Studies on Salt and Water Movement in Secondary Salinized Greenhouse Soil under Subsurface Drainage

2012 ◽  
Vol 518-523 ◽  
pp. 98-101
Author(s):  
Ting Ting Chang ◽  
Xiao Hou Shao ◽  
Jie Zhang ◽  
Long Wang
Keyword(s):  
Considerable Increase ◽  
Surface Soil ◽  
Water Movement ◽  
Drainage System ◽  
Subsurface Drainage ◽  
Greenhouse Soil ◽  
Moisture Contents ◽  
Field Investigations

The secondary salinized greenhouse soil was provided with subsurface pipe drainage system with drainage spacing 6 m and drain depth 0.4m to study the movement of salt and water. The field investigations indicated that the resalination rates of the surface soil with subsurface drainage system were lower than those with non-drained system (CK) in an irrigation circle of the crop. The resalination rate of the surface soil right above the drainage tubes (T1) was significantly lower than that between the two drainage tubes (T2). At the 5th day after irrigation, the soil volumetric moisture contents of different treatments were significantly decreased and the resalination of surface soil were obvious. The results showed a considerable increase of resalination rate after irrigation that was varied at the 5th day as following sequence: CK(10.6%) > T2(8%) > T1(7%).

Analysis of the Surface Soil EC Dynamics and the Economic Benefit under the Subsurface Drainage System

2013 ◽  
Vol 275-277 ◽  
pp. 2821-2826
Author(s):  
Yu Min Yan ◽  
Xue Wang ◽  
Mao Mao Hou
Keyword(s):  
Electric Conductivity ◽  
Groundwater Level ◽  
Economic Benefit ◽  
Surface Soil ◽  
Drainage System ◽  
Subsurface Drainage ◽  
Economic Benefits ◽  
Calculation Results ◽  
Economic Indexes ◽  
T1 And T2

Subsurface drainage was known as an effective method to solve salinity problems, in this paper, two different subsurface drainage systems were designed to study how the system affect the surface soil EC(electric conductivity), besides, the economic benefits of the system were evaluated. Results showed that: under the drainage system, the surface soil EC was in a trend of fluctuant reduction, the desalination ratio of T1.1, T1.2, T2.1, T2.2 and CK was 13.5%, 11.2%, 14.8%, 12.6%, and 6.0% respectively; the surface soil EC would present an rising trend in an irrigation cycle on account of the evaporation and the groundwater level, compared with CK, the drainage treatments could better suppress the soil resalination; the calculation results of economic indexes proved that both T1 and T2 could gain favorable economic benefits, and T2 was preferable with higher EIRR (16.4%), ENPV (4536$/hm2) and EBCR (1.48). The results also suggest that the subsurface drainage system was practicable from ecological and economic angle.

scholarly journals Advances and Challenging Issues in Subsurface Drainage Module Technology and BIOECODS: A Review

2018 ◽  
Vol 203 ◽  
pp. 07005 ◽  
Author(s):  
Abdurrasheed Sa'id Abdurrasheed ◽  
Khamaruzaman Wan Yusof ◽  
Husna Bt Takaijudin ◽  
Aminuddin Ab. Ghani ◽  
Muhammad Mujahid Muhammad ◽  
...  
Keyword(s):  
Drainage System ◽  
Numerical Data ◽  
Subsurface Drainage ◽  
Infiltration Capacity ◽  
Sustainable Solutions ◽  
Ecologically Sustainable ◽  
The Impact ◽  
Flow Attenuation ◽  
Permeability Rate ◽  
Over Time

Subsurface drainage modules are important components of the Bio-ecological Drainage System (BIOECODS) which is a system designed to manage stormwater quantity and quality using constructed grass swales, subsurface modules, dry and wet ponds. BIOECODS is gradually gaining attention as one of the most ecologically sustainable solutions to the frequent flash floods in Malaysia and the rest of the world with a focus on the impact of the subsurface modules to the effectiveness of the system. Nearly two decades of post-construction research in the BIOECODS technology, there is need to review findings and areas of improvement in the system. Thus, this study highlighted the key advances and challenges in these subsurface drainage modules through an extensive review of related literature. From the study, more work is required on the hydraulic characteristics, flow attenuation and direct validation methods between field, laboratory, and numerical data. Also, there is concern over the loss of efficiency during the design life especially the infiltration capacity of the module, the state of the geotextile and hydronet over time. It is recommended for the sake of higher performance, that there should be an onsite methodology to assess the permeability, rate of clogging and condition of the geotextile as well as the hydronet over time.

scholarly journals Effects of Surface Soil Removal on Dynamics of Dissolved Inorganic Nitrogen in a Snow-Dominated Forest

2001 ◽  
Vol 1 ◽  
pp. 527-533 ◽  
Author(s):  
M. Ozawa ◽  
H. Shibata ◽  
F. Satoh ◽  
K. Sasa
Keyword(s):  
Soil Solution ◽  
Soil Removal ◽  
Surface Soil ◽  
Water Movement ◽  
Inorganic Nitrogen ◽  
Seasonal Fluctuation ◽  
Early Spring ◽  
Dissolved Inorganic Nitrogen ◽  
And Control ◽  
Treated Site

To clarify the effect of vegetation and surface soil removal on dissolved inorganic nitrogen (N) dynamics in a snow-dominated forest soil in northern Japan, the seasonal fluctuation of N concentrations in soil solution and the annual flux of N in soil were investigated at a treated site (in which surface soil, including understory vegetation and organic and A horizons, was removed) and control sites from July 1998 to June 2000. Nitrate (NO3–) concentration in soil solution at the treated site was significantly higher than that of the control in the no-snow period, and it was decreased by dilution from melting snow. The annual net outputs of NO3–from soil at the treated site and control sites were 257 and –12 mmol m–2year–1, and about 57% of the net output at the treated site occurred during the snowmelt period. NO3–was transported from the upper level to the lower level of soil via water movement during late autumn and winter, and it was retained in soil and leached by melt water in early spring. Removing vegetation and surface soil resulted in an increase in NO3–concentration of soil solution, and snowmelt strongly affected the NO3–leaching from treated soil and the NO3–restoration process in a snow-dominated region.

scholarly journals Radioactive Contamination due to 241Am Lightning Rod Failure

2020 ◽  
Vol 13 ◽  
pp. 262
Author(s):  
K. L. Karfopoulos ◽  
G. N. Papadakos ◽  
D. J. Karangelos ◽  
P. K. Rouni ◽  
N. P. Petropoulos ◽  
...  
Keyword(s):  
Health Risk ◽  
Gamma Ray ◽  
Surface Soil ◽  
Collection Efficiency ◽  
Drainage System ◽  
Radioactive Material ◽  
Building Roof ◽  
The Public ◽  
The People

It is estimated that until 1978 about 200000 lightning conductor rods with -a emitting sources attached to their end were installed worldwide. The sources were supposed to increase the lighting collection efficiency of these rods through the ionization of the surrounding air. Nevertheless, this improvement has never been established conclusively. Such devices are, in most cases, not accessible by the pub- lic; therefore, the dose to the population is considered insignificant. However, the possibility of radioactive material leakage, due to the source attachment failure, and the subsequent contamination of the surroundings that could lead to possible health risk of the public cannot be excluded. In this work, the case of 241Am contamination due to a lightning rod conductor failure is investigated. This contamination was accidentally detected on the surface soil around a laboratory building in the National Technical University of Athens Campus, during a routine in-situ gamma-ray measurement campaign that took place in 2003. A detailed survey revealed that this 241Am contamination was due to the leakage from two lightning rods on the building roof. Consequently the rods were removed from the building and the contamination pattern on the roof and on the surface soil around the building was examined in detail. From the results obtained so far it may be concluded that there exists well localized contamination on the roof and also around the building. It was established that the pathway through which contamination reached the ground was  the rainwater drainage system of the building. The gamma ray dose rate due to 241Am contamination found on the roof and on the surface soil is low compared to that due to its natural radioactivity and does not seem to pose any health risk to the people working in the building or to the public.

Field Investigations on Sediment Occurrence and Behaviour in Brussels Combined Sewers

1992 ◽  
Vol 25 (8) ◽  
pp. 71-82 ◽  
Author(s):  
M. Verbanck
Keyword(s):  
Drainage System ◽  
Solid Material ◽  
Field Studies ◽  
Main Trunk ◽  
Limited Mobility ◽  
Sediment Bed ◽  
Research Activities ◽  
Field Investigations ◽  
Dry Spells ◽  
Receiving Waters

Although sewer sediments are now widely recognized as a major source of misfunction of urban drainage systems (for both hydraulic and environmental considerations), it is still too infrequent that priority of research activities in this area is given to field studies. The measuring campaigns conducted since 1986 in the drainage system of Brussels-North have been focused on sedimentation processes in the major sewer lines. There is an obvious distinction to be made between solids constituting the sediment bed of a man-entry sewer, which are relevant for its hydraulic capacity, and the ones contributing to the pollutional impact of CSOs upon receiving waters. The material which is removed several times a year from the main trunk sewer of Brussels is coarse, granular and has a low environmental impact, notably because of its limited mobility. This appears to be due to a very efficient granulometric grading, as a result firstly of the retention of the coarsest solids in highly selective gully-pot inlets, and secondly of an elutriation process removing from the sediment bed all fine organic-rich particles during daily peak flows. There is evidence to show that the build-up of the sediment bed in these large-sized sewers is driven by a bed-load process (active even during dry spells), while the solid material responsible for the detrimental effects of CSOs (which is much finer) is primarily transported through wash-load and suspended-load.

Risk Analysis of Permeable Layer in Pavement Subsurface Drainage System

2019 ◽  
Vol 145 (3) ◽  
pp. 04019028 ◽  
Author(s):  
Shubham A. Kalore ◽  
G. L. Sivakumar Babu ◽  
Rajib B. Mallick
Keyword(s):  
Risk Analysis ◽  
Drainage System ◽  
Subsurface Drainage ◽  
Permeable Layer

Changes in the Diameter of Apical Dendrites During Spreading Depression

1958 ◽  
Vol 192 (3) ◽  
pp. 457-463 ◽  
Author(s):  
A. Van Harreveld
Keyword(s):  
Considerable Increase ◽  
Spreading Depression ◽  
Water Movement ◽  
Contralateral Hemisphere ◽  
Cortical Cells ◽  
Resistance Change ◽  
Resistance Increase ◽  
Extracellular Compartment ◽  
Transport Of Ions ◽  
Apical Dendrites

One of the concomitants of spreading depression is a considerable increase in the cortical electrical resistance. After cortical asphyxiation a similar resistance increase has been observed. It was postulated that these resistance increases are due to a transport of ions from the extracellular compartment into the cortical cells and fibers. To maintain osmotic equilibrium this has to be accompanied by water transport causing a swelling of cortical elements. A swelling of nerve cells and apical dendrites has been found to accompany the asphyxial resistance increase. In the present paper the diameters of apical dendrites during spreading depression were compared with the dendritic diameters in the contralateral hemisphere where no spreading depression was in progress. A mean increase in diameter of 17% was observed during spreading depression. No swelling of the apical dendrites was observed in the retrosplenial area which is not normally invaded by spreading depression. These findings support the notion that the resistance change during spreading depression is due to the same mechanism as that after cortical asphyxiation, namely to an ion transport accompanied by a water movement from extra- into intracellular spaces.

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