World's Arid Regions Research Articles

Millets: The Sustainable Super-Food with Anti-aging Properties

Millets, a type of cereal from the Poaceae family, are among the earliest crops still produced today. They are a customary staple meal in the world's arid regions. It is a drought-resistant crop that needs minimal upkeep. This paper examines the possible anti-aging benefits of many millet species, including finger millet, foxtail millet, and pearl millet, as well as their diverse nutritional profiles. Rich in vital minerals like vitamin E, selenium, and amino acids, as well as antioxidants like polyphenols and flavonoids, millets assist tissue repair, improve collagen synthesis, and lessen oxidative stress on the skin. Their low glycemic index also helps to stabilize blood sugar levels, which lowers the risk of age-related illnesses including diabetes and heart disease. Additionally, millets support intestinal health, which is essential for absorbing nutrients and maintaining general vitality. Millets are an environmentally friendly crop that promotes agricultural sustainability because they demand little in the way of resources to grow. By integrating millets into the diet, individuals can benefit from a natural approach to longevity, promoting both personal health and environmental well-being.

The most relevant drought-tolerant indices for selecting barley drought-tolerant genotypes

During its development cycle, lack of water is one of the factors reducing plant growth and yields, in the world's arid regions. The identification of indices that characterize the most tolerant genotypes to drought is very useful since it allows us to evaluate the tolerance of large varieties collections within a short and early stage. This study aimed to identify the most efficient drought tolerance indicators and evaluate, from the early stage of plant development, the germination parameters that would be correlated with drought tolerance in the field. If such correlations were identified, it would be possible to screen dozens of genotypes in the laboratory and identify the most tolerant ones before moving into the field. To attain this objective, two tests were carried out: The first one was realized in the laboratory to assess some germination parameters (germination rate, root length, root number, etc.) of sixteen North African barley genotypes (Algerians, Tunisians, and Egyptians) at the germination stage, under polyethylene glycol (PEG-6000) induced stress. The second test was carried out in the field to measure the grain yield of the same genotypes, under favorable and limited water conditions. The laboratory test revealed significant differences between root lengths (RL) of different genotypes within each water regime and between different treatments (control and PEG-6000 solution). The obtained result showed the superiority of most Egyptian genotypes, especially under stress conditions induced by PEG-6000. The field trial also showed significant differences in grain yields under both water regimes (stressful and non-stressful regimes) and pointed to the high performance of the majority of Egyptian genotypes. The calculated indices [(STI), (SSI), (YSI), and (TOL)] showed variable correlations depending on the index used and concluded that STI and YSI are the best indicators of drought tolerance compared to the others. Among the germination parameters, only the root length (RL) under PEG stress is positively correlated with grain yield, obtained under drought conditions in the field. Therefore, it would be possible to use this parameter to select, at an early stage, the most drought-tolerant genotypes.

Mapping center pivot irrigation systems in global arid regions using instance segmentation and analyzing their spatial relationship with freshwater resources

Ensuring freshwater availability and supply sufficient for socio-economic development is important for human health and productivity. Globally, increasing industrial agriculture is driving crop productivity, with increasing surface water and groundwater being withdrawn for irrigation. This study mapped center pivot irrigation systems (CPIS), which are indicators of intensified industrial agriculture and large-scale investment in agriculture, with satellite data using a convolutional neural network in global arid areas. A cascade instance segmentation network was adopted, and both the convolutional block attention module technique and PointRend technique were used to increase the performance of off-the-shelf algorithms. Geospatial analysis methods were used to derive the relationships between CPIS and freshwater resources. Overall there were about 10.26 million hectares (Mha) of irrigated areas equipped with CPIS in global arid areas in 2021, and there were 4.41 Mha of CPIS-equipped irrigated fields added in the past twenty years at a relative increase of 75% compared with those at the beginning of this century. Although the largest extent of increased CPIS-equipped irrigated fields was in North America, the other five continents had higher relative increases, with Africa having the highest relative growth of 253%. The analysis of spatial relationships between CPIS and freshwater resources indicates that the stress on freshwater resources from industrial agriculture is intensifying in arid areas globally. Overall, the world's arid regions with the highest water stress from CPIS are mostly located in western North America, northern Africa, and the Arabian Peninsula. The results facilitate a better understanding of the current status of freshwater stress and ecosystem sustainability in relation to the development of agricultural intensification in global arid areas. The outcomes support governments to judge better the environmental consequences of agricultural modernization and further help them make balanced agriculture and water management policies.

Alleviating water scarcity and poverty through water rights trading pilot policy: A quasi-natural experiment based approach

Water poverty is among the most significant global challenges and severely restricts the sustainable development of societies and economies, especially in the world's arid regions. Many countries have attempted to address this challenge. Market-based trading mechanisms represent an essential method of resolving the problem of water shortages and alleviating water poverty. Based on a quasi-natural experiment of water rights trading pilots in China, this study uses panel data from 31 provinces (municipalities) from 2009 to 2019 to explore the impact of water rights trading pilot policy on water poverty through a difference-in-differences (DID) model. The research results show that such policies can effectively alleviate water poverty by improving water-saving irrigation technology, promoting industrial and agricultural water trading, and optimizing the industrial structure. Additionally, dynamic effect and spatial heterogeneity analyses show that the water rights trading pilot policy have long-term effects and have a stronger mitigation effect on the western region of China compared with the central and eastern regions. Therefore, the Chinese government should not only further expand the implementation scope of these policies but also adjust measures according to local conditions to accurately and effectively implement such policies in different regions. Our study provides insights into water policies in China that can better manage natural resources and reduce water poverty in the arid areas around the world.

Variations in local heavy metal concentrations over the last 16,000 years in the central Atacama Desert (22°S) measured in rodent middens

Mining is a major industry in the Atacama Desert, one of the world's leading regions for copper and other minerals. Intense industrialization of copper mining in the mid-twentieth century has likely led to significant environmental pollution through the deposition of heavy metals in the hyperarid Atacama, but how heavy metal pollution has changed over time in arid regions have rarely been assessed. Here, we analyzed both modern and ancient fecal pellets from paleomiddens collected in the central Atacama for heavy metals and by comparing current heavy metal concentrations with pre-industrial ones, we establish ecological baselines for such pollution. Sixteen paleomiddens spanning the last 1000 years from multiple localities in the eastern Calama Basin (22°S) show elevated concentrations of Cu and As in modern compared to older middens, and that heavy metal, alkali metals and alkaline earth metals show positive correlations with each other. Heavy metals also tend to be higher in paleomiddens collected along perennial rivers in comparison to those collected from surrounding ranges, irrespective of sample age. Twenty paleomiddens spanning the last c. 16,000 years from a single locality (El Hotel) between the Calama and San Pedro de Atacama basins were used to establish long term variations in plant communities and associated heavy metals since the last glacial termination. Results show that heavy metal concentrations including Cr, Mo and B vary over time and tend to be higher in paleomiddens for which Cactaceae are more abundant whereas those dominated by annuals show less of an effect from trace metals. Our results imply that climate change-driven plant community composition plays a key role in explaining how contamination varies in these desert ecosystems and show that paleomiddens are a unique and unexplored source for understanding how heavy metals vary over time. Given their ubiquity in many of the world's arid regions, they can be used to establish long-term ecological baselines to compare against human alterations.

Alleviating water scarcity and poverty in drylands through telecouplings: Vegetable trade and tourism in northwest China

Water scarcity and poverty are among the most significant global challenges, especially in the world's arid regions. Many countries have been trying to address these challenges. Facilitated by the construction of infrastructure (e.g., high-speed rails) and development of services industries (e.g., hotels and resorts), telecouplings (human-nature interactions over distances, e.g., vegetable trade and tourism industry) are expected to alleviate both water scarcity and poverty, and have been much supported by the central government of China. However, the extent to which these telecouplings can save water and reduce poverty remains unclear and requires quantification. Employing the simulated results from an integrated hydrological model, crop growth model, and multiple socioeconomic data from a large arid region of northwest China, the Heihe River Basin, we evaluated water scarcity using a composite index that considered both water resources and poverty between 2000 and 2012, and assessed the effects of the vegetable trade and tourism on water scarcity and income. Our results show that the vegetable trade contributed 30% of the total water saving and brought an extra 33% of income to rural residents. The tourism industry's contribution of saving water increased from 1% of its total water use in 2000 to 22% in 2012 through its ongoing expanding market. Our results also implicate that future water sustainability is determined by climate factors and by social factors, such as population, economy, policy, and technological developments. Our study provides insights into northwest China and can be used to develop arid regions around the world to better manage natural resources and reduce poverty.

Public acceptability of treated wastewater reuse in Saudi Arabia: Implications for water management policy

Treated wastewater reuse is increasingly important for sustainable water resource management, especially in water-stressed countries located in the world's arid regions that rely on groundwater and desalination process for meeting their water demands. This study investigates the socio-demographic variables influencing public perceptions of reusing grey and mixed wastewater for non-domestic uses: firefighting, swimming pools, and car washing. Data were collected from 624 households in the Dammam Metropolitan Area, Saudi Arabia using a structured questionnaire and analyzed using descriptive and inferential statistics. The results from logistic regression indicates that the likelihood of a household to accept reusing treated mixed wastewater is influenced by gender with odds ratio (OR) of 2.71–2.18, residential location (OR = 1.32–1.03), age (OR = 1.22–0.18) and educational level (OR = 1.33–0.98), with a tendency for more acceptance of treated grey wastewater than mixed wastewater. These findings showcase the difficulty that the country could face concerning the public acceptance of treated wastewater for non-domestic uses to augment current freshwater sources even among the educated class. This study is significant because sustainably meeting the country's rising water demands requires the stringent implementation of strategic wastewater reuse policy, including bold steps towards wastewater streams segregation, and intensive public awareness campaigns to change negative perceptions on treated sewage effluent. This study concludes that a substantial reduction in the country's reliance on costly desalinated water and fast depleting non-renewable groundwater requires complete reuse and recycling of treated wastewater for wider non-conventional purposes.

Economics of irrigation water conservation: Dynamic optimization for consumption and investment

Measures to protect irrigation water supplies for food security continue to receive international attention to address growing water scarcity when faced by increased food demands combined with reduced water supply reliability. Yet, a common problem where water is delivered with earthen canals is delivery inefficiency combined with low economic values per unit of water. In many of the world's arid regions, climate stressed water shortages have raised the importance of discovering measures to improve irrigation delivery efficiency. However, little research grade work to date has presented an integrated analysis of the economic performance of irrigation delivery improvements faced by drought and climate stressed regions. This paper's unique contribution is to investigate the economic performance of water conservation infrastructure combined with dynamically optimized use of saved water. We develop a state-of-the arts empirical dynamic optimization model to discover land and water use patterns that optimize sustained farm income. Results from the upper watershed irrigation region of the Canadian Basin in the southwestern US show that canal and delivery system lining can raise the sustained economic value of water for crop irrigation. The saved water can see immediate use in dry years. It can also be stored in wet years to mitigate the most adverse impacts of future climate water stress. This double dividend is especially important in rain-fed watersheds for which surface water supplies for irrigation are difficult to forecast accurately. Findings light a path for water managers and other stakeholders who bear responsibility of finding economically responsible measures to improve irrigation water productivity in the world's dry regions.

Rare plant species do not occupy water-remote refuges in arid environments subject to livestock grazing.

In many of the world's arid regions there has been a dramatic increase in grazing pressure with herds of livestock sustained by the provision of artificial water points. In these systems it has been suggested that grazing-sensitive plant species will have contracted to refuges distant from water points where grazing impacts are low. This association was tested using a large data set of presence/absence records for rare plant species throughout the northeastern Australian arid zone. The presence records of only one of 45 species were statistically associated with lower grazing activity, as a function of distance-to-water, than the absence records. The field observation that this species is rarely grazed suggests it is not susceptible to grazing pressure. In general, the study supports assertions that populations of short-lived plants in drylands are resilient in the face of exaggerated livestock grazing because herbivores are not in sufficient densities to have an impact during the sporadic periods of high rainfall when plants can complete their life cycles. However, long-lived palatable species may be extinction-prone in grazed landscapes over long time frames if recruitment is curtailed by grazing.

Habitat use by two extremophile, highly endemic, and critically endangered fish species (Gambusia eurystoma and Poecilia sulphuraria; Poeciliidae)

Abstract Effective conservation measures for endangered species require basic knowledge of habitat use and critical environmental variables influencing the species' occurrence. However, setting priorities may be difficult when multiple endangered species inhabit the same area and differ in habitat use. This study characterized the physical and chemical environment at 30 sites along a 2.5 km stretch of stream associated with the Baños del Azufre hydrogen sulphide spring complex, home to the only population of the widemouth gambusia (Gambusia eurystoma) in existence. Also present in the spring is Poecilia sulphuraria, a narrowly endemic and endangered species known from only a few populations. This study provides the most detailed report to date for physical and chemical drivers of species density in this small, extreme environment. Gambusia eurystoma were generally rare throughout the stream, and stream flow and substrate size were the best predictors of G. eurystoma densities. Conversely, P. sulphuraria were considerably more abundant, but no physical or chemical variables predicted their density among sites. Size distributions of adult P. sulphuraria were significantly influenced by stream flow and water chemistry, indicating a cost to living in greater proximity to toxic springs with high hydrogen sulphide concentrations. Overall, the results provide the first extensive report of environmental variation and factors associated with G. eurystoma densities, and indicate that conservation measures prioritizing environmental conditions for G. eurystoma will also benefit P. sulphuraria. Fish in sulphide springs provide prime examples of narrowly endemic species in desperate need of conservation, and their habitats face conservation challenges similar to those found in other springs with sympatric, endemic species in the world's arid regions. Copyright © 2016 John Wiley & Sons, Ltd.

Enhancement of oceanic parameters associated with dust storms using satellite data

Atmospheric aerosols play a vital role on the dynamics of climate processes through direct and indirect effects. Dust storms originating over the world's arid regions contribute a large fraction of aerosols in the atmosphere. Using remote sensing data, an anomalous enhancement in the biological productivity of sea was observed in the Gulf of Oman which was attributed only to cold sea surface temperature (SST) eddies (during November to early December months of 1996–1999), whereas recent study has shown that during dust storms (June–July–August and October–November–December months of 1997–2004), major nutrient supply is from atmospheric dust deposition. We have carried out a study of individual cases of major dust storms over the Arabian Sea during the entire year (December 2003–December 2006) to quantify role of dust storms and changes in ocean surface due to chlorophyll bloom. Using Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua, we have found that the deposition of dust along the passage of major dust storms (aerosol optical depth (AOD) ∼0.25–0.41) occuring over the Arabian Sea causes chlorophyll blooming (usually 10–22.43 mg/m3) within a period of 1–2 to up to 3–4 days. However, we have also found significant anomalous cooling of the ocean surface (SST) and relatively higher ocean wind speeds (QuikSCAT) during dust storms that may lead to favorable conditions for blooming. Exact nature and cause of chlorophyll bloom in the semienclosed northern Arabian Sea, surrounded by one of the world's major sources of dust storms (Africa, Middle East, Iran, and Afghanistan), are very important in understanding the productivity and the biogeochemical cycles of the marine ecosystem. The results have been validated using the Indian Remote Sensing Polar‐4 Ocean Color Monitor (IRS P4 OCM) data.

United Nations survey indicates use of desalination plants spreading

Large‐scale use of desalination plants to produce drinkable water in the world's arid regions has increased rapidly in recent years. However, there has been no dramatic breakthrough in costs, according to a new United Nations study.Results of a survey of desalination plants, the second undertaken by the UN, indicates that treatment of sea water and brackish water is now an established procedure in the Mediterranean region, the Caribbean, Australia, Japan, North and South America, and the Middle East, where fuel costs are low. For example, at Juddah, on the Arabian coast of the Red Sea, a single desalination plant produces 5,000,000 gallons of water per day—enough for 100,000 persons.