Gypsiferous Soils Research Articles

Potential for Pastoral Irrigation Using Sulphate-Rich Waters at Macraes Gold Mine, Southern New Zealand

There is growing recognition that elevated dissolved sulphate around mines will lead to significant environmental issues within the industry that need specific management. Various sulphate attenuation engineering methods exist, and so processes that could occur within a mine site are of particular interest. In this pilot study, we investigate the possibility of using high-sulphate mine water (~ 2500 mg/L) for irrigation of farm land. This approach is made feasible from mildly alkaline (pH ~ 8), non-toxic discharge waters at a semi-arid gold mine site. Geochemical models predicted Ca-sulphate will readily precipitate from the mine water at pH 6 and potentially attenuate downstream concentrations of dissolved sulphate. We used the slightly acidic natural soil environment (pH 5–6) of the mine to test initial model predictions in the laboratory and field trials. Ca-sulphate in gypsum formed in experimental soil columns, and the pH of input water lowered by 2–3 units. In the field, only minor soil gypsum was observed, and instead Mg-sulphate and Ca-carbonate were found more readily on evaporation surfaces. Additional terrestrial effects of soil dilution, leaching, and plant uptake of sulphate are discussed. Irrigated pasture had healthy, green plants that supported a potentially dual benefit of mine water irrigation to enhancing farm productivity in the local community. Irrigation is an effective way to manage mine waters with high dissolved sulphate but requires further trials to refine methods and the feed values of pasture.

EFFECT OF BLENDED TRIPLE SUPERPHOSPHATE WITH UREA ON N, P CONCENTRATIONS IN PLANT AND GROWTH OF BROAD BEAN IN A GYPSIFEROUS SOIL

A field experiment was conducted on a gypsiferous sandy clay loam soil to examine the effects of blending Triple superphosphate (TSP) with urea on N, P concentrations in plant and growth parameters of broad bean. The experiment was a factorial randomized complete block design (RCBD) with three replicates. The first factor was type of application as briquettes which include T1 (one layer of TSP between two layers of urea) and T2 (one layer of urea between two layers of TSP), the second factor was application depth (5 and 10 cm D1 and D2), and the third factor was application rate (1.0, 1.25, and 1.50 as much as N and P fertilizer recommended for broad bean, R1, R2 and R3). Broad bean was planted and the following growth parameters were taken: plant height, no. of leaves, plant dry weight, chlorophyll content, leaf area, N and P concentration in plant. Results showed that the following treatments: T1 of blending (briquette no. 1), D1 and R2 were significantly superior over other treatments in all growth parameters and N, P concentration in plant. The triple interaction treatment T1D1R2 was significantly superior over other treatments with values reached 60.99 cm, 442.7 leave plant-1, 20.32 cm2, 63.87 Spad, 5.59 g plant-1, 5.55 %, and 0.27 %, respectively for plant height, no. of leaves plant-1, leaf area, chlorophyll content, plant dry matter, N and P conc. in plant.

Mitigation of collapse characteristics of gypseous soils by activated carbon, sodium metasilicate, and cement dust: An experimental study

AbstractThis study includes adding chemicals to gypseous soil to improve its collapse characteristics. The collapse behavior of gypseous soil brought from the north of Iraq (Salah El-Deen governorate) with a gypsum content of 59% was investigated using five types of additions (cement dust, powder sodium meta-silicate, powder activated carbon, sodium silicate solution, and granular activated carbon). The soil was mixed by weight with cement dust (10, 20, and 30%), powder sodium meta-silicate (6%), powder activated carbon (10%), sodium silicate solution (3, 6, and 9%), and granular activated carbon (5, 10, and 15%). The collapse potential is reduced by 86, 71, 43, 37, and 35% when 30% cement dust, 6% powder sodium meta-silicate, 10% powder activated carbon, 6% sodium silicate solution, and 10% granular activated carbon are used, respectively.

Effect of Adding Cement Dust Waste on the Geotechnical Properties Behavior of Selected Gypseous Soil in Al-Najaf City

The Gypseous soils are soils that cause major engineering problems such as collapse or settlement in several cities in Iraq, and the world. For these reasons, several methods were used to get rid of these engineering problems, including, using additives. This study utilized cement dust waste as an additive in the form of cement dust to improve some of the physical and engineering properties of gypseous soils collected from two sites in Al-Najaf city, with various content of gypsum. Cement dust waste was used in different percentages of %5, 10%, and 15%. Results showed a slight improvement in some properties, where the percentage of the liquid limit increased with the increase in the percentage of additives. Values of the specific gravity decreased in all the added percentages of cement dust. The values of the maximal weight were little decreased, while the optimal moisture percentage increased by increasing the percentage of the additive. Results of the direct shear tests, utilized a percentage of 15 % of cement dust waste, were used in two cases for dry soil and soaked soil for curing 1 day and 7 days. The results showed increasing the quantity of additives by 15% increased the cohesion value which is due to the action of cement dust particles forming bonding bonds with gypseous soil grains. The internal friction angle of cement dust was lower than the internal friction angle of gypseous soil, resulting in a small decrease in the internal friction angle.

Residual effects of agricultural gypsum on soil chemical and microbiological characteristics

AbstractAgricultural gypsum can improve the chemical quality of low fertility soil, providing calcium and sulphur. In this study, we evaluated the effects of agricultural gypsum application at five dosage rates (0, 3, 6, 9 and 12 Mg ha−1) on the chemical and microbial soil characteristics of an acid oxisol (0–0.1 m and 0.1–0.2 m layers) and the impact on wheat grain yield. Increasing agricultural gypsum dosage rates increased Ca, S as well as the Ca/Mg ratio and microbial biomass of carbon in the 0–01 m soil layer. In the 0.1–0.2 m soil layer, agricultural gypsum affected organic C (Corg), Ca and the Ca/Mg ratio. The microbial biomass of carbon had positive correlations with most chemical and microbial variables. In the 0–0.1 m soil, the microbial biomass of C and N had negative relationships with arylsulphatase and β‐glucosidase, respectively. At 0.1–0.2 m depth, arylsulphatase activity correlated negatively with Corg and positively with Al. Agricultural gypsum soil amendments increased the microbial biomass of carbon, especially at the highest application rate (12 Mg ha−1). The highest biochemical index activity was found in the 3 Mg ha−1 (0–0.1 m) and 9 Mg ha−1 (0.1–0.2 m) treatments. At 70 months after application, we found that maximum wheat grain yield was rendered by an agricultural gypsum application rate close to 3 Mg ha−1.

Impact of eccentricity and depth-to-breadth ratio on the behavior of skirt foundation rested on dry gypseous soil

AbstractGypseous soils are considered one of the most problematic soils. The skirted foundation is an alternative technology that works to improve the bearing capacity and reduce settlement. This paper investigates the use of square skirted foundations resting on gypseous soil subjected to concentric and eccentric vertical load with eccentricity values of 4, 8, and 17 mm in 16 experimental model tests. To obtain the results by using this type of foundation, a small-scale physical model was designed to obtain the load–settlement behavior of the square skirted foundation; the dimension of the square footing is 100 mm × 100 mm with 1 mm thickness, the skirt depth (Ds) was 0.5, 1, and 1.5B(whereBis the footing width). The footing rests on dry gypseous soil with a relative density of 33%. The tests show that the gypsum content of the soil is 59%. The result shows that the highest bearing capacity for the square shape footing withDs/B= 1.5 subjected to concentric load results in an improvement ratio of 190%. For the eccentric load, withDs/B = 1.5, the increase in bearing capacity is about 120% ate= 8 mm when compared with using a foundation without a skirt.

Role of Gypsum Content on the Long-Term Performance of Lime-Stabilised Soil.

The role of gypsum level on the long-term strength and expansion of soil stabilised with different lime contents is not well understood. This research, therefore, studied the effect of varying gypsum concentrations of 0, 3, 6, and 9 wt% (equivalent to the sulfate contents of 0, 1.4, 2.8, and 4.2%, respectively) on the performance of sulfate soil stabilised with two lime levels (4 and 6 wt%). This was carried out to establish the threshold level of gypsum/lime (G/L) at which the increase in G/L ratio does not affect the performance of lime-stabilised sulfate soil. Both unconfined compressive strength (UCS) and expansion, along with the derivative thermogravimetric (DTG) analysis, were adopted to accomplish the present objective. Accordingly, the result indicated that the strength and expansion were proportional to the lime and sulfate content, of which a G/L ratio of 1.5 was the optimum case scenario for UCS, and at the same time, the worst-case scenario for expansion. This discovery is vital, as it is anticipated to serve as a benchmark for future research related to the design of effective binders for suppressing the sulfate-induced expansion in lime-stabilised gypseous soil.

Gypsum in the desert landscape: Floristic variations within the Cuatro Ciénegas basin in Coahuila, Mexico

Plant species growing on gypsum substrates, usually found in arid and semi-arid zones, create characteristic landscapes that can harbor highly specialized species, several of which are endemic. In the Cuatro Ciénegas basin (CCB) gypsum is abundant and creates patches of plant assemblages, but little is known about the floristic differences between them and the ecological factors driving them. In this study, we describe and compare the floristic composition of twelve fixed plots placed in six different positions on the landscape (five gypsum-rich sites and one with a minimal gypsum concentration, as a control site) within the CCB and the nearby La Virgen valley. Species presence was recorded twice a year for two years, the floristic composition of each plot was determined and compared through Beta diversity. A principal component analysis was performed to identify species contribution to the assemblage differentiation and the effect of gypsum and topographic variables were tested. A total of 98 species from 62 genera and 31 families were registered. The results show that gypsum plays an important role in community assembly and differentiation, and within gypsum-rich sites, species assemblages are related to the effect of topographic factors, slope and altitude. However, we suggest that within gypsic soils, more punctual environmental conditions like microclimate, water dynamics, and most likely soil characteristics such as salinity or texture (rockiness), other than gypsum concentration, influence community floristic differentiation.

Investigation of the Impacts of Nanomaterials on the Micromechanical Properties of Gypseous Soils

Investigation of the Impacts of Nanomaterials on the Micromechanical Properties of Gypseous Soils

Behavior of Square Footing Erected on Gypseous Soil Treated by Ceramic Wastes

Gypseous soil, as is well known, includes a specific quantity of gypsum. Gypsum is a water-soluble salt with a solubility of (2.2-2.6) gram/liter in distilled - water. As a result, the presence of gypsum poses a challenge when building structures on this soil, since gypsum dissolves when exposed to water, producing gaps between soil particles and so causing soil collapse. This study examines the behavior of a shallow foundation rested on gypseous soil. Three types of gypseous soil with gypsum contents of (61%, 45.3%, and 27.9%, respectively) are used, and treated with ceramic wastes, which is a waste product of construction. The Soil samples were collected from the site of Tikrit University's campus. The study consists of six test cases, two for each type of soil, one dry and the other wet, where the first test for each case was used as a baseline for comparison, which was the soil test without the addition of ceramic wastes, and the rest was added in three proportions (3%, 6%, and 9%) and three mixing depths for each ratio (B/2, B, 3B/2).The percentage 9% ceramic wastes gives best results of improving, the bearing capacity of the soil improved by 233%, 256 %, and 289% for high gypseous soil, and by 78%, 94%, and 111% for medium gypseous soil, with a percentage of 60%, 87%, and 113% for low gypseous soils. Adding ceramic wastes to wet gypseous soil improves the bearing strength of the soil, lowers settlement to some extent, and reduces the influence of water on it.

Recent and ancient evolutionary events shaped plant elemental composition of edaphic endemics: a phylogeny-wide analysis of Iberian gypsum plants.

Summary The analysis of plant elemental composition and the underlying factors affecting its variation are a current hot topic in ecology. Ecological adaptation to atypical soils may shift plant elemental composition. However, no previous studies have evaluated its relevance against other factors such as phylogeny, climate or individual soil conditions.We evaluated the effect of the phylogeny, environment (climate, soil), and affinity to gypsum soils on the elemental composition of 83 taxa typical of Iberian gypsum ecosystems. We used a new statistical procedure (multiple phylogenetic variance decomposition, MPVD) to decompose total explained variance by different factors across all nodes in the phylogenetic tree of target species (covering 120 million years of Angiosperm evolution).Our results highlight the relevance of phylogeny on the elemental composition of plants both at early (with the development of key preadaptive traits) and recent divergence times (diversification of the Iberian gypsum flora concurrent with Iberian gypsum deposit accumulation). Despite the predominant phylogenetic effect, plant adaptation to gypsum soils had a strong impact on the elemental composition of plants, particularly on sulphur concentrations, while climate and soil effects were smaller.Accordingly, we detected a convergent evolution of gypsum specialists from different lineages on increased sulphur and magnesium foliar concentrations.

Quantifying soil physical quality by using indicators and pore volume-function characteristics of the gypsiferous soils in Iraq

Despite the fact that indicators of soil physical quality (SPQ) are direct or indirect manifestations of pore volume function, optimal pore volume-function parameters of gypsiferous soils are still to be identified. The study's goals were to: i) to determine the impact of soil gypsum content on the SPQ and pore volume distribution characteristics, ii) develop an optimal pore volume distribution recommendation using the indicators, iii) using indicators and pore volume distributions, evaluate the SPQ of a poly-γ-glutamic acid-amended gypsiferous soil. Using undisturbed soil cores and grab materials from 15 gypsiferous soils, the SPQ indices were determined in the lab. To determine pore volume ranges and water-released curves, the van Genuchten equation was used to fit desorption values using soil cores and grab materials. The best overall SPQ was found in soils with a gypsum content of 135–150 g kg−1, according to the determined indicators, which was applied to determine an optimal pore volume distribution. There were two different types of non-optimal soils. The first group had a gypsum content of 30–123 g kg−1, which was much below “optimal” and had a higher proportion of small pores, whereas the second group had a gypsum content of 164–301 g kg−1, which was generally over “optimal” and had a lower proportion of small pores. The SPQ and maize yield of soils with gypsum content of 30 and 301 g kg−1 were improved by adding poly-γ-glutamic acid. For measuring the physical quality of gypsiferous agricultural soils, the SPQ indicators should be considered in conjunction with optimal pore volume distribution and Dexter “S-value”.

Gypsum endemics accumulate excess nutrients in leaves as a potential constitutive strategy to grow in grazed extreme soils.

Extreme soils often have mineral nutrient imbalances compared to plant nutritional requirements and co‐occur in open areas where grazers thrive. Thus, plants must respond to both constraints, which can affect nutrient concentrations in all plant organs. Gypsum soil provides an excellent model system to study adaptations to extreme soils under current grazing practices as it harbours two groups of plant species that differ in their tolerance to gypsum soils and foliar composition. However, nutrient concentrations in organs other than leaves, and their individual responses to simulated herbivory, are still unknown in gypsum plants. We studied plant biomass, root mass ratio and nutrient partitioning among different organs (leaves, stems, coarse roots, fine roots) in five gypsum endemics and five generalists cultivated in gypsum and calcareous soils and subjected to different levels of simulated browsing. Gypsum endemics tended to have higher elemental concentration in leaves, stems and coarse roots than generalist species in both soil types, whereas both groups tended to show similar high concentrations in fine roots. This behaviour was especially clear with sulphur (S), which is found in excess in gypsum soils, and which endemics accumulated in leaves as sulphate (>50% of S). Moreover, plants subjected to clipping, regardless of their affinity to gypsum, were unable to compensate for biomass losses and showed similar elemental composition to unclipped plants. The accumulation of excess mineral nutrients by endemic species in aboveground organs may be a constitutive nutritional strategy in extreme soils and is potentially playing an anti‐herbivore role in grazed gypsum outcrops.

Recycling of Construction Waste Concrete as a Stabilizer for Gypseous Soils

This study presents the possibility of recycling Crushed Waste Concrete resulting from the demolition of buildings, and making practical use of these abundantly available materials, by grinding them and adding them in different proportions to gypseous soils to increase their maximum bearing capacity and reduce compressibility. A laboratory model with dimensions (300*300 *600mm) of galvanized steel, 4 mm thick, was used to study the effect of mixing (0%, 2%, 4%, 6%, and 8%) Crushed Waste Concrete with three types of water-flooded natural gypseous soils with different percentages of gypsum (30%, 46%, and 66%). Loading tests were carried on square steel footing (70*70mm) and 9mm thick, placed on these soils. More than 15 tests were conducted on the laboratory model, in addition to the usual classification tests on the soils used in the study. All tests were carried after submerging gypseous soils due 24 hours. The study showed a clear improvement in the susceptibility of the three gypseous soils using all the addition percentages of concrete powder, the best percentage was 8%, while the improvement rates were less using 2%, 4%, and 6%. As the bearing capacity of the soil increased after mixing it with this ratio due to filling the voids formed as a result of melting gypsum during the water immersion process, which compensated for it at this stage. Mixing gypseous soil with crushed waste concrete by 8% increases ultimate bearing stress about 8 times, while it is 2.5 times for model mixed with 2% of this additive, compared with the untreated one.

INFLUENCE OF PARTIAL ROOT-ZONE DRYING ON WATER USE EFFICIENCY AND PHOSPHORUS UPTAKE OF CORN (ZEA MAYS L.) IN A GYPSIFEREOUS SOIL

Pot experiment was conducted to study the alternate and fixed partial root zone drying on irrigation water use efficiency and phosphorus absorption efficiency of corn (Zea mays L.) in a gypsiferous soil during the spring growing season. The experiment included three irrigation techniques, which were conventional irrigation (C1), alternating partial root-zone drying (APRD) and fixed partial root-zone drying (FPRD), and three levels of phosphate fertilizer application (40, 80, 120 Kg h-1), for three stages of plant growth, jointing stage (40 days from planting), booting stage (60 days from planting) and maturing stage (105 days from planting). The experiment was carried out with a complete randomized design with nine replications. Yellow corn seeds variety DKC6664 were planted on 20/3/2020. During the aforementioned growth stages, the development of the root system and vegetative parts of corn plants were studied and the water use efficiency was calculated for each growth stage. Results showed a decrease in the ratio of root to the vegetative weight under the alternating and fixed root-zone drying for the three fertilization levels and the three-growth stage (jointing, booting, maturing). The conventional irrigation treatment gave a grain yield of 40.53, 51.44 and 57.71 g pot-1 for the fertilization levels of 40, 80 and 120 kg P h-1 with a significant difference compared to alternate and fixed partial root-zone drying treatments. Alternate partial root-zone drying give the highest water use efficiency of 0.90, 0.93 and 0.98 kg m-3. Higher values of phosphorus absorption was recorded with CI treatment. The phosphorus absorption was high in the jointing and booting stages of corn growth. Phosphorous reduced some of the negative effects of water shortage on plant growth and yield and the reason for an increase in water use efficiency.

Diagnostics and Characterization of Micro morphological Features of some Soil Series in Baiji City, Central Iraq

Three pedons were selected representing the soil series of the study area in Baiji city, which are Khadraniya, Al-Sharqat, and Manjour soils series, representing calcareous and gypsiferous soils, to diagnose some of micro-morphological Features in soil series horizons. Pedons were morphologically described, and disturbed and undisturbed soil samples were collected from each horizon. The presence of (calcic) and (gypsic) horizons has been diagnostic by morphological field results, ccumulation of lime and gypsum in soil matrix as vertical gypsic threads and beards and aggregates under gravel and gypsum crystals the size of coarse sand, as well as some lime and gypsum as nodules intertwined within soil structure units in soil horizons that reflects the influence of parent material and primary sedimentation sources .The results of morphological characteristics are represented by the presence of gypsum crystals in distinct shapes, including lenticular, and spindle as Enhedral and subhedral, and the size of fine to coarse sand, as well as the granules that in filling pores, as well as the presence of pores in vughs and chamber, as well as the spongy and granular structure, as well as the presence of iron coating in the form Encases of gypsum crystals.

Determination of Civil Engineering Problems Using Resistivity Methods in Ramadi, Western Iraq

Many civil engineering problems resulting from the presence of gypsum soil near the surface and the water table in shallow depth led to the solubility of the soil and creates a subsurface weak area in Ramadi city. 2D and 3D electrical resistivity imaging were applied using a Dipole-dipole array with an n-factor of 6 and a-spacing values of 2 m. Imaging data sets have been acquired along five traverses with a line distance of 4 meters. The inversion model is generated by the robust inversion model constraint method, which clearly shows that the boundary of the weak area is sharper and straighter. The results show the presence of two main zones, the first represents the topsoil layer which extends to a depth of 2.5 m with a resistivity ranging from 28 to 312 Ωm. The second zone is located at 2.5 m depth and extends to 10 m with a resistivity value ranging from 0.267 to 28 Ωm. The variation of the water table, inhomogeneity of the sediment, weak areas, and sedimentation lenses are the main reasons for the failure of civil engineering. These failures may cause many problems such as wall cracks, foundation damage, and building collapses.

Investigation of the Bearing Capacity and Collapsibility of Gypseous Soil Using Geotextile Reinforcement

This study aims to increase the bearing capacity of the soil by using geosynthetics in a single, double, or triple distribution pattern. The gypseous soil samples were brought from a site near Sawa Lake in Al-Muthanna Governorate with a gypsum content of about (37%), the Soil-Model apparatus of dimensions (60 × 60 × 50) cm with the proposed square footing of dimensions (10 × 10) cm are used in the experimental program of this study. To achieve this goal, a series of (48) different model tests were used on gypseous soil subjected to vertical stress in both dry and wet (saturation) conditions. Depending on the results of load-settlement curves relationships, the ultimate bearing capacity of dry and wet gypseous soil models was determined using the Two Tangent Intersection technique. The results also showed that the number of geotextile layers and the relative density of the gypseous soil samples significantly impact the improvement of the bearing capacity of gypseous soil models. Furthermore, the results showed that the improvement ratio in bearing capacity (BCR%) for gypseous soil models tested after being reinforced with geotextile layer for dry and wet (saturation) at relative density (RD) of 30% and 60% in single, double and triple distribution pattern. The percentage of the improvement in the wet case was higher than in the dry case. It was 143 % in the wet case when using triple-layer geotextile at different depths of reinforcement, while it was 96 % in the dry case.

Enhancing gypseous soil behavior using casein from milk wastes

AbstractGypseous soil is a metastable soil that causes problems in the constructions built on it under wetting conditions. Due to the harmful effects of traditional soil binders such as lime or cement on the environment, alternative environmental-friendly materials have been used to decrease this impact. Casein biopolymer is introduced in this study as a new binder for gypseous soil improvement and milk waste minimizing purposes. The study focused on three primary soil features: compaction properties, shear strength, and collapse potential. These three soil properties are important in the ground improvement techniques. In this study, different casein concentrations were added to the soil with varying gypsum contents. According to the compaction results casein reduces the maximum dry density while increasing the optimum moisture content. Soil treated with casein had a collapse potential of 65–80% lower than untreated soil. The shear strength of casein-treated soil increased significantly in both dry and moist conditions. The current study results suggest the recycled casein as an eco-friendly additive for gypseous soil treatment rather than traditional chemical materials.

Influence of double cavities on anchors capacity

Abstract Soil is considered an essential component of the factors that are affecting the structures. Due to the problems that are faced under various conditions while the structure is in use, the behavior of the soil is complex. The presence of cavities inside various types of soil, such as gypsum soil and the soil of some old towns, is one of its difficult problems. The formation of these cavities is due to natural and industrial causes, one of the natural causes being the dissolve of salts inside them. As for the industrial one, it is due to the presence of some old buildings. The presence of this type of cavities affects the life of the structures and as a result, it creates cracks in the foundation, therefore reducing the life of the structures. The unexpected formation of cavities inside the soil was based mainly on some practical experiments for this research. Two cavities have been created inside the soil with different locations from the anchor to study the capacity of the anchor. The results showed that the presence of the cavity affects the capacity of the anchor according to its location from the plate as well as from the rod. The closer the cavity are to the plate; the capacity have been decreased by a certain percentage depending on the distance from the plate anchor.