Deciphering the driving factors and probabilistic health risks of potentially toxic elements in arid surface water: Insights from the Tarim River Basin.

Potentially toxic elements (PTEs) in surface water in arid areas pose a serious threat to environmental safety and human health within a basin. It is important to determine the factors controlling PTEs and to assess the likelihood that they will pose a risk to human health in order to support the development of environmental protection and risk management strategies. In this study, a structural equation model and Bayesian method were combined to discuss the distribution and probabilistic health risks of PTEs in surface water in arid area, and the Tarim River Basin was taken as a case study. The results show that the average concentrations of As, Co, Cu, and Ni in the surface water in the Tarim River Basin ranged from 0.04 to 2.92 µg/L, which do not exceed the international standard values. However, the maximum value of As (19.20 µg/L) exceeded both the recommended drinking water standards and the Chinese irrigation water standards. Spatially, the high As concentrations were distributed in the upper reaches of the Kashgar River, and the high Co, Cu and Ni concentrations were distributed in reservoirs and lakes on the main stream of the Tarim River. The concentrations of the PTEs in the surface water in the basin were not only affected by random anthropogenic factors such as traffic discharge, agricultural activities and mining industry, but were also directly and indirectly influenced by climatic factors. The results of the probabilistic health risk assessment showed that the 95th percentile the total hazard index for infants exceeded the allowable value of 1, and the total carcinogenic risk of PTEs exposure in four age groups was at the notable level. In this study, we conducted a comprehensive analysis of the controlling factors and health risks associated with PTEs in surface water in the Tarim River Basin, and the findings are expected to provide a scientific basis for regional water environment management and safety control.

Cultivating sustainability: a multi-assessment of groundwater quality and irrigation suitability in the arid agricultural district of Dzira (Ksour Mountains, Algeria).

Groundwater serves a range of essential functions such as supplying drinking water, facilitating agricultural practices, and supporting industrial processes. This study examines with multiple methods the quality of groundwater in the agricultural region of Dzira, Algeria. By collecting 38 groundwater samples of different wells and boreholes, valuable awareness of the aptness of groundwater for irrigation in this arid landscape was gained. Most wells met Food and Agriculture Organization (FAO) criteria for the total dissolved solids (TDS) and the potential of hydrogen pH, but some areas had higher mineral content and electrical conductivity. Results show significant TDS variations, with 10.81% of wells exceeding limits and acceptable pH levels. Elevated EC values in 67.57% of wells show high salinity, affecting soil and plant growth. Major ions such as Mg2+ and SO4- exceeded FAO standards in 43.24% and 64.86% of wells, respectively, highlighting substantial mineral content in the groundwater. Suitability indices reveal that most wells pose low sodium hazards and are generally suitable for irrigation, though some areas face moderate to high restrictions. The irrigation water quality index (IWQI) ranged from 45.36 to 96.30, averaging 80.77, with 54.04% classified as "low restriction," suitable for sandy soils with good permeability but requiring caution on salt-sensitive soils. Hydrogeochemical analysis using principal component analysis (PCA) and hierarchical cluster analysis (HCA) identifies rapid evaporite dissolution from Triassic saline formations, with a correlation matrix showing associations between TDS and Ca2⁺, Mg2⁺, Na⁺, Cl⁻, and SO42⁻. This mineralization is likely from gypsum and halite. Zoning maps based on IWQI and other parameters depicted spatial variations in groundwater quality, guiding effective irrigation management strategies. Overall, the study underscores the importance of comprehensive water quality assessment for sustainable agriculture and emphasizes the need for targeted interventions to mitigate potential challenges associated with soil salinity and sodicity. Therefore, these findings can be useful to decision-makers and stakeholders in order to optimize water use and protect this vital resource.

Mapping of trace elements in topsoil of arid areas and assessment of ecological and human health risks in Qatar.

Soil is the incubator of human activities. Mapping of soil contaminants needs to be constantly updated. It is fragile in arid regions, especially if it accompanies dramatic and successive industrial and urban activities in addition to the climate change. Contaminants affecting soil are changing due to natural and anthropogenic influences. Sources, transport and impacts of trace elements including toxic heavy metals need continuous investigations. We sampled soil in accessible sites in the State of Qatar. An inductively coupled plasma-optical emission spectrometry (ICP-OES) and an inductively coupled plasma-mass spectrometry (ICP-MS) were used to determine the concentrations of Ag, Al, As, Ba, C, Ca, Ce, Cd, Co, Cr, Cu, Dy, Er, Eu, Fe, Gd, Ho, K, La, Lu, Mg, Mn, Mo, Na, Nd, Ni, Pb, Pr, S, Se, Sm, Sr, Tb, Tm, U, V, Yb and Zn. The study also presents new maps for the spatial distribution of these elements using the World Geodetic System 1984 (projected on UTM Zone 39N) which is based on socio-economic development and land use planning. The study assessed the ecological risks and human health risks of these elements in soil. The calculations showed no ecological risks associated with the tested elements in soil. However, the contamination factor (CF) for Sr (CF > 6) in two sampling locations calls for further investigations. More important, human health risks were not detected for population living in Qatar and the results were within the acceptable range of the international standards (hazard quotient HQ < 1 and Cancer risk between 10-5 and 10-6). Soil remains a critical component with water and food nexus. In Qatar and arid regions, fresh water is absent and soil is very poor. Our findings enhance the establishment of scientific strategies for investigating soil pollution and potential risks to achieve food security.

Transcriptomic analysis revealing the molecular response to arsenic stress in desert Eremostachys moluccelloides Bunge.

The saline, alkaline environment of arid soils is conducive to the diffusion of the metalloid arsenic (As). Desert plants in this area are of great ecological importance and practical value. However, there are few studies on the mechanism of arsenic action in desert plants. Therefore, in this study, Eremostachys moluccelloides Bunge was treated with different concentrations of As2O5 [As(V)] to analyze the physiological, biochemical, and transcriptomic changes of its roots and leaves and to explore the molecular mechanism of its response to As(Ⅴ) stress. The activities of catalase, superoxidase, peroxidase, and the contents of malondialdehyde and proline in roots and leaves first increased and then decreased under the As(Ⅴ) stress of different concentrations. The content of As was higher in roots than in leaves, and the As content was positively correlated with As(Ⅴ) stress concentration. In the differentially expressed gene analysis, the key enzymes of the oxidative stress response in roots and leaves were significantly enriched in the GO classification. In the KEGG pathway, genes related to the abscisic acid signal transduction pathway were co-enriched and up-regulated in roots and leaves. The related genes in the phenylpropanoid biosynthesis pathway were significantly enriched and down-regulated only in roots. In addition, the transcription factors NAC, HB-HD-ZIP, and NF-Y were up-regulated in roots and leaves. These results suggest that the higher the As(V) stress concentration, the more As is taken up by roots and leaves of E. molucelloides Bunge. In addition to causing greater oxidative damage, this may interfere with the production of secondary metabolites. Moreover, it may improve As(V) tolerance by regulating abscisic acid and transcription factors. The results will deepen our understanding of the molecular mechanism of As(Ⅴ) response in E. moluccelloides Bunge, lay the foundation for developing and applying desert plants, and provide new ideas for the phytoremediation of As pollution in arid areas.

The Influence of Soil Organic Carbon and Climate Variability on Crop Yields in Kongwa District, Tanzania.

This study assessed the influence of soil organic carbon (SOC) accumulation and climate variability on crop yields in Kongwa District, central Tanzania. In doing so, climate data and soil samples were collected from Mnyakongo and Ugogoni villages through soil sampling, interviews and surveys. Walkley-Black method, Mann-Kendall test, and MS Excel were used to analyze SOC, climate, crop yields respectively. The results exhibited that the accumulation of SOC was significantly greater in soils under organic fertilization (1.15 and 0.80 MgC ha-1 at soil 0-20 cm and 20-30 cm depth) than under no-fertilization (0.35 and 0.30 MgC ha-1 at 0-20 cm and 20-30 cm) and decreased with increasing soil depths. Under these two soil treatments, the average yields for maize, sorghum and millet were almost 1.8 tn ha-1 under organic fertilization and 0.6 tn ha-1 under no-fertilization. Specifically, maize yields ranged from 1.5 to 2.2 tn ha-1, while both sorghum and millet had 1.1-1.7 tn ha-1. Therefore, yields were significantly higher under organic fertilizations than under no-fertilizations. Besides, the mean annual rainfall or temperature (1980‒2020) fluctuated at a decreasing (R2 = 0.21) or an increasing trend (R2 = 0.30). Comparatively, the yields for maize, sorghum or millet fluctuated at a decreasing trend at R2 = 0.07, 0.05, or 0.85, respectively. Correspondingly, it was found that the temporal increase in rainfall and temperature had positive (R2 ~0.5) and negative (R2 ~0.3) correlations with crop yields, respectively. In contrast, the decline in rain's intensity and frequency had negative impacts on crop yields. Thus, both SOC and climate correlated with crop yields.

Predicting potential reforestation areas by Quercus ilex (L.) species using machine learning algorithms: case of upper Ziz, southeastern Morocco.

The selection of appropriate areas for reforestation remains a complex task because of influence by several factors, which requires the use of new techniques. Based on the accurate outcomes obtained through machine learning in prior investigations, the current study evaluates the capacities of six machine learning techniques (MLT) for delineating optimal areas for reforestation purposes specifically targeting Quercus ilex, an important local species to protect soil and water in upper Ziz, southeast Morocco. In the initial phase, the remaining stands of Q. ilex were identified, and at each site, measurements were taken for a set of 12 geo-environmental parameters including slope, aspect, elevation, geology, distance to stream, rainfall, slope length, plan curvature, profile curvature, erodibility, soil erosion, and land use/land cover. Subsequently, six machine learning algorithms were applied to model optimal areas for reforestation. In terms of models' performance, the results were compared, and the best were obtained by Bagging (area under the curve (AUC) = 0.98) and Naive Bayes (AUC = 0.97). Extremely favorable areas represent 8% and 17% of the study area according to Bagging and NB respectively, located to the west where geological unit of Bathonian-Bajocian with low erodibility index (K) and where rainfall varies between 250 and 300 mm/year. This work provides a roadmap for decision-makers to increase the chances of successful reforestation at lower cost and in less time.

Effect of vegetation density on survival of South African free-ranging indigenous chicken broods.

The survival of juveniles from hatching until recruitment is a critical determinant of indigenous chicken population growth under extensive free-range production systems. A longitudinal study was conducted to investigate the impact of vegetation cover on survival of indigenous chicken broods in Msinga, South Africa. Survival records of 281 chicks hatched in sparsely vegetated (SV) communal lands and 233 hatched chicks in densely vegetated (DV) resettlement areas were collected from hatch until 12 weeks of age. Data on probable cause of death of individual chicks was collected using a structured checklist. Kaplan-Meir survival distributions and log rank tests were used to estimate the survival functions of broods between vegetation cover types. Logistic regression analysis was used to determine the association between management factors and mortality risk in SV and DV. Chick survival from hatching to 12 weeks was higher in SV (55 ± 3.14%) than DV (41 ± 4.19%) (P < 0.05). Mean chick survival time did not differ between SV (56 ± 3.30 days) and DV (49 ± 3.23 days) (P > 0.05). Aerial predators were the major cause of chick mortality (over 60%) followed by terrestrial predators (30%) in both vegetation cover types. The odds of mortality were higher in DV compared to SV (P < 0.05). It was concluded that increasing vegetation cover decreases survival of scavenging chicks between hatching and end of brooding at 12 weeks of age, and therefore brood management actions should ensure adequate protection of free-ranging chicken broods in densely vegetated rearing habitats.

Influence of atmospheric states in semi-arid areas on hospital admission in cardio-surgical department.

The influence of the changes in atmospheric state, typical for areas close to big deserts, on acute myocardial infarction (AMI) was analyzed. Under test was the group of 3256 patients (77 % males, 23 % females), hospitalized in the Cardio-Surgical Department of Soroka Medical Center at Ben-Gurion University (BGU, Israel) during 2000-2008. To explore the relationship between atmospheric parameters and AMI, multivariate regression analysis has been performed. AMI was most frequent in winter to spring and least in summer. The highest number of cases was recorded in December and the lowest in September. Hospital admissions showed a higher prevalence in men than in women; the ratio is 3.3/1.0. About 60 % of males were aged between 45 and 65 years old with maximum ∼55 (21 %), whereas 60 % of women hospital admissions were aged between 65 and 80 years old with maximum ∼72 (24 %). The result suggested that the monthly mean relative humidity at daytime and its overall daily differences, wind speed, and respirable fraction of particulate concentration are associated with the admission for AMI. The results of the study confirm the importance of atmospheric state variability for cardiovascular diseases.

Spatial distribution and health risk assessment for groundwater contamination from intensive pesticide use in arid areas.

Arid and semiarid areas face major challenges in the management of scarce groundwater. This valuable resource is under pressures of population, economic expansion, contamination and over-exploitation. This research investigates groundwater vulnerability to pesticide contamination in the Al-Kharj area of Saudi Arabia. It explores the spatial distribution of pesticide concentrations in groundwater and other relevant factors. Thin permeable soils, permeable aquifers and shallow water tables, which are prevalent in the area, are especially vulnerable to pesticides. Analyses of 40 groundwater samples were performed using a gas chromatograph mass spectrometer coupled with a quadrupole mass spectrometer with a GC column. The analysis was conducted to detect 32 pesticides from different chemical families, and a total of 22 pesticides were detected. All 40 water samples were positive for at least one of the pesticides studied. In total, 21 compounds were above the quantification limit and 10 of them exceeded the legal limit. Total pesticide levels ranged from 0.18 to 2.21 µg/L, and 68 % of the analyzed samples exceeded the maximum allowable pesticide concentrations established by the European Community. Comparison of the daily intake peak (DIP) and daily intake mean (DIM) relative to the acceptable daily intake (ADI) shows that groundwater contamination with pesticides is a serious problem. Prolonged exposure to pesticides can cause adverse effects to human health and the ecosystem. Spatial distribution maps of groundwater contamination were developed using GIS. These maps will help risk managers identify vulnerable sources and provide a relative assessment of pesticide hazards to human health and the environment.

Characterization of Rhizobial Bacteria Nodulating Astragalus corrugatus and Hippocrepis areolata in Tunisian Arid Soils.

Fifty seven bacterial isolates from root nodules of two spontaneous legumes (Astragalus corrugatus and Hippocrepis areolata) growing in the arid areas of Tunisia were characterized by phenotypic features, 16S rDNA PCR-RFLP and 16S rRNA gene sequencing. Phenotypically, our results indicate that A. corrugatus and H. areolata isolates showed heterogenic responses to the different phenotypic features. All isolates were acid producers, fast growers and all of them used different compounds as sole carbon and nitrogen source. The majority of isolate grew at pHs between 6 and 9, at temperatures up to 40°C and tolerated 3% NaCl concentrations. Phylogenetically, the new isolates were affiliated to four genera Sinorhizobium, Rhizobium, Mesorhizobium and Agrobacterium. About 73% of the isolates were species within the genera Sinorhizobium and Rhizobium. The isolates which failed to nodulate their host plants of origin were associated to Agrobacterium genus (three isolates).

Effects of water restriction on the growth performance, carcass characteristics and organ weights of naked neck and ovambo chickens of southern Africa.

In semi-arid areas of Southern Africa, dehydration can compromise the performance and welfare of local chickens, particularly during the growing period when confinement is curtailed and birds are left to scavenge for feed and water. The effect of water restriction on the growth performance was compared in Naked Neck (NNK) and Ovambo (OVB) chickens that are predominant in Southern Africa. A total of 54 eight-wk-old pullets each of NNK and OVB chickens with an initial average weight of 641±10 g/bird were randomly assigned to three water intake treatments, each having six birds for 8 wk. The water restriction treatments were ad libitum, 70% of ad libitum and 40% of ad libitum intake. Nine experimental pens with a floor space of 3.3 m(2) per strain were used. The pens were housed in an open-sided house with cement floor deep littered with a 20 cm layer of untreated wood shavings. Feed was provided ad libitum. Average daily water intake (ADWI), BW at 16 weeks of age (FBW), ADG, ADFI, feed conversion ratio (FCR) and water to feed ratios (WFR) were determined. Ovambo chickens had superior (p<0.05) FBW, ADG and ADWI than NNK chickens. Body weight of birds at 16 weeks of age, ADG, ADFI, ADWI, and WFR declined progressively (p<0.05) with increasing severity of water restriction while FCR values increased (p<0.05) as the severity of water restriction increased. Naked Neck chickens had better FCR at the 40% of ad libitum water intake level than Ovambo chickens. The dressing percentage per bird was higher in water restricted birds than those on ad libitum water consumption, irrespective of strain. Heart weight was significantly lower in birds on 40% of ad libitum water intake than those on ad libitum and 70% of ad libitum water intake, respectively. In conclusion, NNK chickens performed better than OVB chickens under conditions of water restriction and would be ideal to raise for meat and egg production in locations where water shortages are a major challenge.

Influence of environmental factors on the occurrence of gastrointestinal and cardiopulmonary nematodes in the red fox in the semi-arid Mediterranean areas of the Iberian Peninsula.

Human-induced ecosystem fragmentation is one of the drivers causing wildlife migration from their natural habitats to urban areas, among other reasons. The red fox (Vulpes vulpes) is the most abundant wild canid in the semi-arid Mediterranean areas of the Iberian Peninsula. Water scarcity may result in areas shared by synanthropic fox populations and domestic animals becoming hotspots for parasite transmission. This study describes the gastrointestinal and cardiopulmonary nematode species affecting fox populations in these semi-arid areas and the influence of environmental variables on parasite abundance. A total of 167 foxes collected from 2015 to 2021 in the Region of Murcia (SE Spain) were analysed. Parasite abundance and spatial distribution were evaluated using environmental variables and host characteristics with a Generalised Linear Model and the Moran index. Eleven species (seven from the gastrointestinal tract and four from the cardiopulmonary tract) were described. The influence of biotic and abiotic variables was studied for Angiostrongylus vasorum, Crenosoma vulpis, Uncinaria stenocephala, Toxocara canis and Toxascaris leonina. Temperature, humidity and areas of forest or agricultural land influenced the abundance of these parasites, providing optimal conditions for free-living stages of the direct life cycle nematodes and intermediate hosts. Absolute abundance distribution maps showed defined locations for C. vulpis, T. canis and T. leonina. The results for U. stenocephala, T. canis and T. leonina were particularly important as their higher abundance levels were found close to anthropized areas, which need to be carefully evaluated to prevent transmission of these nematodes between domestic and wild canids and human health.

Optimization of irrigation and fertilization of apples under magnetoelectric water irrigation in extremely arid areas.

Apple (Malus pumila Mill.) is one of the important economic crops in the arid areas of Xinjiang, China. For a long time, there has been a problem of high consumption but low yield in water and fertilizer management, prevent improvements in apple quality and yield. In this study, 5-year-old 'Royal Gala' apple trees in extremely arid areas of Xinjiang were used as experimental materials to carry out field experiments. considering 5 irrigation levels (W1, 30 mm; W2, 425 mm; W3, 550 mm; W4, 675 mm; W5, 800 mm) and 5 fertilization levels (F1, 280 kg·ha-1; F2, 360 kg·ha-1; F3, 440 kg·ha-1; F4, 520 kg·ha-1; F5, 600 kg·ha-1) under magnetoelectric water irrigation conditions. The results demonstrated that magnetoelectric water combined with the application of 675 mm irrigation amount and 520 kg·ha-1 fertilization amount was the most effective combination. These results occurred by increasing net photosynthetic rate of apple leaves, improved the quality of apples, increased apple yield, and promoted the improvement of water and fertilizer use efficiency. Additionally, the quadratic regression model was used to fit the response process of yield, IWUE and PFP to irrigation amount and fertilization amount, and the accuracy was greater than 0.8, indicating good fitting effects. The synergistic effect of water and fertilizer has a positive effect on optimizing apple water and fertilizer management. Principal component analysis showed that the magnetoelectric treatment combined water and fertilizer mainly affected apple yield, water and fertilizer use efficiency and vitamin C content related to quality. This study provides valuable guidance for improving water and fertilizer productivity, crop yield and quality in extreme arid areas of Xinjiang by using Magnetoelectric water irrigation.

Salinity decreases the contribution of microbial necromass to soil organic carbon pool in arid regions.

Saline soils are widely distributed in arid areas but there is a lack of mechanistic understanding on the effect of salinity on the formation and biochemical composition of soil organic carbon (SOC). We investigated the effects of salinity on the accumulation of microbial necromass under natural vegetation and in cropland in salt-affected arid areas stretching over a 1200-km transect in northwest China. Under both natural vegetation and cropland, microbial physiological activity (indicated by microbial biomass carbon normalized enzymatic activity) decreased sharply where the electrical conductivity approached 4 ds m-1 (a threshold to distinguish between saline and non-saline soils), but microbial biomass was only slightly affected by salinity. These indicated that a larger proportion of microbes could be inactive or dormant in saline soils. The contribution of fungal necromass C to SOC decreased but the contribution of bacterial necromass C to the SOC increased with increasing soil salinity. Adding fungal and bacterial necromass C together, the contribution of microbial necromass C to SOC in saline soils was 32-39 % smaller compared with non-saline soils. Fungal necromass C took up 85-86 % of microbial necromass C in non-saline soils but this proportion dropped to 60-66 % in saline soils. We suggested that the activity, growth, and turnover rate of microbes slowed by salinity was responsible for the decreased accumulation of fungal necromass in saline compared with non-saline soils, while the increased accumulation of bacterial residue in saline soils could be induced mainly by its slower decomposition. Soil microbial biomass was a poor predictor for the accumulation of microbial necromass in saline soils. We demonstrated a reduced contribution of microbial necromass to SOC and a shift in its composition towards the increase in bacterial origin in saline relative to non-saline soils. We concluded that salinity profoundly changes the biochemistry of SOC in arid regions.

Evaluating effects of selected water conservation techniques and manure on sorghum yields and rainwater use efficiency in dry region of Zimbabwe.

Sorghum production in semi-arid areas of Zimbabwe is constrained by low and erratic rainfall, low fertility and soil moisture stress. Sorghum grain yields ranges from 0.2 to 0.4 t ha-1 in sandy-to-sandy loam soils respectively. The objective of the study was to assess cattle manure and rainwater harvesting techniques in improving sorghum grain yield in a semi-arid region of Zimbabwe. The experiment used a randomised complete block design with rainwater harvesting technique as a main treatment factor at three levels. Sub-plot factor was cattle manure at five levels (0, 2.5, 5, 10 and 15 t ha-1) and two sorghum varieties (Macia and SV1) as sub-sub plot factor. Sorghum grain yields were improved significantly (p < 0.05) for both varieties using tied contours. Increasing application rates of cattle manure, showed significant increase (p < 0.05) in sorghum grain yield over the control (0 t ha-1). Tied contour had higher grain yield (1.15 t ha-1) with the use of Macia variety. Stover yield was highly influenced by rainwater harvesting method of tied contour (p < 0.05) compared with infiltration pit and standard contour. Increase in application levels of cattle manure show significant (p < 0.05) increase in stover yields. Tied contour had the highest (3.11 kg ha-1 mm-1) rainwater use efficiency which show significant differences (p < 0.05) from infiltration pits and standard contour. Interaction of tied contour and different rates of cattle manure showed significant increments in rainwater use efficiency with increases in manure application rates. Tied contours, 15 t ha-1 cattle manure and Macia variety are potential strategy to achieve climate smart agriculture and improve food security in semi-arid areas. Sorghum production in marginalised areas can be productive with adoption of tested techniques.

Transformation and environmental risk of 90Sr and 137Cs under extreme rainstorm at a proposed nuclear facility site in China.

This paper explores the environmental hazards associated with nuclear facilities in arid regions, focusing on the rapid migration of radionuclides facilitated by flood runoff resulting from extreme rainstorms. Through a case study of a proposed nuclear facility site in China, the study developed a comprehensive model to calculate the transformation of 90Sr and 137Cs in flood and subsurface water during accidents. The methodology employs a combination of field tests, radionuclide adsorption tests, the SWAT model, and the HGS model to create a fully integrated model. This approach allows for the several complex couplings (radionuclide-flood runoff-subsurface water) that have not been previously examined in the reactive solute transport. The findings reveal that despite groundwater movement being relatively sluggish, 90Sr and 137Cs migrate downstream rapidly due to their transportation by floods, which permeate the Upper Pleistocene gravel aquifer along the route. The study underscores the importance of considering the migration of radionuclides carried by floods generated by extreme rainstorms, as it poses a significant risk that cannot be ignored.

Predicting the geographical distribution and niche characteristics of Cotoneaster multiflorus based on future climate change.

Introduction: Arid and semi-arid regions are climate-sensitive areas, which account for about 40% of the world's land surface area. Future environment change will impact the environment of these area, resulting in a sharp expansion of arid and semi-arid regions. Cotoneaster multiflorus is a multi-functional tree species with extreme cold, drought and barren resistance, as well as ornamental and medicinal functions. It was found to be one of the most important tree species for ecological restoration in arid and semi-arid areas. However, bioclimatic factors play an important role in the growth, development and distribution of plants. Therefore, exploring the response pattern and ecological adaptability of C. multiflorus to future climate change is important for the long-term ecological restoration of C. multiflorus in arid and semi-arid areas. Methods: In this study, we predicted the potential distribution of C. multiflorus in China under different climate scenarios based on the MaxEnt 2.0 model, and discussed its adaptability and the major factors affecting its geographical distribution. Results: The major factors that explained the geographical distribution of C. multiflorus were Annual precipitation (Bio12), Min air temperature of the coldest month (Bio6), and Mean air temperature of the coldest quarter (Bio11). However, C. multiflorus could thrive in environments where Annual precipitation (Bio12) >150 mm, Min air temperature of the coldest month (Bio6) > -42.5°C, and Mean air temperature of the coldest quarter (Bio11) > -20°C, showcasing its characteristics of cold and drought tolerance. Under different future climate scenarios, the total suitable area for C. multiflorus ranged from 411.199×104 km² to 470.191×104 km², which was 0.8~6.14 percentage points higher than the current total suitable area. Additionally, it would further shift towards higher latitude. Discussion: The MaxEnt 2.0 model predicted the potential distribution pattern of C. multiflorus in the context of future climate change, and identified its ecological adaptability and the main climatic factors affecting its distribution. This study provides an important theoretical basis for natural vegetation restoration in arid and semi-arid areas.

Pond water quality and its relation to fish yield and disease occurrence in small-scale aquaculture in arid areas.

The study was conducted to determine the associations between water availability and management practises with pond water parameters in small-scale aquaculture in arid areas. Further, the study determined the associations between fish yield and disease incidence with the pond water parameters. We visited 36 tilapia farmers in Dodoma, a semi-arid region in Tanzania, for interviews and measurements of pond water parameters. The interviews collected information about pond type, pond age, water sources, feed type, pond fertilisation, stocking density, and disease incidences. The sources of water for the aquaculture activities were tap water, boreholes, and shallow wells. The source of water and management practises were linked to the parameters of the pond water. On the other hand, the parameters of the pond water were associated with fish yield and the likelihood of disease occurrence. Fish yield had a non-linear relationship with DO, turbidity, salinity, and stocking density and a linear association with pH. To expand aquaculture development in arid areas, efficient use of water through integrated aquaculture is recommended. Training farmers in good management practises and integration is necessary to ensure sustainable aquaculture development in arid areas.

Effects of Human Activities on Evapotranspiration and Its Components in Arid Areas.

With the increasing impact of human activities on the environment, evapotranspiration (ET) has changed in arid areas, which further affects the water resources availability in the region. Therefore, understanding the impact of human activities on ET and its components is helpful to the management of water resources in arid areas. This study verified the accuracy of Fisher's model (PT-JPL model) for ET estimation in southern Xinjiang, China by using the evaporation complementarity theory dataset (AET dataset). The ET and the evapotranspiration components (T:E) of six land-use types were estimated in southern Xinjiang from 1982 to 2015, and the impact of human activities on ET was analyzed. In addition, the impact of four environmental factors (temperature (Temp), net radiation (Rn), relative humidity (RH), and NDVI) on ET were evaluated. The results showed that the calculated ET values of the PT-JPL model were close to the ET values of the AET dataset. The correlation coefficient (R2) was more than 0.8, and the NSE was close to 1. In grassland, water area, urban industrial and mining land, forest land, and cultivated land, the ET values were high, and in unused land types, the ET values were the lowest. The T:E values varied greatly in urban industrial and mining land, forest land, and cultivated land, which was due to the intensification of human activities, and the values were close to 1 in summer in recent years. Among the four environmental factors, temperature largely influenced the monthly ET. These findings suggest that human activities have significantly reduced soil evaporation and improved water use efficiency. The impact of human activities on environmental factors has caused changes in ET and its components, and appropriate oasis expansion is more conducive to regional sustainable development.

Study on spatio-temporal simulation and prediction of regional deep soil moisture using machine learning.

Deep soil moisture (SM) plays a crucial role in vegetation restoration, particularly in semi-arid areas. However, current SM products have limited access and do not meet the spatio-temporal scale and soil depth requirements in eco-hydrological research. Thus, this study constructs a random forest prediction model for SM at different depths by identifying driving factors and quantifying the correlation effect of vertical SM based on the international SM network dataset. Subsequently, the SMAP product is integrated into the model to expand SM from point scale to regional scale, yielding an SM data product with a suitable scale and continuous time and space. The results indicate that the correlation between precipitation and SM changes into the interaction between adjacent SM layers as the depth increases. The lag time of SM in the shallow surface layer (0-3 cm) to precipitation was 1 day, and there was no delay on the daily scale in the 3-20 cm layers of the three underlying surface types. The response time of 50 cm SM to 20 cm SM was 1-2 days in cropland and grassland and 2 days in forest. Slope, land use type, clay proportion, leaf area index, potential evapotranspiration, and land surface temperature were the key driving factors of SM in the Shandian River region. The random forest model established in this study demonstrated good prediction performance for SM at both site and regional scales. The obtained daily products had higher spatial fineness than CLDAS products and could describe the SM characteristics of different underlying surfaces. This study offers new ideas and technical support for acquiring deep SM data in arid and semi-arid areas of northern China.