Water Conductivity Research Articles

Hydrogen peroxide in attenuation of salt stress effects on physiological indicators and growth of soursop.

To mitigate the deleterious effects of salt stress, substances capable of acting as mitigators and/or inducers of tolerance to stress have been used, enabling the use of saline waters and contributing to the development of irrigated agriculture. In this context, the aim of the present study was to evaluate the effect of foliar spraying with hydrogen peroxide as an attenuator of salt stress effects on soursop morphophysiology. The experiment was conducted under greenhouse conditions in Campina Grande - PB, Brazil, using a randomized block design, in a 4 × 4 factorial arrangement, whose treatments resulted from the combination of four levels of electrical conductivity of irrigation water - ECw (0.8 - control, 1.6, 2.4, and 3.2 dS m-1) and four concentrations of hydrogen peroxide - H2O2 (0, 10, 20, and 30 μM), with three replicates. Foliar application of hydrogen peroxide at a concentration of 10 µM increased growth, chlorophyll synthesis, and relative water content in the leaves and consequently reduced the foliar water saturation deficit of soursop irrigated with ECw up to 1.6 dS m-1. The concentration of hydrogen peroxide of 30 µM intensified the salt stress on the electrolyte leakage in the leaf blade and the photosynthetic pigments of soursop, 270 days after transplanting.

The impact of saline and water stress on the agronomic performance of beet crops.

Excessive salts in irrigation water and water stress have a negative impact on the productive yield of agricultural crops. In this regard, the objective was to evaluate the effect of combined saline and water stress on the agronomic performance of the beet crop. The experiment was conducted in a greenhouse located at the Universidade da Integração Internacional da Lusofonia Afro-Brasileira, in Redenção, Ceará. The experimental design used was completely randomized with split-plots arrangement. The main plots were formed by the electrical conductivities of the irrigation water (0.8, 1.5, 3.0, 4.5, and 6.0 dS m-1), while the irrigation depths of 50 and 100% of the crop evapotranspiration (ETc) were the subplots, with 6 replications. Saline stress negatively affected growth, biomass, tuber root length, and productivity, while increasing the soluble solids of the beet crop. Excessive salts in the irrigation water caused reductions in physiological indices of the beet crop, although with less severity under the 100% ETc.

Trocas gasosas e crescimento de algodoeiro colorido sob estresse salino e aplicação de ácido salicilico

ABSTRACT The occurrence of water sources with high salt content stands out as a limiting factor for the expansion of irrigated agriculture in the semi-arid region. In this context, it is essential to look for strategies to mitigate the effects of salt stress, and the application of salicylic acid stands out. The objective of this study was to evaluate gas exchange and growth of the naturally colored cotton cv. BRS Jade under saline water irrigation and foliar application of salicylic acid under semi-arid conditions. The experiment was carried out in containers adapted as drainage lysimeters, under open air conditions at the Center of Science and Agri-Food Technology of the Federal University of Campina Grande in Pombal, Paraíba, Brazil. A randomized block design was adopted, in a 5 × 5 factorial scheme, with treatments resulting from the combination of five levels of electrical conductivity of irrigation water - ECw (0.3, 1.8, 3.3, 4.8, and 6.3 dS m-1) associated with five concentrations of salicylic acid - SA (0, 1.5, 3.0, 4.5, and 6.0 mM), with three replicates. Water salinity from 0.3 dS m-1 limited the photosynthetic efficiency and therefore the growth of cotton cv. BRS Jade. Foliar application of SA at concentration of 6.0 mM mitigated the effects of salt stress on the stomatal conductance and leaf transpiration of these plants. However, SA concentrations ranging from 0 to 6.0 mM reduce the internal CO2 concentration, growth in stem diameter and plant height, and root and stem dry mass accumulation of cotton plants cv. BRS Jade.

Peróxido de hidrogênio na atenuação do estresse salino em gravioleira

ABSTRACT In semi-arid regions, the use of saline water for irrigation has become an increasingly frequent reality due to the qualitative and quantitative scarcity of water sources occurring most of the year. Thus, the use of hydrogen peroxide can be a strategy capable of mitigating the deleterious effects of salt stress on plants and guaranteeing the agricultural production of crops such as soursop. Thus, the objective of this study was to evaluate the effects of foliar application of hydrogen peroxide on the physiological and growth indices of soursop plants cv. Morada Nova irrigated with waters of different salinity levels. The treatments were distributed in a randomized block design, in a 4 × 4 factorial scheme, corresponding to four levels of electrical conductivity of irrigation water and four concentrations of hydrogen peroxide, with three replicates. Foliar application of hydrogen peroxide at concentrations of 12, 18 and 15 µM, respectively, attenuated the effects of salt stress on stomatal conductance, CO2 assimilation rate and chlorophyll a synthesis of soursop, at 780 days after transplanting. The 30 µM hydrogen peroxide concentration intensified salt stress on gas exchange, variable fluorescence and electrolyte leakage in the leaf blade of soursop plants cv. Morada Nova, 780 days after transplanting.

Clay powder in polymer composite membranes enhanced the performance of direct methanol fuel cells

Polyvinyl alcohol has the potential to be used in fuel cell membranes due to its chemical, mechanical, and membrane-forming capabilities, as well as its higher hydrophilicity and low methanol permeability. However, the pure PVA membrane has a lower proton conductivity than the NafionTM membrane. With the addition of some ceramic fillers, PVA can be a possible alternative to NafionTM membranes. Therefore, we used the solution method to prepare three polyvinyl alcohol-based composite membranes with the following compositions: a) 5 wt% PVA (polyvinyl alcohol), b) 5 wt% PVA/2 wt % PEG (polyethylene glycol)/wt.1% silicon dioxide (SiO2) nanoparticles, and c) 5 wt% PVA/2 wt% PEG/wt.1% clay powder. The membranes were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), Energy dispersive X-ray (EDX), oxidative stability, ion exchange capacity, water absorption characteristics, conductivity, and permeability. FITR, EDX, and SEM confirmed the successful fabrication of the composite membrane, while TGA demonstrated membrane thermal stability and other parameters relevant to fuel cell membranes. The methanol permeability of the membrane is pure 5 wt % PVA, 5 wt%PVA/2 wt%/1 wt% SiO2, and 5 wt% PVA/2 wt% PEG/wt.1% Clay measured 2.37 × 10−6 cm2/s, 2.89 × 10−6 cm2/s, and 1.57 × 10−6 cm2/s, respectively. The methanol permeability of 5 wt% PVA/2 wt% PEG/wt.1% Clay is better than of Nafion117 (5.16 × 10−6 cm2/s as reported). The membrane 5 wt% PVA/2 wt% PEG/1% Clay exhibits satisfactory levels of oxidative stability (RW% = 94.09 at 1.32 h), IEC (0.232 meq/g), conductivity (0.00432 S/cm), methanol permeability (1.57 × 10−6 cm2/s), selectivity (3.63 × 10−4 Ss/cm3), and better water uptake properties at fuel cell operating temperature. As a result, it is reasonable to expect that PVA-based modified membranes will outperform NafionTM membranes in the future.

Distribution of benthic macroinvertebrate communities in different kind of inland water bodies in northeastern Algeria.

Benthic macroinvertebrates are integral parts of inland waters, inhabiting a diversity of aquatic ecosystems where communities are spatially structured. Macroinvertebrates of some Mediterranean regions such as North Africa are still not well studied. Due this reason we proposed study the community structure in water bodies located in Northeastern Algeria. For this objective, we sampled 12 different kind of water bodies, two dams, three rivers, and seven streams during the period from October 2020 to September 2021. To biotic and abiotic data, a redundancy analysis (RDA) was applied with the aim of determine the role of both kind of variables for grouping the sites. Also, two types of Null models were considered: species co-occurrence and niche sharing for study the potential associations between species reported. Redundancy analysis showed that water velocity and conductivity were the main drivers of community structure of macroinvertebrates. The species co-occurrence results reveal that species associations are ramdom, except for two sites: El fadjoudj and Ain ben baida corresponding to Seybouse river. At the same time, there is no niche sharing and in consequence, there is no interspecific competition except in the two sites: Salah Salah Salah stream and Bouhamdane dam. The results revealed similarities with other similar studies for Algerian rivers and dams, and with other similar water bodies with Mediterranean climate.

Production and postharvest quality of <i>Passiflora edulis</i> Sims under brackish water and potassium doses

<abstract> <p>The aim of this research was to assess the yield and postharvest characteristics of 'BRS Sol do Cerrado' sour passion fruits based on irrigation with varying levels of saline water and potassium fertilization. The study was conducted under field conditions at an experimental farm in São Domingos, Paraíba, Brazil. A randomized block design was implemented in a 5 × 4 factorial arrangement, with five levels of electrical conductivity of water (ECw): 0.3, 1.1, 1.9, 2.7, and 3.5 dS m<sup>−1</sup>, and four potassium doses (KD): 60, 80,100, and 120% of the recommended amount, with 3 replications. The potassium dose equivalent to 120% of the recommended dose in combination with low-salinity water resulted in the highest fresh mass accumulation in the sour passion fruit. Water electrical conductivity up to 2.7 dS m<sup>−1</sup>, along with the lowest recommended KD, led to increased levels of soluble solids and ascorbic acid in the sour passion fruit. Irrigation with water of 3.5 dS m<sup>−1</sup> and using 80 to 100% of the recommended KD enhanced the total sugar content in the sour passion fruit. On the other hand, irrigation with water of 3.5 dS m<sup>−1</sup> combined with 60% of the recommended KD resulted in a higher pulp yield in the 'BRS Sol do Cerrado' sour passion fruit 160 days post-transplantation. Adjustments in potassium fertilization management at different irrigation water salinity levels played a crucial role in maintaining both the production and quality of the sour passion fruit.</p> </abstract>

Desempenho agronômico da cultura do sorgo sob estresse salino em solo com cobertura morta vegetal

ABSTRACT Excess salts in irrigation water affect the production potential of agricultural crops; however, the use of plant mulch can mitigate salt stress. In this context, the objective was to evaluate the yield of sorghum crop under salt stress and different strategies for using plant mulch. The experiment was conducted under field conditions from July to October 2021, in the municipality of Redenção, Ceará, in the Baturité Massif region, Brazil. The experimental design used was randomized blocks, in a 5 x 2 factorial scheme, referring to the mulching strategies (MS1: with mulch throughout the cycle; MS2: without mulch throughout the cycle; MS3: with mulch during stage 1 = germination until panicle initiation; MS4: with mulch during stage 2 = panicle initiation until flowering; MS5: with mulch during stage 3 = flowering until physiological maturity) and two levels of electrical conductivity of water - ECw (0.8 dS m-1 and 6.0 dS m-1), with 4 repetitions. Using plant mulch throughout the cycle and the control treatment are more efficient for panicle weight. Using plant mulch throughout the cycle under irrigation mitigates salt stress and promotes greater yield in sorghum. From the beginning of panicle appearance until flowering, irrigation with water of lower salinity led to higher yield.

Irrigação com águas salinas e aplicação foliar de H2O2 altera a homeostase iônica do maracujazeiro-azedo

ABSTRACT Qualitative and quantitative scarcity of water sources is a reality in the Brazilian semi-arid region and restricts the expansion of irrigated areas in this region, where high levels of soluble salts are common. Thus, it is extremely important to seek strategies to enable the production of fruit crops such as sour passion fruit. In this context, the objective of this study was to evaluate the levels of NPK, Na+ and Cl- in leaf and stem tissues of sour passion fruit cv. BRS Rubi do Cerrado as a function of irrigation with saline water and exogenous application of hydrogen peroxide. The experiment was carried out in drainage lysimeters under greenhouse conditions in Campina Grande, PB, Brazil. The design was completely randomized in split plots, with five levels of electrical conductivity of water - ECw (0.6, 1.2, 1.8, 2.4 and 3.0 dS m-1) considered plots and four concentrations of hydrogen peroxide – H2O2 (0, 15, 30 and 45 µM) considered subplots, with three repetitions. Sodium content in the leaves decreased when the H2O2 concentration of 45 µM was applied. N/P and N/Na ratios in the leaves of sour passion fruit cv. BRS Rubi do Cerrado decreased with the increase in irrigation water salinity from 2.76 and 2.03 dS m-1, respectively. Chloride content in the leaves of sour passion fruit increased as a function of irrigation water salinity, regardless of H2O2 application.

The physiological quality of Vigna unguiculata L. seeds shows tolerance to salinity.

Salinity reduces feijão-caupi production, and the search for tolerant varieties becomes important within the agricultural context, as, in addition to being used in the field, they can be used in genetic improvement. The objective was to for a identify variety that is tolerant to salinity considering the physiological quality of seeds and seedling growth. A 2 × 4 factorial scheme was used, referring to the varieties Pingo-de-ouro and Coruja, and four electrical conductivities of water (0; 3.3; 6.6 and 9.9 dS m-1). The physiological quality of seeds and the growth of seedlings were analyzed, in addition to the cumulative germination. The Pingo-de-ouro variety showed no germination, length of the shoot and root, dry mass of the shoot and root compromised up to electrical conductivity of 6 dS m-1 in relation to 0.0 dS m-1. On the other hand, the Coruja variety showed reduced germination, increased shoot and root length. The creole variety Pingo-de-ouro proved to be tolerant to salinity.

Insights into the complexities of fungus‐insect‐plant interaction: The laurel wilt disease

AbstractLaurel wilt disease, caused by the fungus Harringtonia lauricola and transmitted by the ambrosia beetle Xyleborus glabratus, poses a significant ecological and economic threat to various species of the Lauraceae family, particularly avocado. The disease is characterized by the formation of tyloses blocking xylem vessels, hindering water conductance, and decreasing leaf gas exchange. The relationship between the fungus and the beetle is complex and not fully understood, which can be described, in general, as ambrosial symbiosis depending on the habitat. The secretome of the pathogen includes hydrolytic enzymes that aid in colonization and resistance of host defence. This paper reviews the current understanding of the causes, impacts, and management strategies for laurel wilt disease. Also, it provides an overview of the complex relationship between the fungal pathogen and its beetle vector and explores the various virulence factors and secretome of H. lauricola that contribute to the aggressive nature of the disease. Moreover, this review states the ecological and economic impacts of laurel wilt, particularly on ecologically and economically valuable plants such as avocado. Current management strategies for controlling the disease, including the use of insecticides, fungicides, and biological control methods, are reviewed. Finally, we highlight some critical key points in ambrosia symbiosis biology that are of importance for disease control.

Gamma-aminobutyric acid treatment promotes resistance against Sogatella furcifera in rice.

The Sogatella furcifera (Horváth) (Homoptera: Delphacidae) is a white-backed planthopper (WBPH) that causes "hopper burn" in rice, resulting in severe yield loss. Gamma-aminobutyric acid (GABA) is a well-known neurotransmitter that inhibits neurotransmission in insects by binding to specific receptors. In this study, we investigated the potential role of GABA in modulating rice resistance to WBPH and evaluated possible defense mechanisms. The experiment was conducted in green house in pots consist of four groups: control, GABA-treated, WBPH-infested, and WBPH-infested treated with GABA. Among the various tested concentration of GABA, 15 mM GABA was applied as a single treatment in water. The treatment was administered one week before WBPH infestation. The results revealed that 15 mM GABA treatment strongly increased WBPH resistance. A plate-based assay indicated that direct application of 15 mM GABA increased the mortality rate of WBPH and increased the damage recovery rate in rice plants. We found that GABA treatment increased the activation of antioxidant enzymes and reduced the reactive oxygen species content and malondialdehyde contents, and reduced the damage rate caused by WBPH. Interestingly, GABA-supplemented plants infested with WBPH exhibited increased phenylalanine ammonia-lyase and pathogenesis-related (PR) genes expression levels. GABA induced the accumulation of abscisic acid (ABA) and salicylic acid (SA) and enhanced the stomata closure and reduced leaf vessels to reduce water conductance during WBPH stress. Furthermore, we found that GABA application to the plant induced the expression of Jasmonic acid (JA) biosynthesis genes (LOX, AOS, AOC, and OPR) and melatonin biosynthesis-related genes (TDC, T5H, ASMT, and SNAT). Our study suggested that GABA increases resistance against WBPH infestation by regulating antioxidant defense system, TCA cycle regulation, phytohormonal signaling, and PR gene regulation.

The use of HDPE geocells for drainage channel coating to replace reinforced concrete structures

Typically water conduction channels are lined with reinforced concrete structures. Often, such alternatives consume high construction costs and percentages of total investments destined for water infrastructure and maintenance. In this context, the function of engineering is to seek alternatives that allow, in a responsible and safe manner, to replace typical reinforced concrete structures, focusing on technical and economic aspects. Thus, the use of High Density Polyethylene (HDPE) geocells filled with concrete, to line channels, is intended to facilitate and accelerate the installation of this system, providing a good result, mainly due to its constructive simplicity. In addition, the technology in HDPE geocells is sufficiently stable to withstand the external forces generated on the fluid conduction structures, thus dispensing with the use of steel reinforcement, in addition to formwork, expansion joints, etc. Thus, some of the main analyzes used to demonstrate the effectiveness of the use of HDPE geocells filled with concrete for lining channels will be presented, as: resistance to extraction with cell confinement, shear stress, surface abrasion, stability due to under pressure and excessive deformations. Finally, the main benefits that these structures present in relation to conventional ones are listed, and a comparison addressing productivity, installation and costs, sustaining their success through executed cases, as well as successful cases applied to different requests in Latin America.

Analysis of the Impact of Coal Mineacid Water on River Water Quality, Biota, and Human Health Around Mining

Acid Mine Drainage (AMD) or Acidic Acidic Drainage (AAT) is a type of water runoff that happens when certain sulfide minerals in rocks come in contact with water and oxygen, triggering an oxidation process that results in water with acidic properties. To understand more about this phenomenon, a literature review was conducted using relevant keywords on online information sources. The indicators used to measure the level of acidity in mine water include pH, metal concentration, Total Suspended Solid (TSS) or turbidity level, electrical conductivity, sulfate, and sulfuric acid content. High electrical conductivity in mine water usually indicates the presence of metals such as iron (Fe) and manganese (Mn). High levels of manganese (Mn) in water can cause health problems for humans. Moreover, an increase in the concentration of Fe can cause an increase in turbidity or TSS because iron metal can dissolve in air and form solid particles that can cause turbidity. To reduce acidity and environmental pollution, passive or active treatment techniques can be used to neutralize AMD.

2011–2018年兴凯湖水体物理和化学指标监测数据集

Xingkai Lake is the largest boundary lake between China and Russia, and its water quality is closely related to cross-regional ecological security. In this paper, we collected the physical and chemical properties of water quality sampled in May and September at 10 monitoring sites of Xingkai Lake wetland ecosystem national observation and research station in Heilongjiang Province from 2011 to 2018. The dataset covers 4 physical parameters (water temperature, pH, conductivity and salinity) and 15 chemical parameters (sodium ion, total nitrogen, total phosphorus and chemical oxygen demand etc.). The data acquire through the collection, storage and transportation of samples as well as the subsequent laboratory analysis adhere rigorously to national standards and quality control systems. The dataset is expected to provide information on the dynamic processes of water quality in Xingkai Lake, and contribute basic data support for the study of the relationship between wetland hydrological processes and structure and function in Xingkai Lake, integrated watershed management, and ecological security of the China and Russia boundary lake.

FLUID FLOW CONTROL IN POROUS MEDIA WITH CONSIDERATION OF ELECTROKINETIC EFFECTS

The paper presents results of the research on the influence of electrokinetic characteristics of fluids on its flow in porous media. Experimental studies have shown the effect of fluid slippage in the channels of porous media due to the electrically charged boundary "liquid-porous medium". It is shown that the change of flow velocity profile and pressure gradient is caused by the display of electrokinetic effects in the filtration of polar liquids.The investigation has shown that the process of the electrolyte solutions filtration in a porous medium is accompanied by the change in the liquid flow rate and the electro-potential of the flow. The periodic nature of changes in flow characteristics is explained by continuous charge formation and charge interaction in the diffuse layer. Periodic charge accumulation and subsequent charge transfer across the channel cross section depending on the charge sign acquired, as well as compression of the diffuse layer with increasing NaCl electrolyte concentration in aqueous solution may be the cause of fluid flow variations. The observed effects may serve as a tool for controlling fluid flow in water-oil-saturated formations and, in particular, injectivity of injection wells by controlling electrical conductivity of water injected into the formation.

Physio-Chemical Analysis of Drinking Water in Populated Villages of District Skardu

Objective The purpose of this study was to establish whether the water used by inhabitants of the five surrounding village communities of Kachura, Qomra, Kwardu, Hoto, and Gamba in the district of Skardu Gilgit-Baltistan is portable or not for human consumption. Skardu is located at 35°17’25”N 75°38’40”E, with an elevation of 2,228 meters above sea level in Northeastern Pakistan. Methods Three water samples were collected from each of the 5 villages in the district. Total dissolved solids (TDS), total suspended solids (TSS), total solids (TS), total hardness (TH), calcium, magnesium, total alkalinity (TA), chloride, nitrate, conductivity, sodium, and potassium were determined using established chemical analysis techniques, according to recommended World Health Organization (WHO) standards. Results The findings showed that water samples had not been treated before being consumed by people. Variations between the communities were found when the parameters were analyzed. TSS ranged from 11 to 44 mg/L; total solids ranged from 94 to 392 mg/L; and TDS ranged from 82 to 348 mg/L. Calcium varied from 72 to 232 mg/L, magnesium ranged from 16 to 88 mg/L, and total hardness ranged from 88 to 320 mg/L. Chloride levels ranged from 8 to 12 mg/L, total alkalinity was between 72 and 248 mg/L, and nitrate levels were within acceptable bounds. Water conductivity varied between 139 and 612 S/cm. While potassium ranged from 49 to 147 mg/mL, sodium ranged from 33 to 118 mg/mL. Notably, the water samples from Kwardu, Hoto, Gamba, and Kachura had potassium levels that were higher than allowed. Only three of the samples taken from the village of Qomrah were within acceptable ranges. Conclusion According to the study’s findings, water samples from the Skardu district were not treated before being consumed by people. The high potassium content in drinking water increases the risk of hyperkalemia and can cause serious health issues, especially in people with kidney, cardiac, and diabetes conditions. Consequently, it is recommended to use reverse osmosis (RO) to remove excess potassium from water. Also, it is advised to boil drinking water before consuming to kill microbes. To reduce potential health hazards connected with drinking untreated water, it is essential to increase the local residents’ awareness of waterborne issues.

Investigation of Gas Diffusion Layer Degradation in Polymer Electrolyte Fuel Cell Via Chemical Oxidation

The gas diffusion layer (GDL) is a key part of the membrane electrolyte assembly and is critical for the transport of fuel, oxygen and water. The GDL is made up of two layers: macroporous substrate (MPS) and microporous layer (MPL) (1). To achieve the hydrophobicity required for water management, the two layers are typically treated with polytetrafluoroethylene (PTFE) (2). In many long-term experiments, it has been observed that GDL degradation, such as carbon corrosion and PTFE loss, leads to a deterioration of water management, conductivity and mass transport (3).To solve this durability problem, a thorough and in-depth understanding of the GDL degradation mechanism is required. In this study, GDLs are subjected to an accelerated stress test to investigate degradation by chemical oxidation. GDLs are soaked in Fenton's reagent for 24 hours. The hydrophobic properties of pristine and soaked GDLs are compared based on contact angle measurements, thermogravimetry and scanning electron microscopy. In addition, the chemical composition of the solutions before and after the immersion test is analyzed using a total organic carbon analyzer and an ion chromatograph. The results show that the hydrophobicity of GDL exposed to Fenton reagent is decreased by 5 and 4 degrees for the MPL and the MPS respectively. Fig 1. depicts a decrease in surface contact angle, which is associated with surface oxidation and PTFE deterioration.AcknowledgementThis research work is performed under the project AlpeDHues (AlpeDHues / FFG 889328) which is supported by the Austrian Research Promotion Agency (FFG).References C. Csoklich, R. Steim, F. Marone, T. Schmidt and F. Büchi, ACS Applied Materials & Interfaces, 13, 9908–9918 (2021).A. Ozden, S. Shahgaldi, X. Li and F. Hamdullahpur, Progress in Energy and Combustion Science, 74, 50–102 (2019).Y. Yang, X. Zhou, B. Li and C. Zhang, Applied Energy, 303, 117688 (2021). Figure 1

A Novel Coupler of Capacitive Power Transfer for Enhancing Underwater Power Transfer Characteristics

Compared to inductive power transfer (IPT) technology, capacitive power transfer (CPT) technology offers unique advantages such as being cost-effective, lightweight, and free from eddy-current losses, making it more suitable for underwater power transfer. Unlike air, water can conduct electricity and the electric conductivity of different kinds of waters varies with different ion concentrations, which would greatly affect the equivalent model of the underwater couplers. To address this issue, multiple types of underwater coupler working in different kinds of water are compared and analyzed. The influence of the electrical conductivity of water on the capacitive coupler is comprehensively analyzed, and the novel capacitive coupler and its equivalent model are proposed to improve power transfer efficiency. To verify the theoretical analysis, the double-sided LC-compensated CPT circuit is built and tap water is used in the experiment. The experimental results are consistent with the theoretical analysis. In addition, the experimental results also validate the superiority of the proposed capacitive coupler compared to existing research.

Plant testing with hemp and miscanthus to assess phytomanagement options including biostimulants and mycorrhizae on a metal-contaminated soil to provide biomass for sustainable biofuel production

The need of biofuels from biomass, including sustainable aviation fuel, without using agricultural land dedicated to food crops, is in constant demand. Strategies to intensify biomass production using mycorrhizal fungi, biostimulants and their combinations could be solutions for improving the cultivation of lignocellulosic plants but still lack well-established validation on metal-contaminated soils. This study aimed to assess the yield of Miscanthus x giganteus J.M. Greef & Deuter and Cannabis sativa L. grown on a metal-contaminated agricultural soil (11 mg Cd, 536 mg Pb and 955 mg Zn kg−1) amended with biostimulants and/or arbuscular mycorrhizal fungi, and the shoot Cd, Pb and Zn uptake. A pot trial was carried out with soil collected from a field near a former Pb/Zn smelter in France and six treatments: control (C), protein hydrolysate (a mixture of peptides and amino acids, PH), humic/fulvic acids (HFA), arbuscular mycorrhizae fungi (AMF), PH combined with AMF (PHxAMF), and HFA combined with AMF (HFAxAMF). Metal concentrations in the soil pore water (SPW), pH and electrical conductivity were measured over time. Miscanthus and hemp shoots were harvested on day 90. Both PH and PHxAMF treatments increased SPW Cd, Pb, and Zn concentrations (e.g. by 26, 1.9, and 22.9 times for miscanthus and 9.7, 4.7, and 19.3 times for hemp in the PH and PHxAMF treatments as compared to the control one, respectively). This led to phytotoxicity and reduced shoot yield for miscanthus. Conversely, HFA and HFAxAMF treatments decreased SPW Cd and Zn concentrations, increasing shoot yields for hemp and miscanthus. Shoot Cd, Pb, and Zn uptakes peaked for PH and PHxAMF hemp plants (in μg plant-1, Cd: 310–334, Pb: 34–38, and Zn: 232–309 for PHxAMF and PH, respectively), while lowest values occurred for PH miscanthus plants mainly due to low shoot yield. Overall, this study suggested that humic/fulvic acids can be an effective biostimulant for increasing shoot biomass production in a metal-contaminated soil. These results warrant further investigations of the HFAxAMF in field trials.