scholarly journals Redistribution of Zn towards light-density fractions and potentially mobile phases in a long-term manure-amended clayey soil

Geoderma ◽  
2021 ◽  
Vol 394 ◽  
pp. 115044
Author(s):  
Thiago A. Formentini ◽  
Isabelle Basile-Doelsch ◽  
Samuel Legros ◽  
Daniel Borschneck ◽  
Julia S. Venzon ◽  
...  
Keyword(s):  
Clayey Soil ◽  
Density Fractions ◽  
Mobile Phases ◽  
Light Density

scholarly journals A Study on the Characteristics of Stress History of Kwang-Yang Port Clayey Soil Based on the Long-term Consolidation Test

2012 ◽  
Vol 28 (6) ◽  
pp. 31-38
Author(s):  
Jin-Young Kim ◽  
Seung-Seok Ryu ◽  
Won-Jin Baek ◽  
Jae-Rok Shim ◽  
Jong-Shin Oh ◽  
...  
Keyword(s):  
Clayey Soil ◽  
Stress History ◽  
Consolidation Test ◽  
History Of

scholarly journals Pedogenic, mineralogical and land-use controls on organic carbon stabilization in two contrasting soils

2010 ◽  
Vol 90 (1) ◽  
pp. 15-26 ◽  
Author(s):  
A F Plante ◽  
I. Virto ◽  
S S Malhi
Keyword(s):  
Thermal Analysis ◽  
Organic Carbon ◽  
Clay Mineralogy ◽  
Density Fractionation ◽  
Scanning Calorimetry ◽  
Organic C ◽  
Soil C ◽  
Density Fractions

Organo-mineral complexation in soils is strongly controlled by pedogenesis, but the mechanisms controlling it and its interaction with cultivation are not yet well understood. We compared the mineralogy and quality of organic carbon (C) among organo-mineral fractions from two soils with contrasting pedogenic origin. Sequential density fractionation (SDF; using 1.6, 1.8, 2.1, 2.4 and 2.6 g mL-1 sodium polytungstate solutions) followed by thermal analysis was applied to a Chernozem from Ellerslie, Alberta, and a Luvisol from Breton, Alberta, each under native and cultivated land uses. Similar clay mineralogy suggested that pedogenic controls on organic C stabilization were related to long-term vegetation cover. In addition to large differences in total organic C quantities, bulk soil and isolated fractions showed significant differences in organic C quality. Samples under native vegetation revealed greater organo-mineral complexation at Ellerslie compared with Breton, as expressed by less solubilisation, more organic C recovered in intermediate-density fractions, and exothermic differential scanning calorimetry peak signals associated with more stable forms of organic C. Long-term cultivation resulted in an overall shift to more stable organo-mineral complexes. The proportion of soil C in the 2.1-2.4 g mL-1 fraction increased under cultivation from 21 to 32% in Breton samples, and from 6 to 16% in Ellerslie samples. The quality of inherited pedogenic soil organic C stored in a soil thus appears to determine its response to long-term cultivation.Key words: Cultivation, sequential density fractionation, organic carbon, organic matter, thermal analysis

scholarly journals Variation of soil organic matter depends on light-fraction organic matter under long-term monocropping of different crops  

2021 ◽  
Author(s):  
Futao Zhang ◽  
Yunfa Qiao ◽  
Xiaozeng Han ◽  
Bin Zhang
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Principal Component ◽  
Light Fraction ◽  
Bulk Soil ◽  
Density Fractions ◽  
Chemical Structures ◽  
Light Fraction Organic Matter ◽  
The Difference

Cultivating crops influences soil organic matter (SOM), but the effect of different crops remains unclear, particularly under long-term monocropping. The objective of this study was to identify how different crops influence the content and chemical structures of SOM under long-term monocropping. Here, soils were sampled (0–20 cm) under 27-year soybean and maize monocropping and separated into different physical fractions. The content and chemical structures of SOM in all fractions were determined. SOM contents were higher under soybean than maize in bulk soil and macroaggregates and their light-fractions instead of microaggregates and silt and clay. The difference in SOM chemical structure was observed in aggregates and density fractions rather than bulk soils and supported by the result of principal component analysis. The proportion of O-alkyl C in macro- and microaggregates and all free light fractions and that of aromatic C in mineral-associated fractions were higher, while that of carbonyl C was lower under maize than soybean. These results demonstrated that different crops monocropping influences the content and chemical structures of SOM, and the variations were mainly in the light-fraction SOM and highlight a higher sensitivity of physical fractions than bulk soil to different crops.  

scholarly journals Long-Term Tillage Induced Changes in Physical Attributes of a Clayey Soil in Eastern Mediterranean Region

2018 ◽  
Vol 1 (1) ◽  
pp. 32-39
Author(s):  
İsmail Çelik ◽  
Hikmet Günal ◽  
Mert Acar ◽  
Zeliha Barut Bereket ◽  
Nurullah Acir ◽  
...  
Keyword(s):  
Best Management Practices ◽  
Mediterranean Region ◽  
Clayey Soil ◽  
Eastern Mediterranean ◽  
Soil Health ◽  
Eastern Mediterranean Region ◽  
Root Penetration ◽  
Undisturbed Soil ◽  
Available Water

Abstract Comparing responses of the same soil under long-term different treatments is vital in determining the best management practices to conserve soil health and sustain productivity. This study was investigated to determine the effects of longterm (2006-2015) two conventional (CT), three reduced (RT) and a no-till (NT) treatment on bulk density (BD), field capacity (FC), wilting point (WP), available water content (AWC) and total porosity (TP) of a clayey soil in eastern Mediterranean region, Turkey. Undisturbed soil samples were collected from 0-10, 10-20 and 20-30 cm depths of experimental plots with a crop rotation of winter wheat (Triticum aestivum L.), soybean (Glycine max. L.), grain maize (Zea mays L.). The AWC under CT was higher than the RT and NT. The BD was increased with depth in all treatments, and was higher under RT and NT than the CT. The long-term experiment revealed that BD increase under long-term RT and NT should be monitored to avoid deterioration of soil health, and yield loss due to limiting root penetration and storing available water needed during drought periods.

scholarly journals LONG-TERM EXPOSURE TO MALARIA AND DEVELOPMENT: DISAGGREGATE EVIDENCE FOR CONTEMPORANEOUS AFRICA

2017 ◽  
Vol 83 (1) ◽  
pp. 129-148 ◽  
Author(s):  
Matteo Cervellati ◽  
Elena Esposito ◽  
Uwe Sunde
Keyword(s):  
Economic Development ◽  
Sickle Cell Trait ◽  
Local Development ◽  
Malaria Risk ◽  
High Exposure ◽  
Country Level ◽  
Malaria Exposure ◽  
Light Density

Abstract:Malaria afflicts mankind since thousands of years and still imposes serious health impediments and considerable mortality on the affected populations. Empirical investigations of the role of malaria for economic development at the country level deliver mixed findings, however. We study the role of long-term malaria exposure on development today using disaggregate within-country variation for the whole of Africa with 1 × 1 degree cells as units of observation. Local development is measured by light density at night. Based on insights from epidemiology, which documents that genetic and acquired immunities reduce Malaria risk for adults in holoendemic areas, the effect is hypothesized to be nonlinear, with a peak for intermediate rather than high exposure to the pathogen. The empirical findings support this hypothesis. The results also suggest the existence of a significant moderating effect of genetic immunities measured by the prevalence of the sickle cell trait in the population.

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