Saline Soil Area Research Articles

Mapping spatial variability of soil salinity in a coastal area located in an arid environment using geostatistical and correlation methods based on the satellite data

Saline lakes can increase the soil and water salinity of the coastal areas. The main aim of this study is to distinguish the characteristics of the spectral reflectance of saline soil, analyze the statistical relationship between soil EC and characteristics of the spectral reflectance of saline soil, and to map soil salinity east of the Maharloo Lake. The correlation between field measurements of electrical conductivity and remote sensing spectral indices was evaluated using multiple regression analysis. In this study, Kriging, CoKriging, and multiple regressions were applied for soil salinity mapping and classification using 100 soil samples. After radiometric, geometric, and atmospheric corrections of Landsat OLI images, the statistical correlation between the electrical conductivity of field measurements and spectral reflectance was investigated. According to obtained results, the modified salinity index (MSI) with the highest correlation (R2=0.78) was used as an auxiliary variable for the coKriging method. Kriging with a spherical model was selected for soil salinity mapping (RMSE = 50.5 and R2 = 0.18). The RMSE and R2 values for CoKriging were (43.2 and 0.42), respectively. Because of their acceptable R2 (=0.65) and low standard deviation (33.8) for salinity analysis, MSI and difference vegetation index (DVI) were used to estimate and zonate soil salinity in the study area. The results showed that soil salinity could be estimated via spectral indices with acceptable accuracy, R2 and RMSE. Overall, this method leads to a decrease in the costs involved in the soil mapping of saline soil areas.

Morphological Character Variability of Javanese Local Taro [Colocasia esculenta] Germplasm

<p>Taro (Colocasia esculenta) is a plant that has been long cultivated in Indonesia, which belongs to Colocasia genus and Araceae family. Taro has an ecological uniqueness, which can grow in an extreme condition such as on submergence area, saline soil, and shaded areas. In Indonesia, Java Island is the main concentrated area of taro plantation. This research aimed to investigate the variability of local taro germplasm from Java Island based on morphological character. A total of 164 accessions were planted in Pacet Field Experimental and were observed for its morphological characters, i.e. root and plant type, leaves, and corm characters. The Javanese taro local genetic resources indicated variation in some of its plant type characteristic and corm as well as several of leaves character. A total of 17 accessions were identified as a unique collection. The identification of suspected duplicate accessions within the collection may be strengthened further by molecular characterization in order to provide more accurate information regarding the genetic variability of taro collection.</p>

SALINE SOILS IN THE SOUTHERN PART OF THE ARARAT VALLEY: EXPERIENCE OF MAPPING BY LANDSAT-8 DATA

The distribution of saline soils in the southern part of the Ararat valley is considered in connection with the prospect of agriculture intensifying there. For an approximate assessment of the saline soils localization, satellite images of Landsat-8 with a resolution capacity of 30 m were used. Of the total area of the investigated territory, 111809 hectares, the plain part itself occupies about 75 thousand hectares, and the area of saline soils is 21503 ha. Consequently, within the plain part of the valley, suitable for agricultural use, saline soils, that require hydraulic engineering and (probably) chemical reclamation, occupy 28.7% of the area. Saline soils are least widespread in the western part of the plain, and most - in the central part at the foot of the Ararat Mount. In the eastern part, saline soils alternate with hydromorphic (overmoistened) soils. Key words : saline soils, space image, Ararat valley

Vegetation succession influences soil carbon sequestration in coastal alkali-saline soils in southeast China

The area of saline soils accounts for 8% of the earth’s surface, making these soils an important terrestrial carbon sink. Soil organic carbon (SOC), microbial biomass carbon (MBC), dissolved organic carbon (DOC), soil enzyme activity, and soil bacterial abundance and biodiversity were measured in four successive coastal tidal flat ecosystems representing: bare saline soil (BS), Suaeda glauca land (SL), Imperata cylindrica grassland (IG), and Jerusalem artichoke field (JF). A decrease in soil salt content resulted in increased SOC content. With vegetation succession, MBC and DOC concentrations showed a positive trend, and activities of soil urease, catalase, invertase and alkaline phosphatase increased. A next-generation, Illumina-based sequencing approach showed that Proteobacteria, Acidobacteria, Chloroflexi, Bacteroidetes, Gemmatimonadetes, Actinobacteria, Nitrospirae and Planctomycetes were the dominant bacterial communities (a total of 597 taxa were detected, and 27 genera showed significant differences among the vegetation communities). Bacterial diversity at two soil depths was enhanced with the succession of vegetation ecosystems, with the increases in operational taxonomic units (OTUs) and the Shannon and Chao1 indices ranked in the order: JF > IG > SL > BS. The SOC and C/N were the most determinant factors influencing diversity of bacterial communities in the succession ecosystems.

Accelerated Life Testing of Reinforced Concrete Based on Performance Degradation and Reliability Modeling

AbstractThis paper proposes a design for a testing program for accelerated life testing of reinforced concrete in the sulfite saline soil area. According to the situation of saline soil area, a con...

Types, harms and improvement of saline soil in Songnen Plain

Saline soil is an extremely difficult and modified soil, widely distributed around the world. According to UN-UNESCO and FAO, the world’s saline soil area is about 9.54×108hm2, and there is a growing trend, every year in 1.0×106-1.5×106hm2 speed growth, the effective utilization of land resources to the world is the most serious threat. The total area of saline-alkali land in China is about 9.91×107hm2, including the Songnen Plain, which is called one of the three major saline soil concentrations in the world. The Songnen plain is an important grain producing area in China, and the saline soil occupies most of the Songnen plain, so it is of great significance to study the saline soil and improvement in Songnen plain.

Salinity tolerance of germinating alternative oilseeds

Integrating oilseed crops into rotations can improve soil health benefits, nutrient retention, and pollinator provisions. Field margins represent areas where incorporation of oilseeds is feasible. However in the northern Great Plains, field margins can oftentimes be areas of saline soil, which can impact seed germination and seedling establishment. Therefore, a replicated growth chamber experiment was used to determine winter camelina (Camelina sativa), winter pennycress (Thlaspi arvense L.), echium (Echium plantogineum), cuphea (Cuphea viscosissima X Cuphea lanceolata), and calendula (Calendula officinalis) tolerance to germinating under saline conditions. A total of 50 seeds, replicated 3 times were germinated in petri dishes saturated with NaCl, CaCl, and Na2SO4 solution at 0, 0.2, 2, 4, 8, and 16 dS m−1 in an incubator at constant 20 °C. Fully germinated seeds were counted and removed daily for 7 days, followed by every other day for a total of 21 days. Final germination percent, corrected germination rate index, and germination velocity were calculated. Germination percent, corrected germination rate index and germination velocity were negatively affected by increases in salinity for camelina, pennycress, cuphea, and calendula. Echium germination was not impacted by salt or salinity level. Sodium based salts were more detrimental for camelina, pennycress, and calendula. Camelina and cuphea germination was tolerant to salinity, with average salinity thresholds of 8.0 and 3.1 dS m−1 and a 25% germination decline at 35.3 and 11.0 dS m−1, respectively. Pennycress and calendula germination was moderately tolerant to salinity with average salinity thresholds of 5.9 and 2.7 dS m−1 and a 25% germination decline at 9.4 and 7.7 dS m−1, respectively. These oilseeds show potential for adoption in saline soils.

Dynamics expression of Osr40c1 gene and growth of maize (Zea mays) calluses in responding to salt stress

Saputro TB, Sholihah NF, Ermavitalini D. 2017. Dynamics expression of Osr40c1 gene and growth of maize (Zea mays) calluses in responding to salt stress. Biodiversitas 18: 801-808. Maize (Zea mays L) is one of the most planted cereal plants worldwide. The demand of maize plant is increased over the years since its various usage in industry. Unfortunately, the production rate does not meet the demands caused by the significant reduction of plantation area for housing and the others building. The marginal saline soil area can be a promising area to grow the maize although contains a high amount of salt. The high concentration of salt can significantly reduce the plant growth and productivity. The aims of this study were to determine the tolerant level of Manding and Bluto varieties against salt stress. There were two main stages on this research. First, callus induction through in vitro culture (MS0 + 2,4-D 3 mg/L), then the calluses were subcultured on the selection medium (MS0 + 2,4-D 3 mg/L + NaCl concentrations (0, 2500, 5000 and 7500 mg/L)). Second, Q-PCR analysis was used to observe the differences of gene expression level. The result shows that NaCl stress can alter the color of callus, from yellow to brown. The percentage of surviving callus was 100% in both varieties, although the callus weight decreased along with the increment of NaCl concentrations. In 7500 mg/L, Manding has 0.023 g in fresh weight, while Bluto 0,027 gr. Interestingly, the expression of Osr40c1 gene showed different level between those two varieties. Manding had only 0.82 fold, while Bluto had 4.86 folds compared with the control. Taken together, Bluto has a better performance in high content of NaCl.

Pavement mechanic response of sulfate saline soil subgrade section based on fluid–structure interaction model

It is a consensus that salt heaving and frost heaving are urgent and typical distress in the sulfate saline soil area. To further investigate the microscopic performance of pavement structure in this special area, Jinan-Dongying Freeway in Shandong Province is selected as a case study engineering and the mechanic responses under salt heaving, frost heaving and traffic loads were analyzed through the finite element (FE) Program (ANSYS). In this paper, the process of salt heaving and frost heaving was divided into 3stages and FE models were established based on fluid–structure interaction (FSI) model. It is shown that under both effects of salt heaving and frost heaving, the tensile stress of asphalt surface course could be up to 96.75% of its tensile strength, which means its tensile strength was seriously inadequate; however, traffic loads could help to dramatically counteract effects of salt heaving and frost heaving, which could decrease 40–80% of the tensile stress in asphalt surface course. It is also shown that in Jinan-Dongying Freeway effects of salt heaving had slightly larger effects on pavement compared with that of frost heaving, probably because salt heaving occurred from the top to the bottom of subgrade. However, as a whole, in sulfate saline soil area, compared with general area, crack resistance of asphalt courses and foundation treatment should always be strengthened.

Pavement Mechanic Response in Sulfate Saline Soil Area Based on FSI Model

It is a consensus that salt heaving and frost heaving are typical distresses in the sulfate saline soil subgrade. To further investigate the mechanic response of pavement structure in sulfate saline soil area, a finite element(FE) model was established based on fluid-structure interaction(FSI) model in this paper. Then the mechanic response of the asphalt pavement under traffic loads, salt heaving and frost heaving was simulated and analyzed. It is shown that only under salt heaving and frost heaving, the tensile strength of asphalt surface course was seriously inadequate and that at the bottom of semi-rigid base course were negative, which may be helpful to crack resistance at the bottom of base courses. Besides, traffic loads could help to dramatically counteract displacement, tensile stress and strain. However, as a whole, in sulfate saline soil area, asphalt courses should strengthen crack resistance and foundation treatment.

A Study on the Coupled Model of Hydrothermal-Salt for Saturated Freezing Salinized Soil

Water and heat interact in the process of freezing for the saturated soil. And for the salinized soil, water, heat, and salt interact in the freezing process, because salinized soil has soluble salt. In this paper, a one-dimensional mathematical coupled model of hydraulic-thermal-salt is established. In the model, Darcy’s law, law of conservation of energy, and law of conservation of mass are applied to derive the equations. Consider that a saturated salinized soil column is subjected to the condition of freezing to model the moisture migration and salt transport. Both experiment and numerical simulation under the same condition are developed in the soil column. Then the moisture content and salt content between simulation and experiment are compared. The result indicates that simulation matches well with the experiment data, and after 96 hours, the temperature distribution becomes stable, freezing front reaches a stable position, and a lot of unfrozen water has time to migrate. Besides, the excess salt precipitates when the concentration is greater than the solubility, and the precipitation is distributed discontinuously. These results can provide reference for engineering geology and environmental engineering in cold region and saline soil area.

Analysis of the Culvert Foundation Settlement under Different Construction Methods in High Salinity Regions

In this paper, a key treatment technology of the culvert foundation is presented, which is on the high salt saturated fine sand in a new China local railway from XieTieshan to North Hobsonis. In the procedure，for the two kinds of culvert foundation treatment technology(gravel pile foundation and rubble replacement), the settlement laws of culvert under China-load are explored by comparing with the field observation data and numerical analysis conclusion. The results show that in saline soil area, using rubble fill to reinforce groundwork is a appropriate treatment technology for culvert foundation.

Influence of Polyacrylamide (pam) on the Soil and Water Conservation Effects of White Clover (trifolium Repens L)

In order to explore the technology of soil and water conservation in coastal saline soil area, improve the prevention and control of soil erosion, white clover (Trifolium repens L) combined with different dosage of polyacrylamide (PAM) was applied to the soil and water conservation in plot tests, and the influence of PAM on the soil and water conservation effects of white clover (Trifolium repens L) was examined. The results showed that compared to the only planting white clover, the addition of 1-5 g/m 2 PAM reduced soil erosion by 516.0-1326.3 t/(km 2 ·a), which were 29.5-75.8% of the yearly soil erosion; inhibited soil evapotranspiration by 24.3-43.4%; improved the total rain water interception by 18.0-44.1 mm; and decreased the cumulative percentage of water loss (CP) by 0.4-4.7% in the 30th day after the plants harvest. From the aspects of reduction efficiency of erosion modulus and reduction efficiency of evapotranspiration, the optimistic dosage of PAM was 1 g/m 2 . The synergy of PAM mainly focus on the early stage of white clover. In addition, PAM may still slightly prevent the water loss after the plants harvest.

Soil Salinity Mapping Using Satellite TM and Field Data in Southeastern Isfahan

This study aimed to evaluate the performance of TM satellite data acquired in June 2009 to map soil salinity in southeast of Isfahan province. Ground salinity data (EC) was collected within 9 pixels, covering an area of approximately 8100 m using stratified random sampling technique at 53 sample sites. Spectral indices including TM bands, BI, SI1, SI2 and SI3, PC1, PC2, PC3 and also multiple linear regression modeling and maximum likelihood classification techniques were applied to the geometrically corrected image. Results of regression analysis showed that the TM band 4 had the strongest relationship with EC data (R=0.48) and also the relationship of the modeling image using TM 3, TM 4, TM5 and PC3 was significant at the 99% confidence level. The accuracy assessment of the stratified TM4 and modeling image into five classes including 0-4, 4-20, 20-60, 60-100 and EC>100 ds/m indicated that there was more than 86% agreement with the field measurements of EC data. Therefore, it can be concluded that the discretely classified salinity maps have higher accuracy than regression methods for identifying broad areas of saline soils, and can be used as appropriate tools to manage and combat soil salinization.

Experimental Research on Engineering Properties of Natural Coarse Saline Soil as the Subgrade Filler

Bases on the project of typical natural coarse saline soil area ,Startis from the saline soil salt expansion characteristics of seven cycles of freeze-thaw cycling test and saline soil subgrade model test ,concluses not only the oil can make roadbed fillers for highway and first-class highway directily , but provides experiences for saline land area of natural coarse particles of high highway designs and construction engineering. Meanwhile, this paper also provides reference experiences for the design and construction of high level road engineering at natural coarse saline soil regions.

Subgrade Design and Construction Technology for Saline Soil Area

The design scheme and engineering construction technology are proposed for an accommodation highway subgrade on the basis of forming reasons and hazard analysis of saline soil in Xinjiang region. In the design, major measures adopted include basement replacement, setting aeolian sand layer and composite geotextile layer, strengthening the subgrade waterproofing and drainage, antiseptic treatment of structures, etc. This paper introduces the subgrade design and construction technology, of which the implementation and application on the test section have achieved a favorable effect and can be taken as the basis for design and construction of similar saline soil subgrade.

Identification of the valid reference genes for quantitative RT-PCR in annual ryegrass (Lolium multiflorum) under salt stress.

Annual ryegrass (Lolium multiflorum) is a cool-season annual grass cultivated worldwide for its high yield and quality. With the areas of saline soil increasing, investigation of the molecular mechanisms of annual ryegrass tolerance under salt stress has become a significant topic. qRT-PCR has been a predominant assay for determination of the gene expression, in which selecting a valid internal reference gene is a crucial step. The objective of present study was to evaluate and identify suitable reference genes for qRT-PCR in annual ryegrass under salt stress. The results calculated by RefFinder indicated that eEF1A(s) was the most stable reference gene in leaves, whereas EF1-a was the least stable; meanwhile, TBP-1 was the most optimal in roots and in all samples, and the eIF-5A shouldn’t be utilized for normalization of the gene expression. eEF1A(s) is more suitable than TBP-1 as reference gene in leaves when verified with P5CS1 and Cyt-Cu/Zn SOD genes. We should choose optimal reference genes in specific tissues instead of the most stable one selected from different conditions and tissues.

A study of soil dispersivity in Qian'an, western Jilin Province of China

Saline soil is vulnerable to water erosion because of its dispersivity. This characteristic has a great influence on dam and slope engineering. There is a large area of saline soil in western Jilin Province, the seasonal frost zone, and this soil is highly dispersive. We studied the properties of soil samples collected from vertical holes near Qian’an Dabusu Lake, assessing the particle size distribution and the chemical components. We also comprehensively identified the level of soil dispersivity by three standard methods, the pinhole test, the crumb test, and the double-hydrometer test. The soil composition and basic physicochemical properties are proved to be the most important factors which determine the dispersion degree of the saline soil. Our results showed that, within depth ranges from 0 to 1 m, silt particles highly influenced the soil dispersivity, and the total soluble salt accounted for ≥0.3%. At the first sampling point, in a tall soil column, the dispersion degree decreased with increasing depth, but this was not as obvious at the second sampling point, which was in a flat area. Nevertheless, the superficial soils of these two sampling sites were strongly dispersive, which must be taken into consideration for soil engineering in this region.

Spatial Variability of Soil Salinity under Subsurface Drainage

In the coastal area of eastern China with monsoon climate and high water table, soil salinity exhibits strong spatial heterogeneity at the field scale. Using basic tools of geostatistics and geographic information systems (GIS), we explored the spatial characteristics of soil salinity under rain-fed conditions and subsurface drainage. The results showed that (1) spatial variability in soil salinity could be reduced significantly by leaching with rain water and subsurface drainage (LD) during the rainy season. The variability in soil salinity after LD decreased from strong to moderate. (2) After LD, soil salinity remained at more than 0.85 g/kg irrespective of values before the rainy season. In other words, it was almost impossible to remove all the salts in the plow layer. (3) Spatial heterogeneity of soil salinity showed a homogenizing tendency based on the critical point of 7 g/kg. Soil salinity less than 7 g/kg (79% of samples) homogenized to within 1.5–2 g/kg under LD and that more than 7 g/kg decreased to 1.5–4.5 g/kg. However, at this level, most salt-tolerant crops could grow. (4) The homogeneity was also reflected in the transformation of salinity grade in different areas. Before LD, the moderately and heavily saline (2–10 g/kg) soil area accounted for 88% of the pilot field in which the heavily saline area constituted 57.45% of the total salt load within the 0- to 30-cm layer; after LD, the mildly saline (1–2 g/kg) area was dominant with more than 75% ratio, contributing 65.24% of total salt load. (5) Intensive and frequent rainfall and long-term LD may reduce the spatial variability in salinity and allow for better reclamation and utilization of saline land. These results provide a scientific basis for integrated management of water and agricultural production.

Long-term changes in the area of saline soils recognized by LANDSAT images in Shauldersk irrigated massive

Possibilities to use the archive images obtained by Landsat TM5 in different years have been comprehensively analyzed with the aim at recognizing the soils with different salinity degree. Special approaches were proposed to study the dynamics of saline soils by using the satellite imagery. Based upon a computer analysis of the information transmitted by Landsat in 1987-1988 and 2009-2010 as well as the data of field soil survey, it seemed reasonable to identify changes in the area of such soils in Shauldersk irrigated massive (the South-Kazakhstan region, Republic of Kazakhstan). It was concluded that the share of saline soils revealed an increase at the studied territory within the period from 1987 to 2010.