Water Limitation Research Articles

GIS‐based surface irrigation potential assessment of Gololcha River Watershed, Awash Basin, Ethiopia

AbstractThe Gololcha River Watershed is lacking comprehensive assessment of land suitability for surface irrigation, available water potential, and prioritized irrigable areas. This study aims to evaluate the potential of land and water resources for surface irrigation in the Gololcha River Watershed. The study employed a multi‐criteria analysis approach using the analytical hierarchy process (AHP) and ArcGIS to assess land suitability, considering factors like slope, land use/cover, soil characteristics, and proximity to water sources. The observed mean monthly water flow potential for each sub‐watershed was statistically evaluated, and the area ratio approach was used to transfer discharges from gauged sites to the site of interest. Irrigation water requirements for three major crops in the study area were calculated using the CROPWAT8.0 model. The findings revealed an average water availability for irrigation of 2.70 m3/s/month, 1.10 m3/s/month, and 1.03 m3/s/month for the Kurkura, Midagdu, and Wefi sub‐watersheds, respectively, with a total annual river flow of 161 m3/s. Based on the suitability analysis, 2508 ha (7.27%) of the watershed area was classified as highly suitable for surface irrigation, 16,420 ha (47.565%) as moderately suitable, 1502 ha (4.35%) as marginally suitable, and 14,029 ha (40.71%) as unsuitable. The overall surface irrigation potential, aligned with available water, was estimated at 4872.58 ha. However, due to water limitations, only 14.15% of the total suitable land can be irrigated using existing flows. The study highlights the significant potential for expanding surface irrigation in the Gololcha River Watershed, particularly during the rainy seasons when substantial water flows are available. The findings provide valuable insights for developing sustainable irrigation strategies, enhancing agricultural productivity, and contributing to food security in the region.

Single and combined applications of dopamine and 24-epibrassinolide in soybean seedlings under water deficiency: tolerance mechanisms essential to inhibit deleterious effects

Water limitations often cause plants’ physiological, biochemical and morphological disorders, restricting their growth and performance and negatively impacting agricultural yield and global food security. Dopamine (DOP) is an essential water-soluble antioxidant, representing an exciting alternative for use in agriculture, as it maximises plant tolerance under adverse stress conditions. The 24-epibrassionolide (EBR) has the most bioactive function on plant metabolomics, being biodegradable and environmentally friendly. EBR can promote plant tolerance under stress conditions, including water deficiency. Therefore, this study aimed to verify the possible contributions of pre-treatment with DOP and EBR in soybean seedlings subjected to water deficiency, evaluating the responses linked to root anatomy, germination, antioxidant system and biomass accumulation. The single and combined use of growth regulators (DOP and EBR) mitigated the harmful effects caused by water deficiency in seedlings. However, the single use of DOP under the conditions of this research had better results. DOP and EBR positively affected root anatomy, modulating plastic changes in the epidermis tissues, metaxylem and vascular cylinder tissues. Increments in biomass and growth of seedlings exposed to drought and treated with growth regulators can be explained by the intense activities of antioxidant enzymes, maximising redox metabolism and protecting root tissues from oxidative damage.

Performance and mechanism insights into S-doped superhydrophilic carbon nitride for photocatalytic hydrogen evolution and degradation

Carbon nitride (CN) photocatalyst possesses great potential in alleviating energy and environmental crisis, while the insufficient active sites exposure, limited light harvest and poor charge behavior, as well as inferior dispersibility in water limit its photocatalytic activity. In this research, a loose porous crimp S doped CN photocatalyst with superhydrophilicity was tailored via facile one-pot thermal-melting followed thermal induce copolymerization of urea with 2-mercaptonicotinic acid. The dope of 2-mercaptonicotinic acid leads to the significant enhancement of specific surface area, range/intensity of visible-light harvest and charge behavior, as well as hydrophilicity of CN. The photocatalytic hydrogen evolution rate achieves a remarkable improvement of 7.61 times compared to CN alone, reaching 88.14 μmol h−1. Additionally, the photodegradation of tetracycline is enhanced by approximately 3.96 times compared to pristine CN, resulting in a degradation efficiency of 90.5 %. Via active species capture tests, ESR, LC-MS, toxicity prediction and DFT calculations, the main active species, degradation pathway, intermediates toxicity and promoted mechanism of photocatalytic performance are explored. This study presents a straightforward and cost-effective approach to enhance the intrinsic activity of CN-based photocatalysts by simultaneously regulating their active sites exposure, light absorption and charge behavior for addressing environmental and energy concerns.

Assessing drinking water quality in Eloued, south-East Algeria, using the groundwater pollution index (GPI) and the synthetic pollution index (SPI) model.

Groundwater quality degradation is a significant environmental issue worldwide, with potentially severe economic consequences and harm to ecosystems and biodiversity. This can directly affect human health, particularly in developing countries where rapid and uncontrolled urbanization is on the rise. Groundwater is the primary resource for meeting the water needs of the Eloued region, located in southeastern Algeria. Water is considered unfit for human consumption if its physico-chemical elements exceed national or international standards or guidelines. We used the GPI and SPI indices to evaluate the quality of groundwater suited for drinking. Groundwater samples were obtained from 22 wells at depths of more than 250m. Standard analytical procedures were used to determine the physicochemical characteristics of the collected samples, which included pH, EC, TDS, Na+, Ca+2, Mg+2, K+, Cl-, HCO3-, SO4-2, NO3-, NO2-, NH4+ and PO4-3. Multivariate statistical analysis and GIS techniques were used to process the results. The results of the selected physicochemical parameters were compared with World Health Organization (WHO) guidelines to determine the quality of drinking water. The findings indicate that the waters of the terminal complex aquifer are salty and contain medium to high quantities of main ions that surpass the established drinking water limits. The primary ions' relative abundance is Cl- > SO4-2 > HCO3- > NO3 for anions and Na+ > Ca+2 > Mg+2 > K+ for cations. Groundwater chemical types were dominated by Na+, Ca+2, Cl-, and SO4-2. Principal Component Analysis (PCA) showed that alteration and dissolution of carbonates, evaporates, salts, partly silicates, and evaporation, are the main reasons affecting the chemical composition of water in Eloued. The GPI results show that 18.18%, 54.54%, and 27.27% of the water samples were classed as lightly polluted, moderately polluted, or substantially polluted for drinking purposes, respectively. According to the SPI study, 9.09%, 36.36%, 36.36%, and 18.18% were considered drinkable, mildly contaminated, moderately polluted, and seriously polluted for drinking purposes, respectively. According to the GPI and SPI models' geographical distribution maps, potable water is generally scarce and concentrated in the northeastern section of the research area, near the town of Ourmes.

Effect of Soil Moisture on Future Heatwaves Over Eastern China: Convection‐Permitting Regional Climate Simulations

AbstractSoil moisture deficiencies exacerbate heatwaves through soil moisture‐temperature feedback, an effect that is expected to intensify with climate change, resulting in critical impacts on society and ecosystems. This study aims to investigate the evolving soil moisture‐heatwave relationship over eastern China in the future, using a convection‐permitting (CP, ∼4 km) regional climate model (RCM). The CP‐RCM model simulates historical (1998–2007) and future (2070–2099) climates over eastern China, with three pseudo‐global warming (PGW) experiments conducted under the RCP2.6, RCP4.5, and RCP8.5 scenarios. Results indicate a substantial increase in heatwave frequency (HWF) and magnitude (HWM) over eastern China, particularly under the RCP8.5 scenario. The largest HWF (up to 23 days) is expected in South China (SC), and the largest HWM (up to 3.25°C) is expected in Loess Plateau (LP) and North China Plain (NCP), indicating a pronounced future risk of heatwave in the region. Antecedent soil moisture exhibits a negative correlation with heatwave indices (HWM and HWF) in most areas of eastern China, suggesting its role in mitigating heatwaves. Quantile regression analysis shows that antecedent soil moisture exerts a stronger effect on the upper quantile of the HWF/HWM than on the lower quantile. With global warming, the amplifying effect due to soil moisture deficiency on future heatwaves is expected to expand spatially and become more pronounced. Increased soil moisture control on heatwaves can be attributed to reduced energy limitation and intensified water limitation. A comprehensive investigation across five sub‐regions reveals the role of various soil moisture regimes in modulating heatwaves over eastern China.

The rhizosphere bacterial community of water yam (Dioscorea alata L.) under limited water conditions

AbstractIntroductionYam cultivation in West Africa, the largest yam production area, has expanded to the northern Guinea savanna, which receives an annual rainfall of 800–1000 mm. However, variations in rainfall are problematic for the stable productivity of yams. Integrated soil fertility management is urgently needed to improve and stabilise yam productivity. Plants have complex interactions with bacterial communities, influencing their health and environmental adaptability. Although the growth of water yams (Dioscorea alata L.) at various rainfall levels might be related to their interaction with the bacterial community, their structure under water limitation is yet to be elucidated. Here, we evaluated the bacterial community structure in the rhizosphere (Rh) and roots of ‘A‐19’ under water limitation conditions.Materials and MethodsPlants were grown under normal conditions, and watering was reduced to less than 70% for 1 month. Rh and root samples were collected for DNA extraction, and downstream amplicon sequencing analyses were performed.ResultsThe dry weight of the shoots, particularly the leaves, decreased under water limitation. Bacterial diversity in the rhizocompartments was significantly reduced. However, bacterial community composition was not affected by water limitation. Despite water‐limited conditions, bacterial community structure was robust in the Burkholderia‐Caballeronia‐Paraburkholderia and Streptomyces clades. These taxa accounted for approximately 60% of the relative abundance in the roots under water limitation.Conclusionidentifying bacterial community composition of ‘A‐19’ under water‐limited conditions provides fundamental information for developing integrated soil fertility management strategies across rainfall gradients in West Africa. Our study indicates that ‘A‐19’ has a robust bacterial community structure for beneficial interactions with bacteria despite soil water conditions.

Rational design of carbon dot nanozymes for ratiometric dual-signal and smartphone-assisted visual detection of nitrite in food matrices

Developing reliable nitrite (NO2−) sensors is essential for food safety and reducing health risks from NO2− exposure. In this study, we strategically designed nitrogen-doped carbon dot (N-CD) nanozymes to establish an accessible dual-signal ratiometric sensing system for detecting NO2− in food matrices. This system utilizes the photoluminescence and enzyme-like properties of N-CD nanozymes combined with NO2−-triggered diazotization reactions of substrates such as o-phenylenediamine (OPD) or 3,3',5,5'-tetramethylbenzidine (TMB). The resulting N-CD/OPD and N-CD/TMB composites provide dual-mode detection—fluorescence and colorimetric—with high selectivity for NO2− and excellent resistance to interference. These sensors exhibit clear color changes under both ultraviolet and visible light, and can be combined with smartphones for visual, on-site detection of NO2−. By incorporating a ratiometric strategy, dual-signal output, and smartphone compatibility, our system achieved a low detection limit (≤ 1.92μM) and satisfactory recovery rates (85.6~115%) in environmental water and food samples. This highlights the potential of smartphone-assisted sensors for environmental monitoring and food safety applications. Our carbon dot-based platform offers a practical and effective solution for on-site NO2− detection, contributing valuable insights to the field.

No Future Growth Enhancement Expected at the Northern Edge for European Beech due to Continued Water Limitation.

With ongoing global warming, increasing water deficits promote physiological stress on forest ecosystems with negative impacts on tree growth, vitality, and survival. How individual tree species will react to increased drought stress is therefore a key research question to address for carbon accounting and the development of climate change mitigation strategies. Recent tree-ring studies have shown that trees at higher latitudes will benefit from warmer temperatures, yet this is likely highly species-dependent and less well-known for more temperate tree species. Using a unique pan-European tree-ring network of 26,430 European beech (Fagus sylvatica L.) trees from 2118 sites, we applied a linear mixed-effects modeling framework to (i) explain variation in climate-dependent growth and (ii) project growth for the near future (2021-2050) across the entire distribution of beech. We modeled the spatial pattern of radial growth responses to annually varying climate as a function of mean climate conditions (mean annual temperature, mean annual climatic water balance, and continentality). Over the calibration period (1952-2011), the model yielded high regional explanatory power (R2 = 0.38-0.72). Considering a moderate climate change scenario (CMIP6 SSP2-4.5), beech growth is projected to decrease in the future across most of its distribution range. In particular, projected growth decreases by 12%-18% (interquartile range) in northwestern Central Europe and by 11%-21% in the Mediterranean region. In contrast, climate-driven growth increases are limited to around 13% of the current occurrence, where the historical mean annual temperature was below ~6°C. More specifically, the model predicts a 3%-24% growth increase in the high-elevation clusters of the Alps and Carpathian Arc. Notably, we find little potential for future growth increases (-10 to +2%) at the poleward leading edge in southern Scandinavia. Because in this region beech growth is found to be primarily water-limited, a northward shift in its distributional range will be constrained by water availability.

In pursuit of change: Divergent temporal shifts in climate sensitivity of Norway spruce along an elevational and continentality gradient in the Carpathians

Across much of Europe, climate change has caused a major dieback of Norway spruce (Picea abies L.), an economically important tree species. However, the southeasternmost fringe of this tree species – the Eastern Carpathians – has not yet suffered large-scale dieback. Studying temporal shifts of climate sensitivity (TSCS) over time may elucidate the degree to which Norway spruce may be vulnerable to climate-change induced decline in upcoming decades. Under this framework, we analyzed a regional tree-ring network comprising >3000 trees, with the aim of quantifying TSCS since 1950. We mathematically defined TSCS as the slope parameter of the regression of climate sensitivity (the correlation coefficient) over time. Given the often-observed contrasting shift of climate sensitivity at low versus high elevations, we were particularly interested in studying potentially divergent TSCS along elevational and spatial gradients. Our analyses revealed several indications of TSCS for Norway spruce in the Eastern Carpathians. First, at high elevations (>1100 m a.s.l.), we found that the positive link between summer temperature and spruce growth decreased significantly over the study period. In turn, these trees, over time, featured an increasing positive relationship with late winter temperatures. At low elevations (<800 m a.s.l.), the signal of positive summer Standardised Precipitation-Evapotranspiration Index (SPEI) correlation became more frequent among sites towards 2021, while the strength of the positive winter SPEI correlation from the previous growing season weakened. Our results revealed that TSCS was driven significantly by an elevational climate gradient and a longitudinal continentality gradient. Overall, our findings indicate that Norway spruce is increasingly affected by water limitations under climate change at low elevations, highlighting a potentially rising risk of decline of this species in the Eastern Carpathians.

Effects of water limitation and competition on tree carbon allocation in an Earth system modelling framework

Abstract Earth system models (ESMs) have a limited capacity to represent plant functional diversity and shifts in trait distributions. Approaches to improving the representation of this complexity in ESMs include (i) optimality‐based approaches that predict trait–environment responses and (ii) explicitly modelling coexistence and community assembly. These approaches are expected to converge only when optimality‐based approaches identify competitively dominant strategies, which often differ from strategies that maximize ecosystem functioning or fitness components in monoculture. We used two models, LM3‐PPA (a vegetation demographic model designed as an ESM component) and BiomeE (a computationally efficient analog for LM3‐PPA), to explore how water limitation affects carbon allocation strategies of canopy trees. We compared competitive allocation strategies and those that maximize biomass or productivity in monoculture. We did not explicitly model coexistence or community assembly. Rather, we used model experiments to identify competitive and maximizing strategies in a two‐dimensional trait space under different precipitation and mortality scenarios. At 10 eastern US locations, we simulated historical, wet and dry climate scenarios, novel drought and three different mortality scenarios (low, medium or high sensitivity to water deficit). For each site and scenario, we identified the competitive strategy and three maximizing strategies (maximum biomass, productivity or drought‐tolerance). Root: leaf ratios tended to increase and leaf area tended to decrease with increasing water stress (increasing water limitation and its effects on mortality). However, relative to maximizing strategies, competitive strategies shifted towards greater allocation to roots and leaves with increasing water stress. Competitive overinvestments (greater allocation to roots and leaves by competitive strategies compared with maximizing strategies) were robust across different modelling contexts, including vegetation parameter sets (Acer vs. Populus), models (LM3‐PPA vs. BiomeE) and uncalibrated vsersus calibrated BiomeE versions. Synthesis: The theoretical prediction that competitive and maximizing allocation strategies differ under water limitation is confirmed for a demographic model designed as an ESM component. Optimality‐based trait predictions can simplify representing trait diversity in ESMs but do not always correspond to competitive outcomes. Explicitly modelling coexistence and community assembly in ESMs is challenging but is likely the most general approach to representing trait diversity.

Phylloclades of Jacksonia (Fabaceae)—leaf-like branches as adaptation to seasonally arid environments

Abstract Leaves of seed plants were evolutionarily derived through syngenesis (fusion) of the photosynthetic cylindrical axes of the earliest land plants and subsequent morphological diversification. However, in some later evolved taxa leaves became very reduced or entirely lost and photosynthesis was again restricted to stems. Reduction of photosynthetic area to stems is mostly found in plants from arid environments and is generally considered disadvantageous in competition for light with plants with leaves but may be useful if water is limiting. For taxa that cannot form normal leaves on adult plants, increasing photosynthetic area is only possible by modification of other plant parts. Some taxa produce leaf-like phylloclades that are developmentally different from leaves. We investigated Jacksonia floribunda and J. anthoclada (Fabaceae) leaves and phylloclades. In all Jacksonia species true leaves are only developed in the earliest ontogenetic stages, and subsequently are reduced to minor, nonphotosynthetic brownish scales. After several nodes on the seedling, photosynthetic phylloclades, each inserted in the axil of a scale, form the foliage. Immature phylloclades have vestigial nonphotosynthetic leaves borne on small projections from the edge of the blade. These soon abscise. The phylloclades are flattened branches and when mature have a distinctly reticulate venation and a sinuous margin with alternating mucronate tips where the vestigial leaves were attached. Jacksonia species demonstrate a transformational series where in most species foliage is reduced to branchlets. In a few others branchlets are winged forming cladodes or are condensed and laterally expanded to form phylloclades. Our findings on the more derived species in Jacksonia illustrate the complexity of plant morphological responses to evolutionary pressures of seasonal water limitation.

Contribution of land-atmosphere coupling in 2022 CONUS compound drought-heatwave events and implications for forecasting

Severe compound drought-heatwave events were observed over three regions of the Contiguous United States (CONUS), Northwest (NW), Great Plains (GP), and Northeast (NE) regions, during July and August 2022. In this study, we have found that the developments of these drought-heatwave events were shaped by different land-atmosphere coupling behaviors which are associated with water and energy limitation regimes in these regions. In the NW and GP regions, the surface soil moisture (SM) and evapotranspiration (ET) were coupled through water-limited processes. Heatwaves in these two regions were affected by the decrease of ET and the available SM due to the precipitation deficit. This type of land-atmosphere coupling was especially prominent in the GP. In the NE region, the heatwave governed ET through the increase of potential ET (PET) based on energy-limited coupling, which played a crucial role in the development of drought.The impacts of the different land-atmosphere coupling behaviors on the predictability of the 13-km Geophysical Fluid Dynamics Laboratory (GFDL) System for High-resolution prediction on Earth-to-Local Domains (SHiELD) were also investigated by checking its 10-day forecasts during the same period. The analysis was particularly focused on the GP and NE regions, where different land-atmosphere coupling behaviors were observed. The model's warm bias in the GP region was associated with the overestimated net radiation, and the bias was further amplified through the water-limited coupling. In the NE region, the PET-related variables, including surface air temperature, influenced the predictability of drought onset by limiting ET through the energy-limited coupling. Based on our findings, this study highlights the crucial role of land-atmosphere coupling behaviors and provides a scientific strategy for enhancing the model predictability of compound drought-heatwaves.

Tracing pesticide dynamics: High resolution offers new insights to karst groundwater quality

Generally, karst aquifers and springs are highly susceptible to contamination due to the high permeability and, therefore, groundwater flow velocities. The often thin soil cover, accompanied by dolines, can lead to fast infiltration of precipitation water loaded with mobilized contaminants such as pesticides and their transformation products. To date, continuous, temporally highly resolved in-situ monitoring to decipher concentration dynamics for a broad range of pesticides is missing. Therefore, a transportable HPLC-HRMS/MS system (MS2field) was positioned at two karst study sites in the Swiss Jura. Water samples were collected and analyzed for pesticides and their transformation products in-situ every 20 min for 6 weeks in 2021 and 8 weeks in 2022. During the spraying season in 2021, six rain events at site 1 and three at site 2 in 2022 were captured. Concurrently, the water quality parameters electrical conductivity, pH, nitrate, turbidity, and water level, were monitored continuously at high temporal resolution. Further, bacterial cell counts were monitored via online flow cytometry.In 2021, several pesticides and pesticide transformation products were detected in peak concentrations after rain events, of which metamitron showed the highest concentration of up to 1000 ng/L. In one rain event, the Swiss federal and EU drinking water limit of 100 ng/L was exceeded for up to 38 h. Compared with highly frequent MS2field samples collected every 20 min, 42-hours composite samples severely underestimated peak concentrations for all compounds, especially for labile ones. Therefore, it was demonstrated that exceedences of the regulatory limit would have been missed if just composite sampling would have been conducted. Peak concentrations of pesticides coincided with peaks in nitrate concentration and bacterial cell counts following rain events. The correlation analysis showed strong correlations between the three analyzed contaminants (pesticides, nitrate and bacteria), and the proxy parameters electrical conductivity, and pH. The investigation of a second spring revealed similar dynamics indicating that these can be expected in other karst aquifers as well.

PEG treatment is unsuitable to study root related traits as it alters root anatomy in barley (Hordeum vulgare L.)

BackgroundThe frequency and severity of abiotic stress events, especially drought, are increasing due to climate change. The plant root is the most important organ for water uptake and the first to be affected by water limitation. It is therefore becoming increasingly important to include root traits in studies on drought stress tolerance. However, phenotyping under field conditions remains a challenging task. In this study, plants were grown in a hydroponic system with polyethylene glycol as an osmotic stressor and in sand pots to examine the root system of eleven spring barley genotypes. The root anatomy of two genotypes with different response to drought was investigated microscopically.ResultsRoot diameter increased significantly (p < 0.05) under polyethylene glycol treatment by 54% but decreased significantly (p < 0.05) by 12% under drought stress in sand pots. Polyethylene glycol treatment increased root tip diameter (51%) and reduced diameter of the elongation zone (14%) compared to the control. Under drought stress, shoot mass of plants grown in sand pots showed a higher correlation (r = 0.30) with the shoot mass under field condition than polyethylene glycol treated plants (r = -0.22).ConclusionThese results indicate that barley roots take up polyethylene glycol by the root tip and polyethylene glycol prevents further water uptake. Polyethylene glycol-triggered osmotic stress is therefore unsuitable for investigating root morphology traits in barley. Root architecture of roots grown in sand pots is more comparable to roots grown under field conditions.

PDE models for vegetation biomass and autotoxicity

Numerical techniques are widely used to simulate population dynamics in space. In vegetation dynamics, these techniques are very useful to investigate how plants grow, compete for resources, and react to environmental factors within the ecosystem. Plant–soil feedback (PSF) refers to the process where plants or a community alter the biotic and abiotic characteristics of soil that affects the growth of plants or community subsequently growing in that soil. During the last three decades, PSF has been recognized as an important driver for the emergence of vegetation patterns. The importance of studying such vegetation patterns is that they provide an insight into potential ecological changes and illustrate the flexibility and resilience of an ecosystem. Despite the fact that water depletion was once thought to be a major factor in the development of vegetation patterns the existence of patterns in ecosystems without water limitations serves as evidence that this is not the case. In this study, we examine how negative plant–soil feedback contributes to the dynamics of plant biomass. We provide a comparison of different reaction–diffusion PDE models explaining the dynamics of plant biomass in the presence of autotoxicity produced by litter decomposition. We introduce different growth terms, including logistic and exponential, along with additional factors such as extra mortality and inhibitor terms, and develop six distinct models to investigate their individual and combined effects on biomass toxicity distribution. By applying appropriate numerical techniques, we solve the proposed reaction–diffusion PDE models in MATLAB to predict the impact of soil toxicity on plant biomass.

Foliar H2O2 Application Improve the Photochemical and Osmotic Adjustment of Tomato Plants Subjected to Drought

Water limits may have a disastrous impact on agricultural productivity, and the current climate change scenario presents additional problems for crops that rely on regular rainfall. Reactive oxygen species, such as hydrogen peroxide (H2O2), are a recognized stress-sensing mechanism in plants, and may be investigated as an approach for reducing stress impact via systemic acquired acclimation. Here, we looked at how H2O2 foliar application impacts tomato plants’ photosynthetic activity, antioxidant system, sugar chemical profile, and osmotic adjustment during drought and recovery. The experiment was in randomized blocks, 3 × 2 factorial design, with no, one, or two foliar application of 1 mM H2O2, on plants that were either continually watered or subjected to drought. The plants were tested both during the drought period and after they had resumed irrigation (recovered). Leaf water potential, chlorophyll a fluorescence, gas exchange, lipid peroxidation, H2O2 concentrations, phenols, proline, antioxidant enzyme activity, and sugar chemical profile were all measured. Our findings showed that H2O2 application generated metabolic alterations in tomato plants independent of water status, and that two applications in drought plants resulted in a 30% decrease in oxidative stress during drought and faster recovery following irrigation return, with greater production of defence-related molecules such as the APX enzyme, phenols, arabinose, and mannose. Continually watered plants also benefited from H2O2 application, which increased carbon assimilation by 35%.

Polymer composites from waste plastics and reclaimed rubber from tires for sustainable development

AbstractThe swift growth of the automobile industry has resulted in the generation of huge quantities of waste rubber from end‐of‐life tires. Incidentally, the humungous quantities of waste plastics that are an integral part of the legacy landfills/dumpsites, lying unattended and about which not many valorization schemes are available, pose various geoenvironmental issues apart from occupying a lot of landfill space. These situations might end up being a blessing in disguise if a strategy to utilize both waste rubber and waste plastic, segregated post landfill/dumpsite biomining, in tandem by manufacturing polymer composites by resorting to extrusion process followed by the injection molding, for different engineering applications. Thus, the physical, mechanical, thermal, morphological, and leaching properties of the manufactured polymer composites were evaluated in this study. The tensile strength and impact resistance of polymer composites were between 4.3–26.9 MPa and 9.4–20 kJ/m2, respectively. Their glass transition temperature lies between −81.13 and − 50.04°C. The leachable concentration of heavy metals and organic compounds was within acceptable limits for drinking water and permissible limits for inland surface water disposal. Therefore, this study contributes valuable insights into using waste materials for polymer composites manufacturing, which would be further helpful in achieving sustainable development goals and circular economy.

Planting Geometry May Be Used to Optimize Plant Density and Yields without Changing Yield Potential per Plant in Sweet Corn.

Planting geometry is one of the most important management practices that determine plant growth and yield of corn. The effects of eight planting geometries (35 × 23 cm, 40 × 21 cm, 45 × 19 cm, 50 × 18 cm, 55 × 17 cm, 60 × 16 cm, 65 × 15 cm, 70 × 15 cm) on plant growth and yields of three sweet corn hybrids (Argos F1, Challenger F1, Khan F1) were investigated under Erzurum, Türkiye conditions in 2022 and 2023 years. Variance analysis of the main factors shows a highly significant effect on whole traits but in two-way interactions some of the traits were significant and in the three-way interactions, it was insignificant. As an average of years, the number of plants per hectare at the harvest varied between 92,307 (35 × 23 cm) and 120,444 (70 × 15 cm) according to the planting geometries. The highest marketable ear number per hectare (107,456), marketable ear yield (24,887 kg ha-1), and fresh kernel yield (19,493 kg ha-1) were obtained from the 40 × 21 cm planting geometry. The results showed that the variety Khan F1 grown at 40 × 21 cm planting geometry obtained the highest marketable ear number (112,472), marketable ear yield (29,788 kg ha-1), and fresh kernel yield (22,432 kg ha-1). The plant density was positively correlated with marketable ear number (r = 0.904 **), marketable ear yield (r = 0.853 **), and fresh kernel yield (r = 0.801 **). The differences among the varieties were significant for the studied traits, except for plant density and kernel number per ear. In conclusion, the variety Khan F1 should be grown at the 40 × 21 cm planting geometry to maximize yields under study area conditions without water and nutrient limitations.

Multiphase distribution in partly saturated hierarchical nonwoven fibre networks under applied load using X-ray computed tomography

In many industrial applications, nonwoven fibre networks are facilitated to operate under partly saturated conditions, allowing for filtration, liquid absorption and liquid transport. Resolving the governing liquid distribution in loaded polyamide-6 (PA6) fibre networks using X-ray computed micro-tomography is a challenge due to the similar X-ray attenuation coefficients of water and PA6 and limitations in using background subtraction techniques if the network is deformed, which will be the case if subjected to compression. In this work, we developed a method using a potassium iodide solution in water to enhance the liquid’s attenuation coefficient without modifying the water’s rheological properties. Therefore, we studied the evolving liquid distribution in loaded and partly saturated PA6 fibre networks on the microscale. Increasing the external load applied to the network, we observed an exponential decrease in air content while the liquid content was constant, increasing the overall saturation with increasing network strain. Furthermore, the microstructural properties created by the punch-needle process in the manufacturing of the network significantly influenced the out-of-plane liquid distribution. The method has been proven helpful in understanding the results of adaptions in both the fibre network design and manufacturing process, allowing for investigating the resulting liquid distribution on a microscale.

Analysis of Heavy Metals in Water and Wastewater

The primary focus of the study is to assess the presence and concentration of heavy metals in the water and evaluate its suitability for drinking purposes. Given that a significant portion of the local population depends on groundwater for their daily needs, the study is critical in understanding the potential health risks associated with consuming contaminated water. The study begins with a comprehensive survey to gauge the extent of water usage among the local population and their perceptions of water quality. Results from the survey reveal that nearly half of the households in the region are not connected to a formal drinking water network, relying instead on wells and springs. While the majority of respondents perceive the water quality as good, the analytical findings suggest otherwise. Groundwater samples were collected from twelve wells and three springs across the region. These samples were subjected to rigorous analysis using inductively coupled plasma-atomic emission spectrometry (ICP-AES) to detect the concentration of various heavy metals, including aluminum, silver, iron, cadmium, arsenic, chromium, cobalt, zinc, lead, and copper. The results indicate that many of these metals are present in concentrations that exceed the World Health Organization's recommended limits for safe drinking water. Iron, in particular, was found at high levels in all sampled locations, raising significant concerns. The study also employs the Heavy Metal Pollution Index (HPI) to provide a more comprehensive assessment of water quality. The HPI values calculated for the sampled water sources reveal that a majority of the wells and all of the springs have levels of heavy metal contamination that render the water non-potable. This finding is particularly alarming given the region's dependence on water, especially during periods of drought when alternative water sources are scarce.