Water Electrical Conductivity Research Articles

Pigmentos fotossintéticos, crescimento, e produção de tomate cereja sob estresse salino e peróxido de hidrogênio

ABSTRACT Excess of salts in water and/or soil stands out as one of the stresses that compromise the development of crops, including cherry tomato, requiring the use of strategies that reduce salt stress effects, such as foliar application of hydrogen peroxide. Thus, the objective of this study was to evaluate the effect of foliar application of H2O2 on the contents of photosynthetic pigments, growth, and production of cherry tomato under irrigation water salinity. The design used was randomized blocks, in a 5 × 5 factorial scheme, with five values of electrical conductivity of water - ECw (0.3, 1.0, 1.7, 2.4, and 3.1 dS m-1) and five concentrations of hydrogen peroxide - H2O2 (0, 15, 30, 45, and 60 μM). Application of hydrogen peroxide at concentration of 60 μM attenuated the deleterious effects of salt stress on the growth and number of leaves of cherry tomato up to ECw of 3.1 dS m-1. Hydrogen peroxide concentration of 45 μM increased root dry mass, synthesis of chlorophyll b and total chlorophyll under electrical conductivity of water of 0.3 dS m-1 and synthesis of chlorophyll a up to ECw of 0.8 dS m-1. Foliar application of 30 μM reduced the effects of salt stress on leaf, shoot and total dry mass accumulation up to ECw of 3.1 dS m-1. Electrical conductivity of water from 1.41 dS m-1 reduced the production of cherry tomato.

Survey and Characterization of Ground Water Quality and its Effect on Soil Properties in Malpura Block of Tonk District Rajasthan, India

In Malpura block of Tonk district, a survey was conducted to evaluate the quality of the groundwater and determine how it affected the soil qualities. Using a handheld GPS, 60 groundwater samples and 60 soil samples overall were taken at six sites include Lawa(V1), Borkhandi(V2), Kadila(V3), Jankipura(V4), Diggi(V5) and Nukkad(V6) in the Malpura block of the Tonk district. The pH, EC, SAR and RSC of ground water ranged from 6.95-8.40, 2.18-3.15(dsm-1), 2.73-10.45 (m mol/L), 1.64-22.3 (meq/L), respectively. The anion contents followed the pattern Cl>SO42> HCO3>NO3>CO32 whereas the cations were found to be in the following order: Na+> Mg2+> Ca2+> K+. The village of Lawa had the lowest saturation rate (22.84%) and Diggi had the highest saturation percentage (38.34%). The correlation coefficient revealed that electrical conductivity (EC) of soil saturation extract was significantly and positively correlated with EC (0.625), Cl- (0.200) and Na+ (0.242) of Groundwater used for irrigation.

Technical note: Two-component electrical-conductivity-based hydrograph separation employing an exponential mixing model (EXPECT) provides reliable high-temporal-resolution young water fraction estimates in three small Swiss catchments

Abstract. The young water fraction represents the portion of water molecules in a stream that have entered the catchment relatively recently, typically within 2–3 months. It can be reliably estimated in spatially heterogeneous and nonstationary catchments from the amplitude ratio of seasonal isotope (δ18O or δ2H) cycles of stream water and precipitation, respectively. Past studies have found that young water fractions increase with discharge (Q), thus reflecting the higher direct runoff under wetter catchment conditions. The rate of increase in the young water fraction with increasing Q, defined as the discharge sensitivity of the young water fraction (Sd*), can be useful for describing and comparing catchments' hydrological behaviour. However, the existing method for estimating Sd*, which only uses biweekly isotope data, can return highly uncertain and unreliable Sd* when stream water isotope data are sparse and do not capture the entire flow regime. Indeed, the information provided by isotope data depends on when the respective sample was taken. Accordingly, the low sampling frequency results in information gaps that could potentially be filled by using additional tracers sampled at a higher temporal resolution. By utilizing high-temporal-resolution and cost-effective electrical conductivity (EC) measurements, along with information obtainable from seasonal isotope cycles in stream water and precipitation, we develop a new method that can estimate the young water fraction at the same resolution as EC and Q measurements. These high-resolution estimates allow for improvements in the estimates of the Sd*. Our so-called EXPECT (Electrical-Conductivity-based hydrograph separaTion employing an EXPonential mixing model) method is built upon the following three key assumptions: We construct a mixing relationship consisting of an exponential decay of stream water EC with increasing young water fraction. This has been obtained based on the relationship between flow-specific young water fractions and EC. We assume that the two-component EC-based hydrograph separation technique, using the above-mentioned exponential mixing model, can be used for a time-source partitioning of stream water into young (transit times < 2–3 months) and old (transit times > 2–3 months) water. We assume that the EC value of the young water endmember (ECyw) is lower than that of the old water endmember (ECow). Selecting reliable values from measurements of ECyw and ECow to perform this unconventional EC-based hydrograph separation is challenging, but the combination of information derived from the two tracers allows for the estimation of endmembers' values. The two endmembers have been calibrated by constraining the unweighted and flow-weighted average young water fractions obtained with the EC-based hydrograph separation to be equal to the corresponding quantities derived from the seasonal isotope cycles. We test the EXPECT method in three small experimental catchments in the Swiss Alptal Valley using two different temporal resolutions of Q and EC data: sampling resolution (i.e. we only consider Q and EC measurements during dates of isotope sampling) and daily resolution. The EXPECT method has provided reliable young water fraction estimates at both temporal resolutions, from which a more accurate discharge sensitivity of the young water fraction (SdEXP) could be determined compared with the existing approach. Also, the method provided new information on ECyw and ECow, yielding calibrated values that fall outside the range of measured EC values. This suggests that stream water is always a mixture of young and old water, even under very high or very low wetness conditions. The calibrated endmembers revealed a good agreement with both endmembers obtained from an independent method and EC measurements from groundwater wells. For proper use of the EXPECT method, we have highlighted the limitations of EC as a tracer, identified certain catchment characteristics that may constrain the reliability of the current method and provided recommendations about its adaptation for future applications in catchments other than those investigated in this study.

Water, Salt, and Ion Transport and Its Response to Water-Saving Irrigation in the Hetao Irrigation District Based on the SWAT-Salt Model

Soil salinization is one of the main hazards affecting the sustainable development of agriculture in the Hetao Irrigation District (HID) of Inner Mongolia. To grasp the water and salt transport patterns and spatial–temporal distribution characteristics of the HID at the regional scale, the improved Soil and Water Assessment Tool with a salinity module (SWAT-Salt) model was used to establish the distributed water and salt transport model for the watershed in this study. The results demonstrated that the modified model could more accurately represent the process of water and salt changes in the HID. The coefficient of determination (R2) in the simulation of streamflow and discharge salt loading was 0.83 and 0.86, respectively, and the Nash–Sutcliffe efficiency (NSE) was 0.80 and 0.74, respectively. Based on this, different hydrological processes (surface runoff, lateral flow, groundwater, soil seepage) as well as spatial–temporal distribution characteristics of water salinity in groundwater and soil were analyzed in the HID. Differences in groundwater and soil salinity in different land uses and soil types were also compared. Of these, surface runoff and lateral flow salt discharge loading are concentrated in the southwestern portion of the basin, while groundwater salt discharge loading is concentrated in the eastern as well as southwestern portions of the basin. The salt discharge loading from groundwater accounts for about 98.7% of the total salt discharge loading from all hydrological pathways and is the major contributing part of salt discharge from the irrigation area. Soil salinity increases gradually from west to east. Groundwater salinity (2946 mg/L) and soil water electrical conductivity (0.309 dS/m) were minimized in the cropland. Meanwhile, rational allocation of irrigation water can appropriately increase the amount of salt discharge loading. In conclusion, the model could provide a reference for the investigation of soil salinization and water–salt management measures in irrigation areas.

Uncertainty and sensitivity analysis of a travel‐time distribution‐based stream water electrical conductivity model

AbstractIn this paper, we analyse the uncertainty and parameter sensitivity of a conceptual water quality model, based on a travel time distribution (TTD) approach, simulating electrical conductivity (EC) in the Duck River, Northwest Tasmania, Australia for a 2‐year period. Dynamic TTDs of stream water were estimated using the StorAge Selection (SAS) approach, which was coupled with two alternate methods to model stream water EC: (1) a solute‐balance approach and (2) a water age‐based approach. Uncertainty analysis using the Differential Evaluation Adoptive Metropolis (DREAM) algorithm showed that: 1. parameter uncertainty was a small contribution to the overall uncertainty; 2. most uncertainty was related to input data uncertainty and model structure; 3. slightly lower total error was obtained in the water age‐based model than the solute‐balance model; 4. using time‐variant SAS functions reduced the model uncertainty markedly, which likely reflects the effect of dynamic hydrological conditions over the year affecting the relative importance of different flow pathways over time. Model parameter sensitivity analysis using the Variogram Analysis of Response Surfaces (VARS‐TOOL) framework found that parameters directly related to the EC concentration were most sensitive. In the solute‐balance model, the rainfall concentration Crain and in the age‐based model, the parameter controlling the rate of change of EC with age (λ) were the most sensitive parameter. Model parameters controlling the age mixes of both evapotranspiration and streamflow water fluxes (i.e., the SAS function parameters) were influential for the solute‐balance model. Little change in parameter sensitivity over time was found for the age‐based concentration relationship; however, the parameter sensitivity was quite dynamic over time for the solute‐balance approach. The overarching outcomes provide water quality modellers, engineers and managers greater insight into catchment functioning and its dependence on hydrological conditions.

DISCUSSION OF THE MECHANISM OF THE ELECTRICAL CONDUCTIVITY OF PURE WATER IN THE FRAMEWORK OF THE BJERRUM MODEL

An alternative mechanism of electrical conductivity and ionization of molecules in pure water is considered. Calculation of the temperature dependence for the activation energy of ionization of water molecules was carried out using data on the value of its ionic product. The calculated activation energies for the ionization and flow processes show the presence of a certain proportionality between them. This suggests that the ionization of water is caused by intermolecular forces rather than intramolecular forces. Accordingly, the electrical conductivity of water is associated with the appearance and movement in it of L and D defects of hydrogen bonds between water molecules, which have significant electrical pseudo charges and are considered in the Bjerrum model for ice. This work proposes a new interpretation of the mechanism of ionization (pseudoionization) of molecules and generation of L and D defects in water. Rotation is considered not for one, but for two of its molecules in opposite directions with partial compensation of their angular momentum, and the breaking of not three bonds for one molecule, but four bonds with neighbors for two molecules. Moreover, these four neighbors do not include molecules from water clusters that have stronger bonds, since neighboring molecules with weaker bonds can be found for the process of rotation activation. Accordingly, the exponential contribution made by molecules from water clusters is absent or small in the ionization activation energy. In this way, the activation energy for the flow, which occurs throughout the entire volume of the liquid and automatically includes molecules from clusters, differs from the activation energy of electrical conductivity, which occurs for individual molecules in chains of bonds. The presence of a maximum in the ionic product of water near 250 ⁰C can be explained by the rapid decrease in the lifetime of L and D defects with heating, which prevents the use of the standard equation for accurate calculation of the ionization activation energy above 100...200 ⁰C. However, the presence of this maximum contradicts the generally accepted model of proton hopping between neighboring hydronium and water molecules in the mechanism of its electrical conductivity.

Modification of Hilhorst model for saturated extract electrical conductivity estimation of coir using frequency domain reflectometry sensors – A laboratory study

Frequency domain reflectometry (FDR) sensors can measure moisture content and electrical conductivity (EC) of growing media, thus providing information for effective water and nutrient management of crops. FDR sensors generally provide the bulk EC (σb) value, which is different from the saturated extract EC (σe) values that most growers and practical studies generally use. To properly estimate σe of media, we modified the previous Hilhorst model that calculates pore water EC (σp) from FDR sensor readings. The 16 coir samples with four moisture and four EC levels were prepared, and their changes in the dielectric constant of bulk medium (εb), σb, and medium temperature from the FDR sensors were recorded and used for analysis. As a result, the εσb=0 (εb when σb is 0) of the coir used in this experiment was 1.64, which was much lower than the εσb=0 suggested for mineral soil (4.1), indicating that the medium-specific εσb=0 should be adjusted. Although σe value estimation through the Hilhorst model with adjusted εσb=0 improved, the values were still unreliable to represent the actual σe values (root mean square error, RMSE = 2.280, R2 = 0.30). To convert the σp derived from the Hilhorst model with adjusted εσb=0 to actual σe, the regression equation was applied as σe = 0.5381 × σp + 1.6493. The adjusted Hilhorst model could provide a more reliable σe estimation (RMSE = 0.929, R2 = 0.62). These results indicate that proper adjustment of εσb=0 for the specific medium is necessary, and adjusting the equation for converting σp into σe would be helpful to properly interpret the σb to practically utilize the FDR sensors for effective water and nutrient management.

Thermal Conductivity, Rheology and Electrical Conductivity of Water- and Ethylene Glycol-Based Nanofluids with Copper and Aluminum Particles

Thermal Conductivity, Rheology and Electrical Conductivity of Water- and Ethylene Glycol-Based Nanofluids with Copper and Aluminum Particles

Morfofisiologia de feijão-caupi sob estresse salino e aplicação de nanobioestimulante de carbono na fase vegetativa

ABSTRACT Several technologies have been implemented to improve plant performance in irrigated crops, and one of them is the use of nanobiostimulants. Therefore, the aim of the present study was to explore the effects of applying different concentrations of a carbon-based biostimulant on the morphophysiology of cowpea plants subjected to varying electrical conductivities of irrigation water. The experiment was performed in a completely randomized design, in a 2 × 6 factorial scheme, with two electrical conductivities of irrigation water (ECw: 0.35 and 4.0 dS m-1) and six concentrations of nanobiostimulant applied through the leaves (0, 80, 160, 240, 320, and 400 mg L-1), with four replications. Growth and gas exchange variables were evaluated 31 days after sowing (V9 stage). Concentrations between 240 and 320 mg L-1 of carbon-based nanobiostimulant promoted greater increases in growth and physiological variables, but they caused decreases in non-photochemical quenching. Water electrical conductivity of 4.0 dS m-1 reduced the number of leaves (17.1%), stem diameter (10.0%), SPAD index (10.3%), net photosynthesis (10.9%), stomatal conductance (46.4%), transpiration (34.5%), instantaneous carboxylation efficiency (22.4%), and photochemical quenching (4.5%); in contrast, it increased the ratio between internal and ambient CO2 concentration (18.0%), leaf temperature (2.9%), water use efficiency (32.5%), and non-photochemical quenching (12.4%). Concentrations of 240 to 320 mg L-1 of the nanobiostimulant enhance the development and gas exchange of cowpea plants under non-stress conditions, whereas the concentration of 240 mg L-1 promotes the maximum increase in plant height under salinity.

Response of the TEROS 12 Soil Moisture Sensor under Different Soils and Variable Electrical Conductivity.

In this work, the performance of the TEROS 12 electromagnetic sensor, which measures volumetric soil water content (θ), bulk soil electrical conductivity (σb), and temperature, is examined for a number of different soils, different θ and different levels of the electrical conductivity of the soil solution (ECW) under laboratory conditions. For the above reason, a prototype device was developed including a low-cost microcontroller and suitable adaptation circuits for the aforementioned sensor. Six characteristic porous media were examined in a θ range from air drying to saturation, while four different solutions of increasing Electrical Conductivity (ECw) from 0.28 dS/m to approximately 10 dS/m were used in four of these porous media. It was found that TEROS 12 apparent dielectric permittivity (εa) readings were lower than that of Topp's permittivity-water content relationship, especially at higher soil water content values in the coarse porous bodies. The differences are observed in sand (S), sandy loam (SL) and loam (L), at this order. The results suggested that the relationship between experimentally measured soil water content (θm) and εa0.5 was strongly linear (0.869 < R2 < 0.989), but the linearity of the relation θm-εa0.5 decreases with the increase in bulk EC (σb) of the soil. The most accurate results were provided by the multipoint calibration method (CAL), as evaluated with the root mean square error (RMSE). Also, it was found that εa degrades substantially at values of σb less than 2.5 dS/m while εa returns to near 80 at higher values. Regarding the relation εa-σb, it seems that it is strongly linear and that its slope depends on the pore water electrical conductivity (σp) and the soil type.

Hydrogeological structures of karst features using hydrographs in an underground river basin formed in a peak cluster depression, southwest China

Understanding of the hydrological behaviors in different karst features is crucial for evaluating the hydrological storage and transfer functions of a karst system. In this study, the Maocun karst underground river system, characterized by typical karst features, was selected as the research area in the southwest region of China. The main objectives of this research are to analyze the hydrogeological structure characteristics of each karst feature and assess water storage capacity in different aquifer media. Frequency distribution curve (FDC) of electrical conductivity (EC) values revealed that recharge sources in the five karst features differed and varied according to the amount of precipitation. All hydrographs of water levels in five karst features were divided into three periods due to the presence of triple aquifer media in the basin. The spatial structure of each feature was interpreted by analyzing the variation characteristics of recession exponential coefficients (λ). Additionally, the ratios of fissure water, fracture water, and conduit water sources were calculated based on the recession curves of water levels. Results showed that fast water flow had the highest proportion in the relatively open subsystem located upstream, while fracture water flow had the lowest proportion. The slow water flow was the main pattern of water storage in the basin. Values of EC in water decreased with a well-connected spatial structure and high hydraulic conductivity. There were significant differences in the values of EC among conduit water, fracture water, and matrix water. These values were calculated using mathematical relationships between EC and water level hydrographs. The results indicated that the EC values in matrix water exceeded 200 μS/cm, while EC values in conduit water/channel water were below 100 μS/cm. Finally, hydrogeological conceptual models were constructed for five karst features based on the depletion characteristics of the aquifer media during each recession period. These characteristics were interpreted using variation curves of EC and hydrographs of water levels. These findings not only elucidated the characteristics of hydrogeological structures in multiple karst features, but also had significant implications for the assessment of karst water sources.

Effects of Environmental Variables on Some Aquatic Biota of Jabi Lake, Federal Capital Territory, Abuja

The presence of environmental variables above regulatory permissible limit especially, high levels of toxic substances and heavy metals in freshwater bodies represents a global public health issue. Aquatic ecosystems are critical components of the global environment and essential contributors to biodiversity and ecological productivity. The effects of environmental variables on some aquatic biota of Jabi Lake was studied from January, 2022 to December, 2023 using a combination of insitu and laboratory analyses. Seven stations were selected; the tributaries (3 stations), the confluent station and 3 stations within the Lake, to determine the physico-chemical, nutrients and biological characteristics based on the activities in and around the various stations. Physico-Chemical parameters measured were: Atmospheric temperature, Water temperature, pH, Dissolved Oxygen (DO), Turbidity, Water Electrical Conductivity (WEC), Water current, Biological Oxygen Demand (BOD), Total Dissolved Solid (TDS), Alkalinity, Chemical Oxygen Demand (COD) and Nitrite. Nutrients: Phosphate and Nitrate. Metals: Copper (Cu), Iron (Fe), Lead (Pb), Zinc, Chromium and Cadmium. Some of the parameters were within the regulatory permissible limit while few above the standard. There were significant differences (P&lt;0.05) between these parameters, within the months, stations and seasons. The result of biotic fauna recorded shows composition and abundance of 4 phyla, 9 classes, 25 families and 45 species. Temperature has the most pronounced effect on the distribution and abundance of aquatic fauna, followed by DO in the CCA analysis. The Shannon Weiner species diversity index is 1.14. Pearson correlation ®between fauna family and hydro-chemical parameters shows that phosphate was significant at P&lt; 0.05 followed by COD, EC and BOD.

Determining Liquid Limit and Plastic Limit of Clay Soils by Electrical Surface Conduction and Diffuse Double Layer Thickness

The aim of this study was to propose a new approach to determine the liquid limit and plastic limit of clay soils by considering electrical conductivity (EC) measurements. The proposed method included incorporating a new parameter, F, which is the ratio of the volumetric water contents of diffuse double layer (DDL) water and free water. In addition, the EC parameter, σ, was considered as the ratio of electrical surface conductivity and electrical conductivity of water. The changes in the thickness of DDL (χ) were also assessed to obtain corresponding equations to establish a connection with clay mineralogy, water content, and specific gravity in the final prediction. Three-dimensional surface analyses were conducted to find a correlation among F, σ, and χ to identify an appropriate method to predict liquid limit and plastic limit. The study was conducted with 39 different types of samples, and the outcomes from the EC approach were validated against the conventional methods. Overall, the coefficient of determination, R2 = 0.90, and Lin’s concordance correlation coefficient, (LCCC) = 0.91, were obtained for liquid limit prediction, whereas R2 = 0.64 and LCCC = 0.80 were obtained for plastic limit determination.

Analysis of Temperature, pH, and Electrical Conductivity of Water in Response to Taheri Consciousness Field 2

Water, as the most abundant molecule on Earth's surface and a vital component of living organisms, has always been the subject of investigation and analysis in the scientific community regarding its physicochemical properties and changes resulting from environmental variables. In previous studies on the effects of T-Consciousness Fields, changes in the pH and temperature of water as a result of exposure to these fields have been investigated. In this study, in addition to these two parameters, changes in the electrical conductivity of water molecules under the influence of T-Consciousness Field 2 have been examined, with the aim of finding a parameter of water that is more sensitive and responsive to T-Consciousness Fields. According to the results of this research throughout 8, 24, and 48 hours, changes in pH in the sample and control groups showed an increase, and temperature changes showed a decrease. Furthermore, changes in the electrical conductivity of water under the influence of T-Consciousness Field 2 were significant. To complement the current study, the examination of the levels of oxygen and carbon dioxide gases in pure water under the exposure of T-Consciousness Field 2 is on the agenda of the authors.

Study of the dyeing industry pollution after mandatory installation of ETP in Madhabdi municipality, Bangladesh

ABSTRACT Madhabdi municipality of the Narsingdi district of Bangladesh, the “Manchester of the East,” is famous for its cloth market and fabric dyeing industries. The untreated effluent discharge has been mixed with the water and soil, degrading the environmental standards of this area for years. Installing an effluent treatment plant (ETP) in all textile industries in Bangladesh is mandatory. This study evaluates the soil condition, surface water quality, and heavy metal contamination in cultivated vegetables after the compulsory installation of ETP. Soil and water samples from eight locations and cultivated vegetable samples from three locations are collected and analyzed for this study. The pH, EC (electric conductivity), TDS (total dissolved solids), DO (dissolved oxygen), and heavy metal concentrations are observed. The water quality index, contamination index, metal evaluation index, pollution load index, and metal pollution index are calculated from the collected samples. The study found that the physico-chemical properties of water pH (9.19), EC (2232.38 µScm-1), and DO (0.79 mgL-1) violate the national standards. The mean TDS is below the maximum permissible level. The heavy metal concentrations of Cr and Pb in water are 1.03 and 0.13 mgL-1, crossing the permissible limit, respectively, but Mn, having 0.89 mgL-1, is within the limit. The water quality is unsuitable for domestic and agricultural use, contamination is “medium,” and metal evaluation is “medium.” The soil is alkaline, having a pH of 8.58. The soil’s Cr, Pb and Mn concentrations are 68.21 µgg-1, 52.73 µgg-1and 805.16 µgg-1, respectively. The soil contamination level is low to moderate. Cultivated leafy vegetables have a concentration of Cr, Pb and Mn; 2.61 µgg-1, 0.30 µgg-1and 288.67 µgg-1, respectively, where Cr has crossed, Pb is within, and Mn is lower than the permissible limit. Produced vegetables have high (12.10–33.09) MPI (metal pollution index) and are at a high-risk level for consumption as food.

Monitoring of soil EC for the prediction of soil nutrient regime under different soil water and organic matter contents

Smart farms and precision agriculture require automatic monitoring and supply of water and nutrients for crops, but sensors to monitor plant available nutrients in soil are not available. Soil electrical conductivity (EC) is related to nutrients in soil solution, which can be affected by soil organic matter, soil texture, temperature, and water content. Therefore, the objective of this study is to evaluate factors influencing soil EC sensor values by monitoring EC under different soil organic matter and water contents. Ten soil samples with various sand and clay contents, EC, pH, and organic matter contents were selected and saturated with water. Volumetric water content and EC of the soil were monitored while drying the soil. Humic acid and manure were added to soils in order to evaluate the effect of organic matter on soil EC. Soil EC values linearly increased with increasing water content at 10–25% which is favorable water content for plant growth. The EC increased when organic matter was added to soils, which was related to ions released from the organic matter. Soil EC calibration factor for soil water content increased when EC of the soil was high and organic matter was added. The sensor EC values in sandy loam and loam soils was related to the ion contents in pore water, and exchangeable ions in soil, respectively. Sensor EC values were highly correlated with organic matter and K contents in soil and can be used as an indicator for plant available nutrients in soil. Therefore, the sensor EC at optimal soil water content for plant growth can be used to monitor changes in plant available nutrients in soil.

Production and postharvest quality of &lt;i&gt;Passiflora edulis&lt;/i&gt; Sims under brackish water and potassium doses

&lt;abstract&gt; &lt;p&gt;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&lt;sup&gt;−1&lt;/sup&gt;, 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&lt;sup&gt;−1&lt;/sup&gt;, 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&lt;sup&gt;−1&lt;/sup&gt; 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&lt;sup&gt;−1&lt;/sup&gt; 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.&lt;/p&gt; &lt;/abstract&gt;

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.

The dynamic of pH and EC in the Katingan tidal irrigation system, under influences of acid water, brackish water, and tidal movement

The Katingan tidal irrigation area frequently experiences high salinity due to its coastal position and acidity due to the acid sulphate soil type and water discharge from the neighboring peat forests. This study aims to investigate the dynamic of pH and Electrical Conductivity (EC) caused by the interaction of peat water and brackish water, which is impacted by tides in an acid sulphate soil environment. Field measurements were conducted to collect data on water level, pH, and EC in both channels and fields. The dynamic of acid water from peat forests and acid sulphate soils with brackish water in the irrigation network was investigated using HEC-RAS simulations. The simulation incorporates water level, EC, and pH recorded at the Katingan River from December 22, 2022, to January 5, 2023. The results of simulations are calibrated with observed data at the main channel. The influence of brackish water on increasing pH and EC (pH = 5–7, EC = 0∼5.94 dS/m) is more significant in hydrotopography Type A, but it is less significant (pH = 4∼5.5, EC = 0∼2.25 dS/m) in hydrotopography Type B, which is less affected by brackish water. The water pH is more acidic in hydrotopography Type C, which is not impacted by tides. These simulation results may serve as a foundation for developing and operating sluice gates to improve water quality by allowing or preventing the entry of water into the irrigation network.

Population dynamics of pelagic rotifers in Marala Headworks (Pakistan).

Research work was designed to investigate the density and diversity of pelagic rotifers in a Lake near Marala Headworks. The physico-chemical parameters of water such as pH, dissolved oxygen, temperature, electrical conductivity, transparency and turbidity were evaluated. Correlation between rotifers and these parameters was also studied. Plankton sampling was done on monthly basis in order to check the population density of rotifers. In total, 18 species of rotifers were identified which belonged to 11 genera. The highest number of rotifers and their diversity was shown by genera namely Brachionus, Keratella, and Filinia. The Brachionus calyciflorus was dominant species in all the samples with mean population density (41%). Analysis of variance of physico-chemical parameters presented that the air and water temperature, electrical conductivity, transparency, dissolved oxygen and oxygen saturation were statistically significant in all the months. While pH was statistically non-significant (p≥0.05. Pearson correlation showed that oxygen and transparency were negatively correlated with rotifers density and diversity. Air and water temperature, concentration of hydrogen ions (pH), electrical conductivity and salinity showed positive relationship with density and diversity of rotifers.