Prolonged Drought Periods Research Articles

Assessment of the Drought Risk in Constanta County, Romania

Drought poses a significant risk in many parts of the world, especially in regions reliant on agriculture. Evaluating this risk is an essential step in preventing and reducing its impact. In this context, we assess the drought intensity at six sites in Constanța County (Romania) using the de Martonne aridity index. The risk of aridity and vulnerability to drought were evaluated by the Drought Hazard Index (DHI) and Drought Risk Index (DRI), computed based on the Standardized Precipitation Index (SPI). The de Martonne index indicates a variation between the slightly arid and semi-arid climates for Adamclisi station, with periodic changes from semi-arid to arid. At Cernavodă station, we notice a passage from an arid period towards a moderately humid one (in 2005), followed by a movement in the opposite direction to the limit of the arid zone (in 2011), and a return inside the “limits” of the semi-arid to moderately arid climate. A similar variation for 2000–2018 is noticed at Medgidia, Hârșova, and Mangalia. DRI classifies two stations in the low risk to drought category and one in the moderate risk to drought class. The other two locations experience a high or very high risk of drought. The drought intensities varied in the intervals 0.503–1.109 at Constanța, 0.473–1.363 at Mangalia, 0.511–1.493 at Adamclisi, 0.438–1.602 at Hârșova, 0.307–1.687 at Medgidia, and 0.463–1.307 at Cernavodă, and the prolonged drought periods were over 99 months at all stations.

Management and Performance Analysis of Textile Effluent Treatment Plants in Laundries of The Local Productive Arrangement of Pernambuco

Objective: The present study aimed to assess 10 laundries for compliance with Brazilian legislation Theoretical Framework: The Local Productive Arrangement (APL) of Pernambuco plays a crucial role in job creation and economic growth in the state. However, the jeans beneficiation process consumes a significant amount of water and involves the use of various chemicals, which generate effluents with high organic loads, color, and toxicity. This has caused serious environmental problems. The issue is exacerbated during prolonged drought periods and by intermittent river flows, which reduce the natural self-purification capacity of the rivers. Method: A total of 334 influent and effluent samples were collected. All the laundries studied employed physicochemical treatment processes (flocculation followed by sedimentation). Results and Discussion: The WWTPs proved to be efficient in the removal of settleable solids, demonstrating that the coagulation and flocculation processes are effective for this purpose, even in scenarios with management deficiencies. On the other hand, poor operation of the treatment plants has resulted in other parameters, such as pH, oils, and greases, being out of compliance with current legislation. The efficiency in reducing BOD was highly inconsistent, with fluctuations ranging from over 90% efficiency to negative values, indicating significant operational issues. High concentrations of organic matter can compromise oxygen levels in the receiving bodies. It is essential to intensify monitoring and improve treatment processes to mitigate negative environmental impacts.

Does pigmentation provide protection to bdelloid rotifers in a high ultraviolet B environment?

AbstractAquatic species found in habitats with limited shade and little dissolved organic carbon (DOC) have increased vulnerability to ultraviolet radiation (UVR) damage. Pigmentation is a common mechanism used by animals for protection from UVR. A pigmented bdelloid rotifer, Philodina, occurs in high densities in shallow rock pools in El Paso Co., TX, and is subject to repeated desiccation and high UVR. To understand the roles of DOC, pigmentation, and dormancy in reducing the effects of UVR exposure in these rotifers: (1) DOC levels in rock pools were measured before and after the summer monsoon season and (2) hydrated or dormant bdelloids (desiccated for 0, 1, 7, or 32 d) that differed in degree of pigmentation (highly, moderately, lightly, and none) were exposed to three intensities of UVB radiation (low, mid, or high) and monitored for survival after 48 h. Pigmented bdelloids were found in rock pools with lower DOC concentrations. Logistic regression analysis indicated that pigmentation level, desiccation time, and UVB intensity all affected survival. Bdelloids in the dormant form for 1 d were more resistant to UVB exposure at all pigmentation levels. However, as desiccation time increased, the odds of surviving decreased. Hydrated highly pigmented bdelloids were three times more likely to survive desiccation, UVB radiation, and their combined effects. Prolonged periods of drought due to the changing climate will alter DOC concentrations, causing photoprotection to become an increasingly important survival strategy for aquatic invertebrates, especially those inhabiting shallow waters.

How water circularity can help to reduce and regulate water waste in urban districts

Abstract Global water consumption has increased sixfold in the past 100 years and is growing at about 1% per year due to population growth, economic development, and changing consumption patterns; therefore, climate change, combined with urbanization and population growth, is causing water availability problems in cities around the world. Rethinking circular cities that put water at the centre of their priorities and that manage it cyclically and keep it within the urban environment as much as possible to maximize its value must become the fundamental goal. However, to date, cities are not even close to maximizing the use of water that reaches their buildings. As a result, two main issues have emerged as crucial in the international debate: the scarcity of water resources due to its wastefulness and overuse, and extreme weather events, such as heavy rains alternating with periods of prolonged drought, a consequence of global warming. In response to these issues, this research aims to investigate the potential of a design approach that takes into account the two phenomena of water excess and shortage, integrating water from the earliest decision-making stages of building design. Starting from the definition of architectural strategies, replicable solutions are defined and evaluated against specific KPIs to develop a resilient and climate-neutral architectural and urban design model.

The role of hydrological measuring devices in monitoring changes in the flow rate of the Boudraa River during the year 2023 (sub-watershed of Oued M’hasser, Morocco).

Abstract Tracking the water flow and surface runoff is of utmost importance in light of the climate changes experienced globally and specifically in Morocco. In recent years, Morocco has been facing a significant water deficit due to declining rainfall and prolonged drought periods, which affects various water uses. As the Atlas and Rif regions serve as the natural water reservoirs for Morocco, it has become essential to track the water flow and valleys in these areas to study their hydrological behavior. This understanding is crucial for determining their functioning mechanisms and making appropriate decisions to ensure the sustainability of these resources. In this context, we have monitored the changes in the flow of Ain Boudraa in the basin of Wadi Mhasser in the Central High Atlas. We have studied the impact of climatic factors on the water flow and water levels, employing a methodology that involves statistical analysis of precipitation data from the nearby station, along with conducting hydrological measurements of the flow and construction a calibration curve.

Experimental investigation of collapsible soils under oedometric loading: effect of internal erosion

Collapsible soils, geological formations characterized by pronounced structural instability upon saturation, present a significant challenge in geotechnical engineering. This experimental study aims to deepen our understanding of the mechanisms governing the behavior of these soils, which are particularly prevalent in arid and semi-arid regions subject to extreme hydrological cycles. Collapsible soils, sensitive to climatic variability, undergo profound alterations in their hydromechanical properties due to alternating periods of prolonged drought and intense rainfall events. These fluctuations induce significant modifications in the soil's pore structure, promoting the development of internal erosion phenomena such as suffusion. The results obtained from this experimental investigation on reconstituted samples highlight the combined influence of various factors, such as water content, dry density, particle size, and flow rate, on the collapse potential. It appears that fine particles play a predominant role in the formation of fragile structures, susceptible to collapse upon saturation. Moreover, the intensity and duration of infiltration significantly influence the propagation velocity of ultrasonic waves, thus offering a promising tool for monitoring the evolution of damage within the soil mass. Furthermore, this study provides essential insights for assessing the risks associated with collapsible soils and contributes to the development of more reliable characterization and modeling methods. It emphasizes the need to consider the complex interactions between the physical, chemical, and mechanical properties of the soil, as well as the influence of environmental conditions, for better control of the risks associated with these materials.

The ectomycorrhizal fungus Paxillus involutus positively modulates Castanea sativa Miller (var. Marsol) responses to heat and drought co-exposure

Castanea sativa Miller, a high-valuable crop for Mediterranean countries, is facing frequent and prolonged periods of heat and drought, severely affecting chestnut production. Aiming to tackle this problem, this study unraveled the influence of mycorrhizal association with the fungi Paxillus involutus (Batsch) on young chestnut plants' responses to combined heat (42 °C; 4 h/day) and drought (no irrigation until soil moisture reached 25%) over 21 days of stress exposure. Heat stress had no harmful effects on growth, photosynthesis, nor induced oxidative stress in either mycorrhizal (MR) or non-mycorrhizal (NMR) chestnut plants. However, drought (alone or combined) reduced the growth of NMR plants, affecting water content, leaf production, and foliar area, while also hampering net CO2 assimilation and carbon relations. The mycorrhizal association, however, mitigated the detrimental effects of both stresses, resulting in less susceptibility and fewer growth limitations in MR chestnut plants, which were capable of ensuring a proper carbon flow. Evaluation of the oxidative metabolism revealed increased lipid peroxidation and hydrogen peroxide levels in NMR plants under water scarcity, supporting their higher susceptibility to stress. Conversely, MR plants activated defense mechanisms by accumulating antioxidant metabolites (ascorbate, proline and glutathione), preventing oxidative damage, especially under the combined stress. Overall, drought was the most detrimental condition for chestnut growth, with heat exacerbating stress susceptibility. Moreover, mycorrhizal association with P. involutus substantially alleviated these effects by improving growth, water relations, photosynthesis, and activating defense mechanisms. Thus, this research highlights mycorrhization's potential to enhance C. sativa resilience against climate change, especially at early developmental stages.

Effects of drought and moisture stress on the growth and ecophysiological traits of Schima superba seedlings.

Changes in rainfall patterns are important environmental factors affecting plant growth, especially when larger precipitation events and prolonged drought periods occur in subtropical regions. There are many studies on how drought reduces plant biomass through drought-sensitive functional traits, but how excess water affects plant growth and ecophysiology is still poorly understood. Therefore, a greenhouse experiment was conducted on Schima superba (Theaceae), a dominant tree species in subtropical forests and commonly used in forestry, in a closed chamber under control (25% soil water content (SWC) as in local forests), drought stress (D, 15% SWC) and moisture stress (W, 35% SWC). Plant growth and ecophysiological traits related to morphology, leaf gas exchange, water potential and structural traits were measured. Compared to control, S. suberba under dry conditions significantly decreased its aboveground biomass, photosynthetic rate (A), leaf water potential and nitrogen use efficiency, but increased intrinsic water use efficiency, root to shoot ratio and specific root length. S. superba under wet conditions also significantly decreased its total biomass, aboveground biomass and specific root length, while W had no effect on A and leaf water potential. Our results indicate that S. superba shows a decrease in carbon gain under drought stress, but less response under wet conditions. This emphasizes the need to consider the strength and frequency of rainfall pattern changes in future studies because rainfall may either alleviate or intensify the effects of drought stress depending on the moisture level, thus suitable water conditions is important for better management of this tree species in subtropical China.

The effect of successive summer drought periods on bacterial diversity along a plant species richness gradient.

Drought is a major stressor to soil microbial communities, and the intensification of climate change is predicted to increase hydric stress worldwide in the coming decades. As a possible mitigating factor for the consequences of prolonged drought periods, above and belowground biodiversity can increase ecosystem resistance and resilience by improving metabolic redundancy and complementarity as biodiversity increases. Here, we investigated the interaction effect between plant richness and successive, simulated summer drought on soil microbial communities during a period of 9 years.To do that, we made use of a well-established biodiversity experiment (The Jena Experiment) to investigate the response of microbial richness and community composition to successive drought periods alongside a plant richness gradient, which covers 1-, 2-, 4-, 8-, 16-, and 60-species plant communities. Plots were covered from natural precipitation by installing rain shelters 6 weeks every summer. Bulk soil samples were collected 1 year after the last summer drought was simulated. Our data indicate that bacterial richness increased after successive exposure to drought, with the increase being stable along the plant richness gradient. We identified a significant effect of plant species richness on the soil microbial community composition and determined the taxa significantly impacted by drought at each plant richness level. Our data successfully demonstrates that summer drought might have a legacy effect on soil bacterial communities.

The Sugarcane ScPetC Gene Improves Water-Deficit and Oxidative Stress Tolerance in Transgenic Tobacco Plants

Water deficit is the main limiting factor constraining sugarcane productivity, and its impact is expected to increase due to climate changes. During prolonged drought periods, most plants become extremely vulnerable to ROS accumulation, which can severely damage their photosynthetic apparatus. The PetC gene, encoding a Rieske FeS protein (ISP), has been shown to regulate the electron transport chain and protect photosystems (PSs) under drought conditions in some plant species. In sugarcane, transcriptome analysis revealed that ScPetC is repressed during drought stress in the field. In this study, we have overexpressed ScPetC in tobacco plants and evaluated its role in water-deficit tolerance. Our results indicate that the ScPetC protein structure is conserved when compared to other species. ScPetC overexpression reduced the negative impact of water deficit on plant development. This effect was associated with a positive impact on ScPetC quantum efficiency and the electron transport rate of PSII, the photosynthetic rate, and water use efficiency. The total chlorophyll content under water deficit was higher in plants overexpressing ScPetC, and this was correlated with less chlorophyll degradation from oxidative damage. Together, these results demonstrate that ScPetC confers tolerance to water deficit and oxidative stresses, making it a candidate gene for crop improvement.

Diel and seasonal mixing patterns and water quality dynamics in a multipurpose tropical semiarid reservoir.

Eutrophication has become a recurrent concern in reservoirs worldwide. This problem is intensified in tropical semiarid regions, where the reservoirs have high seasonal and annual variability of water level and volume. Therefore, an extensive understanding of the diel variation of water quality key-parameters can help improve management of such reservoirs. This study focuses on Castanhão reservoir with the largest multipurpose dam in the Brazilian semiarid. Its main water uses are irrigation, fish farming, and human supply. The reservoir faced a decline in water quality due to a prolonged drought period. While previous research has predominantly emphasized the seasonal dynamics of thermal and chemical stratification, our investigation provides diel assessments of multiple water quality parameters, including nutrient concentrations and phytoplankton abundance. Our primary objective is to compare seasonal and diel variations in stratification and nutrient distribution within the reservoir. Key findings reveal a diel cycle of thermal stratification, primarily during dry season, driven by higher wind speeds. This is corroborated by a significant negative correlation between wind speed and the relative water column stability index. In contrast, during the rainy season, the reservoir experiences continuous thermal stratification due to inflowing water being warmer than the reservoir's water temperature. Notably, a significant negative correlation between total phosphorus and chlorophyll-a, along with a two-fold increase of this nutrient throughout the day during the rainy season, underscores the influence of the phytoplankton community dynamics on the diel nutrient variation. Chemical stratification of dissolved oxygen occurred during dry and rainy seasons, indicating that even during the dry season, where there is no significant inflow, the internal nutrient loading can also significantly impact the water quality of a reservoir. This study advances the understanding of diel water quality dynamics in tropical semiarid reservoirs, shedding light on both climatic and anthropogenic influences on water resources.

Gamma amino butyric acid (GABA) application modulated the morpho-physiological and yield traits of fragrant rice under well-watered and drought conditions

BackgroundChanging climate is causing erratic rainfall and prolonged drought periods, thus posing serious threats to crop productivity. Owing to severity of drought events, it is imperative to take proactive measures to enhance the resilience of drought sensitive crops like rice. Therefore, the present study was carried out to improve the drought stress tolerance in rice through gamma amino butyric acid (GABA) application.MethodsThe experiment was included four GABA concentrations i.e., 0 mM as control, 1 mM, 1.5 mM, and 2 mM, two water levels i.e., 100% and 50% field capacity (referred as FC100 for well-watered and FC50 for drought conditions, respectively), and two fragrant rice cultivars i.e., Super Basmati and Basmati-515.ResultsThe findings unveiled a comprehensive improvement in various parameters with GABA application in fragrant rice under both well-watered (FC100) and water-limited (FC50) conditions, compared to the control. Specifically, GABA induced enhancements were observed in plant height, root length, fresh weight, dry weight, total soluble protein content, and total free amino acid content across both cultivars. Moreover, GABA application significantly improved peroxidase (POD) and catalase (CAT) enzyme activities, alongside elevating anthocyanin levels, while concurrently reducing H2O2 contents in both FC100 and FC50 treatments. Furthermore, the positive impact of GABA extended to morphological traits, with notable increases in panicle length, total tillers and productive tillers per hill, branch and grain numbers per panicle, and 1000-grain weight for Super Basmati and Basmati 515 cultivars under both water regimes, compared to Ck. Similarly, the grain yield increased by 31.01% and 27.32% under FC100 and 36.85% and 27.71% under FC50 in Super Basmati and Basmati-515, respectively, in response to GABA application, compared to Ck. Additionally, principal component analysis (PCA) revealed significant variances attributed to Dim1 and Dim2, with 86.1% and 4.0% of the variance, respectively, across three bi-plots encompassing rice cultivars, water levels, and GABA treatments. Notably, all tested indices, except for H2O2 and non-productive tillers per hill, exhibited positive correlations amongst themselves and with rice yield, further emphasizing the beneficial effects of GABA application on fragrant rice under well-watered and drought conditions.ConclusionsGABA significantly improved fragrant rice performance under both well-watered (FC100) and water-limited (FC50) conditions. Moreover, integrating GABA application into rice cultivation practices could not only improve the crop resilience to drought stress but also potentially benefiting the future food and nutritional security globally. However, however; further research is needed to understand the cellular and molecular mechanisms of the functionality of GABA in fragrant rice, particularly under drought conditions.

Soil drought stress and high-temperature effects on photosystem II in different juvenile spruce provenances

Abstract With prolonged periods of drought and temperature extremes becoming more frequent, the stress on Norway spruce has increased, as its ecological optimum is in colder and more humid environments. However, it is a tree species with a good adaptability, due to its great geographic and intraspecific variability. In this study, we tested the sensitivity of chlorophyll a fluorescence tools for the early detection of drought and heat stress, as well as their combined effect, in four Slovak Carpathian provenances, under controlled laboratory conditions. Responses in photosynthetic parameters of fast and slow (light response curves) kinetics of chlorophyll a fluorescence were analysed in spruce seedlings under four treatments: control, drought, heat, and combined drought + heat. Heat and drought + heat stresses led to the decrease of photosynthetic efficiency to a greater extent than in the case of only individual drought stress. The less sensitive parameter impacted by the stresses was the maximum quantum yield of PSII photochemistry (Fv/Fm), while the more sensitive parameters were: the performance index based on absorption of light energy (PIABS), the effective quantum yield of the PSII (ΦPSII), and the coefficients of non-photochemical fluorescence quenching (NPQ, qN). The significant variability in responses of individual provenances was also observed. Seedlings from two studied provenances responded better to these abiotic stresses (Pa-680 and Pa-1500); however, Pa-1500 provenance from the highest altitude showed the best ability of resistance to soil drought stress, as well as to high temperature effect. This rapid screening of photosystems II efficiency showed the importance of the selection of more resistant populations to concurrent stresses as one of the measures to mitigate climate change impacts.

European beech (Fagus sylvatica L.): A promising candidate for future forest ecosystems in Central Europe amid climate change

Abstract On the one hand, the European beech (Fagus sylvatica L.) is the tree of the future due to ongoing climate changes, on the other hand, there are questions about its expansion and economic use as a replacement for the declining Norway spruce (Picea abies [L.] Karst.). This literature review examines 140 studies summarizing basic research on beech in the context of climate change. As a climax tree species, beech is becoming dominant again in parts of its original range at the middle and higher altitudes of Central Europe, following spruce. It is a shade-loving species that can thrive in various types of mixed forest stands. To cultivate beech, close-to-nature methods, shelterwood, or selection management are optimal. The occurrence of the beech seed year is influenced by factors such as precipitation, temperature, drought, and air pollution. Although beech is generally considered resistant to abiotic and biotic factors, it often needs protection against hoofed game browsing in the earliest stages of development. As climate change progresses, it is essential to cultivate beech in areas rich in precipitation and nutrients where it can thrive even under more extreme conditions. In optimal conditions, beech has shown intensive regeneration in recent years, aggressively displacing other tree species. However, with insufficient precipitation and prolonged periods of drought, beech loses its vigor, production, and ability to compete. For adaptation to climate change, it is recommended to select appropriate beech provenance, promote natural regeneration, and cultivate structurally differentiated stands through positive-selection thinning from above.

Critical factors in soil organic carbon mineralization induced by drying, wetting and wet-dry cycles in a typical watershed of Loess Plateau

As global climate change progresses, soil will experience prolonged periods of both drought and heavy rainfall, leading to a more frequent drought-re-wetting process that may impact the ecosystem's carbon (C) cycle. However, understanding the extent to which different water conditions and wet-dry cycles alter the process of soil organic carbon (SOC) mineralization remains limited. Therefore, our study focused on the dammed land unique to the Loess Plateau, silted by check dams constructed for erosion control. We implemented three water gradients-drought (30% WHC), water stress (100% WHC), and wet-dry cycling (30–100%)-indoors to observe the SOC mineralization process five times. We identified a transient excitation effect of the wet-dry cycles on SOC mineralization. Soil mineralization decreased gradually with the alternation of wet-dry cycles. The wet-dry cycles not only significantly impacted the contents of SOC and TN but also stimulated the activities of enzymes related to C and N cycles. As the cycle frequency increased, the utilization of C sources by soil microorganisms gradually decreased, and the dominance of carbohydrates, amines, and acids evolved into a single acid, esters, or alcohols. Phosphatase and Chloroflexi were the main factors influencing SOC mineralization under drought stress, while TN and Ascomycota were the primary factors under water stress. SOC and Gemmatimonadetes were the main limiting factors for SOC mineralization under the wet-dry cycles. Additionally, we quantified the direct and interactive contributions of each factor to SOC mineralization. The direct contributions of drought stress, water stress, and the wet-dry cycles to SOC mineralization were 0.961, 0.736, and 0.942, respectively. This study contributes to a more comprehensive understanding of the mechanisms underlying SOC mineralization in the Loess Plateau under changing conditions.

Analysis of the sustainability of swimming pools: Water and energy cycles

The objective of this article is to conduct a literature review aimed at analyzing recent research conducted between 2018 and March 2023 concerning the water and energy cycles in swimming pools. This review aims to provide updated information by considering the impact of the COVID-19 pandemic on the sector. Additionally, it serves as a complementary review to a previous study that encompassed research up until 2018. Four challenges that the review seeks to analyze and investigate are identified: water balance, energy balance, chemical balance, water treatment, and diverse legislation. Regarding the water balance, the importance of reducing evaporation from swimming pools is highlighted, especially in Mediterranean climates with prolonged drought periods. Various solutions to improve the water balance are analyzed, such as the use of solar covers and the optimization of the water recirculation and filtration system. In relation to the energy balance, it is recognized that the use of pumps and filters consumes a lot of energy. The review emphasizes the importance of optimizing the water recirculation and filtration system, and various ways to improve the energy efficiency of pool heating and air conditioning are examined. In addition, the use of renewable energy technologies, such as solar panels, to reduce the energy demand of pools is considered. In summary, this review updates previous research on the water and energy cycles in swimming pools, with a focus on water and energy balance. The review identifies challenges and solutions to improve the sustainability of pools and highlights the importance of addressing the complexity of applicable legislation. The results of this review are expected to be useful for future research and to promote more sustainable management of swimming pools.

Plants in the caatinga possess multiple adaptative leaf morphoanatomical traits concurrently, a pattern revealed from a systematic review

Plants in seasonally dry forests, such as the Caatinga in Brazil, possess adaptive characteristics to endure prolonged periods of drought and intense sunlight. However, few studies have delved into understanding, as proposed here, the convergence of these traits based on morphoanatomical features. Therefore, based on a systematic review, we investigated the morphoanatomical traits of Caatinga plant's leaves in terms of their occurrence and frequency among species, as well as their combinations. This review encompasses data from 69 species distributed across 24 botanical families, with 13 species exclusive to the Caatinga. Through this review, we present the most common morphoanatomical leaf traits of Caatinga plants, discussing their functional significance in dry forests. Traits such as uniseriate epidermis, tector trichomes, amphistomatia, dorsiventral mesophyll and crystals were the most prevalent. Additionally, traits not typically described as advantageous for semi-arid regions, such as stomata at the same level and/or above common epidermal cells, were identified. Our review unveils the significant sharing of morphoanatomical leaf characteristics among Caatinga plants, with the observation of three clusters associated with these traits, composed of subshrub, shrub, arboreal and/or herbaceous species. The shared traits underscore the evolutionary association between traits and the environment. Finally, this comprehensive overview of these traits allows us to understand the dynamics of Caatinga plants and serves as a foundation for future analyses of the varying vulnerability of plants within each cluster to climate change.

Hydroponic corn (Zea mays L.) fodder production through the implementation of mineral fertilization: a comparative study

R Objective: To produce hydroponic corn forage using a mineral fertilization planning with three different seed types and to determine the optimal concentration for production and livestock feeding. Design/Methodology/Approach: A completely randomized experimental design was used. The following study variables were included in the design: plant height, root length, stalk thickness, and fresh biomass. Five hundred grams of three different variety seeds were selected, washed, disinfected, soaked, covered, aerated, and placed in plastic trays. Starting from the fifth day, the seeds were watered with formulated solutions until the end of production. Results: Plant height reached 17.25 cm, at a 50% concentration; root were 12.55 cm long, at a 25% concentration with Sinaloa seeds; stalks were 2.40 mm thick, at a 25% concentration with Bajío seeds; and biomass recorded 1.184 kg at a 50% concentration with Sinaloa seeds. Study Limitations/Implications: A greenhouse is not essential for fodder production, as long as the minimum necessary conditions (light, humidity, and temperature) are met. Findings/Conclusions: The 50% nutrient solution had a positive influence on the study variables that used Sinaloa variety seeds. Therefore, hydroponics would be a reliable and practical technique for producers, useful during periods of prolonged drought; it would significantly counteract agroclimatological setbacks in the agricultural, livestock, and environmental sectors.

Prolonged drought periods over the last four decades increase flood intensity in southern Africa

In semi-arid sub-Saharan Africa, climate change and the intensification of human activities have altered the hydrological balance and modified the recurrence of extreme hydroclimatic events, such as droughts and floods. The geomorphological heterogeneity of river catchments across the region, the variable human pressure, and the lack of continuous hydroclimatic data preclude the definition of proper mitigation strategies, with a direct effect on the sustainability of rural communities.Here, for the first time in Africa, we characterize hydrological extreme events using a multidisciplinary approach that includes sedimentary data from dams. We focus on the Limpopo River basin to evaluate which factors control flood magnitude since the 1970. Extreme flood events were identified across the basin in 1988–89, 1995–96, 1999–2000, 2003–04, 2010–11, 2013–14 and 2016–17. The statistical analysis of sedimentary flood records revealed a dramatic increase in their magnitude over the studied period. A positive correlation between maximum river flow and antecedent prolonged drought conditions was found in South Africa and Mozambique. Most importantly, since 1980, we observed the likely decoupling of extreme floods from the magnitude of La Niña events, suggesting that the natural interannual variability driven by El Niño-Southern Oscillation (ENSO) has been disrupted by climate changes and human activities.

The Applicability of the Drought Index and Analysis of Spatiotemporal Evolution Mechanisms of Drought in the Poyang Lake Basin

Poyang Lake, the largest freshwater lake in China, is an important regional water resource and a landmark ecosystem. In recent years, it has experienced a period of prolonged drought. Using appropriate drought indices to describe the drought characteristics of the Poyang Lake Basin (PLB) is of great practical significance in the face of severe drought situations. This article explores the applicability of four drought indices (including the precipitation anomaly index (PJP), standardized precipitation index (SPI), China Z-index (CPZI), and standardized precipitation evapotranspiration index (SPEI)) based on historical facts. A systematic study was conducted on the spatiotemporal evolution patterns of meteorological drought in the PLB based on the optimal drought index. The results show that SPI is more suitable for the description of drought characteristics in the PLB. Meteorological droughts occur frequently in the summer and autumn in the PLB, with the frequency of mild drought being 17.29% and 16.88%, respectively. The impact range of severe drought or worse reached 22.19% and 28.33% of the entire basin, respectively. The probability of drought occurrence in the PLB shows an increasing trend in spring, while in most areas, it shows a decreasing trend in other seasons, with only a slight increase in the upper reaches of the Ganjiang River (UGR). One of the important factors influencing drought in the PLB is atmospheric circulation. The abnormal variation of the Western Pacific Subtropical High was one of the key factors contributing to the severe drought in the PLB in 2022. This study is based on a long-term series of meteorological data and selects the drought index for the PLB. It describes the spatiotemporal distribution characteristics and evolution patterns of drought and investigates the developmental path and influencing factors of drought in typical years. This study provides a reliable scientific basis for similar watershed water resource management.