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Background Aims Methods Results Conclusions Science‐based decisions regarding forest management require the knowledge of the impact of thinning regimens on the forests’ vitality and resilience. There is no systematic study analysing the role of forest management approaches on the nutritional status of forests, serving as a surrogate for their health and growth.We assessed the impact of ‘heavy thinning from above’ versus ‘no management’ on the foliar chemistry of old‐growth European beech stands on a calcareous site with cambisol/chromic luvisol soil in Thuringia, Germany.Macro‐ and micronutrients were analysed by serial foliar analysis of six trees per experimental plot over 13 years (2009–2021). To assess potential differences of foliar chemistry between the two plots and over time, a linear mixed‐effects model was applied.Foliar concentrations of all macro‐ and micronutrients were not significantly different between the two plots (p > 0.05), demonstrating that the management approach had no relevant impact on the nutritional status of beech trees growing at the calcareous site. Furthermore, all foliar concentrations were dynamic over the 13‐year evaluation period. Hence, long‐term forest monitoring is crucial to capture the complex interplay between the trees and environmental conditions.Serial foliar analysis allows for a reliable evaluation of a forest's nutritional status. The results indicate that either regimen, that is, ‘heavy thinning from above’ or ‘no management’, shall not pose any risk in terms of growth and stability. Our results add to the understanding of beech forest dynamics and may provide a further piece for science‐based strategies of sustainable forest management. [ABSTRACT FROM AUTHOR]

Background and aims: Proteaceae are a prominent plant family in south-western Australia. Most Proteaceae are 'calcifuge', occurring exclusively on old phosphorus (P)-impoverished acidic soils, with a few 'soil-indifferent' species also found on young P-richer calcareous soils. Calcium (Ca)-enhanced P toxicity explains the calcifuge habit of Proteaceae. However, previous research has so far been focused exclusively on the roles of Ca and P in determining Proteaceae distribution, and consequently there is little knowledge on how other soil-based strategies influence this distribution. We aimed to study the effects of young calcareous soils on four soil-grown Proteaceae and assess differences between calcifuge and soil-indifferent Proteaceae to better understand their natural distribution. Methods: Two calcifuge and two soil-indifferent Proteaceae from south-western Australia were grown in six contrasting soils, including young calcareous, and old acidic soils. Results: When grown in calcareous soils all species showed root growth inhibition, micronutrient deficiency, Ca-enhanced P toxicity, and negative impacts on physiology. Calcifuge species were more sensitive to calcareous soils than soil-indifferent ones, although this varied between genera. Soil-indifferent species tended to produce more cluster roots, release more carboxylates per root mass, and allocate less Ca to their leaves, compared with calcifuges; they also had smaller seeds and were less sensitive to Ca-enhanced P toxicity. Conclusion: We surmise that a combination of these traits allows soil-indifferent species to tolerate calcareous soils. This study provides insight into how Proteaceae respond to young calcareous soils and how this influences their distribution. [ABSTRACT FROM AUTHOR]

Collapse occurs in soils as a result of inter-particle bond breakage caused by wetting and/or stressing. Inter-particle bond is usually provided by either suction, clay, calcium carbonate or other salts but upon wetting and/or loading they undergo repacking due to bond softening/weakening. Despite the large body of research in this subject, there is still poor understanding of the process of softening/weakening and the collapse mechanism of certain bond elements, particularly CaCO3, considering its low solubility in water. Because CaCO3 is common in natural soils, reaching 1–30% contents in most commonly known natural collapsible soil, understanding its influence on the collapse phenomenon is crucial for geotechnical characterization of soils. In this study, the impact of calcite bond content and wetting fluid type on the collapse potential (CP) and rate of collapse of calcareous silty-clay soils are investigated. CP was estimated by the percentage decrease in height of an oedometer specimen due to wetting. Distilled water and a 5% acid solution (AS) were used as wetting fluids. Wetting was mainly done at 300 kPa overburden stress. Results reveal that the magnitude and rate of collapse are controlled mainly by the calcite content, and pH of wetting fluid. Both magnitude and rate of collapse decrease with increasing CaCO3 content. Increasing clay content resulted in higher CP for non-calcareous samples but resulted in lower CP for calcareous samples. Wetting with acid solution demonstrated higher CP and tends to prolong time to reach complete collapse resulting also in long-term collapse. [ABSTRACT FROM AUTHOR]

Drip technologies have been suggested as practical for irrigation under conditions of high salinity and for reclamation of saline soils. Drip irrigation triggered by soil water potential thresholds was applied to both reclaim a severely saline calcareous gypsiferous soil and irrigate a waxy corn crop (Zea mays L. sinesis Kulesh). However, there is a lack of knowledge on the sustainability of reclamation of saline soils with drip irrigation and the changes in soil salinity and salt ion composition during the amelioration process. Therefore, effects on soil salinity, its ionic composition, and on crop growth and yields were evaluated in an experiment conducted in the Yinchuan Plain, northwest China. Treatments included fields in their first to fourth years of the drip irrigation reclamation-cropping scheme and adjacent native, non-cropped or irrigated salinesodic land as control. Yield of waxy corn increased and days of growth to maturity decreased as a function of time and reclamation management. The improvement in crop performance could be largely credited to the reduction of soil salinity and changes in salt composition under the drip-irrigated reclamation protocols. The drip irrigation regime created a region of low salinity proximal to the emitters conducive to germination and plant growth. Deleterious ions for crop growth such as Na+ and Cl- were reduced while Ca2+ and Mg2+ concentration increased, especially in the upper 40 cm of soil. After only a single season of drip-irrigated waxy corn production, both Cl-/SO42- ratios and sodium adsorption ratio (SAR) decreased dramatically. The results suggested that drip irrigation is an effective technology for reclamation of severely saline-affected soils, such as those widely distributed over the Ningxia Plain in China and that this or similar reclamation strategy could be appropriate for reclamation of other hard to manage calcareous and gypsiferous soils. [ABSTRACT FROM AUTHOR]

Conventional farming always modifying by good innovation in agriculture, while the holistic idea of organic farming checks the use of synthetic inputs where in opposite side, the concept of natural farming allowing farming with few traditional and locally available inputs. The all three farming concepts are fundamentally different, to check it on real field, a experiment was conducted on medium black calcareous clayey soil at Junagadh (Gujarat) during rabi2019-20 to kharif 2020 in order to evaluate low cost natural farming, organic farming and conventional farming in major six crops of Gujarat. The experimental results revealed that conventional farming module significantly increased yields of crops as compared to organic farming and low cost natural farming. Significantly higher available nitrogen, phosphorous and potassium after harvest was found under conventional farming, while organic farming module registered significantly higher organic carbon, heat soluble S; DTPA extractable Fe, Zn, Cu and Mn after harvest, which was found at par with conventional farming. Economic analysis showed that maximum net returns gross returns, and B:C ratio were observed under conventional farming module. [ABSTRACT FROM AUTHOR]

This study was conducted in the research and practices of greenhouses at the University of Selçuk, Faculty of Agriculture and Horticulture Department. The effects of three different mycorrhiza species and combinations of strawberry plants on plant growth and nutrition were investigated in three different strawberries cultivars. According to the results, it was determined that Glomus chlorodum mycorrhiza alone and in combination increased stem fresh and root fresh weights, leaf relative water content, number of stems, and number of leaves compared to control plants. However, no significant changes could be obtained with mycorrhizal applications on membrane permeability and chlorophyll values in all strawberry varieties used. Nutrient analysis of nitrogen, magnesium, iron, manganese, and boron in the leaves of the application of mycorrhiza with significant increases has been achieved. Glomus etunicatum + Glomus chlorodum and Glomus deserticola + Glomus etunicatum applications had the best results. As a result of this study, it can be suggested that Glomus etunicatum and Glomus chlorodum can be used to promote plant growth in strawberry calcareous soil conditions. [ABSTRACT FROM AUTHOR]

Copyright of Menoufia Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The main purpose of this laboratory study is to indicate the variation in some characteristics of the sandy, sandy calcareous, and clay soil under the effect of the magnetically treated tab and/or salt water. Salt water (SW, 2000-ppm) was prepared by dissolving the sodium chloride (NaCl) salt in tap water TW (2 g L-1). Tab water and/or SW were magnetically treated by passage through a permanent electromagnetic field of 14٫000 G (1.4 Tesla) strength for 10 min, and then allowed to percolate through a soil column continuously for 2 h. Some characteristics of the studied soil samples were estimated after the infiltrate of the magnetically (M) and non-magnetically (NM) treated TW and/or SW. The MSW has decreased the hydraulic conductivity (HC, m day-1) by 41.1, 12.8, and 51.4% compared to NMSW for sandy, sandy calcareous, and clay soil, respectively. Magnetic induction may affect the coagulation of the fine particles to form larger aggregates. For clay soil, MTW decreased the sum of fine particles by 40.5%, while the MSW decreased it by 28.75%, which may be a dispersing effect of NaCl soluble salt. The Zeta potential ζ values were slightly shifted by SW and MSW. The calculated electrophoretic mobility (U) of the colloidal particles has increased under the effect of the SW by 15.6%, 28.6%, and 58.1% for the sandy, sandy calcareous, and clay soil, respectively. Magnetized water may affect the soil properties positively and/or negatively depending on the soil class and the application conditions.

Major malnutrition in Bangladesh is zinc (Zn) and iron (Fe) deficiency as most people commonly depend on cereals, chiefly rice and wheat. The main objectives are to enhance Zn and Fe concentrations through the use of selected varieties and the application of respective fertilizers. Field experiments were conducted at Bangladesh Agricultural University (BAU) farm, Mymensingh (AEZ 9, non-calcareous soil) and at Bangladesh Institute of Nuclear Agriculture (BINA) substation, Ishwardi (AEZ 11, calcareous soil) for two consecutive wheat seasons (2014–15 and 2015–16) with 10 varieties and 15 advanced lines. Varieties BARI Gom 25, 27, 28 & 29 and breeding lines Vijay, HPYT-5, 15 & 21 and BL-1883 have been recognized as Zn-enriched wheat varieties (24–30 μg g−1). Among the genotypes, Zn further increased by 4–8 μg g−1 due to Zn fertilization. Concerning Fe-enriched wheat genotypes (24–30 μg g−1), five varieties viz. Shatabdi, Prodip, BARI Gom 25 & 28 and Sufi, and four lines such as HPYT-12, BL-1883, BL-1040 and Fery-60 have been identified. The grain Fe concentration of wheat genotypes increased when Fe was added, the increment being 6–12 μg g−1. A positive relationship between Zn and N is observed with increased protein content. The grain yield of wheat was increased by 3.8–25.7% due to Zn application over the varieties and locations but Fe addition had no effect. The result of the current study showed that a potential breeding line with appropriate fertilization can improve Zn and Fe levels in wheat grain, without incurring loss to wheat yield.

The soils of Algeria are generally poor in nitrogen and always pose the problem of the availability of available phosphorus especially in arid regions, where there is also the problem of salinity which is often accompanied by the presence of limestone. The present work aims to examine the optimization of phospho-nitrogen fertilization on a durum wheat crop in saline and carbonate conditions through the use of different types, forms and doses of nitrogen and phosphate fertilizers. The fertilizers used are: Urea(46%), triple super phosphate TSP(46%), simple super phosphate SSP(20%), Potassium Nitrate KNO3(13%), Monammonium phosphate MAP(12%, 61%), NPK(15%,15%,15%), NPK(20%,20%,20%), NPK(13%,40%,13%), NPK(30%,10%,10%), NPK(4%,20%,25%), combined with three doses (D1=150U N and P ha-1, D2=200U N and P ha-1 and D3=250U N and P ha-1). The results obtained show that phospho-nitrogen fertilization has a very important effect on the parameters studied. Indeed, we notice that the best results are obtained by compound fertilizers, height of the plants: (HP) =MAP and NPK(15%,15%,15%) (250U ha-1) and (KNO3-SSP) (150U ha-1), yield and its components: Number of grains ear-1 (NG E-1) =NPK(13%,40%,13%) (250U ha-1), 1000 grains weight (TGW) =NPK(4%,20%,25%) (250U ha-1), grain Yield (GY) =NPK(13%,40%,13%) (250U ha-1) and NPK(15%,15%,15%) (150U/ha), straw yield (SY) =NPK(15%,15%,15%) (250U ha-1) and (KNO3-SSP) (150U ha-1). However the highest nitrogen and phosphorus content of the grains is obtained by simples fertilizers, N= (Urea-SSP) with the dose (200 and 250 U ha-1), and P = (Urea-TSP) with the dose (150U ha-1). It is noted that the NPK(15%,15%,15%) fertilizer was able to give better grain and straw yields with the lowest dose as well as obtaining the best plant height and better straw yield with the lowest dose of (KNO3-SSP) fertilizer.

Conventional farming always modifying by good innovation in agriculture, while the holistic idea of organic farming checks the use of synthetic inputs where in opposite side, the concept of natural farming allowing farming with few traditional and locally available inputs. The all three farming concepts are fundamentally different, to check it on real field, a experiment was conducted on medium black calcareous clayey soil at Junagadh (Gujarat) during rabi 2019-20 to kharif 2020 in order to evaluate low cost natural farming, organic farming and conventional farming in major six crops of Gujarat. The experimental results revealed that conventional farming module significantly increased yields of crops as compared to organic farming and low cost natural farming. Significantly higher available nitrogen, phosphorous and potassium after harvest was found under conventional farming, while organic farming module registered significantly higher organic carbon, heat soluble S; DTPA-extractable Fe, Zn, Cu and Mn after harvest, which was found at par with conventional farming. Economic analysis showed that maximum net returns gross returns, and B:C ratio were observed under conventional farming module.

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chemical and physical properties of clay samples collected from the deposits in the Ramgarh-Naudiha of Sonbhadra district, Uttar Pradesh were examined for their utilisation in ceramic industry. The raw clays from the deposits were found to be siliceous ball clays, contained less kaolinite, non-plastic and were unsuitable for making ceramic items. These clays have been subjected to standard beneficiation techniques which removed the free quartz. The beneficiated clays were less siliceous, had improved properties that can be used as partial replacement material in making ceramic items. [ABSTRACT FROM AUTHOR]

Introduction: Low soil fertility and high fertilizer costs are constraints to wheat production, which may be resolved with integrating fertilizer phosphorus (P) and farm-yard manure (FYM). Study objectives were to evaluate P source impacts on soil, P efficiency, and wheat growth in a calcareous soil. Methods: Treatments included P fertilizer (0, 17, 26, or 39 kg P ha-1) and/or FYM (0 or 10 T ha-1) in a: 1) incubation experiment and 2) wheat (Triticum aestivum spp.) field experiment. Results and Discussion: Soil organic matter increased (30-72%) linearly for both fertilizer and FYM, whereas pH decreased (0.1-0.3 units) with fertilizer only. Addition of fertilizer and FYM increased plant available P (AB-DTPA extractable soil P) an average of 0.5 mg P kg-1 soil week-1 with incubation. The initial increase was 1-9 mg P kg-1, with further increase after 84 d of ~3-17 mg P kg-1. There was also a significant increase of available P in the soil supporting plants in the field study, although the magnitude of the increase was only 2 mg kg-1 at most for the highest fertilizer rate + FYM. Grain (66 to 119%) and straw (25-65%) yield increased significantly, peaking at 26 kg P ha-1 + FYM. The P Absorption Efficiency (PAE), P Balance (PB), and P Uptake (PU) increased linearly with P rate, with the highest levels at the highest P rate. The P Use Efficiency (PUE) was highest at the lowest rates of P, with general decreases with increasing P, although not consistently. Principal component analysis revealed that 94.34 % of the total variance was accounted for with PC1 (84.04 %) and PC2 (10.33 %), with grain straw yield significantly correlated to SOM, PU, and PAE. Regression analysis showed highly significant correlation of PB with P-input (R2= 0.99), plant available P (R2= 0.85), and PU (R2= 0.80). The combination of FYM at the rate of 10 T ha-1 and fertilizer P at 26 kg P ha-1 was found as the optimum dose that significantly increased yield. It is concluded that FYM concoction with fertilizer-P not only improved SOM and residual soil P, but also enhanced wheat yields with reasonable P efficiency. [ABSTRACT FROM AUTHOR]

Climate models project that many terrestrial ecosystems will become drier over the course of this century, leading to a drastic increase in the global extent of arid soils. In order to decrease the effects of climate change on global food security, it is crucial to understand the arid environment and the constraints associated with arid soils. Although the effects of aridity on aboveground organisms have been studied extensively, our understanding of how it affects soil processes and nutrient cycling is lacking. One of the primary agricultural constraints, particularly in arid locations, is water scarcity, due to which arid soils are characterized by sparse vegetation cover, low soil organic carbon, poor soil structure, reduced soil biodiversity, and a high rate of soil erosion via wind. Increased aridity will limit the availability of essential plant nutrients and crop growth, and subsequently pose serious threats to key ecological processes and services. The increasing rate of soil salinization is another major environmental hazard that further limits the agricultural potential of arid soils. These soil constraints can be ameliorated and the crop yields increased through case-specific optimization of irrigation and drainage management, enhancing the native beneficial soil microbes, and combinations of soil amendments, conditioners, and residue management. This review explores technologies to ameliorate soil constraints and increase yields to maintain crop output in arid soils. [ABSTRACT FROM AUTHOR]

IntroductionLow soil fertility and high fertilizer costs are constraints to wheat production, which may be resolved with integrating fertilizer phosphorus (P) and farm-yard manure (FYM). Study objectives were to evaluate P source impacts on soil, P efficiency, and wheat growth in a calcareous soil.MethodsTreatments included P fertilizer (0, 17, 26, or 39 kg P ha-1) and/or FYM (0 or 10 T ha-1) in a: 1) incubation experiment and 2) wheat (Triticum aestivum spp.) field experiment.Results and DiscussionSoil organic matter increased (30-72%) linearly for both fertilizer and FYM, whereas pH decreased (0.1-0.3 units) with fertilizer only. Addition of fertilizer and FYM increased plant available P (AB-DTPA extractable soil P) an average of 0.5 mg P kg-1 soil week-1 with incubation. The initial increase was 1-9 mg P kg-1, with further increase after 84 d of ~3-17 mg P kg-1. There was also a significant increase of available P in the soil supporting plants in the field study, although the magnitude of the increase was only 2 mg kg-1 at most for the highest fertilizer rate + FYM. Grain (66 to 119%) and straw (25-65%) yield increased significantly, peaking at 26 kg P ha-1 + FYM. The P Absorption Efficiency (PAE), P Balance (PB), and P Uptake (PU) increased linearly with P rate, with the highest levels at the highest P rate. The P Use Efficiency (PUE) was highest at the lowest rates of P, with general decreases with increasing P, although not consistently. Principal component analysis revealed that 94.34 % of the total variance was accounted for with PC1 (84.04 %) and PC2 (10.33 %), with grain straw yield significantly correlated to SOM, PU, and PAE. Regression analysis showed highly significant correlation of PB with P-input (R2= 0.99), plant available P (R2= 0.85), and PU (R2= 0.80). The combination of FYM at the rate of 10 T ha-1 and fertilizer P at 26 kg P ha-1 was found as the optimum dose that significantly increased yield. It is concluded that FYM concoction with fertilizer-P not only improved SOM and residual soil P, but also enhanced wheat yields with reasonable P efficiency.

In this study, the acid resistance characteristics of commercial aggregates that are commonly employed in concrete construction, were investigated. The aggregates studied were of three categories, namely: (1) the siliceous group consisting of reef–quartzite, metaquartzite, and granite, (2) the siliceous–calcareous group consisting of dolerite and amphibolite, and (3) dolomite of the calcareous group. Samples of the aggregates were oven-dried, immersed in 20% by weight concentration of hydrochloric or sulphuric acid maintained at 60°C for 24 h, and then their mass loss values were measured. Mineralogical compositions and phase reaction changes in the aggregates were examined using X-ray fluorescence, Rietveld quantitative X-ray diffraction analysis, petrography, and scanning electron microscopy coupled with energy dispersive spectroscopy. A strong, nonlinear inverse correlation was found between quartz content and mass loss, for which aggregates that had SiO2≥70% exhibited very low or negligible mass loss. Metaquartzite and granite aggregates of the siliceous group showed the most superior resistance responses to acid attack, owing to their high levels of quartz content. Reef–quartzite, dolerite, and amphibolite all showed a partial or moderate level of acid resistance. Dolomite exhibited high susceptibility to acid attack, forming gypsum as a reaction product upon exposure to sulphuric acid. [ABSTRACT FROM AUTHOR]

A detailed systematic study of calcareous nannofossils was carried out for the Jaddala Formation in (Aj-10) well, Central Iraq. Seventy one species belong to twenty four genera of calcareous nannofossils were identified including sixty two of them were previously named and nine species were identified for the first time and they would not be given names until more information is obtained in the future to support this identification. It is a recorded of five biostratigraphic zone, which suggested the age of the Jaddala Formation to be of early to late Eocene. The recorded biozone includes the following: Reticulofenestra dictyoda (Deflandre in Deflandre & Fert, 1954) Stradner & Edwards, 1968 Partial Range Biozone (CNE 5); Discoaster sublodoensis Bramlette and Sullivan, 1961 Interval biozone (CNE 6-7); Nannotetrina cristata (Martini, 1958) Perch-Nielsen, 1971 Interval biozone (CNE 8); Nannotetrina alata (Martini in Martini & Stradner, 1960) Haq and Lohmann, 1976 Interval biozone (CNE 9); Chiasmolithus gigas Bramlette & Sullivan, 1961Range Biozone (CNE 10-11).

Salt lakes are major sources of dust. Formation of natural evaporitic salt crusts can reduce the dust efflux, but protection is dependent on environmental conditions and the mineralogical composition of lakebed deposits. Chemical stabilization with conventional additives can benefit in further reducing the dust efflux. These however disrupt the soils' biogeochemical cycles which are reliant on intertwining pore networks—a perspective commonly overlooked by engineers. In making provision for an engineered thin, porous, and lightweight crust that limits the dust deflation and preserves the soil's open structure, this work examines prospects of administrating a mixture of ground rubber (GR) from the waste tire and five grades of mediated colloidal nanosilica (NS) hydrosol to calcareous lake sand. This research presents evidence for interaction between carbonates in the sand and the added NS that yields a matrix of calcium silicate hydrates (C–S–H). It also presents SEM micrographs of novel honeycomb sand-GR open structures bonded with C–S–H units. The resulting sand-GR-NS mat offers reasonable unconfined compressive strength equal to levels seen in sand-NS systems, following a 28-day of curing. The preserved open network of pores functions as an ideal air and water conveyance system. Overall, a NS content in 15–25% mixed with 5% by weight of GR seems to have offered optimal strength and post-peak response. [ABSTRACT FROM AUTHOR]

Calcium bentonite mined in Smith County, Mississippi, has been reported in numerous publications to be derived from the weathering of volcanic ash. These interpretations were based on the bentonite having similar properties to bentonites actually formed from volcanic precursors. No recent detailed stratigraphic mapping in combination with modern laboratory analyses had been conducted for this area. Calcium bentonite, found at Olmstead, Illinois, in contrast, formed in situ from the weathering of biotite, glauconite, quartz, and other materials found in shallow calcareous marine deposits. Detailed stratigraphic mapping in Smith County in 2011 was carried out by Mississippi State University as part of a proposed surface reservoir study. The mapping, utilizing GPS and continuous sonic core samples, indicated that calcium bentonite was present and similarly formed by the in situ weathering of calcareous, glauconitic, marine marl in several formations in the Oligocene Vicksburg Group. The bentonite was not restricted to one stratigraphic interval as would be the case for a true ashfall deposit. Additional research conducted at Mississippi State University and more recently by others confirmed that the bentonite was formed by weathering and contemporaneous microbial action of the calcareous glauconitic marls. No volcanic ash was detected in any of the samples tested. The preponderance of other material present in the Smith County bentonite renders the presence of minute amounts of volcanic detritus volumetrically insignificant in the formation of the clay mass. A conceptual model is presented showing how the bentonite was formed and why it is restricted to this small area of the Oligocene outcrop. [ABSTRACT FROM AUTHOR]

This article compares measurements of particle shape parameters from three-dimensional (3D) X-ray micro-computed tomography (μCT) and two-dimensional (2D) dynamic image analysis (DIA) from the optical microscopy of a coastal bioclastic calcareous sand from Western Australia. This biogenic sand from a high energy environment consists largely of the shells and tests of marine organisms and their clasts. A significant difference was observed between the two imaging techniques for measurements of aspect ratio, convexity, and sphericity. Measured values of aspect ratio, sphericity, and convexity are larger in 2D than in 3D. Correlation analysis indicates that sphericity is correlated with convexity in both 2D and 3D. These results are attributed to inherent limitations of DIA when applied to platy sand grains and to the shape being, in part, dependent on the biology of the grain rather than a purely random clastic process, like typical siliceous sands. The statistical data has also been fitted to Johnson Bounded Distribution for the ease of future use. Overall, this research demonstrates the need for high-quality 3D microscopy when conducting a micromechanical analysis of biogenic calcareous sands. [ABSTRACT FROM AUTHOR]

Vertisols of India are calcareous and have a heavy texture with high clay content but low to medium content of Olsen estimated phosphorus (P). The on-farm and on-station trials revealed that Vertisols with various levels of P2O5 responded negligibly to fertilizer application on soybean crops. In Vertisols, the inorganic P is primarily associated with Ca (Ca-P), which gradually solubilizes under acidic conditions surrounding rhizosphere. Hence, in order to correlate both the findings, the current study investigated the rhizosphere/rhizoplane pH. The study used agar plate technique to observe that the pH of the rhizosphere and rhizoplane soils, which was observed to be acidic although the soil pH was 7.6. The correlation between P uptake and soil-available P measured using the four test methods (Bray 2, Olsen, Truog, and Mehlich 3) revealed that Bray 2 had high correlation with the amount of P absorbed by soybean. Bray 2 method extracts approximately 10 times more P from Vertisols than does the Olsen extractant. This could be a plausible reason for insignificant difference in crop post fertilizer application due to sufficient P fertility of the Vertisols. Hence, Bray 2 method was established as a suitable method for the extraction of P from Vertisols, in which the pH of the extraction solution was the most acidic, among the selected four extraction methods and had high correlation with the amount of P absorbed by soybeans. Hence, this method is recommended for P estimation for Vertisols present in Central India. Essentially, this study provided information that an accurate measurement of P availability is required to explain the non-responsive nature of soybean to P fertilizers in Vertisols. Additionally, the current study emphasized the need for optimum recommendations of P from the view point of rhizosphere; it may facilitate the reduction of the application rates of P to the crops, without reducing the crop yields. [ABSTRACT FROM AUTHOR]

Climate models project that many terrestrial ecosystems will become drier over the course of this century, leading to a drastic increase in the global extent of arid soils. In order to decrease the effects of climate change on global food security, it is crucial to understand the arid environment and the constraints associated with arid soils. Although the effects of aridity on aboveground organisms have been studied extensively, our understanding of how it affects soil processes and nutrient cycling is lacking. One of the primary agricultural constraints, particularly in arid locations, is water scarcity, due to which arid soils are characterized by sparse vegetation cover, low soil organic carbon, poor soil structure, reduced soil biodiversity, and a high rate of soil erosion via wind. Increased aridity will limit the availability of essential plant nutrients and crop growth, and subsequently pose serious threats to key ecological processes and services. The increasing rate of soil salinization is another major environmental hazard that further limits the agricultural potential of arid soils. These soil constraints can be ameliorated and the crop yields increased through case-specific optimization of irrigation and drainage management, enhancing the native beneficial soil microbes, and combinations of soil amendments, conditioners, and residue management. This review explores technologies to ameliorate soil constraints and increase yields to maintain crop output in arid soils.

This work focuses on Cr(VI) sorption by Calcareous and nZVI/Calcareous was investigated. The purpose of this study is to understand the mechanisms that govern the elimination of Cr (VI) and to find a suitable kinetics model of removal. Spectroscopic studies including FTIR, (TG‐DSC), SEM, Methylene blue and Iodine number were used for its characterization. Equilibrium data was examined using a comparison of linear Langmuir, Freundlich, Temkin and Dubinin– Radushkevich isotherm models. The Freundlich isotherm provided the best fit to the experimental data for Cr(VI) ions as indicated by the values of the regression coefficient. The kinetic rates were modeled by using the Lagergren‐first‐order, pseudo‐second‐order, Elovich and Intraparticle diffusion model. The Elovich model was found to explain the adsorption kinetics most effectively. The presence of intra‐particle diffusion mechanism was prominent, although it was not the sole rate‐determining step. The results showed that Calcareous and nZVI/Calcareous, can be effective for removing Cr(VI) ions from solution.

The study area was located in the North of Iraq. Five sites were selected that have formed from the limestone parent material. One pedon dug in each site and was divided into a number of horizons. Thirty-five soil samples were collected for physical and chemical analyses. The climate of study sites were similar to the Mediterranean Sea climate which is hot dry in summer and cool humid in winter. The mean of annual precipitation, varies from one site to another. Studied soils classified as Mollisols, Inceptisols, Vertisols, and Aridisols. Study soils were relatively high clay content and its content at the surface horizons is lower than it at subsurface horizons, and soil texture was ranged between clayey to loamy, the high value for clay content indicates to soil development. Fine clay/Coarse clay ratio showed that the pathway of fine clay similar to the pathway of total clay. CEC values increased with increasing clay. Organic matter was high in the surface horizons and decrease with depth. The following pedogenic processes occurred in study soils loss, gain, leaching, illuviation, eluviation, alkalization, humification, lessivage, desalinization, calcification, decomposition, and synthesis. [ABSTRACT FROM AUTHOR]

Three extractions were used to assess the availability of micronutrients in different soil collections. The suitability of some extractions under the conditions of Egyptian soils will be discussed. Three extraction methods (Mehlic 3, Soltanpour and Kelowna) were used for the determination of available Fe, Zn, Mn, Cu and B content of the soil samples (sand, calcareous and clay) during 2020 season. Surface soil samples (0-30 cm) were collected from three sites of Al Boston area in the new Nobaria, Governorate, Egypt, during 2020 season. From each selected plot, ten points were selected in a zig-zag path. The results revealed that the highest values of available Fe, Zn and Cu were given with the extraction solution of Soltanpour, while the highest values of available Mn and B were given with the extraction solution of Mehlic 3. On the other hand, the results showed that clay soil recorded the maximum available Fe, Zn, Mn and Cu, while calcareous soil recorded the maximum available boron content. The interaction between different extraction methods and soil samples was highly significant during 2020 season. [ABSTRACT FROM AUTHOR]

The survey was conducted to determine chemical weathering indices in western of Anbar governorate. The study area is located between longitudinal (41°42' 02" and 42° 27' 03") E, and latitude (34° 02' 24" and 34° 32' 08") N, within the lower valleys unit. Eight weathering indices were evaluated, namely Ruxton Ratio (R), Vogt's Residual Index (V), Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), Plagioclase Index of Alteration (PIA), and Product of Weathering Index (PWI), SI/Fe, SI/Ses., and B/A. It was carried out on 6 pedons of soil after obtaining samples and carrying out laboratory measurements to measure the percentage of oxides in the soil with depth. The variations of the indicators are studied vertically and horizontally and according to the correlation coefficient between indicators. The results of the study showed that there is no clear chemical weathering in the study pedons and for all indications, due to the little of leaching of calcium carbonate in sufficient quantities due to the little of rain and the accumulation of quartz in the soil surface, which indicates that the soils are newly formed. The highest values of the indicators were in pedon (p1), where the values were close to the minimum for the effectiveness of chemical weathering. The study also showed the high values of the indicators (V, CIA, CIW, PIA) in the third subsurface layers in pedon p3, while the indicators (R, Si/Fe, Si/Ses., B/A) were high in the p5 for the same layer due to the inverse relationship among the indicators because there is a negative correlation between the indicators' values (CIA, CIW, PIA) and the indicators values (R, SI/Ses., B/A). [ABSTRACT FROM AUTHOR]

The paleoecologic conditions of eastern Dahomey (Benin) Basin during Late Campanian-Eocene were investigated using foraminifera as proxies. Twenty-four (24) samples obtained from four (4) exploration boreholes and three (3) exposed outcrop sections were subjected to conventional micropaleontological processing techniques. Thirty-one (31) species of foraminifera (25 benthic and 6 planktic species) were identified from the samples. The recovered assemblages consist predominantly of Paleocene calcareous benthic species such as Anomalinoides midwayensis, Anomalinoides umboniferus, Eponides pseudoelevatus, Gavellina guineana, and Cibicides succedens. Sparse occurrence of Late Cretaceous agglutinated benthic species comprising Ammobaculites coprolithiformis and Textularia hockleyensis was also recorded. The Upper Cretaceous strata are either devoid of microfauna or contain few agglutinated taxa suggestive of continental to brackish water settings. The development of calcareous benthic foraminiferal assemblages in Paleogene strata of the study area signaled the incursion of open marine neritic conditions. Influx of sandy sediments at some horizons in the studied boreholes resulted into increased pore-water oxygenation leading to poor preservation of benthic foraminifera at these horizons. Planktic/benthic (P/B) ratio analysis of the foraminiferal assemblages suggests paleo-water depth not exceeding 65 m. [ABSTRACT FROM AUTHOR]

Introduction Increasing demand for an international classification system as a unique communication tool in soil science has caused development of different systems. Like many other countries, Soil Taxonomy and WRB are the most popular soil classification systems in Iran. Genetic and morphologic soil properties are used for soil classification in both systems. However, correlation of the two systems and efforts to harmonize them have been a major concern among soil scientists. Comparing Soil Taxonomy and WRB in gypsiferous and calcareous soils of central Iran, Sarmast et al. (13) reported that WRB using various qualifiers is more effective than Soil Taxonomy. Since no study on soils of Iranshahr and Dalghan Regions located in Sistan and Baloochestan Province has performed and/or no reported data is available, the present research was performed to: 1) study morphological, physical, and chemical soil properties in the area, 2) classify soils based on Soil Taxonomy (2014) and WRB (2015) systems, 3) compare the two systems for soil description in Iranshahr and Dalghan regions as a part of Sistan and Baloochestan Province, central Iran. Material and Methods: The study area starts from Iranshahr (590 m asl) in the center of the province and extends to Dalghan (390 m asl) in west. Alluvial fan, pediment, playa, and hill were among different landforms identified using field studies, topography maps (1:50000), and Google Earth image observations. To cover the maximum soil variations in the area, 10 representative pedons were selected, described, and sampled. Results and Discussions: Calcic, gypsic, anhydritic, argillic, natric, and salic horizons identified after field work and laboratory analysis. Results of the study showed that addition of Yermic Torrifluvent, Yermic Torriorthent, Calcic Gypsiargid, Gypsic Natrsalid, Natric Gypsisalid, Anhydritic Gypsisalid, Anhydritic Calcisalid subgroups to Soil Taxonomy system from one hand, and addition of anhydrite and aquic (for Solonchak reference soil group) qualifiers to WRB system from the other hand, causes a higher correlation and more harmonization between the two classification systems. Meanwhile, the minimum percentage of calcium carbonate equivalent necessary for calcic horizon identification in coarse textured soils including gravel in Soil Taxonomy is also suggested to be added to WRB system. Besides, requirements of salic horizon in WRB system is recommended to be added to Soil Taxonomy. At the same time, soil names in WRB system provide more information and data about soil properties and characteristics in young soils (such as yermic qualifier showing desert pavement) compared to Soil Taxonomy. Soil Taxonomy is not able to properly classify saline soils of arid regions down to subgroup level which is a weak point for this system. That is why newly added Gypsic Natrsalids is suggested for soils with natric, gypsic, and salic horizons in the upper 100 cm of the soil. On the other hand, the requirements of salic horizon in WRB system (the minimum EC content of 15 dS/m and the EC multiplied by the horizon thickness of more and/or equal to 450) are also suggested for Soil Taxonomy. Conclusion: Results of the study for both saline and sodic soils show more capability of WRB system compared to Soil Taxonomy to classify soils. From soil management point of view, natric horizon causes more negative effects compared to salic horizon because Na disperses the soil particles and destroys soil structure and sodic soils need more practices to be improved compared to saline soils. Results for gypsiferous soils also show more capability of WRB system compared to Soil Taxonomy because gypsum content which is important for gypsiferous soils management is properly concerned in WRB system. However, lack of anhydritic horizon in WRB seems to be a weak point for this classification system. That is why it is suggested to be added to WRB (13). Since Soil Taxonomy does not use independent abbreviations for anhydritic horizon compared to gypsic horizon, the Ba and Baa abbreviations are also suggested for Soil Taxonomy to be added. [ABSTRACT FROM AUTHOR]

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In order to effectively manage large quantities of discharged iron ore tailings (IOTs), this investigation studied the application of calcareous IOTs in cement production with the analysis of clinker phases and hydration products using X-ray diffraction, thermogravimetric analysis, and scanning electron microscopy. Furthermore, the influence of the addition of calcareous IOTs on the physical strengths of the prepared cement was evaluated. The results showed that the clinker phases were C3S, C2S, C3A, and C4AF, and the cement hydration products were claviform ettringite, granular C-S-H gels, and flaky Ca(OH)2. In addition, the maximum amount of IOTs added for a 52.5 grade cement production was 6 wt.%. This investigation is beneficial in both reducing the use of conventional cement materials and the management of IOTs. [ABSTRACT FROM AUTHOR]

Single extraction and sequential extraction assays were used to compare the effect of low-temperature biochar and its non-pyrolyzed composted biosolids on Pb and Cd mobility in the buffered conditions of calcareous river sediments. Results showed that amendment reduced the mobility of both metals, though under higher pH conditions, the effect of the non-pyrolyzed composted biosolids on the mobility of Pb was more apparent. On the other hand, the low temperature biochar had a more significant effect on the mobility of both metals under low pH conditions. The single extraction scheme used to simulate varying physicochemical conditions confirmed that amendment decreased Pb mobility up to 49% and Cd up to 96%. Sequential extraction assays confirmed a shift in predominant metal-fraction associations; from potentially mobile fractions to the more immobile ferromanganese oxide and organic matter fractions. These results highlighted the significant impact biochar amendment can have on metal mobility even when temporarily buffered by the physicochemical conditions in the calcareous substrates. [ABSTRACT FROM AUTHOR]

Foraminifera biostratigraphy and paleoenvironmental analysis of the sediments penetrated by Sahaiawei-1 Well in the Northern Delta Depobelt, Niger Delta Basin was carried out in order to determine the foraminifera biozonation, age, paleobathymetry, depositional environment and paleo-oxygen condition of the well. The total foraminifera population recovered was two thousand, three hundred and sixty five (2365), with planktic foraminifera constituting one hundred and fifty four (154) forms, while calcareous benthic and agglutinated benthic foraminifera recovered accounted for two thousand, one hundred and sixty two (2162) and fourty nine (49) of the total foraminifera population respectively. The total foraminifera species recovered was fifty nine (59); planktic accounted for twenty (20) foraminifera species, while calcareous and agglutinated benthic foraminifera accounted for thirty one (31) and eight (8) foraminifera species respectively. Five benthic foramineferabiozones were identified: lumped P7-P13, P5-P6/P7, lumped P3-P4, lumped P1-P2 and M18 Zones of Blow (1969, 1979). The result of the analysis indicates that the entire analysed interval (1800ft -- 10680ft) was deposited during the Late Maastrichtian to Late Eocene epoch. The depositional environments of the Well varied from littoral, marginal, shallow and deep marine environments. [ABSTRACT FROM AUTHOR]

Halimeda opuntia merupakan rumput laut Chlorophyta berkapur yang memiliki kandungan nutrisi untuk pangan fungsional. Namun, pergeseran komposisi nutrisi dapat terjadi akibat perubahan lingkungan akibat limpasan nutrien dan bahan organik lainnya yang umum terjadi di perairan pesisir Indonesia. Penelitian ini bertujuan untuk melakukan identifikasi pergeseran kandungan nutrisi H. opuntia yang tumbuh di zona intertidal agar dapat digunakan sebagai dasar pemilihan lokasi pengambilan bahan baku H. opuntia untuk produk fungsional. Pengambilan sampel dilakukan di empat lokasi perairan di Indonesia, yaitu perairan Binuangeun (Banten), Lampung Selatan, Lombok Timur (Nusa Tenggara Barat) dan Konawe Selatan (Sulawesi Tenggara). Karakteristik nutrisi dari rumput laut target meliputi kadar air, abu, protein, lemak, karbohidrat, dan serat kasar. Informasi lingkungan dari habitat sampel ditunjukkan melalui variabel kimia air yaitu DO, pH, salinitas, pCO2, kalsium aragonit, nitrogen anorganik terlarut, serta fosfat anorganik terlarut. Hasil analisis menunjukkan kondisi lingkungan eutrofik berpengaruh secara signifikan terhadap komposisi nutrisi H. opuntia. pH dan salinitas menjadi faktor determinan positif (R2 = 0,75 pada p

The adsorption experiment of three different calcareous soils two loam and one clay textures) for Nineveh governorate (Tel Aakoub, Ibrahim Al-Khalil, and Tel Kaif) was classified under Aridsol-Calciorthids with a slight slant to alkaline (7.43), non saline (3.24 dS m-1), Low content of organic matter (17.3 kg-1), cation exchange capacity (42 Cmolc kg-1), high content of carbonate minerals (409 g kg-1). Lead adsorption was studied by batch equilibrium method at a temperature of (298 Kelvin) for lead solutions (5,10,20,40,80,100 mg L-1). For 48 hours, the lead was measured in equilibrium solutions and the adsorption criteria were calculated according to Langmuir, Freundlich and the DR equations. The results of the mathematical description of lead adsorption showed high efficiency in the use of Langmuir, Freundlich and the DR equations at the concentrations used. The lead added to the soil was also distributed between the equilibrium solution and the solid soil phase in terms of propagation coefficient values (Kd), which ranged from (111.8) to (255.5 l kg-1) with an average of 169 l kg-1. The exceeded the Langmuir and Freundlich equivalents in the description of lead adsorption to obtain the highest coefficient of determination (R2) and a lesser standard error (SE). The adsorption capacity (qm) of the lead ion in the study of soil (13.63 - 41.48 mol g-1). The K value associated with the adsorption capacity ranged from (-0.44) to (- 1.24) (mol2 KJ -2). The value of (E) is the free energy rate of the reaction ranged from the lead adsorption values (0.63 - 1.06 KJmol-1). [ABSTRACT FROM AUTHOR]