Calcareous Soils Research Articles

The phytosiderophore analogue proline-2′-deoxymugineic acid is more efficient than conventional chelators for improving iron nutrition in maize

ABSTRACT Iron (Fe) is an essential nutrient but has poor bioavailability because of its low solubility under conditions of high pH, such as calcareous soils. Previously, we synthesized an analogue of the natural Fe(III) chelator 2′-deoxymugineic acid secreted by graminaceous plants for efficient Fe uptake, designated as proline-2′-deoxymugineic acid (PDMA). Soil application of Fe(III)-PDMA ameliorated symptoms of Fe deficiency in rice. In the present study, we explored the potential of PDMA as Fe nutrition supplement in maize, a major graminaceous crop, and rice for comparison. In calcareous soil pots, Fe deficiency chlorosis of maize was efficiently recovered by a single application of Fe(III)-PDMA. In contrast, maize plants treated with conventional Fe(III)-chelator complexes, such as Fe(III)-ethylenediaminetetraacetic acid (EDTA) or Fe(III)-N,N′-di(2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid monohydrochloride (HBED), showed little or no recovery. Similarly, rice Fe chlorosis in calcareous soil pots was efficiently recovered by a single application of Fe(III)-PDMA, but not by other conventional Fe(III)-chelator complexes. Application of Fe(III)-PDMA was also effective in ameliorating Fe deficiency chlorosis in hydroponically grown maize seedlings; other Fe(III)-chelator complexes showed minimal or no efficacy. Addition of low concentrations of metal-free PDMA recovered Fe chlorosis of maize or rice in the presence of Fe(III)-EDTA, suggesting possible ligand exchange from EDTA to PDMA for subsequent Fe(III)-PDMA uptake by ZmYS1 and OsYSL15 transporters. Similar effects were observed with Fe(III)-HBED, which has a higher stability constant, but to a lesser extent than Fe(III)-EDTA, suggesting that ligand exchange from HBED to PDMA might be less prone to occur than for chelators with moderate stability constants, such as EDTA. Ferric-chelate reductase assays of maize roots showed substantial reduction of Fe(III)-PDMA, but this reduction activity was not increased under Fe-deficient condition. These results suggested that PDMA is an efficient reagent for improvement of Fe nutrition in graminaceous crops, including maize, because of suitability of Fe(III)-PDMA as a substrate for chelation-based Fe uptake systems.

Phosphorus and Silicon Uptake By Corn (Zea mays L.) in Response to Silicon Application in Calcareous Soil

Phosphorus and Silicon Uptake By Corn (Zea mays L.) in Response to Silicon Application in Calcareous Soil

Microbial Consortia: Sustainable Alternative to Maize Residue Burning and Way to Enhance Nitrogen in Calcareous Soil

Microbial Consortia: Sustainable Alternative to Maize Residue Burning and Way to Enhance Nitrogen in Calcareous Soil

Rapid phenanthrene biodegradation in highly calcareous saline sodic soil using an artificial halophile bacterial consortium

Rapid phenanthrene biodegradation in highly calcareous saline sodic soil using an artificial halophile bacterial consortium

Applying Some Tillage Practices and Organic Waste Low Economic Value to Enhance the Productivity of Calcareous Soil and Some Oil Crops.

Applying Some Tillage Practices and Organic Waste Low Economic Value to Enhance the Productivity of Calcareous Soil and Some Oil Crops.

Study on the salt-dissipating and settlement-preventing performance of composite modified cushion layers in the roof-propping body of earthen sites' basal sapping zone

Cushion layer replacement is currently an important method for preventing and treating salinized deterioration in the earthen sites' basal sapping zone. The water resistance, salt-dissipating property, and load-bearing capacity are key indicators for evaluating the effectiveness of capping replacement. In this study, gravel is an inorganic admixture for the calcareous soil base material. Prepared 19 soil samples through the cross-combination of gravel with three types of organic binders. These samples were subjected to tests on wave velocity, volume shrinkage, permeability, capillary rise, and consolidation. The suitability of the composite materials for reinforcing the rammed earth heritage capping layers was further studied using the AHP-CRITIC-TOPSIS method. The results show that: (1) The wave velocity and volume shrinkage rate of the samples increased over time and reached stability after 7 days. Moreover, the water resistance, salt dissipation, and load-bearing capacity of the samples were significantly enhanced; (2) Comprehensively evaluating the suitability of the composite materials for the capping layers in the earthen sites' basal sapping zone using six indicators: wave velocity, volume shrinkage rate, permeability coefficient, capillary water absorption rate, compression coefficient, and final settlement, it was found that the SMS-S: G7:3 mixture showed the best suitability. This study provides a reliable theoretical basis for the restoration of earthen sites in the arid areas of Northwest China.

Bioavailability and environmental implications of major and trace metals in manihot esculenta (cassava) grown on shaly and calcareous soils in parts of southern benue trough, nigeria.

bioavailability and environmental implications of major and trace metals in manihot esculenta (cassava) grown on shaly and calcareous soils in parts of southern benue trough, nigeria.

UCS and microscopic experimental study of coconut coir fiber-waterborne epoxy resin composite modified calcium sand

To address the issues of high porosity and low strength in calcium sand of artificial islands, this study focuses on improving the calcium sand’s mechanical properties. The effects of WER curing methods and coconut fiber modification on the UCS and microscopic mechanisms of calcium sand are investigated. The results indicate that both fiber incorporation and the increase in WER ratio can enhance the unconfined compressive strength of calcareous sand, with the addition of a certain amount of coconut coir fiber showing a more significant strength increase. The optimal recommended dosage of WER is 15%, which results in an UCS of 1218 kPa, an increase of nearly 4.27 times compared to 9% WER dosage. Coconut coir fiber has good tensile strength that can improve the compressive strength of calcareous sand after curing. The UCS of calcareous sand cured with a fiber content of 0.3% to 0.5% is increased by 1247 kPa to 1792 kPa compared to cured soil with no fiber. The strong binding nature of WER addresses the issue of large porosity in calcareous sand. Together with the penetrating coconut coir fibers, it forms a three-dimensional reticular framework structure, thereby enhancing the compressive performance of the calcareous sand-cured soil mass.

Synergistic Effects of Microbial Gibberellic Acid and Vitamins on Onion (Allium cepa L.) Yield, and Quality in Low-Fertility Soil

Onion is one of the most popular vegetables that play a major role in boosting immunity against diseases. As a result of the successive population increase, many farmers resort to excessive use of chemical plant growth enhancers to increase the crop's productivity, which causes many health and environmental problems and reduces the sustainability of the soil. Microbial phytohormones and vitamins are safe, eco-friendly, and effective natural solutions to increase the crop's productivity and maintain the soil health at the same time. To our knowledge, until know there is no information about the roles of microbial gibberellic acid (GA3), and vitamins on the growth and quality traits of onions. Two field experiments were conducted during two consecutive winter seasons in a sandy calcareous soil farm. Two treatments were in the main plot (without and with microbial GA3), and six were in the sub-plot (control, chemical thiamine, ascorbic acid, riboflavin, and microbial ascorbic acid and riboflavin). Plant growth parameters including plant height, fresh weight, leaf number, bulb diameter, and neck diameter were recorded. Onion yield and their quality traits of sugar content, protein, antioxidants, vitamin C, phenols, flavonoids, and NPK were measured. The major findings revealed that plants treated with applications of microbial GA3 or vitamin treatments significantly improved the onion yield, phenotypic, physiological, and biochemical characteristics in both seasons. In the majority of the measured parameters, the microbial ascorbic acid treatment outperformed the other vitamin treatments. The combination of foliar microbial GA3 spray and vitamins, especially microbial ascorbic acid, and microbial riboflavin, produced the high onion yield, growth and quality traits of plant height, number of leaves, fresh weights, bulb diameter, sugar content, vitamin C, total antioxidants, total phenols, and flavonoids during both seasons. The application of microbial GA3 in combination with microbial vitamins as foliar spraying are promising eco-friendly, cheap, plant bio-stimulators that could be used safely in the field, especially under low-fertility soil, for good growth, yield, and high-quality onions.

Foliar applications of zinc oxide nanoparticles and boric acid affect leaf oxidative metabolism and productivity in young pecan trees

Zinc and boron are nutrients that often suffer low bioavailability to pecan trees grown in calcareous soils whereas adequate supplies of these two elements is essential for commercial pecan production. Working with young pecan trees, we evaluated changes in oxidative metabolism, levels of bioactive compounds, yield components and foliar nutrient concentrations in response to foliar sprays (50 or 100 mg L−1) of zinc oxide nanoparticles (ZnO NPs) and boron (H3BO3). Four different treatment solutions were applied in a completely randomised design with six replications per treatment (24 trees in total). Zinc and B treatments were applied before pistil receptivity (3 weeks before anthesis) and at stem elongation stage 31, 39/60; flowering stage 69; fruit stages 7–75 and continued for a total of five applications at 14-day intervals. We evaluated enzyme activities (SOD, H2O2, CAT and GPx), AC, phenols, flavonoids, leaf area, chlorophyll, total anthocyanins and nut yield and quality (nut weight and % kernel). The mineral concentrations in the leaflets were also determined. The mineral concentrations (N, P, K, Ca, Mg, Fe, Cu, Mn, Ni, Zn and B) in the leaflets were also determined. Spraying ZnO NPs and B increased SOD activity, CA, chlorophyll concentration, mineral nutrients (N, K, Ca, Zn and B) and yield. However, reductions were observed for CAT activity, nut quality and concentrations of phenol, flavonoid, anthocyanin and Fe. Boron increased GPx activity and P concentration. These results demonstrate that spraying low doses (50 mg L−1) of ZnO NPs and B can help reduce oxidative stress and increase yield, nut quality and leaf concentrations of Zn and B in young cv. Wichita pecan trees established on a calcareous soil.

Do phosphorus amendments enhance biodegradation activity in stalled petroleum hydrocarbon-contaminated soil?

Phosphorus (P) fertilizers promote soil petroleum-hydrocarbon (PHC) bioremediation by correcting carbon-to-P ratio imbalances. While these inputs create conditions favorable to microbial growth, areas of a site or an entire site with low degradation rates (i.e., "stalled") occur for unknown reasons. We hypothesized that soil conditions limit P bioavailability, leading to stalls in PHC bioremediation, and adding the correct P amendment restarts microbial activity. Soils were collected and characterized from four cold calcareous PHC-impacted sites in Saskatchewan, Canada, undergoing bioremediation. A generalized linear mixed model identified that regions with lower degradation rates possessed a neutral pH with high magnetic and salinity values. In a subsequent laboratory experiment, the proportion of benzene degraded at greater rates within active (i.e., higher degradation rates) than stalled soils, thereby following model predictions (p-value=0.19, Kruskal-Wallis). The PHC degradation efficiency of different P amendments was tested by doping stalled soils (n=3) with one of five treatments: 0 (control), 0 (autoclaved control), or 50mg phosphate kg-1 soil as sodium diphosphate, triethyl phosphate, or tripolyphosphate. Tripolyphosphate accelerated benzene degradation (75.5±5.4%) in one stalled soil (Outlook 323) and increased degradation non-significantly (43.9±9.4%) in another (Allan 917). Alternatively, the final sample (Davidson 421) possessed the greatest benzene removal with no amendments. This implies that soil P bioavailability may not be the sole cause of decreased microbial activity. Accordingly, combining model outputs with mineralogy and microbiology investigations could enhance PHC biodegradation rates in these cold calcareous soils.

Effects of biochar and magnesium oxide on cadmium immobilized by microbially induced carbonate: Mobilization or immobilization in alkaline agricultural soils?

Microbially induced carbonate precipitation (MICP) is a promising technique for remediating heavy metal-contaminated soils. However, the effectiveness of MICP in immobilizing Cd in alkaline calcareous soils, especially when applied in agricultural soils, remains unclear. Biochar and magnesium oxide are two environmentally friendly passivating materials, and there are few reports on the combined application of MICP with passivating materials for remediating heavy metal-contaminated soils. Additionally, the number of treatments with MICP cement and the concentration of calcium chloride during the MICP process can both affect the effectiveness of heavy metal immobilization by MICP. Therefore, we conducted MICP and MICP-biochar-magnesium oxide treatments on agricultural soils collected from Baiyin, Gansu Province (pH = 8.62), and analyzed the effects of the number of treatments with cement and the concentration of calcium chloride on the immobilization of Cd by MICP and combined treatments. The results showed that early-stage MICP could immobilize exchangeable cadmium and increase the residual cadmium content, especially with high-concentration calcium chloride MICP treatment. However, in the later stage, soil nitrification and exchange processes led to the dissolution of carbonate-bound cadmium and cadmium activation. The fixing effect of MICP influence whether the MICP-MgO-biochar is superior to the MgO-biochar. Four treatments with cement were more effective than single treatment in MICP-biochar-magnesium oxide treatment, and the MICP-biochar-magnesium oxide treatment with four treatments was the most effective, with passivation rates of 40.7% and 46.6% for exchangeable cadmium and bioavailable cadmium, respectively. However, attention should be paid to the increase in soil salinity. The main mechanism of MICP-magnesium oxide-biochar treatment in immobilizing cadmium was the formation of Cd(OH)2, followed by the formation of cadmium carbonate.

Environmental and climatic significance of the Pliocene-Pleistocene calcretes in North Africa

The North African calcretes formed during the Plio-Pleistocene are a prominent and stratigraphically significant palaeoclimatic marker. We studied the calcrete along a north–south transect in Tunisia that crosses the climatic boundaries between the latitudes 33° and 37° N to elucidate the palaeoenvironmental and climatic significance of the calcrete for the Plio-Pleistocene. Macroscopic, petrographic, Scanning Electron Microscopy (SEM), and Cathodoluminescence (CL) observations obtained in the field and from thin sections of the non-powdery horizons of all sites allowed to identify 4 facies: Pisolithic (limestones with clast(s) coated by laminae), laminar (limestones with a succession of laminae), massive brecciated (brecciated limestones), and groundwater facies (limestones with no biogenic features). Notably, soil-forming processes were evident at all sites except for those situated further south, which exhibited characteristics indicative of a groundwater environment. The comparison with modern analogues suggests for our study area the climate was similar to modern central Spain (Hot-summer Mediterranean climate Csa) in central Tunisia which is, in turn, similar to the modern climate in North Tunisia. The climate was characterized by strong seasonal contrast: higher winter rainfall than today followed by long dry hot summers modified by a North-South gradient. This gradient was the result of the interplay between westerly winter winds and the orographic effect of the Atlas Mountains confirming the North Atlantic origin of precipitations. We conclude that during the late Pliocene to early Pleistocene, the climate in Northern Africa was more humid than today, with enhanced winter rainfall at all study sites probably at the same time of the establishment of Saharan humid periods. These humid phases may have been long enough, spanning more than 10.000 years, to reduce recharged groundwater salinity and, subsequently, form thick calcareous soil.

Study on Soil Fertility Characteristics of Walnut Orchards with Different Parent Materials and Soil Types in Gyaca County, Tibet

Walnut trees on the Tibetan Plateau have sustainable and nutritious characteristics. They grow naturally without the use of any chemical fertilizers and pesticides. Therefore, the soil fertility of walnut orchards is a key factor influencing walnut yield and quality. This experiment measured and analyzed the basic soil nutrient content, microbial biomass carbon (MBC), nitrogen (MBN), phosphorus (MBP), and leaf nutrient indicators in five types of representative walnut orchard soil parent materials in Gyaca County to clarify the fertility characteristics of different soil types and their correlations with walnut nutrients, providing a basis for the sustainable development of the plateau walnut industry. The results showed that there were significant differences in soil organic matter (SOM), total nitrogen (TN), available nutrient contents, and microbial activity among soil types with different parent materials. The comprehensive representation of available nutrient levels in the soils is as follows: gray-cinnamon soil and calcareous alluvial soil > mountain meadow soil > plateau prairie soil and brush prairie soil. The average MBC, MBN, and MBP contents in the five soils were 368.8 mg/kg, 28.4 mg/kg, and 23.6 mg/kg, respectively, and the content in the topsoil (0–20 cm) was higher than that of the subsoil (20–40 cm). The total nitrogen (PN), total phosphorus (PP), and total potassium (PK) contents in walnut leaves were found to be closely related to the soil physicochemical properties and microbial activity, among which five indicators, including soil TN, available nitrogen (AN), SOM, MBC, and slowly available potassium (SAK), had the greatest impact on leaf nutrient levels. These findings are valuable for the future management and development of walnut orchards. Therefore, for different soil parent materials and soil types, improving the soil fertility and actively applying nitrogen-rich organic fertilizers should be prioritized to improve the yield and quality of Tibetan Plateau walnuts.

Investigating the synergistic potential of Si and biochar to immobilize Ni in a Ni-contaminated calcareous soil after Zea mays L. cultivation

Abstract. In Iran, a significant percentage of agricultural soils are contaminated with a range of potentially toxic elements (PTEs), including Ni, which need to be remediated to prevent their entry into the food chain. Silicon (Si) is a beneficial plant element that has been shown to mitigate the effects of PTEs on crops. Biochar is a soil amendment that sequesters soil carbon and that can immobilize PTEs and enhance crop growth in soils. No previous studies have examined the potentially synergistic effect of Si and biochar on the Ni concentration in soil chemical fractions and the immobilization thereof. Therefore, the aim of this study was to examine the interactive effects of Si and biochar with respect to reducing Ni bioavailability and its corresponding uptake in corn (Zea Mays) in a calcareous soil. A 90 d factorial greenhouse study with corn was conducted. Si application levels were 0 (S0), 250 (S1), and 500 (S2) mg Si kg−1 soil, and biochar treatments (3wt %) including rice husk (RH) and sheep manure (SM) biochars produced at 300 and 500 °C (SM300, SM500, RH300, and RH500) were utilized. At harvest, the Ni concentration in corn shoots, the Ni content in soil chemical fractions, and the release kinetics of DPTA (diethylenetriaminepentaacetic acid)-extractable Ni were determined. Simultaneous utilization of Si and SM biochars led to a synergistic reduction (15 %–36 %) in the Ni content in the soluble and exchangeable fractions compared with the application of Si (5 %–9 %) and SM (5 %–7 %) biochars separately. The application of Si and biochars also decreased the DPTA-extractable Ni and Ni content in corn shoots (by up to 57 %), with the combined application of SM500 + S2 being the most effective. These effects were attributed to the transfer of Ni in soil from more bioavailable fractions to more stable iron-oxide-bound fractions, related to soil pH increase. SM500 was likely the most effective biochar due to its higher alkalinity and lower acidic functional group content which enhanced Ni sorption reactions with Si. The study demonstrates the synergistic potential of Si and SM biochar for immobilizing Ni in contaminated calcareous soils.

Radon Dynamics in Granite and Calcareous Soils: Long-Term Experiments in a Semi-Arid Context

Radon in soil poses a significant health risk when it accumulates inside dwellings. The estimation of radon potential is a difficult task due to the complex dynamics of radon within soil and its relations with the weather. This research focuses on the variability of radon activity, driven by environmental changes, assessed in two loam soils (loamy sand–granite soil and silty clay loam-calcareous soil) with different radium contents. We conducted an experiment with teow soil columns in a semi-controlled outdoor laboratory, in a warm semi-arid climate. We also examined the consequences of abundant rainfall on radon activity through artificial soil water content (SWC) experiment conditions. Statistical analyses reveal that SWC is the most significant parameter influencing radon activity in these experiments. Radon is proportional to SWC and inversely proportional to temperature, evapotranspiration, and pressure in both soils, while wind is negatively related only in the loamy sand soil. Based on our findings, we modelled radon potential considering different soils and climatic contexts. SWC influences radon potential by changing radon emanation, activity, and permeability, depending on the local soil texture and radium concentration.

Comparison of leaf and root nutrients concentration in twenty olive cultivars grown on a calcareous soil

Comparing the absorption and translocation efficiency of the nutrients in olive cultivars can lead to the selection of cultivars with higher efficiency. This research was conducted with the aim of comparing the uptake and translocation capacity in 20 olive cultivars (12 domestic and 8 foreign) in a commercial orchard on calcareous soil in a randomized complete block design. Except for copper (Cu), leaf concentration of other elements was within the optimal range. In ʻAmphesis,ʼ high translocation (5.28%) and in ʻAmigdalolia,’ high uptake capacity (12.6) caused an increase in leaf phosphorus (P). Leaf K in all cultivars was higher than the deficiency limit (0.77%). In none of the cultivars, leaf sodium (Na) concentration was higher than the toxicity limit (0.2%), it accumulated in the root of ʻZard-Aliabadʼ and ʻShengeh,ʼ and reduced in their leaf. Leaf iron (Fe) concentration of all cultivars was in the sufficient range (>63 mg kg−1) and the highest was in ʻGorgan-Aʼ and ʻZardʼ and the lowest in ʻKazeroon,ʼ ʻArbequinaʼ and ʻMission.ʼ Although the leaf Cu in ʻAmphesisʼ (4.32 mg kg−1) and ʻArbequinaʼ (4.03 mg kg−1) was above the sufficient limit, in the rest of the cultivars it was below this critical limit. The highest leaf manganese (Mn) concentration (61.35 mg kg−1) and the highest Mn translocation percentage (84.59) were in ʻFeshomi.ʼ Among these cultivars, ʻAmphesisʼ was higher than others in terms of P, potassium (K), Cu and zinc (Zn) leaf concentrations and ʻAmigdalolia in terms of P, K and Zn, and in most cases the reason for this is the higher translocation efficiency.

Adsorption retention of spiramycin in agricultural calcareous loess soils: Assessing the impact of influential factors and mechanisms

Adsorption retention of spiramycin in agricultural calcareous loess soils: Assessing the impact of influential factors and mechanisms

Efficacy evaluation of biochar and activated carbon as carriers of bacterial inoculants in the remediation of multi-metal polluted soil

ABSTRACT Application of appropriate organic amendments as the carriers of bacterial consortium may improve the remediation efficiency of HMs-polluted soil. A greenhouse experiment was designed and carried out to investigate the capability of biochar, and activated carbon prepared from ostrich manure and almond husk as the carriers of bacterial inoculants in the phytoremediation of a calcareous soil polluted with Pb, Ni, Cd and Zn by maize. Results showed that the application of biochar and activated carbon prepared from ostrich manure increased root (78–129%) and shoot (72.3–272%) dry weight, as compared to the control. The values of metal accumulation in both maize root and shoot were in the order of Cd>Zn>Ni>Pb. While biochar and activated carbon prepared from ostrich manure significantly increased both root and shoot metals uptake, those prepared from almond husk drastically decreased the uptake of some metals. The foremost mechanism involved in the phytoremediation of Cd, Ni and Pb was phytostabilization while that of Zn was due to the phytoextraction. Results of the present study demonstrated the effectiveness of ostrich manure-derived biochar and activated carbon as an efficient treatment in the phytoremediation of multi-metal-polluted soils and the mitigation of HMs phytotoxicity.

Environmental Behaviour of Synthesized and Commercial Agricultural Zinc Products: Leaching, Migration, and Availability in Soils

The aim of this paper is to examine the environmental effect of different chemical characteristics of Zinc (Zn) sources, assessing the transport, leaching and accumulation in the environment in sand, acidic (AS) and calcareous (CS) soils. Comparative short- and long-term studies applying ZnO sources [bulk, laboratory-synthesized and commercial nanoparticles (NP)], ZnSO4, complexed Zn (Zn-lignosulfonate) and chelated Zn (Zn-diethylenetriamine-pentaacetate, Zn-hydroxy-ethylenediamine-tetraacetate and Zn-ethylenediamine-tetraacetate) were carried out. For all treatments and media, the medium- and long-term dissolution kinetic model was fitted to a logistic function. The applied Zn in the form of ZnO was mainly retained at the upper half (0–7.5 cm) of the columns and in very available form (ranging 40–61% of added Zn in AS and 29–31% in CS). Leached Zn reached values below 6% in AS and 3% in CS. The use of chelated Zn in both soils and complexed Zn, and ZnSO4 in AS resulted in excessive leaching of Zn (around 70%). The amount of Zn available at the upper half of the column was less than 5%. In the CS, these fertilizers showed a higher aging than ZnO sources, negatively affecting its availability as a nutrient for crops. ZnO NP showed short- and medium-term dissolution kinetics that allow gradual nutrient release and high availability at the medium-term. These products provide an effective solution for plant nutrition while mitigating the environmental problems observed with more traditional sources related to leaching.Graphical