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Located in the hyper-arid regions of Algeria, the M'zab Wadi basin has historically experienced severe flash flooding, causing severe economic damage and loss of life. Identifying potential flood hazard areas in such an arid environment, challenged by data scarcity, is necessary to forecast flood and to create early warning strategies. The paper aims to map and highlight potential flood hazard areas in the M'zab Wadi basin using geographic information system coupled with the Analytical Hierarchy Process method based on seven related flood hazard factors. The accuracy of the flood hazard map was validated using the Receiver Operating Characteristic based Area Under Curves method. The results show that 3.04% (50.35 km2) and 0.53% (8.74 km2) of the basin area are under high and very high flood vulnerability levels, respectively. The obtained results can offer significant insights to policymakers and decision-makers to make well-informed judgments regarding the effectiveness of flood protective infrastructure/measures. Furthermore, the approach adopted can be advantageous for other regions under similar conditions. [ABSTRACT FROM AUTHOR]

The leaf nitrogen (N) and phosphorus (P) concentrations of terrestrial plants make large contributions to ecosystem function and dynamics. The relationship between aridity and leaf N and P has been established through experimental studies. However, few studies have focused on the large-scale effects of aridity on the leaf N and P of terrestrial plants. In this paper, we used linear regression models to test the effects of aridity on terrestrial plant leaf N and P and the N:P ratio based on global datasets. We found that aridity had significant effects on the leaf N and P and the N:P ratio of terrestrial plants. The strongest relationships were between fern leaf P, the fern N:P ratio, tree leaf P, the tree N:P ratio, vine leaf N, and the tree N:P ratio. Aridity could be used to predict the P and N:P ratio of terrestrial plants, particularly those of ferns and trees, on large scales in arid environments. Our study contributes to maintaining ecosystem functioning and services in arid environments under climate change. [ABSTRACT FROM AUTHOR]

Water is a fundamental human right and a prerequisite for sustainable development because it is an essential element of existence. Notwithstanding, a huge part of the world's population continues to face challenges in accessing clean and safe drinking water. This situation is particularly pronounced in arid and underdeveloped regions where there is a global water crisis that is a huge threat to human health, economic development, and environmental stability. Designed with solar energy, the award-winning "Parabosol" enhances water evaporation and purifies it simultaneously. Parabosol does not require any expensive machines or complicated infrastructural frameworks, making it both cost-effective and efficient for such vulnerable communities. Transporting it easily allows for quick deployment in remote areas during emergencies, ensuring a clean, dependable water supply for basic household use. This innovative measure, which reduces the risk of waterborne diseases and increases access to safe water resources within communities, could greatly contribute to public health promotion efforts. It is intended for daily performance that corresponds to the minimum needs of one family unit (no less than 35 L per person). The processing capacity of each station varies between 120 and 180 L of water per day (depending on geographical and environmental conditions), depending on geographical and meteorological (solar radiation values) factors. However, experimental values are around 250 L. Parabosol illustrates a novel model with its distinctive design and functionality, highlighting the critical role of clean energy in the development of a more sustainable and resilient future. Additionally, unlike macrosystems that require a substantial initial investment and ongoing operating costs, Parabosol is a portable solution that has the potential to address the issue of clean water scarcity in the future. [ABSTRACT FROM AUTHOR]

Background: Endemism is essential in biodiversity, biogeography, and conservation tasks. Based on herbarium specimens kept in some local herbaria, many published literature, and available information, we compiled a comprehensive list and an updated assessment of the Egyptian endemic and near-endemic taxa. The application of quantitative approaches to the distribution patterns, conservation status, and habitat preference of endemic taxa in Egypt was provided. Comparisons of the near-endemic taxa with other neighbouring flora were explained. For each taxon, the distribution patterns, most preferable habitat, biological spectrum, and taxa among 14 phytogeographical regions (Operational Geographical Units; OGUs) of Egypt were determined. Results: In this study, 19 endemics (out of 70) and 76 near-endemics (out of 181) are newly added taxa. Differentiation indices represented the taxonomic degrees of differentiation among endemic taxa. Two different indices were used to assess endemism: single-region endemic taxa (SRET) and multiple-region endemic taxa (MRET). Most endemic and near-endemic taxa were recorded from the mountainous Sinai (S) and the Mareotis sector of the Mediterranean coastal land (Mm). Generally, the most represented families in endemic and near-endemic areas were Asteraceae, Caryophyllaceae, Lamiaceae, and Fabaceae. More than 60% of the endemic taxa occurred in the sandy plains, wadis (desert valleys), and rocky plains and mountains. Applying hierarchical cluster analysis to the occurrences of 70 endemic taxa in the 14 studied OGUs revealed five main floristic groups (I–V), each characterized by certain OGUs. We provided eight groups of near-endemic taxa that represented their extension in neighbouring countries. Conclusions: The presented data will help to fill the gap in our knowledge of endemism, provide baseline information to understand biogeographical processes and facilitate further cooperation toward conservation purposes. [ABSTRACT FROM AUTHOR]

The Shule River Basin (SRB) is a typical arid area in northwest China with a fragile ecology. Understanding vegetation dynamics and its response to climate change and human activities provides essential ecological and environmental resource management information. This study extracted fractional vegetation coverage (FVC) data from 2000 to 2019 using the Google Earth Engine platform and Landsat satellite images, employing trend analysis and other methods to examine spatiotemporal changes in vegetation in the SRB. Additionally, we used partial correlation and residual analyses to explore the response of FVC to climate change and human activities. The main results were: (1) The regional average FVC in the SRB showed a significant upward trend from 2000 to 2019, increasing by 1.3 × 10−3 a–1. The area within 1 km of roads experienced a higher increase of 3 × 10−3 a–1, while the roadless areas experienced a lower increase of 1.1 × 10−3 a–1. The FVC spatial heterogeneity in the SRB is significant. (2) Partial correlation analysis shows that the FVC correlates positively with precipitation and surface water area, with correlation coefficients of 0.575 and 0.744, respectively. A weak negative correlation exists between the FVC and land surface temperature (LST). FVC changes are more influenced by precipitation than by LST. (3) The contributions of climate change to vegetation recovery are increasing. Human activities, particularly agricultural practices, infrastructure development, and the conversion of farmland to grassland, significantly influence vegetation changes in densely populated areas. (4) The area changes of different land types are closely related to climate factors and human activities. Increased construction, agricultural activity, and converting farmland back to grassland have led to an increase in the area proportions of "impervious surfaces", "cropland", and "grassland". Climate changes, such as increased rainfall, have resulted in larger areas of "wetlands" and "sparse vegetation". These results provide valuable information for ecosystem restoration and environmental protection in the SRB. [ABSTRACT FROM AUTHOR]

This research proposes a 10-step methodology for developing an enhanced IAQ dashboard and classroom index (CI) in higher educational facilities located in arid environments. The identified parameters of the enhanced IAQ dashboard–inspired by the pandemic experience, result from the literature review and the outcome of two electronic surveys of (52) respondents, including health professionals and facility management experts. On the other hand, the indicators included in the CI are based on (80) occupant survey responses, including parameters related to IAQ, Indoor Environmental Quality (IEQ), and thermal comfort, amongst other classroom operative considerations. The CI is further tested in four learning spaces at the American University in Cairo, Egypt. The main contribution of this research is to suggest a conceptual visualization of the dashboard and a practical classroom index that integrates a representative number of contextual indicators to recommend optimal IAQ scenarios for a given educational facility. This study concludes by highlighting several key findings: (1) both qualitative and quantitative metrics are necessary to capture indoor air quality-related parameters accurately; (2) tailoring the dashboard as well as the CI to specific contexts enhances its applicability across diverse locations; and finally, (3) the IAQ dashboard and CI offer flexibility for ad-hoc applications. [ABSTRACT FROM AUTHOR]

Permeable surface mapping, which mainly is the identification of surface materials that will percolate, is essential for various environmental and civil engineering applications, such as urban planning, stormwater management, and groundwater modeling. Traditionally, this task involves labor-intensive manual classification, but deep learning offers an efficient alternative. Although several studies have tackled aerial image segmentation, the challenges in permeable surface mapping arid environments remain largely unexplored because of the difficulties in distinguishing pixel values of the input data and due to the unbalanced distribution of its classes. To address these issues, this research introduces a novel approach using a parallel U-Net model for the fine-grained semantic segmentation of permeable surfaces. The process involves binary classification to distinguish between entirely and partially permeable surfaces, followed by fine-grained classification into four distinct permeability levels. Results show that this novel method enhances accuracy, particularly when working with small, unbalanced datasets dominated by a single category. Furthermore, the proposed model is capable of generalizing across different geographical domains. Domain adaptation is explored to transfer knowledge from one location to another, addressing the challenges posed by varying environmental characteristics. Experiments demonstrate that the parallel U-Net model outperforms the baseline methods when applied across domains. To support this research and inspire future research, a novel permeable surface dataset is introduced, with pixel-wise fine-grained labeling for five distinct permeable surface classes. In summary, in this work, we offer a novel solution to permeable surface mapping, extend the boundaries of arid environment mapping, introduce a large-scale permeable surface dataset, and explore cross-area applications of the proposed model. The three contributions are enhancing the efficiency and accuracy of permeable surface mapping while progressing in this field. [ABSTRACT FROM AUTHOR]

Previous studies have shown that adaptation to drought in Brazilian Caatinga trees may involve different physiological and morphological strategies. Particular climatic and soil characteristics occur along this dry ecosystem leading to non-homogeneous water availability. Therefore, in certain niches, some species predominate over others, indicating that best performance of a species is not widespread. We studied changes in initial growth, which is the most critical factor during the life of a plant, of two common species of Caatinga (Erythrina velutina Willd. and Enterolobium contortisiliquum (Vell.) Morong) with variable occurrence through the ecosystem. Young plants were subjected to three water regimes: 450 (control), 225 (moderate stress) and 112.5 mm (severe stress) of water spread over 40 days, which represent years with heavy, moderate and scarce rainfall, respectively. Analyses were performed at 20 and 40 days after the initiation of treatments. When compared to the control group, treatments with water restriction reduced the growth of shoots and roots, the number of leaves and leaflets, the total biomass and the leaf area more in E. velutina than in E. contortisiliquum. Taking into account the adaptation of both species in Caatinga, we present evidence of different drought tolerance strategies. The ecological importance of early changes in the growth of species is discussed in the paper. [ABSTRACT FROM AUTHOR]

Biological nitrogen fixation (BNF) is a well-known synergistic mechanism between specific bacteria and plants that converts atmospheric nitrogen (N≡N) to plant-available forms. Biochar, a soil amendment, can significantly affect symbiotic activities and legume growth. This meta-analysis was conducted to evaluate the quantitative responses of various legume plants to biochar application under various soils, biochars, and climatic conditions. The data from 96 manuscripts were analyzed with regard to biomass, number of nodules, nodule weight, and BNF values of different legumes. We identified improvements in nodulation, BNF, and biomass production in response to biochar application in cool-season and forage legumes, compared to grain and warm-season legumes. Biochar enhancement of BNF and plant biomass was much higher in sandy and loamy soils in comparison to clay soils. The addition of biochar to soil with low N content, carbon (C), and cation exchange capacity (CEC) increased nodule formation, BNF, and plant biomass, compared to more fertile soils. Biochar produced under low pyrolytic temperatures (≤ 550 °C) from plant residues with high C content (> 50%), pH < 8, and CEC > 20 cmol kg−1 had greater improvement in BNF and plant biomass in comparison with other types of biochar. The optimum biochar rate to increase BNF and plant biomass was about 10 − 30 tons ha−1. Overall, the biochar increased the number of nodules, nodule weights, BNF, and biomass production of leguminous plants by about 13%, 12%, 28%, and 22%, respectively. [ABSTRACT FROM AUTHOR]

This paper analyzed the physico-chemical characteristics of natural waters in a drainage system of the Jungar Basin, northwestern China to identify chemical evolution and recharge mechanisms of natural waters in an arid environment. The waters studied are different in mineralization, but are typically carbonate rivers and alkaline in nature. No Cl-dominated water type occurs, indicating an early stage of water evolution. Regolith and geomorphological parameters controlling ground-surface temperature may play a large role in the geological evolution of the water. Three main morphological and hydrological units are reflected in water physico-chemistry. Climate influences the salinization of natural waters substantially. Direct recharge from seasonal snow and ice-melt water and infiltration of rain to the ground are significant recharge processes for natural waters, but recharge from potential deep groundwater may be less important. The enrichment of ions in lakes has been mainly caused by evaporation rather than through the quality change of the recharged water. [ABSTRACT FROM AUTHOR]

Land use and ecosystem services need to be assessed simultaneously to better understand the relevant factors in sustainable land management. This paper analyzed land use changes in the middle reach of the arid Heihe River Basin in northwest China over the last two decades and their impacts on water resources and soil organic carbon (SOC) storage. The results indicated that from 1986 to 2007: (1) cropland and human settlements expanded by 45.0 and 17.6 %, respectively, at the expense of 70.1, 35.7, and 4.1 % shrinkage on woodland, grassland, and semi-shrubby desert; (2) irrigation water use was dominant and increased (with fluctuations) at an average rate of 8.2 %, while basic human water consumption increased monotonically over a longer period from 1981 to 2011 at a rate of 58 %; and (3) cropland expansion or continuous cultivation led to a significant reduction of SOC, while the land use transition from grassland to semi-shrubby desert and the progressive succession of natural ecosystems such as semi-shrubby desert and grassland, in contrast, can bring about significant carbon sequestration benefits. The increased water consumption and decreased SOC pool associated with some observed land use changes may induce and aggravate potential ecological risks for both local and downstream ecosystems, including water resource shortages, soil quality declines, and degeneration of natural vegetation. Therefore, it is necessary to balance socioeconomic wellbeing and ecosystem services in land use planning and management for the sustainability of socio-ecological systems across spatiotemporal scales, especially in resource-poor arid environments. [ABSTRACT FROM AUTHOR]

This paper describes a detailed evaluation of the performance and characteristic behaviour of feed-forward artificial neural network (ANN) and M5 model tree for estimating reference evapotranspiration (ET) at four meteorological sites in an arid climate. The input variables for these models were the maximum and minimum air temperature, air humidity and extraterrestrial radiation. The FAO-56 Penman-Monteith model was used as a reference model for assessing the performance of the two approaches. The results of this study showed that the ANN estimated ET better than the M5 model tree but both models performed well for the study area and yielded results close to the FAO56-PM method. Root mean square error and R for the comparison between reference and estimated ET for the tested data using the proposed ANN model are 5.6 % and 0.98, respectively. For the M5 model tree method these values are 8.9 % and 0.98, respectively. The overall results are of significant practical use because the temperature and Humidity-based model can be used when radiation and wind speed data are not available. [ABSTRACT FROM AUTHOR]

Abstract: Recent research shows the benefits derived from applying compost and sludge to road embankments to enhance the cover crop and reduce soil loss due to erosion, particularly in arid environments. Following this line of research, the study described in this paper analyzes and compares the use of sludge and compost for the purposes mentioned. In the first phase of this study, compost or sludge was applied separately to road embankments, and in the second phase both were applied simultaneously. This paper discusses the results obtained in each case. Our study was conducted on a total of 32 plots, located along a road embankment. The 32 plots, each with an area of 20m2, were divided into two groups of 16. One group was placed on a 2:1 side slope, and the other was on a 3:2 side slope. Each group received four different compost dosages (0, 40, 60 and 80t/ha) and four sludge dosages (0, 60, 80 and 100t/ha). Four plant species were selected to be planted in each plot. Our study analyzes the survival rate of the plants, their growth rate and germination, colonization of the plots by other species, cover crop per plot, and soil loss, all in relation to the compost and sludge dosage as well as the side slope type. The results obtained show that when only sludge or compost was applied to the plot, soil loss was reduced by an average of 35%, whereas when a mixture of sludge and compost was applied, soil erosion was reduced by 63% to as much as 90%. [Copyright &y& Elsevier]

The Tuoshigan-Kumalake River alluvial plain is an oasis located in the Tarim River Basin of Xinjiang, China. Large water consumption reduces the discharge and jeopardizes the ecosystem of the lower reaches of the Tarim River. Therefore a recent regulation is enacted to limit water use in the plain. The objective of this paper is to investigate the hydrological cycle inside an intensively cultivated plain at upstream Tarim River. A conceptual water balance methodology was used for evaluating groundwater movement among riverway, irrigation ditches, irrigation area and non-irrigation area, based on the recorded water diversion. Results show that both irrigation area and non-irrigation area are supported by the water from river way in hyper-arid environment. Irrigation area is supported by surface water through canal system and non-irrigation area is supported by groundwater from canal loss and irrigation area. Nearly half of the water in the non-irrigation area comes from the irrigation area in the form of groundwater. This indicates that water supply of natural plants relies on the water from agricultural ecosystem. Tight water connection between irrigation area and non-irrigation area suggests that natural ecosystem needs to be considered in agricultural management in arid environment. [ABSTRACT FROM AUTHOR]

In an arid environment, especially in sandy areas where surface runoff is of no practical importance in the hydrological budget, it is rainfall, dewfall and evapotranspiration that become the most important variables. To assess actual evapotranspiration, several methods (flux-gradient, BREB, eddy correlation) were applied to data from the Nizzana experimental site in the northwestern Negev Desert. Additionally, a model specifically designed for arid environments is introduced in this paper. This zero plane model shows the most reasonable results compared with the other methods, which overestimate evapotranspiration to a large degree. It is shown that plant transpiration is the dominant process in total evapotranspiration while advective processes do not play a major role in the near-ground boundary layer, although the study area is influenced by a sea breeze. Actual transpiration of Artemisia monosperma was measured in a field experiment to validate the calculated evapotranspiration. The vegetation contributed 41% of the calculated total evapotranspiration in a single month. [ABSTRACT FROM AUTHOR]

This paper reviews recently published literature, most of which was published in Chinese, and searches for regional patterns of Holocene changes useful in depicting global patterns. The Holocene in the Xinjiang region can be divided into three stages: a warming and dry early stage (from 11 ∼ 10 to 8 ∼ 7 ka BP), a warm and wet middle stage (from 8 ∼ 7 to 4.5 ∼ 3 ka BP) and a fluctuating cool and dry late stage (since 4.5 ∼ 3 ka BP). The Holocene in the northern Tibetan Plateau can also be divided into three stages: a warming and wet stage (from 10.5 ∼ 10 to 5 ∼ 4 ka BP), followed by a variable drying and probably warm stage (5 ∼ 4 to 3 ka BP) and ending with a cool and dry stage (since 3 ka BP). In the Inner Mongolian Plateau, the early Holocene (from 10.5 ∼ 9.5 to 8 ∼ 7.5 ka BP) was warming and dry, and a warm and wet climate occurred from 7.5 to 3.5, during which the best time was 6.3–3.8 ka BP; the climate has been variably drying and probably cooling since 3.5 ka BP. In the northwestern part of the Loess Plateau, several Holocene palaeosols have been identified (10–9, 7.5–5, 4–3 and 2.7–2 ka BP) with the 7.5–5 ka BP palaeosol being most strongly expressed. The best-developed palaeosol-equivalent in major valleys is a swamp-wetland facies deposited between 8885 and 3805 14C yr BP under an extremely wet regime. The climate has fluctuated significantly at least three times around a dry and probably cool regime after the swamp-wetland facies-depositional period. Our summary shows that the Holocene Climatic Optimum occurred nearly contemporaneously (8–5 ka BP) at all sites in the Xinjiang region, in the Inner Mongolian Plateau and in the northwestern part of the Loess Plateau. A warming and wet early Holocene (10–8 ka BP) in the northern Tibetan Plateau is most likely related to high effective soil moisture resulting from snow and ice melting. We propose here that the middle Holocene Climatic Optimum (8–5 ka BP) in arid to semi-arid China was primarily a delayed response of the low latitude oceans to high latitude peak insolation (9–8 ka BP). [ABSTRACT FROM AUTHOR]

This study aimed to provide a systematic overview of the progress made in utilizing remote sensing for assessing the impacts of land use and land cover (LULC) changes on water resources (quality and quantity). This review also addresses research gaps, challenges, and opportunities associated with the use of remotely sensed data in assessment and monitoring. The progress of remote sensing applications in the assessment and monitoring of LULC, along with their impacts on water quality and quantity, has advanced significantly. The availability of high-resolution satellite imagery, the integration of multiple sensors, and advanced classification techniques have improved the accuracy of land cover mapping and change detection. Furthermore, the study highlights the vast potential for providing detailed information on the monitoring and assessment of the relationship between LULC and water resources through advancements in data science analytics, drones, web-based platforms, and balloons. It emphasizes the importance of promoting research efforts, and the integration of remote sensing data with spatial patterns, ecosystem services, and hydrological models enables a more comprehensive evaluation of water quantity and quality changes. Continued advancements in remote sensing technology and methodologies will further improve our ability to assess and monitor the impacts of LULC changes on water quality and quantity, ultimately leading to more informed decision making and effective water resource management. Such research endeavors are crucial for achieving the effective and sustainable management of water quality and quantity. [ABSTRACT FROM AUTHOR]

The impacts of regulated deficit irrigation (RDI) and partial root zone drying irrigation (PRD) on water productivity (WP), crop water response factor (Ky), and yield of tomato crop (Solanum lycopersicum) were explored in this study using fresh (0.9 dS m−1) and saline (3.6 dS m−1) water under greenhouse conditions. RDI had four ETc (crop evapotranspiration) levels, i.e., 40, 60, 80, and 100%. PRD adopted 100% ETc for all treatments with changes in its application time (first, second, third, and fourth growth stages). Biochar pyrolyzed at 450–500 °C and added at rate of 4%. The results revealed that the Ky ranged between 0.21 and 0.37, indicating that tomato can tolerate a shortage of irrigation water. The highest value of WP (191 kg m−3) was found in 40% ETc using fresh water with biochar. The highest yield (20.0 kg m−2) was obtained with the application of 100% ETc with fresh water and biochar. Biochar application did not result in favorable yields with saline water due to its high salinity (7.8 dS m−1). The use of PRD in the fourth stage with biochar and fresh water led to the highest yield (20.6 kg m−2). Finally, this study recommends the application of biochar only when fresh irrigation water is available in adequate amounts. [ABSTRACT FROM AUTHOR]

We study in this paper land degradation processes in arid environments that are leading to a major environmental change. These processes, which are mostly the outcome of gully development, have direct impact on agriculture potential, biomass degradation, and escalating desertification. Three representative sites within the Negev Highland, Israel, are studied by utilizing terrestrial laser scans to gain detailed spatial information, accurate estimations, and concisely document overarching trends. The resulting information allows us to thoroughly characterize and quantify the geomorphic and vegetative changes and to calibrate rates and trends that have only been roughly estimated thus far. The scans, which were taken over a four-year span (2009–2013), cover three different types of hydrological seasons and provide unique insights on development rates and subsequent ramifications. The characteristic progression of natural land degradation in the Negev Highlands and the techniques used to document and analyze it can be extended globally to regions undergoing similar transitions. [ABSTRACT FROM AUTHOR]

This article is a collation and synthesis of the literature review with the focus on the vulnerability of rural women in developing countries to climate change on the one hand and being pro-active in adapting to climate change on the other. The geographic coverage of the literature is global but with specific examples from India. The information presented in this paper is derived from diverse sources including journal articles and thematic books, and indicates severe adverse impacts not only on women's livelihood opportunities but also on exacerbating the workload and fatigue while decreasing their self esteem and forcing them to undertake some high risks and hazardous activities. The literature indicates that poverty, gender inequality, insecure land rights, heavy reliance on agriculture, less access to education and information are among the principal reasons for their vulnerability to climate change. The vulnerability is also confounded by the meager asset base, social marginalization, lack of mobility and exclusion from the decision-making processes in response to a disaster. However, the literature also shows that women are not only the passive victims of climate change but are also pro-active and agents of hope for adaptation to and mitigation of abrupt climate change. They utilize their experience and expertise to reduce the adverse impacts by adopting prudent strategies. They are also concerned about environmental issues, and are highly supportive of policies regarding environmental restoration. Large knowledge gaps exist regarding the vulnerability of women to changing and uncertain climate especially in arid regions. Authors of this article suggest some action plans and strategies to minimize vulnerability to climate change such as empowering women economically and educationally, organizing training and outreach programmes, and involving them in formal climate change mitigation and adaptation policies and programmes. Authors also outline research needed in order to identify and implement strategies regarding climate change. Collective and continuous efforts are critical to finding the sustainable solutions for this global phenomenon which is adversely impacting the most vulnerable but critically important members of the society. [ABSTRACT FROM AUTHOR]

Drought is a major abiotic stress that greatly affects canola growth, production, and quality. Moreover, water scarcity is projected to be more severe and frequent as a result of climate change, in particular in arid environments. Thereupon, developing drought-tolerant and high-yielding canola genotypes has become more critical to sustaining its production and ensuring global food security with the continuing population growth. In the present study, ten canola genotypes comprising six developed tissue-cultured canola genotypes, two exotic genotypes, and two commercial cultivars were evaluated under four irrigation regimes. The applied irrigation regimes were well-watered (100% crop evapotranspiration, ETc), mild drought (80% ETc), moderate drought (60% ETc), and severe drought (40% ETc) conditions. Drought-stress treatments (80, 60, and 40% ETc) gradually reduced the chlorophyll content, relative water content, flowering time, days to maturity, plant height, number of pods, number of branches, seed yield, and oil percentage, and increased proline, phenolic, anthocyanin, and glycine betaine contents. The evaluated genotypes exhibited varied responses to drought-stress conditions. The developed tissue-cultured genotypes T2, T3, and T1, as well as exotic genotype Torpe, possessed the highest performance in all evaluated parameters and surpassed the other tested genotypes under water-deficit conditions. Overall, our findings elicited the superiority of certain newly developed tissue-cultured genotypes and exotic ones compared with commercial cultivars, which could be exploited in canola breeding under water-deficit conditions. [ABSTRACT FROM AUTHOR]

Watershed planning is often based on the analysis of morphometric parameters, especially in poorly gauged or ungauged basins. These physiographic parameters have, in fact, a main role in water runoff. In many arid countries such as Morocco, there is a significant need for morphometric studies of watersheds to initiate integrated water resources management. For this purpose, we have carried out the watersheds delineation and morphometric analyses, using the Digital Terrain Model (DTM) and the Geographic Information System (GIS). We have applied this approach based on remote sensing and GIS in four sub-basins of the right bank of the Tensift watershed (Bourrous, Al Wiza, El Hallouf and Jamala). The shape indexes of Gravelius and Horton reveal elongated shapes of the four watersheds. In addition, the maximum slope and the drainage density do not exceed 27.15° and 1 Km/Km2 respectively. The sub-basins do not have a very dense hydrographic network and the Strahler's drainage order is not very high (up to 5). The relief is not very high and do not reach 1000 m. These physiographic conditions do not allow a rapid runoff. The concentration times are precisely quite high (7 to 12 hours for watersheds of 161 to 401 km²). The use of a sufficiently fine DTM resolution and an appropriate GIS software would allow this kind of study to be very useful for effective watershed management. [ABSTRACT FROM AUTHOR]

Groundwater depletion coupled with climate change, increasing temperature, and decreasing precipitation, has led to groundwater quality deterioration and diminishing groundwater quantity, subsequently affecting agricultural productivity in arid environments. The groundwater of the Al-Baha region, Saudi Arabia is located in unconfined shallow aquifers and responds quickly to climate change. The Al-Baha region is facing an increase in temperature and a substantial decrease in precipitation. Over the 24-year period from 1995 to 2019, average temperatures increased by 1.1 °C–1.6 °C, while rainfall decreased by 24–41%. Consequently, this study aimed at investigating the influence of climate change on soil salinity and pomegranate productivity. To achieve this goal, a hundred and fifteen samples of soil and groundwater were collected from different locations in the Al-Baha region. Furthermore, the SALTMED model was calibrated using the salinities of 50 groundwater samples, which are used as irrigation water, and climatic data from the year 2020. The model was then validated using 65 irrigation water salinities and climatic data from the year 2020. Pomegranate fruit yield was used as the main variable for calibration and validation. After successful calibration and validation, the SALTMED model was run using 'what if' scenarios for the years 2044, 2068, and 2092. It is assumed that the temperature will increase, while the annual rainfall will decrease in upcoming decades. Consequently, the groundwater salinities will reach 1.44, 2.59, and 4.67 dS m−1 for the years 2044, 2068, and 2092, respectively. The results revealed that the soil salinities will increase by 113%, 300%, and 675%, respectively, compared with the average soil salinity of the year 2020 (2.22 dS m−1). Furthermore, the pomegranate tree productivity in the Al-Baha region will decrease significantly (24.0%, 36.6%, and 41.6%) in the predicted three years due to deterioration of groundwater quality and increasing temperatures. Interventions by the regional authorities to minimize the impact of climate change on crop and fruit productivity and groundwater deterioration in the Al-Baha region should be planned and carried out as soon as possible. The method used in this investigation can be utilized in similar ecosystems worldwide. [ABSTRACT FROM AUTHOR]

This paper presents the characteristics of the fractionation of water isotopes which occurs during evaporation and freezing of water. It shows how these characteristics can be used for studying some aspects of the physical environment, namely hydrological and glaciological issues. On the one hand, case studies regarding the hydrological cycle are considered. They deal with the relative contributions of runoff and groundwater to the discharge of rivers, of plant transpiration and direct evaporation in the arid regions atmosphere and of different water sources in aquifer recharge. On the other hand, the paper explains how the water isotopes are used in the study of the Antarctic Ice Sheet as climatic archives as well as how they allow to understand the formation of more than 200 m of lake ice present above the liquid water of subglacial Lake Vostok in East Antarctica. This case study approach demonstrates that stable water isotopes can be an ideal tool to account for many processes active in the physical environment.

FAO's Aquacrop is one of the most suited models to water limited and saline conditions. It can help to assess management practices and allows developing better informed decisions concerning management and environmental factors that affect crop production. In this study, Aquacrop was used to determine the acceptable threshold of initial soil salinity and the suited period for sowing barley. Three initial soil salinity levels (3, 6 and 8 dS m-1) were evaluated under different initial soil water content for full (FI) and deficit irrigated barley and two contrasting seasons. Barley yield was predicted also for 8 consecutive sowing dates including the sowing dates used by famers. The model simulations were evaluated using statistical indicators (Root Mean Square Error (RMSE), Mean Bias Error (MBE), Mean Absolute Error (MAE) and the coefficient of determination (r2) and the three season's experimental data. Results show that grain yield and final biomass decrease with delay of sowing date and these reductions were accentuated with high initial soil salinity and the variability of rainfall events. The most suitable period for sowing barley ranging between end of November and the beginning of December. Initial conditions affect yield while the yield reduction started to be considerable (30%) only with the relatively higher level of soil salinity (8 dS m-1) and for dry season and deficit treatment. The comparison between measured and simulated yield and biomass under varied sowing dates and initial soil salinity shows good agreement with RMSE ranging between 0.36 and 1.6 t ha-1, MAE ranging between 0.29 and 1.48 t ha-1, r² about 0.77 and 0.81 for yield and final biomass, respectively. Aquacrop could be a useful tool to determine the optimum barley yield for different restricted factors. [ABSTRACT FROM AUTHOR]

Biskra region currently shows signs of stress and a high risk of groundwater contamination by various chemicals and pesticides. For this purpose, a modified integrated susceptibility index (SI) is coupled with remote sensing (RS) and WetSpass model to assess the sensitivity of the groundwater and the risk of pollution in the most exploited aquifer (Quaternary aquifer) in the study area. The results of the modified SI model show that a major part of the aquifer is at risk of contamination if the farmers do not implement good agricultural practices. Four sensitivity levels are considered, reflecting a vulnerability rating that ranges from low to very high. The very high category is observed in the agricultural areas with an estimated pollution index ranging from 84 to 90.57, while a large part of the aquifer shows a high vulnerability to contamination (64 < SI ≤ 84). This category is found in areas characterized by the dominance of bare soil. In urban areas, the vulnerability level decreases to low category (37 < SI ≤ 45). However, the area of forests is classified as moderate to vulnerability (45 < SI ≤ 64). The different statistical and GIS methods confirm the reliability of the obtained SI map. The combination of the SI method with WetSpass model and RS can give a reliable map to help and assist the authorities and decision-makers in groundwater resources planning and the implementation of monitoring programs and networks to control the quality of groundwater in arid environments. [ABSTRACT FROM AUTHOR]

The rammed earth walls were greatly affected by the change of temperature fields in arid environments, particularly the swell-shrink stress caused by gradient variations of the temperature fields was one of the main factors leading to surface weathering of rammed earth sites. While heat conduction, convection, and radiation were the main factors resulting in temperature variations of rammed earth walls. In this study, the thermocouple sensors were embedded in a rammed-earth test wall, to continuously monitor the temperature gradient field of the rammed earth wall from the near-surface area to the interior. The results revealed that the wall was greatly influenced by seasonal temperature fields together with significant changes in daily temperature differences. The top and the surface of the wall were affected by thermal radiation and convection, while the interior and the foundation were affected by heat conduction. The annual temperature difference reached 62.99 °C, and the maximum daily temperature difference on the surface of the wall was 24.3 °C, which mainly appeared during the spring and autumn seasons. The near-surface thickness of the temperature-sensitive area of the wall was less than 32 cm, within which the temperature varied dramatically at depths of 0–18 cm. The temperature variations at depths of 18–32 cm were somewhat significant with no obvious changes at depths exceeding 32 cm. These trends indicate that the rammed earth wall has an outstanding function of thermal preservation and insulation. This study is expected to be of guidance and reference for multi-field coupling environmental condition setting for surface weathering of rammed earth site bodies, stress and strain caused by temperature field, surface weathering mechanism and strengthening technology as well as the related researches of modern rammed earth building designs. [ABSTRACT FROM AUTHOR]

Seed dispersal by animals such as bears is important in the restoration of ecosystems. From this perspective, we studied dispersal of seed of date palm Phoenix dactylifera by the critically endangered Asiatic black bear Ursus thibetanus gedrosianus in Marz Protected Area, Kerman Province, Iran. We documented feeding signs (n = 6) and scats (n = 55) of the black bear during this study conducted in March-September 2018. Analysis of the scats for the presence of seeds of plant species revealed up to 40 or even more germinated seeds of P. dactylifera in a black bear scat. Seeds of other plants recovered from the scats included Nannorrhops ritchiana, Ziziphus sp. and Moringa peregrina. We concluded that the black bear, which is currently under threat because of poaching, live trapping of cubs and feral donkeys, can play a vital role in the dispersal of seeds of wild and threatened plant species in the mountain areas of Marz Protected Area. [ABSTRACT FROM AUTHOR]

Renewable energy means a source of energy which is renewable and without or with less energy consumption as possible. In the case of the earth to air heat exchanger EAHE, we can find EAHE without fan or blower and systems with it according to prevailing winds. In the present paper, an experimental investigation of the possibilities and influences of using EAHE without a fan and directly after using a fan as a mechanism of air inducing and its impact inside a hot arid region full-scale test room. Temperature and relative humidity inside a test room made of poly-wood are measured. Results show that temperature inside the test room connected to EAHE without and with external fan reduced by 10 and 14 °C, respectively. For relative humidity, it doesn’t exceed 20 to 30 % for both systems, respectively. Obtained results confirmed that fan use allowed EAHE to better thermal performance, but hygrometry must be controlled. The use of EAHE with an external fan could improve thermal comfort inside hot arid region buildings and dwellings.

Abstract: China''s Lop Nur is one of the world''s largest playas, and is located in the driest part of Central Asia. Scientific explorations by Chinese and foreign researchers have been continuously conducted there since the mid- to late 1800s, and much progress has been made, but many issues remain hotly debated. Particularly intense debate focuses on the formation, environmental evolution, drying date of the Lop Nur lake, and cause of the helical salt crusts recently revealed by remote-sensing images. In this paper, we review the status of this research to provide insights that can inform studies in other arid zones that resemble the Lop Nur. The Lop Nur depression is a secondary unit of the Tarim Block, controlled by faults and fractures formed by the Himalayan orogeny, but various competing explanations have been proposed for how these geological structures gave rise to the depression. The depression''s formation date also remains unclear. Several boreholes have been created to reconstruct the environmental evolution at different time scales since the Quaternary, and deposition rates of lake sediments, especially since the Late Pleistocene, have averaged less than 1mm annually. The drying date of the Lop Nur lake is also debated. The helical salt crust structures appear to have formed as the lake shrank, but how and when they formed is unclear. Huge potash reserves have been found, and large-scale potash fertilizer production has begun, but the origin of these deposits is debated. Understanding the factors causing environmental evolution in this region is a central issue that will help us to clarify these and other debated issues. [Copyright &y& Elsevier]

Abstract: In managing river channels, awareness is increasing to acknowledge spatial patterns of channel adjustments, to adopt a holistic catchment perspective, to progress from hard to softer engineering methods, and to utilize a geomorphological approach. However, specific methods for analyzing urban channels have not been related to a management framework. Using Fountain Hills, AZ, as an example of an urbanizing area, this paper develops a dynamic approach for urban river channels that analyzes variations in channel adjustments in a spatial context. The approach requires methods for delineating the drainage network, for dividing the network into channel segments in the area investigated according to road crossings, and for categorizing and characterizing channel segments. Using stream channel hazards as a basis for characterizing channel segments, together with consideration of community views, this approach provides a potential framework for management as illustrated provisionally by indicating the most significant hazards that require management and then suggesting possible management options. [Copyright &y& Elsevier]

The Negev Highlands (Israel) are characterized by a rich settlement history over the last millennia. To sustain life in this arid environment, measures to collect and store water were introduced. Two types of installations to collect and store runoff water were built in the region: open reservoirs, and more elaborate subterranean rock-cut cisterns. This article focuses on the latter. Based on a few inscriptions found in rock-cut cisterns, it is assumed that the majority were constructed in the Hellenistic (Nabatean) to Byzantine period. To evaluate this age assessment, this study was carried out at the Borot Hazaz cisterns system, using optically stimulated luminescence (OSL) dating together with micromorphological analyses. Both were applied to sediments that were relocated during the cistern’s construction and usage and after the maintenance activities ended. Despite unfavourable conditions for resetting the OSL signal, including fluvial transport over short distances and sediment deposition by humans in large quantities, it was possible to reconstruct the life cycle of the cistern system. The present study places the construction of the system during the late Roman to Byzantine period, with utilization and long-term maintenance during the following centuries. Maintenance ceased at the Borot Hazaz cistern system gradually over the course of the last 500 years. [ABSTRACT FROM AUTHOR]

The formation and temporal evolution of perched water bodies in arid environments is the theme of this article. Geological structure and effective recharge or net infiltration volume, which escapes the evapotranspiration capture zone, are the dominant factors controlling the phenomenon of perched water formation. An approach to use a combination of hydrological and geochemical data for present-day known occurrences of perched water bodies, cast in the form of hydrological and geochemical constraints, is proposed. These constraints are: present-day volume of perched water and attainment of steady-state behavior within a time period of less than 20,000 years (last pluvial), and present-day 14 C measurements. [ABSTRACT FROM AUTHOR]