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Alfalfa (Medicago sativa L.) grassland is prone to degradation following multi-year maintenance. Yet, its mechanism regarding the stoichiometry of carbon (C) and nitrogen (N) across plant-soil system is still unclear. To address this issue, the method of space-for-time sampling was employed to investigate alfalfa grasslands with five planting years (5-, 8-, 10-, 15-, and 20-year periods) in the semiarid Loess Plateau. The results showed that the alfalfa above- and underground biomass decreased steadily decrease after the fifth to eighth years, showing a degradation tendency with the extension of planting duration. The mean weight diameter of aggregate registered an increase with planting years. However, the C and N stocks decreased with planting years in five soil aggregate fractions. Specifically, they were the highest in the fifth year and then started to gradually decrease along the 8th, 10th, 15th, and 20th year. Redundancy and correlation analysis confirmed that the C and N stocks of soil aggregates were closely positively associated with those of plant. Overall, the highest stability of soil physical structure was found during the period from the fifth to eighth year, and, afterward, the stability declined. In conclusion, alfalfa plantation improved soil structure stability but aggravated soil C and N stocks, and biomass and soil aggregate indicators accounted for alfalfa field degradation after a certain year of plantation. [ABSTRACT FROM AUTHOR]

Introduction: Long-term application of excessive nitrogen (N) not only leads to low N use efficiency (NUE) but also exacerbates the risk of environmental pollution due to N losses. Substituting partial chemical N with organic fertilizer (SP) is an environmentally friendly and sustainable fertilization practice. However, the appropriate rate of SP in rainfed maize cropping systems in semi-arid regions of China is unknown. Methods: Therefore, we conducted a field experiment between 2021 and 2022 in a semi-arid region of Northern China to investigate the effects of SP on maize growth, carbon and N metabolism (C/NM), and NUE. The following treatments were used in the experiment: no N application (CK), 100% chemical N (SP0, 210 kg N ha-1), and SP substituting 15% (SP1), 30% (SP2), 45% (SP3), and 60% (SP4) of the chemical N. The relationship between these indicators and grain yield (GY) was explored using the Mantel test and structural equation modeling (SEM). Results and discussion: The results found that the SP1 and SP2 treatments improved the assimilates production capacity of the canopy by increasing the leaf area index, total chlorophyll content, and net photosynthetic rate, improving dry matter accumulation (DMA) by 6.2%-10.6%, compared to the SP0 treatment. SP1 and SP2 treatments increased total soluble sugars, starch, free amino acids, and soluble protein contents in ear leaves via increasing the enzymatic reactions related to C/NM in ear leaves during the reproductive growth stage compared with SP0 treatment. The highest plant nitrogen uptake (PNU) and nitrogen recovery efficiency were obtained under the SP2 treatment, and the GY and nitrogen agronomic efficiency were higher than the SP0 treatment by 9.2% and 27.8%. However, SP3 and SP4 treatments reduced DMA and GY by inhibiting C/NM in ear leaves compared to SP0 treatment. Mantel test and SEM results revealed that SP treatments indirectly increased GY and PNU by directly positively regulating C/NM in maize ear leaves. Therefore, in the semi-arid regions, substituting 30% of the chemical N with SP could be considered. This fertilizer regime may avoid GY reduction and improve NUE. This study provides new insights into sustainable cultivation pathways for maize in semi-arid regions. [ABSTRACT FROM AUTHOR]

Xerophytic vegetation re-regulates and allocates water resources through canopy interception, root water uptake and transpiration, and changes the water budget among precipitation, runoff, interception and infiltration, thus having a significant impact on the processes of the hydrological cycle. In this study, we investigated the effect of xerophytic shrub-Salix on soil water redistribution and water budget through an in situ monitoring experiment combined with two-dimensional vegetation water consumption modeling. The results showed that, due to the interception effect of root water uptake, it was difficult for precipitation infiltration to recharge deep soil water and groundwater. The measured data of soil moisture content, hydraulic head and precipitation were used to verify and calibrate the performance of the soil water flow model in the vadose zone by HYDRUS-2D. The effect of roots system on soil water was simulated, and the appropriate spacing of Salix replanting was estimated. Combined with the relationship between the transverse roots system and the crown width obtained by the investigation, it was determined that the spacing between the Salix should be greater than five times the crown width, so that the balance between the water consumption of Salix and the water supply of deep soil by precipitation could be considered. The results of this study are important for estimating groundwater recharge in arid areas and provide practical vegetation replanting options for similar regions. [ABSTRACT FROM AUTHOR]

The Google Earth Engine (GEE) was used to investigate the performance of the Global Land Data Assimilation System (GLDAS) soil temperature (ST) data against observed ST from 13 synoptic stations over a semiarid region in Iran. Three‐hourly ST data were collected and analyzed in two depths (0–10 cm; 40–100 cm) and 5 years. In each depth, GLDAS‐Noah ST data were evaluated for daily minimum, maximum, and average ST (i.e., Tmin, Tmax, and Tavg). Based on the correlation coefficient, Kling–Gupta Efficiency, and Nash–Sutcliffe Efficiency the overall performance of the GLDAS‐Noah is 0.96, 0.66, and 0.79 for Tmin; 0.97, 0.84, and 0.89 for Tavg; and 0.95, 0.89, and 0.89 for Tmax, respectively in the first layer. Likewise, 0.97, 0.85, and 0.86 for Tmin; 0.97, 0.77, and 0.80 for Tavg; and 0.97, 0.69, and 0.69 for Tmax are obtained in the second layer. However, there is a significant negative bias which tends to underestimate ST in the two investigated layers, given by an average bias over all the stations analyzed of −24%, −12%, and −5% for Tmin, Tavg, and Tmax in the first layer, and average bias of −8%, −13%, and −17% for Tmin, Tavg, and Tmax in the second layer. This study reveals that GLDAS‐Noah‐derived ST can be used in arid regions where little or no observation data is available. Moreover, GEE performed as an advanced geospatial processing tool in regional scale analysis of ST in different layers. [ABSTRACT FROM AUTHOR]

The semiarid region of Pernambuco produces 99.5% of the forage corn, considering that 93.8% of the ruminant herd is produced in this region of the Brazilian Northeast. The Agreste Meridional is located in this region, which presents seasonality in production due to water deficit. Silage is one of the adopted roughage conservation strategies, with corn being the forage that presents the best indicators when fed to animals. Agronomic aspects are often neglected, considering that the performance of cultivars may vary with the growing environment. The objective of this research was the introduction and evaluation of corn cultivars for the production for whole-plant silage in the Agreste Meridional of Pernambuco, Brazil. The experiment was carried out in a randomized block design, with seven treatments, of which five non transgenic cultivars (‘Alagoano’, ‘Nordestino’, ‘São Luís’, ‘PV2 Viçosense’ and ‘PV1 Branca’) and two transgenic hybrids (‘LG 6030 VT PRO2’ and ‘AS 1573 YG’). It was observed that all genotypes showed susceptibility to Spodoptera frugiperda and Helicoverpa zea, except for the ‘AS 1573 YG’ hybrid, due to the Bt technology. The biometric characters of the genotypes were influenced by the environment. However, with yield of 10,537 and 10,666 kg ha-1 (dry matter), the genotypes ‘Alagoano’ and ‘AS 1573 YG’, respectively, were selected for cultivation in the Agreste Meridional region for the production of silage, which can be used in intensive production systems or family farming. [ABSTRACT FROM AUTHOR]

Although nitrogen is the nutrient most required by maize, doses of N lower than those recommended are applied to maize grown in semiarid environments, which limits the achievement of profitable yields. The objective of this study was to evaluate changes in soil fertility, nutritional status and dry matter production of maize plants fertilized with organic and mineral fertilizers in a semiarid region. A factorial experiment was carried out in Sobral, Ceará state, Brazil, in a randomized block design. The factors were two N sources (organic compost and urea), and four N rates: 27.5, 55, 110 and 165 kg ha−1, with three replications. We assessed variables associated with soil fertility, plant nutritional status, chlorophyll content, grain yield and total dry matter production. The highest rates of organic compost resulted in the highest levels of P (17.7 mg dm−3) and K (102.2 mg dm−3) in soil when compared to the control (7.7 and 69.0 mg dm−3, respectively). However, organic compost rates below 110 kg ha−1 of N-equivalent fertilizer were not enough to supply the plants' demand for P and K. Low N rates promoted a decrease in soil inorganic N in the second year of application. Applying urea to maize plants led to greater dry matter production than organic compost in the second consecutive crop season. The use of organic compost at rates lower than 110 kg ha−1 of N-equivalent fertilizer decreases soil fertility and has no impact on maize dry matter production. [ABSTRACT FROM AUTHOR]

Carbon sequestration is the process of capturing, securing and storing carbon dioxide from the atmosphere. In this study, the carbon sequestration capacity of Hedera colchica was investigated in soil of a semiarid region in Iran. Samples were taken from plants cultivated in the semiarid area of the polluted metropolis of Tehran and the amount of sequestered carbon in the aboveground and underground parts of the plant was measured. The conversion coefficient of carbon sequestration of plant organs (stem, leaf, and root) was determined separately by the combustion method. Carbon tax policy was used to evaluate the carbon sequestration function, as the shadow price of carbon. The results showed a significant difference in the amount of carbon sequestration in different organs of the plant. Stems and roots with 29.3 and 4.3 t ha−1, respectively, showed the highest and lowest amount of carbon deposition. The results of the economic value showed that the carbon shadow price was $40567.6 ha−1 on average. In general, the results of this study showed that the organs of H. colchica can have a beneficial effect in the process of carbon sequestration. [ABSTRACT FROM AUTHOR]

Management practices might alter soil chemical properties. This study evaluated soil chemical properties in a forage cactus Opuntia stricta (Haw.) Haw. ('Orelha de Elefante Mexicana') (OEM) production system in the Brazilian semiarid region. The experiment was established in June 2011, and the design was a split-split-plot in randomized complete blocks, in which the main plots were formed by distinct levels of organic fertilizer (cattle manure) (0, 10, 20, and 30 Mg ha−1 year−1), the subplots were formed by different levels of N inorganic fertilizer applied as urea (0, 120, 240, and 360 kg N ha−1 year−1), and the sub-subplots were distinguished by the distinct OEM harvesting frequency (annual or biennial). Soil samples were collected for chemical analysis, C and N contents analysis, and stocks analysis at 0 to 10 and 10 to 20 cm depths in August 2019. Organic fertilizer contributed to a linear increase in soil pH, Ca2+, Na+, sum of bases (SB), cation exchange capacity (CEC), and base saturation (V) at both depths (p < 0.05). With the application of 30 Mg ha−1 year−1 of cattle manure, there was storage of approximately 126 Mg C ha−1 and 13 Mg N ha−1 at 0 to 20 cm depths. Managing OEM with organic fertilizer and a biennial frequency of harvesting affects the soil's chemical characteristics in cactus orchards, and it is a sustainable alternative for semiarid regions. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This article presents a study on the spatiotemporal dynamics of land cover and use, vegetation indices, and water content in the semiarid region of Pernambuco, Brazil. This study is based on an analysis of satellite images from the years 2016, 2018, and 2019 using the MapBiomas platform. The results show changes in the predominant land cover classes over time, with an increase in the caatinga area and a decrease in the pasture area. An analysis of the vegetation indices (NDVI and LAI) indicated low vegetation cover and biomass in the study area, with a slight increase in the NDVI in 2018. An analysis of the Modified Normalized Difference Water Index (MNDWI) showed that the water content in the study area was generally low, with no significant variations over time. An increase in the water bodies, mainly due to the construction of a reservoir, was noted. The results of this study have provided important information for natural resource management in the region, including the development of strategies for the sustainable use and management of natural resources, particularly water resources, vegetation cover, and soil conservation. [ABSTRACT FROM AUTHOR]

Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Evidence exists that the Caldenal (caldén (Prosopis caldenia) forest) of the Semiarid Pampas Region functions as a sink of aeolian sediments. These sediments accumulate on a layer of volcanic ash deposited in 1932, which allows to analyze the degree of soil evolution in a 90-year period. Therefore, some physical, chemical and morphological properties of the superficial soil horizon (Ah) of a caldén forest, which evolves from those sediments, were evaluated from windward to leeward. The results indicated that the evolution of the soil was incipient, although soil development tended to be better towards windward than at leeward. [ABSTRACT FROM AUTHOR]

Plant growth-promoting bacteria (PGPB) are bacteria that can enhance protect native plants from abiotic stresses including drought. The inoculation of these PGPB into crop forage plants may increase productivity helping to suppress its growing demand in semiarid regions. The present paper aims to evaluate the Sorghum bicolor L. morphogenic characteristics and growth inoculated with native bacterial isolates from the Brazilian semiarid region under drought conditions. The endophytic bacteria isolated from root nodules of native leguminous plants named Mimosa tenuiflora (isolates – MTBV77, MTP78, MTBV12), Desmanthus pernambucanus (isolates – DPP1) and Mimosa caesalpiniifolia (isolate – MCLR34) were all presumably identified as rhizobia by performing the Polymerase Chain Reaction duplex amplification technique using primers that amplify the nifH and nodC genes. The seeds and roots of sorghum seedlings were inoculated with bacterial isolates. The plants were cultivated in pots under favorable water conditions (80% of the available water) and dry conditions (40% of the available water). The inoculation with bacterial isolates increased emission, elongation and length of the S. bicolor leaves, as well as increased its stem elongation, height, and shoot dry-matter content. However, the magnitude of the effects varied according to the imposed water regime. Thus, rhizobacteria from root nodules of Brazilian native legumes have the potential to promote plant growth. The bacterial isolates DPP1 and MTBV77 attenuate the effects of water stress and promote S. bicolor growth under drought conditions and are therefore promising for the use as an inoculant for S. bicolor sustainable cultivation to forage purposes. [ABSTRACT FROM AUTHOR]

The objective of this work was to evaluate the effect of different sources of phosphorus and its interaction with nitrogen, on the yield, quality, and nutrient extraction of the wheat crop. The field experiment was carried out on an entic Haplustol, in which 8 fertilization treatments (T) were established. T 1 corresponds to the control (without adding P), in T 2, 3, 4, and 5, 18,3 kg.ha-1 of P was applied. T 6, 7, and 8 correspond to fertilizer additions at recommended rates of 30 kg.ha-1 which implies the application of 5,25 kg of P.ha-1. Two nitrogen management procedures were established in divided plots: with and without fertilization. In all the treatments with phosphorus, the addition of N presented statistically significant differences in yield. The WUE was higher in those treatments whose fertilizers have a balanced formulation of nutrients. No significant differences in protein concentration were found. T 2, 3, 4, and 5 presented a positive balance between the P applied with fertilizer and extracted in the grain, T 6, 7, and 8 had a negative balance, while T 1 (control) was the worst situation. [ABSTRACT FROM AUTHOR]

Rural and isolated communities traditionally lack adequate water treatment and distribution systems, and water quality assessment often does not include radioactivity measurement. Here we present, for the first time, the results of Rn measurements and the evaluation of the associated dose in groundwaters of rural communities in a semiarid area in Paraiba State, Brazil. Water samples were analysed using a low-level liquid scintillation spectrometer (LSS). Radon concentrations were higher than EPA and WHO recommended levels in water for most of the wells (range of 5.5–1107.0 Bq/L, average 252.8 Bq/L). Higher Rn concentration was measured in deeper wells and located in area rich in granite and diorite rocks. The annual effective doses varied between 0.021 and 4.317 mSv/y for infants, 0.016–3.182 mSv/y for children, and 0.015–3.022 mSv/y for adults, exceeding, in some cases, the 1 mSv/y reference level recommended by the WHO and UNSCEAR for the public. Thus, water consumption from half of the wells should be avoided unless adequate treatment is provided. Results highlight the need to perform actions to supply water with appropriate quality to the local population. [ABSTRACT FROM AUTHOR]

Nonsessile animals could partition the use of resources in different axes, reducing the effects of competition and allowing coexistence. Here, we investigated the spatial and trophic niche dimensions in four lizard assemblages in the Neotropical semiarid Caatinga to investigate the determinants of resource use and the extent to which lizards partition their niches. We sampled each lizard assemblage once, for 10 days, in the dry season of 2017 and 2018. In two lizard assemblages, we detected nonrandom niche overlap patterns that were higher or lower than expected by chance. The high niche overlap patterns suggest that either there is intense current competition for available microhabitats or an abundance of microhabitats. The lower niche overlap may be influenced by the presence of species adapted to sandy habitats (psammophilous), suggesting that spatial partitioning detected has historical basis, which is supported by the pPCA results and by the lack of patterns in the realized niche distribution of species across niche space. We detected trophic niche partitioning in three lizard assemblages. In one assemblage, we discovered random spatial and trophic niche overlap patterns, revealing that competition is not a determining factor in the structure of that assemblage. In fact, phylogenetic effects were predominantly the main determinants of resource use in the four studied lizard assemblages. Arid and semiarid habitats cover about one third of land surface of the world. Comparisons between our findings and those from other regions of the world may aid identify general trends in the lizard ecology of dry environments. [ABSTRACT FROM AUTHOR]

Drought is a very complex natural phenomenon that affects the water supply and consequently impacts agricultural and socioeconomic activities, causing social and political crises. The objective of this study is to spatiotemporally analyze meteorological and agricultural droughts based on multiple indices in the Upper Paraíba River basin for the 2001–2017 period. The agricultural droughts were analyzed using four drought indices (NDVI, LST, VSWI, and VHI) based on data from the MODIS sensor on the TERRA and AQUA satellites, while the meteorological droughts were characterized using the standardized precipitation index (SPI) at three different time scales based on TRMM rainfall data. The values of LST, NDVI, VHI, VSWI, and SPI revealed how much vegetation is influenced by rainfall variability in this semiarid region of Brazil. The estimated results of VSWI and VHI show the years with extremely wet and dry conditions from spatial and temporal perspectives. The relationship between estimated drought indices and observed relative humidity showed that VSWI (R² = 0.78) was best fitted when compared to VHI (R² = 0.46). Thus, it can be concluded that the VSWI index is better adapted because it presented more consistent results for the behavior of agricultural droughts when compared to the VHI. The results of the SPI analysis were used for the identification of the main drought events that affected the study basin. This combined technique of different drought indices easily produced an alternative method for comprehensive drought assessment. [ABSTRACT FROM AUTHOR]

Eutrophication intensifies Harmful Macroalgae Blooms (HMBs) in coastal environments, reducing habitat suitability for organisms and creating significant challenges for small-scale artisanal fishers. Leveraging fishers' memories, we analyzed over 20 years of data on Ulva lactuca blooms and their effects on fishing activities and fish resources in a tropical semi-arid region of Brazil. We estimated the timing, seasonality, and impacts of these bloom episodes on fish catches, fishing gears, and fishery revenues. Since 2010, blooms have become more frequent, particularly during dry seasons in shallow estuaries, likely exacerbated by nutrient enrichment, extended water residence time, and inadequate wastewater treatment. Net-based gear is particularly affected, with fish catches decreasing by up to sevenfold during bloom seasons, leading to income losses of approximately 50 %. Addressing eutrophication through active public policies on effluent treatment is crucial to mitigating economic impacts on vulnerable communities and managing future blooms, which are expected to worsen with climate change. • Increasing Harmful Macroalgal Blooms threaten marine biodiversity and disrupt ecosystems. • Local Ecological Knowledge from fishers offers key insights into Ulva lactuca blooms in tropical semi-arid regions. • Fishers report U. lactuca blooms have increased since 2008, cutting incomes by up to 50 %. • Increased U. lactuca biomass reduces fish catches, impacting fishing productivity. • U. lactuca blooms require improved management for ecosystem health. [ABSTRACT FROM AUTHOR]

The use of algae-based biostimulants as biopromoters for the growth, flowering, and fruiting phases has been intensified in recent years, despite a lack of information about the ideal quantity for maximum efficiency by the plant. This study aimed to select the concentration and application timing of Ascophyllum nodosum-derived biostimulant capable of modulating the physiology and increasing the yield of soybean plants from a semiarid region. The trials were carried out in a greenhouse by applying leaf spraying of biostimulant at 0, 0.5, 1.0 and 1.5 L ha−1, as a single or double application, in different developmental stages (V4, V4 + R1, R1, R1 + R4) of Extrema soybean cultivar. Growth, water content, pollen viability, gas exchange and grain yield were investigated. The biostimulant promoted a better physiological conditioning and productive responses, depending on the dose and application timing. Ascophyllum nodosum-based biostimulant at 1.5 L ha−1, applied 0.75 L ha−1 at V4 + 0.75 L ha−1 at R1 (T12), was the most significant treatment, improving the net photosynthesis, water status and plant growth, which resulted in a 12% increase in grain yield. In conclusion, the dosage and timing of application play pivotal roles in eliciting physiological and productive responses through biostimulants. Seaweed-based biostimulants emerge as essential components to optimizing the cultivation and yield of soybean plants, serving as efficient and sustainable biological regulators. [ABSTRACT FROM AUTHOR]

Afforestation is an effective approach to rehabilitate degraded ecosystems, but often depletes deep soil moisture. Presently, it is not known how an afforestation‐induced decrease in moisture affects soil microbial community and functionality, hindering our ability to understand the sustainability of the rehabilitated ecosystems. To address this issue, we examined the impacts of 20 years of afforestation on soil bacterial community, co‐occurrence pattern, and functionalities along vertical profile (0–500 cm depth) in a semiarid region of China's Loess Plateau. We showed that the effects of afforestation with a deep‐rooted legume tree on cropland were greater in deep than that of in top layers, resulting in decreased bacterial beta diversity, more responsive bacterial taxa and functional groups, increased homogeneous selection, and decreased network robustness in deep soils (120–500 cm). Organic carbon and nitrogen decomposition rates and multifunctionality also significantly decreased by afforestation, and microbial carbon limitation significantly increased in deep soils. Moreover, changes in microbial community and functionality in deep layer was largely related to changes in soil moisture. Such negative impacts on deep soils should be fully considered for assessing afforestation's eco‐environment effects and for the sustainability of ecosystems because deep soils have important influence on forest ecosystems in semiarid and arid climates. [ABSTRACT FROM AUTHOR]

Copyright of Sustainability in Debate / Sustentabilidade em Debate is the property of University of Brasilia, Center for Sustainable Development and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present study critically investigated the effect of meteorological parameters on the mass concentration of Ultrafine Particulate Matter (PM1) between October 2018 and September 2019 (n=102) in a semiarid region of Rajasthan, India. The concentration of PM1 ranged between 72-110.85 µg.m-3 with distinct seasonal variation. Higher PM1 concentrations are closely linked to decreased wind speeds and colder temperatures, according to the findings. The winter season showed the highest concentration followed by post monsoon and pre monsoon season. The cumulative effect of environmental variables such as temperature, relative humidity, and wind speed, as well as the height of the planetary boundary layer, was investigated using multiple regression analysis (HPBL). A significant negative correlation (p < 0.001) with HPBL and wind speed was observed in all three seasons. The temperature was found to have a significant (p<0.001) negative correlation during winters whereas in other seasons there was a positive but no significant (p>0.001) relationship. Relative humidity showed a negative relationship during withers and pre-monsoon season. The multiple regression model indicated a significant negative (p<0.001) relationship with HPBL in winters (R2=0.70) explaining the 70% effect of HPBL on mass concentration of PM1.During the post-monsoon (R2 = 0.69) and premonsoon (R2= 0.91) explains 69% and 91% effect of HPBL on mass concentrations of PM1.The results indicate that the concentration of PM1 cannot be explained by a single meteorological parameter but all the parameters show a cumulative effect. [ABSTRACT FROM AUTHOR]

The application of machine learning approaches to improve groundwater salinity risk mapping is limited despite all potential advantages. Therefore, there is an ongoing need for investigations that present new techniques, like machine learning, validated against conventional methods. These advances are particularly important for arid and semiarid regions, such as the Bakhtegan Basin (southern Iran), where groundwater use may far outweigh recharge, but groundwater management improvements are essential. To address these needs, groundwater salinity hazard, vulnerability, and risk maps were investigated using an integrated application of statistical (i.e., frequency ratio and statistical index models), machine learning (i.e., random forest and classification and regression trees algorithms), and decision-making models (fuzzy analytic hierarchy process (FAHP)). Results showed that the risk of groundwater salinity was high in the central areas of the region as well as at the margins of Bakhtegan Lake and irrigated farming lands. Based on the modeling results in the testing phase, it was found that the frequency ratio and random forest models exhibited better performance, with Nash–Sutcliffe efficiency metrics of 0.73 and 0.70, respectively, compared to the classification and regression trees and statistical index models, which had Nash–Sutcliffe efficiency metrics of 0.65 and 0.63, respectively. The innovative techniques developed in the current work accurately identified variables such as normalized difference salinity index, distance from mines, and land use associated with the highest weight values (0.59, 0.14, and 0.11, respectively) compared to other variables to identify groundwater salinity areas of vulnerability. The application of the fuzzy analytic hierarchy process method in developing vulnerability maps, integrating them with hazard maps, and developing groundwater salinity risk maps was innovative in this study. The innovative approach is transferrable for groundwater salinity susceptibility, vulnerability, and risk assessments globally in the study area and similar settings. • Mapping groundwater (GW) salinity hazard, vulnerability, and risk into five classes. • Application of the FAHP method in developing vulnerability maps was innovated. • For predicting GW salinity hazard, RF and FR models has been recommended. • Elevation is the more important variables to map of GW salinity hazards [ABSTRACT FROM AUTHOR]

The Caatinga biome, characterized by its dynamic vegetation due to climate and land use changes, experiences varied environmental responses during the dry and rainy seasons. This research aims to dissect the complexity of surface radiation fluxes, vapor pressure, and air and soil temperatures across three distinct vegetation densities within the Caatinga: recovering, degraded, and preserved. Utilizing data from Moderate Resolution Imaging Spectroradiometer/Enhanced Vegetation Index products to analyze these densities offers a novel lens through which to view the biome's reaction to climatic shifts. Our findings unveiled specific patterns of solar and longwave radiation fluxes that correlate with key climatic variables like air temperature and surface albedo. This investigation not only addresses a critical gap in our knowledge of a globally significant but underexplored biome, but it also advances our comprehension of how vegetation density influences radiation fluxes in arid settings. Insights from this study are vital for forecasting and mitigating the ecological and climatic impacts of land cover transformations in semiarid regions worldwide. Significantly, the degraded site displayed nearly double the solar radiation reflection (138 Wm−2) compared to the recovering site (68 Wm−2), underscoring the role of vegetation density in modulating local climate conditions, despite atmospheric consistency across the study sites. [Display omitted] • The Caatinga biome covers the world's most densely populated dry region. • The study observes radiation fluxes over different vegetation densities. • Recovering and degraded vegetation had higher incoming solar radiation. • Preserved Caatinga areas emitted the most intense longwave radiation. • Degraded Caatinga showed the highest surface albedo values. [ABSTRACT FROM AUTHOR]

Background and Aim: In tropical semiarid regions, supplementation with fungi could contribute to rumen modulation, promoting greater production of fibrolytic enzymes and degradation of forage. The objective of this study was to analyze the effect of supplementation with fungi, isolated from the bovine rumen, on the performance and microbiota of the digestive tract of Nellore calves. Materials and Methods: The experiment was conducted in randomized blocks evaluating eight Nellore calves that were daily supplemented with isolates of Aspergillus terreus and Trichoderma longibrachiatum, along with eight calves that were not supplemented. After 55 days, the animals were weighed, and samples of rumen fluid and feces were collected for analysis. The characteristics that showed normal distribution were subjected to analysis of variance and compared using Tukey's test. Whereas, the variables that did not show normal distribution were subjected to the Kruskal-Wallis test, and the frequencies of the bacterial and fungal genera were compared using the Chi-square test. Results: Supplementation with fungi promoted the reduction in ruminal pH (p<0.05). However, the final live weight; average daily weight gain; total weight gain; rumen protozoa; and the count of Enterobacteriaceae, mycelial fungi, and yeasts of ruminal fluid and feces were not influenced by supplementation (p>0.05). Moreover, the protozoa Eodinium spp. was identified only in supplemented calves (p<0.05). Conclusion: Supplementation with the fungi presented the potential for use as possible additives because it did not alter the physiological parameters of the facultative anaerobic microbiota composition in the rumen and feces. In addition, it favored the presence of the ciliate genus Eodinium. However, further studies should be performed to better define suitable dosages for supplementation. [ABSTRACT FROM AUTHOR]

Copyright of Argentinian Horticulture / Horticultura Argentina is the property of Revista Horticultura Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study determined the mineral composition of sorghum Ponta Negra and its silage, irrigated with different leaching fractions with brackish water. Two experiments were performed: The first step evaluated the sorghum irrigated by four leaching fractions with brackish water (0, 5, 10 and 15%) and 4 repetitions. In the second experiment, sorghum was harvested at 101 days to make experimental silos which, according to the leaching fractions, four treatments were formed, with 5 repetitions each, totaling 20 silos stored for 90 days. A randomized block design was adopted. Different leaching fractions with brackish water provided a quadratic behavior was observed for Nitrogen (N), Phosphorus (P) and Sulfur (S) on the sorghum plant. A positive linear effect was observed for Potassium (K), Calcium (Ca), Magnesium (Mg) and Sodium (Na) with the increase in leaching fractions with brackish water in the irrigation of sorghum plant. Regarding sorghum silage, the leaching fractions with brackish water promoted a positive linear effect for the N content and quadratic effect for P, K, Ca, Mg and Na. Despite the high content of soluble salts in the water resources available in arid and semi-arid regions, the use of irrigation leaching fraction has been considered a viable alternative for the production of tolerant forage crops. [ABSTRACT FROM AUTHOR]

Catchments have highly variable yields of runoff and soil erosion. The size, land use and the surface cover play a significant role and influence the catchment response and parameter values of simulation models. Two experimental basins—the Cariri basins—were equipped in a semi‐arid region of Brazil, for obtaining runoff and sediment yield at different catchment scales, as well as, to evaluate the influence of the land use and surface cover. In the first basin, located in the municipality of Sumé, the field studies were carried out at two different scales: four micro‐catchments with an area of around 0.5 ha and nine standard Wischmeier‐type erosion plots of 100 m2. The experimental units had varied vegetation and management. They were subjected only to natural rainfall events, and were monitored from 1982 to 1991. The total runoff and total sediment yield were determined for each of the events. The installations in the second basin, in the municipality of São João do Cariri, from 1999, include two erosion plots, three micro‐catchments, and two sub‐catchments of a small basin. These basins are still being monitored for runoff and sediment production. Among the micro‐catchments two are nested to detect any scale effect at the micro‐catchment level. Nearly 600 events of precipitation, that produced runoff in at least one of the experimental units, have been registered. These data have been used to evaluate the influence of various factors, including cultivation practices and to calibrate hydrological models for plots and micro‐catchments. Parameters have been tested by means of cross validations among micro‐catchments and sub‐catchments. The data sets are made available to all the catchment hydrology researchers and others at https://doi.org/10.5281/zenodo.4690886. [ABSTRACT FROM AUTHOR]

The present study was aimed to assess the surface water pollution sources in a semiarid region of Algeria by characterizing the physicochemical quality of the water of the main Wadis of the El Hodna watershed and determining the water quality index according to the uses of drinking water, irrigation, and aquatic life. This index is calculated in purpose to communicate information on the water quality for concerned citizens and policymakers. The calculated WQI values of the studied Wadis were higher than 100, which indicates that the waters of the El Hodna watershed are unfit for human consumption, irrigation, and aquatic life. The obtained results have shown that different types of pollution (industrial, domestic and agricultural) affect the waters of the El Hodna watershed, which lead to degrade the water quality of this aquatic ecosystem and consequently its biodiversity and public health. [ABSTRACT FROM AUTHOR]

Understanding the hydrochemical and isotopic characteristics of groundwater and hydrogeochemical processes is crucial for groundwater resource development and environmental protection, especially in semiarid regions. To address this question, we collected and tested groundwater and river water samples form the Hongjiannao Lake Basin. The groundwater samples were took from a porous medium aquifer and a pore-fissure aquifer. We studied hydrochemical characteristics of groundwater from both aquifers using major element measurements, statistical calculations, and the use of Piper diagrams. The hydrogeochemical processes taking place in groundwater were identified using the Gibbs diagram, Gaillardet diagram, saturation index calculations, ratios of major ions, and chloro-alkaline indices. We also investigated the origin of groundwater using stable isotopes (D and 18O) and evaluated groundwater age on the basis of piston model of tritium isotope (3H) measurements. Groundwater–river water interactions are also identified using chemical and stable isotope characteristics. The results show that groundwater in both aquifers has a chemical composition dominated by are HCO3 anions that groundwater has a low total dissolved solids (TDS) content. An assessment of the analyzed groundwater chemical data suggests that feldspar dissolution, the dissolution/precipitation of carbonate minerals (dolomite and calcite), and cation exchange play an important role in the hydrochemical evolution of groundwater in the study area. The compositions of stable isotopes and tritium imply that groundwater in the porous medium and pore-fissure aquifers originate from modern and ancient precipitation sources, respectively. The groundwater recharge is influenced by evaporation as water infiltrates through the vadose zone. In addition, river, lake, and groundwater form an organic whole. This study provides effective guidance for groundwater resource development and environmental protection in a similar area. [ABSTRACT FROM AUTHOR]

The first record of the giant fireflies Aspisoma ignitum (Linnæus, 1767) (Coleoptera: Lampyridae: Lampyrinae, Cratomorphini) in the city of Coro, semiarid region of Falcon state, north-western Venezuela, is presented. So far, this appears as the northernmost report of A. ignitum in Venezuela. The importance of lampyrid giant fireflies as potential biological agents to control pests of agricultural and sanitary interest is discussed. [ABSTRACT FROM AUTHOR]

Solifuges represent a poorly described group of arachnids with a worldwide distribution. Within this group, many species have not been described, and for those that are, the geographical distributions are not known. Here, we describe the expanded distribution range of the mummuciid species, Gaucha mauryi, recorded for the first time in the state of Pernambuco, in Northeastern Brazil. In addition, we provide a list, compiled from the literature, of solifuge species in Brazil. [ABSTRACT FROM AUTHOR]

This research aimed to get information about the uranium and radium activity concentrations in surface and ground water in a semiarid region in Brazil. Mean (and range) activity of 0.46 (0.01–1.8), 0.015 (0.0004–0.066) and 0.32 (0.09–1.32) Bq L− 1 were found for 234U, 235U and 238U, respectively. Uranium radioisotopes account for the higher radioactivity in surface and groundwater, 226Ra was found only in few groundwater samples (0.09–0.61 Bq L− 1). 226Ra/238U (0.15–0.43) and 234U/238U (1.18–1.86) activity ratios are indicative of radioactive disequilibrium in groundwater. Expected effective doses from few water sources can be considered significant if untreated water is used for drinking. [ABSTRACT FROM AUTHOR]

In this study, the Google Earth Engine (GEE) platform was used to obtain and manipulate data products derived from satellite images to quantify the forest cover changes in the Brazilian semiarid region (BSAR) between 2000 and 2018 and analyze the annual loss in this period. The relationships among the cumulative gain, loss, and gain–loss between 2000 and 2012 were also analyzed. The Mann–Kendall (MK) and Sen's nonparametric methods were applied to identify trends, and two-way analysis of variance (ANOVA) was used to identify possible similarities among the patterns of forest cover loss in two nine-year periods (2001–2009 and 2010–2018). In 2000, this semiarid region had a forest cover of 225,412.80 km2, and in 2018, a total loss of 60,769.39 km2 occurred, i.e., a total of approximately 26.96% in 18 years. The largest area loss was observed in 2016, and the smallest was observed in 2002. The MK and Sen's tests showed an increasing trend in the annual losses in this semiarid region at the 0.004 significance level. The results can aid efforts to identify the areas most affected by forest cover loss and determine the corresponding trends, which could contribute to implementing public policies to raise the awareness level of the local population regarding the preservation of the BSAR and mitigation of deforestation. [ABSTRACT FROM AUTHOR]

In spite of enormous investment for water harvesting in Maharashtra, the issue of water deficiency persist. Therefore, with the proper understanding of recent (1975–2014) hydrometeorological characteristics in the semiarid region of Maharashtra, the study endeavored to suggest management strategies to optimize the water resources. To understand the inherent characteristics of rainfall, runoff, dam storages and groundwater, statistical techniques including descriptive statistics, correlation, regression and Student's t test were applied. The monsoon rainfall has notable control over the water resources. As the study region characterized by significantly low water availability with high variability which is accountable for higher frequency and intensity of drought, it should be prioritized while formulating a judicial plan for water management. The major rivers of Maharashtra follow the unimodal pattern of rainfall. Whereas the study area displays a peculiar character of the bimodal and unimodal regimes of rainfall and runoff, respectively, this highlights the role of hydrological losses. However, it also indicates that there is a wide scope to harvest surface water, particularly during the months of September and October. Interestingly, the inter-annual variability in the extreme rainfall and runoff events over the study basins is observed to be higher in India. Most of the water (> 50%) received during flashy rainfall events drains out through flashy discharges. The impoundment of this water and modified irrigation schedule by considering the recent hydrological characteristics may diminish the variability and deficiency of surface and subsurface water. Furthermore, for the precise forecast of water availability in the study area, ENSO condition needs to incorporate, as it has a significant connection with rainfall and runoff. [ABSTRACT FROM AUTHOR]

One specimen of the scorpion Tarsoporosus flavus González-Sponga, 1983 (Scorpiones: Scorpionidae: Diplocentrinae) was captured into a bedroom in dwelling of the city of Coro, semiarid north-western region, Falcon state, Venezuela. Potential sanitary importance of this finding is discussed. [ABSTRACT FROM AUTHOR]

Copyright of Anuario do Instituto de Geociencias is the property of Universidade Federal do Rio de Janeiro, Instituto de Geociencias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The degradation of photosynthetic pigments leads to leaf senescence and thus grain yield losses. We determined whether the application of uniconazole to maize in semiarid regions could reduce the degradation of photosynthetic pigments by enhancing the antioxidant defense system. We conducted a field study in the summers of 2015 and 2016 where seeds were soaked in uniconazole at concentrations of 0 (CK1), 25 (S1), 50 (S2), and 75 (S3) mg kg−1 and foliar sprayed at concentrations of 0 (CK2), 25 (F1), 50 (F2), and 75 (F3) mg L−1 at the eight-leaf stage. The application of uniconazole significantly improves the chlorophyll content, soluble protein content, and net photosynthetic rate, where the maximum values were obtained with the S1 and F1 treatments. Uniconazole significantly improved the activities of antioxidant enzymes comprising superoxide dismutase, peroxidase, and catalase, but reduced that of malondialdehyde (MDA) and the accumulation of reactive oxygen species (ROS) during the leaf senescence process. Treatments S1 and F1 had higher antioxidant enzyme activities but reduced MDA, superoxide radical, and hydrogen peroxide contents. Uniconazole significantly reduced leaf senescence in leaves in the bottom layer, while also increasing the middle layer leaf area and decreasing the top layer leaf area. The degradation of photosynthetic pigments was reduced by uniconazole because the enhanced antioxidant activities of enzymes protected plants from harmful ROS. Uniconazole significantly improved the photosynthetic traits, antioxidant defense system, and grain yield in maize in semiarid regions, where the most effective treatment was S1. [ABSTRACT FROM AUTHOR]

High‐frequency (subhourly) changes in soil respiration (Rs), a critical component of the carbon cycle, are not well documented in semiarid ecosystems. We investigate the response of Rs to subhourly soil temperature (Tsoil) and soil volumetric water content (VWC) variation in a semiarid ecosystem across a year of highly variable weather. We propose a probabilistic model to estimate the likelihood of Rs exceeding its annual mean (1.2 μmol CO2/m2s), conditioned on different Tsoil and VWC values. The results show that Rs follows a Gaussian‐like pattern as Tsoil increases, where it follows an upward trend until ~18 °C, and then begins to decline. Rs remains constant at Tsoil beyond ~27 °C. Using our novel conditional probability model, we show both the increasing and decreasing response of Rs to rising Tsoil through two ranges (14–17 and 20–23 °C) where Rs observations show opposing responses. We demonstrate that an increase in Tsoil from 14 to 17 °C causes a rise in Rs by a factor of 1.4 relative to the mean. The proposed model also describes how Rs reduces as Tsoil continues to increase above ~18 °C. Considering VWC and Tsoil into the proposed model, we show that when Tsoil is low (e.g., 17 °C), a rise in VWC yields a decrease of Rs by a factor of 3.6. However, when Tsoil is high (e.g., 23 °C), Rs increases with increasing VWC by a factor of 2.5. Overall, the probabilistic model enables us to detect and characterize changes in Rs distribution in response to different environmental variables and thresholds. Key Points: We propose a probabilistic model where we determine changes in the exceedance probability of soil respiration due to changes in variablesSoil respiration (CO2 flux) follows a Gaussian‐like (bell‐shape) pattern with increasing soil temperatureWhen temperature exceeds the dew point, soil respiration has the potential to raise up to 60% higher compared to dry condition [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to describe the efforts undertaken to convert the large university campus of Jordan University of Science and Technology (JUST) into a green, resource-efficient and low-carbon campus by following an action-oriented strategy. Sustainability features of the campus were discussed and benchmarked. Challenges were identified and remedial actions were proposed. Design/methodology/approach: Taking 2015 as the baseline year, data on energy, water consumption and solid waste generation for the university campus were collected. Energy consumption for cooling, heating and transportation, besides electric power consumption, were reported, and the associated carbon dioxide (CO2) emissions were estimated. By calculating the full time equivalent of students and employees, carbon emission and water consumption per capita were calculated. A comparison with other universities worldwide was conducted. Findings: Although located in a semiarid region with scarce water resources, JUST has set an example by greening its campus through an action-oriented approach. It was found that the per capita carbon emission for JUST campus was 1.33 ton of CO2 equivalent, which is less than the emissions from campuses of other universities worldwide. As for water, this study revealed that the daily per capita water consumption was about 56 L, which is approximately one-third of that for students in institutions in the USA. Furthermore, the findings of this study indicated that the average solid waste generation rate was 0.37 kg per student per day compared to 0.31 kg per capita per day when considering the university community (students and employees) collectively. These figures were less and thus compare favorably to the corresponding data for other universities in both developing and developed countries. Originality/value: This research addresses the issue of greening JUST campus, which is one of the largest university campuses in the world. JUST campus is located in a semiarid, water-scarce country, which on its own poses a serious challenge. The originality and value of this study mainly stem from the facts that on the one hand, this is one of the unique and pioneering comprehensive studies of its type and, on the other hand, other universities with similar conditions can benefit from the findings of this research to meet the sustainability objectives on their campus operations. [ABSTRACT FROM AUTHOR]

Rainfall pulses can significantly influence carbon cycling in water‐limited ecosystems. The magnitude of carbon flux component responses to precipitation may vary depending on precipitation amount and antecedent soil moisture, associated with nonlinear responses of plants and soil microbes. The present study was carried out in a temperate grass ecosystem during 2013–2015 in the semiarid Loess Plateau of China, to examine the response of carbon fluxes to precipitation using the "threshold‐delay" model. The unique contribution of environmental variables such as precipitation amount and antecedent soil moisture before rainfall (SWC_antecedent) to carbon fluxes in response to rainfall was also investigated. The lower threshold of effective rainfall was 6.6 mm for gross ecosystem production (GEP), 8.5 mm for net ecosystem production (NEP), and 4.5 mm for ecosystem respiration (RE); and the upper threshold of effective rainfall was 21.4 mm for GEP and NEP, and 16.8 mm for RE. Rainfall amount was positively affected the relative rainfall responses of GEP, NEP, and RE. However, SWC_antecedent at 20 cm soil depth offset the response of GEP to rainfall pulses, and SWC_antecedent at 5 cm soil depth offset the response of NEP and RE to rainfall pulses, with corresponding partial slopes of linear regressions of −0.50, −0.40, and −0.52. These results indicated that NEP was more sensitive to rainfall pulses and RE was more sensitive to SWC_antecedent. These results demonstrate the importance of rainfall events of <10 mm and that the negative effect of SWC_antecedent should also be considered when estimating ecosystem carbon fluxes in this semiarid region. NEP was more sensitive to rainfall pulse in the studied temperate grass ecosystem. Antecedent soil moistures before rainfall event significantly offset the positive effect of rainfall amount on these carbon fluxes. [ABSTRACT FROM AUTHOR]

The supply of raw water to the inhabitants of metropolises is not a trivial problem, and involves many challenges, both in terms of the quantity and quality of this water. When these metropolises are located in semiarid regions, this challenge takes on enormous proportions, and in many situations, there are no sustainable solutions, especially in times of global climate change. One hypothesis to try to mitigate this problem in coastal cities is the underwater adduction of rivers. The objective of this paper was to make the abstraction of drinking water in the mouths of great rivers near semi-arid regions. This water would be led by a pipeline below the water level and would follow the route of the seacoast, where the energy to move the water would be supplied by an axial hydraulic pump embedded in the pipeline by water-cooled electric motors driven by the energy generated from offshore wind turbines. Estimates have been made for the four metropolises in semi-arid regions: Fortaleza-Brazil, Dalian-China, Tel Aviv-Israel, and Gaza-Palestine, where it was possible to calculate economic viability through the Present Worth Value, the internal rate of return, and payback. The results indicated that Fortaleza had economic viability under restrictions. Dalian proved the ideal result. Tel Aviv and Gaza both had great economic viability, but only if Egypt agreed to supply water from the Nile. This paper proved that the management of the water supply for human consumption through the underwater adduction of rivers could be achieved with real clearance for any deficits in the volume of water that due to global climate change are becoming more frequent. [ABSTRACT FROM AUTHOR]

Agroclimatology concerns those climate processes influencing agricultural production, especially with respect to crops growing under rainfed conditions. A number of methodologies have been used to classify climate variables. The goal of this research was to obtain the agroclimatic delimitation for the Zacatecas region in Mexico using the Papadakis classification and collecting time-series data from 133 weather stations to obtain monthly thermal and monthly water parameters. The dataset is composed of information collected for the period of 1960-2015. For all weather stations data were filtered and chronologically sorted to complete any missing information using a geostatistical and Kalman filter approach. Monthly average values were interpolated using the ordinary Kriging method. Twelve maps were plotted to characterize agroclimatic conditions showing that January, February, November, and December are months that are too cool for agricultural practices. The climate conditions begin to become benevolent for agriculture from April. Three different agroclimatic zones were obtained for Zacatecas region. More than 90% of the surface is under the 2.2 climate type favoring crops such as maize, beans, and soybeans. Agroclimatic understanding is particularly important in semiarid regions because this permits proactive actions for promoting the agricultural potential of regions with scarce rainfall regimes. [ABSTRACT FROM AUTHOR]

Phytoplankton functional groups structure and species abundance vary according to environmental conditions. The present study investigated the natural and anthropogenic stressors that affect phytoplankton functional group biomass in a Brazilian semiarid region reservoir (Argemiro de Figueiredo reservoir). Sampling occurred between August 2007 and July 2009 on a bi-monthly basis for the first year, and in a monthly basis for the last two years. There were three collection points (PC: river confluence; PNC: near the cages; PD: dam site). The water environment analysis of abiotic variables included: temperature, transparency, coefficient of vertical light attenuation, dissolved oxygen, pH, electrical conductivity, alkalinity, dissolved inorganic nitrogen, and reactive soluble phosphorus. Phytoplankton samples were collected into a Van Dorn bottle, and were then preserved in acetic lugol and were quantified using an inverted microscope to determine phytoplankton density and biomass; the identified species were assembled in functional groups. The data were explored by canonical correspondence analysis. Individual analyses were made to test the temporal and spatial variability of the data and the factors that interfered most with the biotic and abiotic variables. Functional groups S1, SN, and K, consisting of filamentous Planktothrix agardhii (Gomont) Anagnostidis & Komárek, Cylindrospermopsis raciborskii (Woloszynska) Seenaya & Subba Raju, and the coccoid Aphanocapsa incerta (Lemmermann) Cronberg & Komárek, respectively, dominated the dry months when the water was warm, turbid, and alkaline. The overflow reservoir served as a natural disturbance reducing the phytoplankton biomass to less than 50 % and the dominance of cyanobacteria, promoting the domain of functional groups F, M, MP, Lo, and X2. The nutrient inputs from intensive fish farming, associated with a low local depth (Zmax = 7.7 m) close to the cages (PNC), resulted in a significant human disturbance that increased the prevalence of functional groups S1, SN, and K, which are composed primarily of cyanobacteria. We concluded that, in reservoirs, overflow events are natural disturbances that have the ability to reduce phytoplankton biomass and alter the structure of local communities, and that intensive fish farming is an anthropogenic disturbance that increases the availability of nutrients and stimulates an increase in biomass of the functional groups that include cyanobacteria. Furthermore, the functional groups of phytoplankton were reliable control of environmental conditions in the reservoirs of tropical semiarid regions. [ABSTRACT FROM AUTHOR]

There is a growing stress on groundwater due to increase in the frequency and intensity of droughts, and the limited availability of surface water. Therefore, proper assessment of available groundwater reserves is highly essential at a microscale (e.g., block level) to take into account spatial variability. In this paper, a methodology for the effective assessment of groundwater resources is demonstrated considering a semiarid river basin of Western India as a study area. The rainfall data of nine raingauge stations and seasonal groundwater-level data of 132 sites over the basin for 20 years (1990-2009) were used. Groundwater availability in the unconfined aquifer was evaluated at a block level in terms of 'static groundwater reserve (SGWR)' and 'dynamic groundwater reserve (DGWR),' and their spatial and temporal variabilities were analyzed. Furthermore, the status of groundwater utilization in individual blocks was explored considering the level of groundwater development (GWDL) and the trends of long-term seasonal groundwater levels. To sustain available groundwater resources on a long-term basis, the runoff potential in the study area was also evaluated. It was found that SGWR varies from 0.09 to 136.97 MCM (million cubic meters), whereas DGWR ranges from −35.85 to 156.26 MCM. During 'normal' years, around 43% of the study area has a SGWR in the range of 20-40 MCM and DGWR in the range of 0-50 MCM. Although the GWDL in the study area varies from about 12 to 124%, the status of groundwater development in the study area is categorized to be 'safe.' The analysis of runoff potential in the study area revealed that it considerably varies with time and space. About 71% of the study area is suitable for rainwater conservation during 'wet' years, whereas this figure reduces to 33% in 'normal' years. It is emphasized that regular monitoring of groundwater at a suitable spatial scale (at least block level) is necessary on long-term basis and the adoption of rainwater harvesting measures are indispensable for sustainable utilization and management of groundwater resources in semiarid regions. [ABSTRACT FROM AUTHOR]

Stabilisation ponds are the most frequently used wastewater treatment technology in Argentina. This study focuses on the performance of two maturation ponds (MPs) that are part of the full-scale sewage treatment system of Puerto Madryn. Seventy-seven shots of surface water were analysed for organic matter, inorganic nitrogen, phytoplankton dynamics and bacterial removal. The system presented a clear evolution with respect to oxygenation and phytoplankton development. The treated wastewater reached values above 8 mg-O2/L, an important organic matter removal, and this was accompanied by a strong increase in pH. [ABSTRACT FROM AUTHOR]

• The response of soil water content (θg) to vegetation restoration mode varied highly. • θg increased with soil depth and the distance from the ephemeral gully (EG) head. • θg was less on EG top with artificial plant than on EG top with natural plant. • Natural succession is recommended to control soil erosion and maintain soil water. Vegetation restoration in an ephemeral gully (EG) can alter the traits of soil, vegetation, and microtopography, and therefore likely influences soil water. Nevertheless, few results have been reported regarding the response of soil water regime to vegetation restoration modes in EGs in semiarid region. This research was designed to clarify the spatial variation in soil water in an EG with different restoration modes on the Loess Plateau of China. For the selected EG, the two banks of ephemeral gully were well restored by natural succession and artificial planting. Soil water content (θg) was quantified on the ephemeral gully floor (F), natural successional restored ephemeral gully top (NT), and artificial planted restored ephemeral gully top (AT) in both the vertical and longitudinal directions. A sloping farmland was selected as the control. The results revealed that θg increased significantly with soil depth (i.e., 0–1 m) and the distance from the ephemeral gully head (i.e., 0–60 m). In the vertical direction, the mean θg of the six test points of the ephemeral gully floor was 1.1 to 1.2 times greater than that of the control in each soil layer, while the mean θg of the six test points of NT and AT decreased by 12.3 % to 15.6 % and 29.2 % to 29.9 % compared to the control in each soil layer. Along the longitudinal direction, the θg (i.e., 0–1 m soil layer) abided by the pattern of F > NT > AT. The difference in θg between the three ephemeral gully units and their variations in the vertical and longitudinal directions were mainly driven by the variations in soil clay content, bulk density, organic matter content, plant root density, plant litter density, and the distance from the ephemeral gully head. The findings are useful to clarify the spatial variation in soil water and to select a reasonable vegetation restoration mode on hillslopes in semiarid regions. [ABSTRACT FROM AUTHOR]

As a drought tolerant plant, jujube ( Ziziphus jujuba Mill.) is commonly planted in Chinese semiarid Loess Plateau Region under rain-fed conditions. To evaluated the effectiveness of branch removal to conserve water resources in rain-fed jujube plantations in the region, two degrees of branch removal treatments (T1–two main branches removed; T2–one main branch removed) were compared with control treatment (none of the three main branches removed) and the effects on water use in Jujube plantations were analyzed. Sap flow was monitored (using the Granier-type thermal dissipation probes) along with meteorological factors, soil water content, vessel diameter, crown projection area and leaf area index, with soil moisture condition divided into water stress and non-water stress. Results showed that branch removal was an efficient way of conserving water resources in jujube plantations. a) It improved soil water content by reducing water loss via total evapotranspiration ( ET ) during jujube growth period. Total ET values were 452, 463 and 478 mm respectively for T1, T2 and the control treatments during jujube growth period in 2012; 408, 426 and 451 mm respectively for T1, T2 and the control treatments during jujube growth period in 2013 and 374, 381 and 392 mm respectively for T1, T2 and the control treatments during jujube growth period in 2014. b) Branch removal not only decreased transpiration per unit ground area (stand transpiration: T g ), but also increased the sensitivity of T g to environmental variables. In contrast, the removal of two (out of three) branches increased transpiration per unit leaf area (leaf transpiration: T l ), making it less sensitive to soil water content. c) Treatment T1 significantly increased the sensitivity of canopy conductance ( G c ) to vapor pressure deficit ( VPD ), which effect was not significant under T2. Isohydric regulation of water loss through G c response to VPD was the same for the three treatments, regardless of the different tree canopy sizes and soil water conditions, but reference canopy conductance ( G cref : canopy conductance at VPD = 1 kPa) was treatment-specific. d) Branch removal improved the tolerant of jujube tree to negative water potential and xylem cavitation by decreasing average vessel lumen diameters. Compared with the control, both branch removal treatments (T1 and T2) resulted in a significant decrease in average vessel lumen diameter at 15 mm below the cambium (40.74, 42.53 and 46.81 μm respectively for T1, T2 and the control treatments). Similarly, T1 and T2 reduced mean vessel lumen diameter at 5 mm below the cambium (43.20, 47.44 and 48.39 μm respectively for T1, T2 and the control treatments). e) Branch removal significantly decreased the fresh fruit yield and water use efficiency except in 2013, during which differences were not significant. Fresh fruit yield values were 8082, 8964 and 11293 kg ha −1 respectively for T1, T2 and the control treatments in 2012; 5691, 5426 and 6000 kg ha −1 respectively for T1, T2 and the control treatments in 2013; 6804, 8341 and 10589 kg ha −1 respectively for T1, T2 and the control treatments in 2014. WUE values were 1.79, 1.94 and 2.36 kg m −3 in 2012; 1.40, 1.28 and 1.33 kg m −3 in 2013; 1.82, 2.19 and 2.70 kg m −3 in 2014. T1 treatment was recommended in terms of improving soil water storage as well as maintaining a certain amount of productivity in jujube plantations in Chinese semiarid Loess Plateau Region. The result of the study is critical for the development of effective water management strategies in jujube plantations ensure that the fragile ecology of the Loess Plateau is sustained. [ABSTRACT FROM AUTHOR]

Although the use of wild mammals as a source of food has been better studied in tropical forest environments, their importance as a source of protein for human communities in semiarid environments is little known. In the latter, the availability of wild animal meat is limited in comparison to other environments. In the semiarid regions of northeastern Brazil, hunting wild mammals for their meat is traditional, playing a crucial role in the livelihoods and food security of various rural and urban communities, especially during the annual drought seasons. In this study, we investigated the role of wild mammals as bushmeat in 10 communities within the Caatinga biome in northeast Brazil. We used key-informant interviews, household surveys, and questionnaires to determine the species hunted and consumed. We found that about 30 species were used for bushmeat, with communities clustering into two main groups. We showed that in almost all municipalities visited, all mammals hunted were reported after interview days. A total of 46.9% of hunters consumed bushmeat at least once a week. However, preference for bushmeat over livestock was perceived to be more a matter of taste (61.50% of respondents) than a real need for protein supplementation from the wild. The ease of entering environmental areas where wild mammals can be found has disadvantages for wildlife in terms of pressure and overexploitation, especially where it concerns endangered species. The key to understanding the socioeconomic, cultural, and ecological contexts in which there are traditional uses is to develop conservationist strategies suitable for the socioeconomic reality of human populations. [ABSTRACT FROM AUTHOR]