Edaphic Characterization, Water and Salt Translocation in Saline Marsh at Local Scale in Songnein Plain, Northeast China

2011 ◽  
Vol 383-390 ◽  
pp. 3744-3750
Author(s):  
Yong Jie Wang ◽  
Jin Ming Luo ◽  
Wen Feng Wang ◽  
Zhong Yan Gao ◽  
Shi Liang Pang
Keyword(s):  
Surface Layer ◽  
Water Content ◽  
Water Conservation ◽  
Northeast China ◽  
Local Scale ◽  
In Situ Observation ◽  
Meadow Soil ◽  
Alkali Soil ◽  
Saline Marsh ◽  
Freeze And Thaw

The degradation of saline marsh in Songnen plain was controlled by many factors. Based on in-situ observation and laboratory analysis, soil properties and matters translocation in Zhalong wetland at local scale as affected by freeze and thaw action was explored. Results show that within the study plot, 1500 m in distance, but varying only 80 cm in altitude, existed four types of soils i.e. Shallow-horizon Alkalic Halosols (SAH), Crust Alkalic Halosols (CAH) and Para-alkalic Dark-Aquic Cambosols (PDC) and Sodic Hapli-Orthic Gleyosols (SHG). High content total porosity with amounts to 62% in surface horizon in marsh would help to water conservation and wetland formation. In contrast, large rate of silt or clay in texture in alkali soil and meadow soil constrain the water content in topsoil, i.e. the saturated water content 0-30 cm horizon of meadow soil and alkali soil were merely 0.83 and 0.7 m3m-3. Residues & roots in surface layer of SHG expand the period of freezing phase as long as 9 months comparing to 7 months in SAH, and maximum freezing fringe in the former was 24 cm deeper than the latter (178 cm versus 154 cm). Seasonal freeze and thaw action has obvious influence on water storage in topsoil in saline marsh, leading different of soil succession therein. Soil moisture content in the surface layer of marsh increased from 2.05 to 2.62 m3m-3(over-saturated), but no obvious change in PDC and Alkali soils. In contrast, electrical conductivity of saturated paste in SAH and CAH increased from 6.5 to above 10 dS m-1. Therefore, it did not accord with the practical situation of Northeast China as that of strong evaporation was the only cause that caused saline marsh alkalinization. Protecting the vegetation or restoring surface coverage by plant in saline land in spring may help land dealkalization in high latitude arid & semiarid regions.

scholarly journals High diversity of nitrogen-fixing bacteria in the upper reaches of the Heihe River, northwestern China

2013 ◽  
Vol 10 (8) ◽  
pp. 5589-5600 ◽  
Author(s):  
X. S. Tai ◽  
W. L. Mao ◽  
G. X. Liu ◽  
T. Chen ◽  
W. Zhang ◽  
...  
Keyword(s):  
Water Conservation ◽  
Bacterial Communities ◽  
Nifh Gene ◽  
Qilian Mountains ◽  
Northwestern China ◽  
Heihe River ◽  
Meadow Soil ◽  
Nitrogen Fixing ◽  
Nitrogen Fixing Bacteria ◽  
Gene Copies

Abstract. Vegetation plays a key role in water conservation in the southern Qilian Mountains (northwestern China), located in the upper reaches of the Heihe River. Nitrogen-fixing bacteria are crucial for the protection of the nitrogen supply for vegetation in the region. In the present study, nifH gene clone libraries were established to determine differences between the nitrogen-fixing bacterial communities of the Potentilla parvifolia shrubland and the Carex alrofusca meadow in the southern Qilian Mountains. All of the identified nitrogen-fixing bacterial clones belonged to the Proteobacteria. At the genus level, Azospirillum was only detected in the shrubland soil, while Thiocapsa, Derxia, Ectothiorhodospira, Mesorhizobium, Klebsiella, Ensifer, Methylocella and Pseudomonas were only detected in the meadow soil. The phylogenetic tree was divided into five lineages: lineages I, II and III mainly contained nifH sequences obtained from the meadow soils, while lineage IV was mainly composed of nifH sequences obtained from the shrubland soils. The Shannon–Wiener index of the nifH genes ranged from 1.5 to 2.8 and was higher in the meadow soils than in the shrubland soils. Based on these analyses of diversity and phylogeny, the plant species were hypothesised to influence N cycling by enhancing the fitness of certain nitrogen-fixing taxa. The number of nifH gene copies and colony-forming units (CFUs) of the cultured nitrogen-fixing bacteria were lower in the meadow soils than in the shrubland soils, ranging from 0.4 × 107 to 6.9 × 107 copies g−1 soil and 0.97 × 106 to 12.78 × 106 g−1 soil, respectively. Redundancy analysis (RDA) revealed that the diversity and number of the nifH gene copies were primarily correlated with aboveground biomass in the shrubland soil. In the meadow soil, nifH gene diversity was most affected by altitude, while copy number was most impacted by soil-available K. These results suggest that the nitrogen-fixing bacterial communities beneath Potentilla were different from those beneath Carex.

scholarly journals Long Term Effects of Ploughing and Conservation Tillage Methods on Earthworm Abundance and Crumb Ratio

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1552 ◽  
Author(s):  
Igor Dekemati ◽  
Barbara Simon ◽  
Igor Bogunovic ◽  
Ivica Kisic ◽  
Katalin Kassai ◽  
...  
Keyword(s):  
Water Content ◽  
Water Conservation ◽  
Conservation Tillage ◽  
Soil Tillage ◽  
Long Term Effects ◽  
No Till ◽  
Cover Ratio ◽  
One Year ◽  
Tillage Methods

In addition to the dry (D) and rainy (R) seasons, a combination of the two i.e., rainy-dry (RD) and dry-rainy (DR), can also be observed in one year. The effects of the dry (D) and rainy (R) on soil are known, hence we hypothesized that the effects of the rainy-dry (RD) and dry-rainy (DR) periods on soil may differ from the former assessments. The aim of the study is to investigate the effect of six tillage treatments (ploughing—P, disk tillage—DT, loosening—L, tine tillage (a deeper—T and a shallower—ST) and no-till—NT) on earthworm abundance and crumb ratio during a long-term research (16 years) on Chernozems. The results related to the four year-groups (D, R, RD, and DR) with different residue cover. Seven degrees of cover ratio (between 12.5% and 62.5%) were selected on stubbles. Higher cover ratio (≥52.5%) improved water conservation, increased earthworm abundance (31 and 41 ind m–2) and crumb (78 and 82%) ratio (p < 0.01). R year came first in the rank of water content and earthworm abundance and DR proved to be more favorable for crumb formation. Considering the rank of soil tillage treatments, ST takes first place in evaluation of soil water content (SWC) and crumb ratio, and NT for earthworm abundance.

Flood forecasting that considers the impact of hydraulic projects by an improved TOPMODEL model in the Wudaogou basin, Northeast China

2016 ◽  
Vol 16 (5) ◽  
pp. 1467-1476 ◽  
Author(s):  
Yong Peng ◽  
Jinggang Chu ◽  
Xinguo Sun ◽  
Huicheng Zhou ◽  
Xiaoli Zhang
Keyword(s):  
Water Conservation ◽  
Northeast China ◽  
Storage Capacity ◽  
Flood Simulation ◽  
Soil Moisture Storage ◽  
Moisture Storage ◽  
Flood Simulations ◽  
Model Parameter Uncertainty ◽  
The Impact ◽  
Engineering Projects

Many hydraulic projects such as reservoirs, ponds and paddy fields as well as soil and water conservation engineering projects have been constructed to improve utilization of water resources upstream of the Wudaogou station basin in Northeast China in recent years. As a result, the local hydrological characteristics of the basin and the flood runoff and process have been changed. These changes in the basin characteristics make basin hydrological forecasting more difficult. In order to model and assess this situation, the TOPMODEL, which includes the dynamic soil moisture storage capacity (DSMSC-TOPMODEL), is used in this study to simulate the flood impact of hydraulic projects. Furthermore, the Bayesian method is used to evaluate model parameter uncertainty and assess the TOPMODEL's performance over the basin. Flood simulation results show that accuracy is significantly improved when the stock version of TOPMODEL is replaced with DSMSC-TOPMODEL, with the qualified ratio of forecasting runoff yield increasing from 65% in the former to 88% in the latter. Moreover, these flood simulations are more suitable for helping observers visualize the process.

scholarly journals THE ROLE OF WATER IN PROTOPLASMIC PERMEABILITY AND IN ANTAGONISM

1956 ◽  
Vol 39 (6) ◽  
pp. 963-976 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Surface Layer ◽  
Water Content ◽  
Active Substance ◽  
External Medium ◽  
Surface Active Substance ◽  
Potassium Ions ◽  
Protoplasmic Surface ◽  
Outer Protoplasmic Surface ◽  
Aqueous Surface ◽  
Surface Active

The behavior of the cell depends to a large extent on the permeability of the outer non-aqueous surface layer of the protoplasm. This layer is immiscible with water but may be quite permeable to it. It seems possible that a reversible increase or decrease in permeability may be due to a corresponding increase or decrease in the water content of the non-aqueous surface layer. Irreversible increase in permeability need not be due primarily to increase in the water content of the surface layer but may be caused chiefly by changes in the protoplasm on which the surface layer rests. It may include desiccation, precipitation, and other alterations. An artificial cell is described in which the outer protoplasmic surface layer is represented by a layer of guaiacol on one side of which is a solution of KOH + KCl representing the external medium and on the other side is a solution of CO2 representing the protoplasm. The K+ unites with guaiacol and diffuses across to the artificial protoplasm where its concentration becomes higher than in the external solution. The guaiacol molecule thus acts as a carrier molecule which transports K+ from the external medium across the protoplasmic surface. The outer part of the protoplasm may contain relatively few potassium ions so that the outwardly directed potential at the outer protoplasmic surface may be small but the inner part of the protoplasm may contain more potassium ions. This may happen when potassium enters in combination with carrier molecules which do not completely dissociate until they reach the vacuole. Injury and recovery from injury may be studied by measuring the movements of water into and out of the cell. Metabolism by producing CO2 and other acids may lower the pH and cause local shrinkage of the protoplasm which may lead to protoplasmic motion. Antagonism between Na+ and Ca++ appears to be due to the fact that in solutions of NaCl the surface layer takes up an excessive amount of water and this may be prevented by the addition of suitable amounts of CaCl2. In Nitella the outer non-aqueous surface layer may be rendered irreversibly permeable by sharply bending the cell without permanent damage to the inner non-aqueous surface layer surrounding the vacuole. The formation of contractile vacuoles may be imitated in non-living systems. An extract of the sperm of the marine worm Nereis which contains a highly surface-active substance can cause the egg to divide. It seems possible that this substance may affect the surface layer of the egg and cause it to take up water. A surface-active substance has been found in all the seminal fluids examined including those of trout, rooster, bull, and man. Duponol which is highly surface-active causes the protoplasm of Spirogyra to take up water and finally dissolve but it can be restored to the gel state by treatment with Lugol solution (KI + I). The transition from gel to sol and back again can be repeated many times in succession. The behavior of water in the surface layer of the protoplasm presents important problems which deserve careful examination.

scholarly journals Enhancing Soil Water Content for Increased Food Production in Semi-Arid Areas of Kenya Results From an On-Farm Trial in Mwala District, Kenya

2014 ◽  
Vol 6 (4) ◽  
pp. 125 ◽  
Author(s):  
Anne Karuma ◽  
Peter Mtakwa ◽  
Nyambilila Amuri ◽  
Charles K. Gachene ◽  
Patrick Gicheru
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Water Conservation ◽  
Crop Yields ◽  
Conservation Tillage ◽  
Cropping Systems ◽  
Soil Conditions ◽  
Tillage Methods

Soil water conservation through tillage is one of the appropriate ways of addressing soil moisture deficit in rainfed agriculture. This study evaluated the effects of tillage practices on soil moisture conservation and crop yields in Mwala District, Eastern Kenya during the long rains (LR) and short rains (SR) of 2012/13. Six tillage systems: Disc plough (MB), Disc plough and harrowing (MBH), Ox-ploughing (OX), Subsoiling – ripping (SR), Hand hoe and Tied Ridges (HTR) and Hand hoe only (H) and, three cropping systems namely, sole maize, sole bean and maize - bean intercrop, were investigated in a split-plot design with four replicates. Data on soil water content was monitored at different weeks after planting and the crop yields at end of each growing season. A three-season average shows that soil water content and crop yields were higher in conventional tillage methods compared to the conservation tillage methods. Long term tillage experiments are thus required at different locations, under various environmental and soil conditions to validate the study findings.

Towards opensource LOD2 modelling of urban spaces using an optimised machine learning and rules-based approach.

2020 ◽  
Author(s):  
Tom Rowan ◽  
Adrian Butler
Keyword(s):  
Water Management ◽  
Machine Learning ◽  
Water Conservation ◽  
Three Dimensional ◽  
Flood Management ◽  
Local Scale ◽  
Small Scale ◽  
Test Case ◽  
Local Planning ◽  
Scale Modelling

&lt;p&gt;&lt;span&gt;In order to enable community groups and other interested parties to evaluate the effects of flood management, water conservation and other hydrological issues, better localised mapping is required.&amp;#160; Although some maps are publicly available many are behind paywalls, especially those with three dimensional features. &amp;#160;In this study London is used as a test case to evaluate, machine learning and rules-based approaches with opensource maps and LiDAR data to create more accurate representations (LOD2) of small-scale areas. &amp;#160;Machine learning is particularly well suited to the recognition of local repetitive features like building roofs and trees, while roads can be identified and mapped best using a faster rules-based approach. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;In order to create a useful LOD2 representation, a user interface, processing rules manipulation and assumption editor have all been incorporated. Features like randomly assigning sub terrain features (basements) - using Monte-Carlo methods - and artificial sewage representation enable the user to grow these models from opensource data into useful model inputs. This project is aimed at local scale hydrological modelling, rainfall runoff analysis and other local planning applications. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;&amp;#160;&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The goal is to provide turn-key data processing for small scale modelling, which should help advance the installation of SuDs and other water management solutions, as well as having broader uses. The method is designed to enable fast and accurate representations of small-scale features (1 hectare to 1km&lt;sup&gt;2&lt;/sup&gt;), with larger scale applications planned for future work. &amp;#160;This work forms part of the CAMELLIA project (Community Water Management for a Liveable London) and aims to provide useful tools for local scale modeller and possibly the larger scale industry/scientific user. &lt;/span&gt;&lt;/p&gt;

scholarly journals Hydrophysical characteristics of selected soils from arctic and temperate zones

2015 ◽  
Vol 29 (4) ◽  
pp. 525-531
Author(s):  
Barbara Witkowska-Walczak ◽  
Piotr Bartmiński ◽  
Cezary Sławiński
Keyword(s):  
Surface Layer ◽  
Water Content ◽  
Soil Water ◽  
Water Retention ◽  
Temperate Zone ◽  
The Arctic ◽  
Arctic Zone ◽  
Water Conductivity ◽  
Water Potentials ◽  
Subsurface Layers

Abstract Hydrophysical characteristics of arctic and temperate zones soils were determined. The soils from the temperate zone showed a greater capability of water retention than those from the arctic zone. In both investigated depths (surface and subsurface layers), the highest water content was observed for the Sądecki Regosol, and the lowest one for Turbic Cryosol formed in the cell forms from Spitsbergen at all soil water potentials. The differences between water content for these soils at the same soil water potentials varied between 20 and 25% vol. in the surface layer, and from 19 to 22% vol. in the subsurface, respectively. The lowest differences (2.7-5.0% vol.) in water content were noticed between the Wyspowy Regosol and Turbic Cryosol (Skeletic) derived in the sorted circles. In both depths, higher values of water conductivity were observed for Regosols than for Cryosols at high soil water potentials, from -0.1 till -7 kJ m-3. These differences were especially high at -0.1 kJ m-3 and they were three or four times higher for soils from the temperate zone than from the arctic ones. For lower water potentials, the differences in water conductivity do not exceed one order in the surface layer and two orders in the subsurface.

scholarly journals The impacts of freeze–thaw cycles on saturated hydraulic conductivity and microstructure of saline–alkali soils

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wenshuo Xu ◽  
Kesheng Li ◽  
Longxiao Chen ◽  
Weihang Kong ◽  
Chuanxiao Liu
Keyword(s):  
Hydraulic Conductivity ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Water Content ◽  
Size Distribution ◽  
Saturated Hydraulic Conductivity ◽  
High Water Content ◽  
Soil Permeability ◽  
Freeze Thaw ◽  
Alkali Soil

AbstractStudy on the microscopic structure of saline–alkali soil can reveal the change of its permeability more deeply. In this paper, the relationship between permeability and microstructure of saline–alkali soil with different dry densities and water content in the floodplain of southwestern Shandong Province was studied through freeze–thaw cycles. A comprehensive analysis of soil samples was conducted using particle-size distribution, X-ray diffraction, freeze–thaw cycles test, saturated hydraulic conductivity test and mercury intrusion porosimetry. The poor microstructure of soil is the main factor that leads to the category of micro-permeable soil. The porosity of the local soil was only 6.19–11.51%, and ultra-micropores (< 0.05 μm) and micropores (0.05–2 μm) dominated the pore size distribution. Soil saturated water conductivity was closely related to its microscopic pore size distribution. As the F–T cycles progressed, soil permeability became stronger, with the reason the pore size distribution curve began to shift to the small pores (2–10 μm) and mesopores (10–20 μm), and this effect was the most severe when the freeze–thaw cycle was 15 times. High water content could promote the effects of freeze–thaw cycles on soil permeability and pore size distribution, while the increase of dry density could inhibit these effects. The results of this study provide a theoretical basis for the remediation of saline–alkali soil in the flooded area of Southwest Shandong.

Effects of degree of compaction and fines content of the subgrade bottom layer on moisture migration in the substructure of high-speed railways

2017 ◽  
Vol 232 (4) ◽  
pp. 1197-1210 ◽  
Author(s):  
Ren-Peng Chen ◽  
Han-Lin Wang ◽  
Peng-Yun Hong ◽  
Yu-Jun Cui ◽  
Shuai Qi ◽  
...  
Keyword(s):  
Surface Layer ◽  
Water Content ◽  
High Speed ◽  
Bottom Layer ◽  
Volumetric Water Content ◽  
Water Retention Capacity ◽  
Wetting Front ◽  
Moisture Migration ◽  
Double Line ◽  
Fines Content

Moisture migration and distribution in the substructure are found to be the important reasons for water-related problems in high-speed railways. In this study, a numerical model of a double-line ballastless track-bed consisting of a substructure (subgrade surface layer, subgrade bottom layer and subsoil) and a superstructure (including two concrete bases right above the substructure) was established. The superstructure was considered as an impermeable boundary in this model, while two fissures were set at the joint edges of the left-line concrete base and the surface layer, simulating the infiltration area of rainwater. The effects of degree of compaction and fines content of the bottom layer due to moisture migration in the high-speed railway substructure were investigated on this model by applying and analyzing the 2013 rainfall data of Hangzhou, China, for a three-year period. The results show that the saturation zones develop in the subgrade, after a three-year period, with the size increasing with the increase in the degree of compaction or fines content due to higher water retention capacity and lower permeability of the soil. Furthermore, the variations of volumetric water content at different depths of the left-fissure profile indicate that as the degree of compaction or fines content increases, the arriving time of the wetting front increases, but the fluctuation amplitude of the volumetric water content after the arrival of the wetting front decreases on the whole. The degree of compaction appears to present a more significant impact on these two parameters. In particular, a threshold value of the degree of compaction between 0.90 and 0.93 is observed, prolonging the arriving time of the wetting front remarkably at a certain elevation. Besides, it takes a longer time for the wetting front to pass through the interface between the surface layer and the bottom layer for each case. From a practical point of view, it will be beneficial to employ drainage methods to drain out the water before it reaches the bottom layer.

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