Construction And Test of An Instrumented 2D Channel With Rainfall And Insolation Control.

2021 ◽  
Author(s):  
Bruno Rogerio da Hora Lobo ◽  
Sandro Lemos Machado ◽  
Edson Pereira Marques Filho
Keyword(s):  
Clayey Soil ◽  
Soil Layer ◽  
Clayey Soils ◽  
Capillary Barrier ◽  
Shrinkage Cracks ◽  
Arid Conditions ◽  
One Year ◽  
Semi Arid ◽  
Coarse Soil

Abstract This paper presents the construction and testing of a large instrumented 2D channel for the simulation of the performance of compacted barriers under controlled conditions of insolation and rainfall. Details of the main apparatus devices and capabilities and the results of a long-term test performed on a capillary barrier (CB) are presented. The performed test aimed to simulate the CB behavior over a period of one year in typical semi-arid conditions. The channel behavior was considered very promising with its components functioning as expected and providing the desired information. Concerning the CB performance, it is shown that the upper clayey layer of soil presented undesirable shrinkage cracks that impacted the CB performance, mainly at the end of the period of evaluation. The obtained results point to the need to use of silty or low plasticity clayey soils in the CB design, despite the higher expected values of hydraulic conductivity, as well as the adoption of layers thicker than usual in order to preserve the integrity of the clayey soil near the interface with the bottom coarse soil layer.

Long-Term Solute Transport under Semi-Arid Conditions: Pedon to Field Scale

2006 ◽  
Vol 5 (1) ◽  
pp. 365-376 ◽  
Author(s):  
S. A. Woods ◽  
R. G. Kachanoski ◽  
M. F. Dyck
Keyword(s):  
Solute Transport ◽  
Field Scale ◽  
Arid Conditions ◽  
Semi Arid

Long-term Movement of a Chloride Tracer under Transient, Semi-Arid Conditions

2003 ◽  
Vol 67 (2) ◽  
pp. 471 ◽  
Author(s):  
M. F. Dyck ◽  
R. G. Kachanoski ◽  
E. de Jong
Keyword(s):  
Arid Conditions ◽  
Semi Arid

Long-term Movement of a Chloride Tracer under Transient, Semi-Arid Conditions

2003 ◽  
Vol 67 (2) ◽  
pp. 471-477 ◽  
Author(s):  
M. F. Dyck ◽  
R. G. Kachanoski ◽  
E. de Jong
Keyword(s):  
Arid Conditions ◽  
Semi Arid

scholarly journals Can Soil Penetration Resistance and Bulk Density Be Determined in a Single Undisturbed Sample?

2015 ◽  
Vol 39 (3) ◽  
pp. 763-766
Author(s):  
Carolina Fernandes ◽  
Roniram Pereira da Silva ◽  
Adolfo Valente Marcelo
Keyword(s):  
Bulk Density ◽  
Clayey Soil ◽  
Soil Layer ◽  
Penetration Resistance ◽  
Clayey Soils ◽  
Undisturbed Soil ◽  
Soil Penetration Resistance ◽  
Undisturbed Sample ◽  
Randomized Experimental Design ◽  
Density Values

Soil quality indicators such as penetration resistance (PR) and bulk density (BD) are traditionally determined in a single undisturbed soil sample. The aim of this study was to assess the effect of PR measurements of undisturbed samples on the determination of BD in the same sample of two soils differing in clay contents. To this end, samples were collected from the 0.00-0.10 and 0.10-0.20 m layers of two soils of clayey and very clayey texture. Volumetric rings were used to collect a total of 120 undisturbed soil samples from each soil layer that were divided into two subsets containing 60 units each. One sample set, designated “perforated samples”, was used to determine PR and BD in the same undisturbed sample; the other, named “intact samples”, was used to determine BD only. Bulk density values for perforated and intact samples were compared by analysis of variance, using a completely randomized experimental design. Means were compared by the t-test at 5 %. The BD values for the clayey soil were similar in perforated and intact samples from the two layers. However, BD of the very clayey soil was lower in the perforated than in the intact samples at both depths. Therefore, PR and BD in clayey soils can be accurately determined in the same undisturbed sample whereas in very clayey soils, different samples are required for this purpose.

Enzyme activity, microbial biomass and community structure in a long-term restored soil under semi-arid conditions

Soil Research ◽  
2015 ◽  
Vol 53 (5) ◽  
pp. 553 ◽  
Author(s):  
I. F. Torres ◽  
F. Bastida ◽  
T. Hernández ◽  
J. Albaladejo ◽  
C. García
Keyword(s):  
Enzyme Activity ◽  
Microbial Community ◽  
Microbial Biomass ◽  
Organic Amendment ◽  
Protein Extraction ◽  
Phospholipid Fatty Acid ◽  
Organic Amendments ◽  
Arid Conditions ◽  
Semi Arid

Our aim was to evaluate the long-term influences of urban organic amendments on the enzymes involved in the carbon cycle under semi-arid conditions, including changes in the biomass and structure of the microbial community. A soil was restored 24 years ago with an organic amendment based on domestic organic waste. Organic amendment was applied to soil in order to increase the content of total organic carbon (TOC) by 0.5% and 1.5% with respect to the original TOC content. Enzyme isoform composition was studied by using zymographic techniques based on protein extraction, separation by gel electrophoresis and further enzyme-specific, in-gel staining. Total cellulose and β-glucosidase activities, microbial biomass estimated by phospholipid-fatty acid analysis and the number of isoforms of each enzyme showed increases related to the initial amount of organic amendment and the consequent development of vegetation. The information obtained by enzyme activity assays may be improved by the use of zymographic techniques, which allow the investigation of the variety of isoforms of each enzyme. This information could improve the understanding of the relationship between the microbial community and carbon cycling in restored areas.

Soft Ground Improvements Using Natural Fiber

2007 ◽  
Vol 544-545 ◽  
pp. 629-632
Author(s):  
Ju Hyong Kim ◽  
Sam Deok Cho ◽  
Yeon Soo Jang ◽  
Soo Sam Kim
Keyword(s):  
Tensile Strength ◽  
Discharge Capacity ◽  
Natural Fiber ◽  
Sea Water ◽  
Clayey Soil ◽  
Natural Fibers ◽  
Clayey Soils ◽  
Initial Discharge Capacity ◽  
Initial Discharge

In this study, natural fiber drains made with coconut coir, rice straw and jute filter were tested to evaluate their practical applicability if used in fields properly. Firstly, the tensile strength, and discharge capacity of the natural fiber drains were tested and verified prior to usage. Based on the test results, natural fiber drains excelled in tensile strength, but their initial discharge capacity obtained from composite discharge capacity tests was less than that of plastic drain board. Although their initial discharge capacity was relatively low compared to that of plastic drain board, the surface settlement from installation of the natural fiber drains, which is one of the most important factors to control the construction progress, was identical to that of plastic drain board. Therefore, it was concluded that the natural fiber drain boards satisfy the required minimum discharge capacity as a vertical drain and have great potential as a substitute for conventional plastic drain board. Secondly, long term changes in tensile strength of natural fiber drains embedded in sea water and clayey soil were examined. The tensile strength of fiber drain board in clayey soils decreased with time. These results indicated active decomposition of natural fibers embedded in sea water and clayey soils.

scholarly journals Vertical Distributions of Soil Nutrients and Their Stoichiometric Ratios as Affected by Long Term Grazing and Enclosing in a Semi-Arid Grassland of Inner Mongolia

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 382
Author(s):  
Juan Hu ◽  
Daowei Zhou ◽  
Qiang Li ◽  
Qicun Wang
Keyword(s):  
Soil Nutrients ◽  
Inner Mongolia ◽  
Surface Soil ◽  
Soil Layer ◽  
Available Phosphorus ◽  
Available Nitrogen ◽  
Vertical Distributions ◽  
Stoichiometric Ratios ◽  
Semi Arid

Grazing and enclosing are two of the most important grassland managements. In order to evaluate the effects of different managements on the ecosystem balance of grassland, the vertical distributions of soil nutrients and their stoichiometric ratios were determined in the plots of grazing and enclosing over 38 years in a semi-arid grassland of Inner Mongolia. The results showed that total nitrogen (TN), total phosphorus (TP), available nitrogen (AN), calcium (Ca), magnesium (Mg) and sulfur (S) contents in 0–100 cm soil in the long term enclosing plot were lower than the long term grazing plot and these changes were much greater in the surface soil than in deep soil. However, the soil organic carbon (SOC) and available phosphorus (AP) contents in the long term enclosing plot in the surface soil were higher (p < 0.01) compared with the long term grazing plot. In addition, long term enclosing increased the C/N ratio in each soil layer and improved C/K and C/P ratios in the surface soil compared with long term grazing. However, significant decreases of N/P and N/K ratios in the long term enclosing plot in each soil layer were observed. In conclusion, enclosing for 38 years decreased most of nutrients and reduced the nutrients’ mineralization in the surface soil especially and thus might restrict nutrients cycling in a semi-arid grassland of Inner Mongolia.

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