microbial activities comprise more than just catabolic processes such as respiration and N mineralization. Recently anabolic processes (biosynthesis and growth) and the partitioning between anabolic and catabolic processes in soil microbial metabolism have gained more attention as they control microbial soil organic matter formation. Understanding the controls on these processes allows an improved understanding of the key roles that soil microbes play in organic matter decomposition (catabolic processes) and soil organic matter sequestration (anabolic processes leading to growth, biomass and necromass formation), and their potential feedback to global change.</p><p>Generally, there are two approaches to study the metabolism of soil microbial communities: First, position-specific isotope labeling is a tool that allows the tracing of <sup>13</sup>C-atoms in organic molecules on their way through the network of metabolic pathways and second, metabolomics and fluxomics approaches can enable disentangling the highly complex metabolic networks of microbial communities, which however have rarely (metabolomics) or never (fluxomics) been applied to soils.</p><p>In this study we developed a targeted soil metabolomics approach coupled to <sup>13</sup>C isotope tracing (fluxomics), in which we extract, purify and measure a preselected set of key metabolites. Our aim was to cover the wide spectrum of soil microbial metabolic pathways based on the analysis of biomarker metabolites being unique to specific metabolic pathways such as  glycolysis/gluconeogenesis (e.g. fructose 1,6-bisphosphate), the pentose phosphate pathway (ribose-5-phosphate), the citric acid cycle (α-ketoglutaric acid), purine and pyrimidine metabolism (UMP, AMP, allantoin), amino acid biosynthesis and degradation (10proteinogenic amino acids and their intermediates), the urea cycle (ornithine), amino sugar metabolism (N-Acetyl-D-Glucosamine and –muramic acid) and the shikimate pathway (shikimate). The minute concentrations of these primary metabolites are extracted from soils by 1 M KCl including 5 % chloroform, salts are removed by freeze-drying, methanol dissolution and cation-/anion-exchange chromatography and the metabolites and their isotopomers quantified by UPLC-Orbitrap mass spectrometry. To cover the wide range of metabolites, compound separations are performed by  hydrophilic interaction chromatography (HILIC) for metabolites such as amino acids, (poly-)amines, nucleosides and nucleobases and by Ion chromatography (IC), to separate charged molecules like amino sugars, sugar phosphates and organic acids.  Here we will show fluxomics results from a laboratory soil warming experiment where we added <sup>13</sup>C-glucose to a temperate forest soil as a proof of concept.</p>

scholarly journals Dissolved biochar promoted photodegradation of tetracycline in aqueous environment

2021 ◽  
Vol 251 ◽  
pp. 02055
Author(s):  
Chenjing Chu ◽  
Mengying Shao ◽  
Xiao Wang
Keyword(s):  
Aqueous Solution ◽  
Organic Matter ◽  
Humic Acid ◽  
Functional Groups ◽  
Aqueous Environment ◽  
Light Illumination ◽  
Environmental Behaviour ◽  
Theoretical Support ◽  
Main Components ◽  
The Impact

As one of the frequently detected antibiotics in aqueous environment, the environmental behaviour of tetracycline has received increasing attention. Dissolved biochar (DBC) is an essential component of dissolved organic matter (DOM) in water enviroment. However, the effect of DBC on the photodegradation of tetracycline was unclear. This study investigated the impact of DBC on the photodegradation of tetracycline in aqueous solution under light illumination. The main components of DBC were humic acid-like and fulvic acid-like, accounting for 78.2% of the total components. The DBC surface had more oxygen-containing functional groups and aromatic functional groups. DBC increased the photodegradation of tetracyline by 46.9%, which was related to the component and structure of DBC. These findings would provid theoretical support for the environmental behaviour of DBC and tetracycline in aqueous environment.

scholarly journals Soil polysaccharides synthesized by microorganisms in soil

1971 ◽  
Author(s):  
◽  
De-Shin Wang
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
High Molecular Weight ◽  
Amino Sugars ◽  
Uronic Acids ◽  
Carbohydrate Fraction

"The carbohydrate fraction of soil organic matter consists mainly of a mixture or heteropolysaccharides of high molecular weight. The major monosaccharide components are several sugars, uronic acids, amino sugars, and amino acids... "-Introduction

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