Effects of the insecticide endosulfan on nitrification in low pH agricultural soils

1990 ◽  
Vol 5 (4) ◽  
pp. 319-336 ◽  
Author(s):  
Glenn W. Stratton
Keyword(s):  
Agricultural Soils ◽  
Low Ph

scholarly journals A simple cultivar suitability index for low‐pH agricultural soils

ael ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Simon Fordyce ◽  
Clain A. Jones ◽  
Sally J. Dahlhausen ◽  
Jennifer Lachowiec ◽  
Jed O. Eberly ◽  
...  
Keyword(s):  
Agricultural Soils ◽  
Low Ph ◽  
Suitability Index

scholarly journals Dissolution of Ag Nanoparticles in Agricultural Soils and Effects on Soil Exoenzyme Activities

Environments ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 22
Author(s):  
Nuno C. Cruz ◽  
Márcia Farto ◽  
Clarisse Mourinha ◽  
Daniela Tavares ◽  
Armando C. Duarte ◽  
...  
Keyword(s):  
Organic Matter ◽  
Agricultural Soils ◽  
Inhibitory Effect ◽  
Low Ph ◽  
Environmental Risks ◽  
Downward Mobility ◽  
Acidic Soils ◽  
Soil Enzymatic Activity ◽  
Soil Extractions ◽  
Chemical Availability

To assess environmental risks related to the mobility and toxicity of AgNPs, the chemical availability of AgNPs and polyvinylpyrrolidone-coated AgNPs (PVP-AgNPs) in three agricultural soils was quantified in a pot experiment. Porewater collection and soil extractions with 0.01 M CaCl2, 0.4 M Glycine (pH 1.5) and 0.05 M NH4-EDTA were performed. The effect on soil exoenzyme activities was also assessed. Porewater concentration was low (<0.4% and <0.04% of dosed Ag, for AgNPs and PVP-AgNPs, respectively) and only detected in acidic soils (pH 4.4 and 4.9). The PVP-coating reduced the downward mobility of AgNPs in soil and possibly also their dissolution rate (and subsequent release of dissolved Ag+ ions into porewater). The effect of variation in organic matter on soil enzymatic activity was larger than that of AgNPs, as no significant additional inhibitory effect from Ag could be observed. Only at low pH and in the presence of complexing ligands that form very stable Ag complexes (0.4 M Glycine extraction at pH 1.5) up to 58% of the Ag added to soil was released (independently of PVP coating). An extraction with glycine is proposed as a useful indicator of potentially available Ag in soils.

scholarly journals Effect of iron oxide on nitrification in two agricultural soils with different pH

2016 ◽  
Author(s):  
Xueru Huang ◽  
Xia Zhu-Barker ◽  
William R. Horwath ◽  
Sarwee J. Faeflen ◽  
Hongyan Luo ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Soil Ph ◽  
N Mineralization ◽  
Agricultural Soils ◽  
Low Ph ◽  
N Transformations ◽  
Fe Oxide ◽  
High Ph ◽  
N Transformation ◽  
Transformation Rates

Abstract. Iron (Fe) affects soil nitrogen (N) cycling processes both in anoxic and oxic environments. The role of Fe on soil N transformations such as mineralization, immobilization, and nitrification depends on its redox activity, which can be regulated by soil pH. We hypothesized that the effect of Fe oxide on N transformation processes would be different in soils as a function of pH. This study aimed to investigate N mineralization-immobilization, especially nitrification, as affected by Fe oxide in soils with different pH. A set of lab incubations under 100 % water holding capacity were carried out to investigate the effect of Fe oxide on N transformation rates in two subtropical agricultural soils with a low pH (pH 5.1) and a high pH (pH 7.8). 15N-labelled ammonium and nitrate were used separately to determine N transformation rates combined with Fe oxide (ferrihydrite) addition. Iron oxide addition stimulated net nitrification in the low pH soil (pH 5.1), while the opposite occurred in the high pH soil (pH 7.8). An explanation for this could be at low pH, Fe oxide increased NH3-N availability by stimulating N mineralization and inhibiting N immobilization. These results suggested that Fe oxide plays an important role in N transformations in soil ecosystem, and the effect of Fe oxide on N transformations depends on soil pH.

scholarly journals Long-Term Adaptation of Acidophilic Archaeal Ammonia Oxidisers Following Different Soil Fertilisation Histories

2021 ◽  
Author(s):  
Jun Zhao ◽  
Baozhan Wang ◽  
Xue Zhou ◽  
Mohammad Saiful Alam ◽  
Jianbo Fan ◽  
...  
Keyword(s):  
Community Composition ◽  
High Throughput Sequencing ◽  
Environmental Changes ◽  
Agricultural Soils ◽  
Terrestrial Ecosystems ◽  
Low Ph ◽  
Ph Change ◽  
Monooxygenase Gene ◽  
Ammonia Oxidising Archaea

AbstractAmmonia oxidising archaea (AOA) are ecologically important nitrifiers in acidic agricultural soils. Two AOA phylogenetic clades, belonging to order-level lineages of Nitrososphaerales (clade C11; also classified as NS-Gamma-2.3.2) and family-level lineage of Candidatus Nitrosotaleaceae (clade C14; NT-Alpha-1.1.1), usually dominate AOA population in low pH soils. This study aimed to investigate the effect of different fertilisation histories on community composition and activity of acidophilic AOA in soils. High-throughput sequencing of ammonia monooxygenase gene (amoA) was performed on six low pH agricultural plots originating from the same soil but amended with different types of fertilisers for over 20 years and nitrification rates in those soils were measured. In these fertilised acidic soils, nitrification was likely dominated by Nitrososphaerales AOA and ammonia-oxidising bacteria, while Ca. Nitrosotaleaceae AOA activity was non-significant. Within Nitrososphaerales AOA, community composition differed based on the fertilisation history, with Nitrososphaerales C11 only representing a low proportion of the community. This study revealed that long-term soil fertilisation selects for different acidophilic nitrifier communities, potentially through soil pH change or through direct effect of nitrogen, potassium and phosphorus. Comparative community composition among the differently fertilised soils also highlighted the existence of AOA phylotypes with different levels of stability to environmental changes, contributing to the understanding of high AOA diversity maintenance in terrestrial ecosystems.

scholarly journals Effect of iron oxide on nitrification in two agricultural soils with different pH

2016 ◽  
Vol 13 (19) ◽  
pp. 5609-5617 ◽  
Author(s):  
Xueru Huang ◽  
Xia Zhu-Barker ◽  
William R. Horwath ◽  
Sarwee J. Faeflen ◽  
Hongyan Luo ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Soil Ph ◽  
Agricultural Soils ◽  
Low Ph ◽  
Soil N ◽  
Fe Oxide ◽  
High Ph ◽  
N Transformation ◽  
Soil N Transformation ◽  
Transformation Processes

Abstract. Iron (Fe) affects soil nitrogen (N) cycling processes both in anoxic and oxic environments. The role of Fe in soil N transformations including nitrification, mineralization, and immobilization, is influenced by redox activity, which is regulated by soil pH. The effect of Fe minerals, particularly oxides, on soil N transformation processes depends on soil pH, with Fe oxide often stimulating nitrification activity in the soil with low pH. We conducted lab incubations to investigate the effect of Fe oxide on N transformation rates in two subtropical agricultural soils with low pH (pH 5.1) and high pH (pH 7.8). 15N-labeled ammonium and nitrate were used separately to determine N transformation rates combined with Fe oxide (ferrihydrite) addition. Iron oxide stimulated net nitrification in low-pH soil (pH 5.1), while the opposite occurred in high-pH soil (pH 7.8). Compared to the control, Fe oxide decreased microbial immobilization of inorganic N by 50 % in low-pH soil but increased it by 45 % in high-pH soil. A likely explanation for the effects at low pH is that Fe oxide increased NH3-N availability by stimulating N mineralization and inhibiting N immobilization. These results indicate that Fe oxide plays an important role in soil N transformation processes and the magnitude of the effect of Fe oxide is dependent significantly on soil pH.

Relationship between golgi apparatus and axonal reticulum in sympathetic ganglion cells

1978 ◽  
Vol 36 (2) ◽  
pp. 598-599
Author(s):  
J. Quatacker ◽  
W. De Potter
Keyword(s):  
Golgi Apparatus ◽  
Sympathetic Ganglion ◽  
Phosphotungstic Acid ◽  
Ganglion Cells ◽  
Low Ph ◽  
Dense Core ◽  
Dense Core Vesicles ◽  
Large Dense Core Vesicles ◽  
Cervical Ganglia ◽  
Axoplasmic Reticulum

Mucopolysaccharides have been demonstrated biochemically in catecholamine-containing subcellular particles in different rat, cat and ox tissues. As catecholamine-containing granules seem to arise from the Golgi apparatus and some also from the axoplasmic reticulum we examined wether carbohydrate macromolecules could be detected in the small and large dense core vesicles and in structures related to them. To this purpose superior cervical ganglia and irises from rabbit and cat and coeliac ganglia and their axons from dog were subjected to the chromaffin reaction to show the distribution of catecholamine-containing granules. Some material was also embedded in glycolmethacrylate (GMA) and stained with phosphotungstic acid (PTA) at low pH for the detection of carbohydrate macromolecules.The chromaffin reaction in the perikarya reveals mainly large dense core vesicles, but in the axon hillock, the axons and the terminals, the small dense core vesicles are more prominent. In the axons the small granules are sometimes seen inside a reticular network (fig. 1).

Mechanism of Human Plasminogen Activation by Streptokinase and Human Plasmin

1964 ◽  
Vol 11 (01) ◽  
pp. 085-093
Author(s):  
W. F Blatt ◽  
JL Gray ◽  
H Jensen
Keyword(s):  
Proteolytic Activity ◽  
Low Ph ◽  
Plasminogen Activation ◽  
Sensitive Tool ◽  
Human Plasminogen

SummaryA sensitive tool has been described for measuring fibrinolysis in reconstituted systems using thrombelastography. Activator mixtures with no appreciable proteolytic activity can similarly be tested in this system when the fibrinogen utilized has sufficient plasminogen present. Exposure of human plasminstreptokinase mixtures formed at pH 7.0 to acid conditions produced a striking loss of activator activity which could not be ascribed to low pH lability of the components, nor to plasmin action on the SK at pH 2.0. This is additional evidence for the hypothesis that human plasmin interacts with SK to form a complex capable of converting human and bovine plasminogen to plasmin.

Influence of Polymer Charge, Temperature, and Surfactants on Surface Sizing of Liner and Greaseproof Paper With Hydrophobically Modified Starch

TAPPI Journal ◽  
2009 ◽  
Vol 8 (2) ◽  
pp. 33-38 ◽  
Author(s):  
ANNA JONHED ◽  
LARS JÄRNSTRÖM
Keyword(s):  
Phase Separation ◽  
Contact Angles ◽  
Low Ph ◽  
Hydrophobically Modified ◽  
Paper Sizing ◽  
Surface Sizing ◽  
Separation Temperature ◽  
Hydrophobic Nature ◽  
Sizing Agents ◽  
Charge Temperature

The aim of this study was to investigate the properties of hydrophobically modified (HM) quaterna-ry ammonium starch ethers for paper sizing. These starches possess temperature-responsive properties; that is, gelation or phase separation occurs at a certain temperature upon cooling. This insolubility of the HM starches in water at room temperature improved their performance as sizing agents. The contact angles for water on sized liner were substantially larger than on unsized liner. When the application temperature was well above the critical phase-separation temperature, larger contact angles were obtained for liner independently of pH compared with those at the lower application temperature. Cobb60 values for liner decreased upon surface sizing, with a low pH and high application temperature giving lower water penetration. Contact angles on greaseproof paper decreased upon sur-face sizing as compared to unsized greaseproof paper, independently of pH and temperature. Greaseproof paper showed no great difference between unsized substrates and substrates sized with HM starch at different pH. This is probably due to the already hydrophobic nature of greaseproof paper. However, the Cobb60 values increased at low pH and low application temperature. Surfactants were added to investigate how they affect the sized surface. Addition of surfactant reduces the contact angles, in spite of indications of complex formation.

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