Semi-arid Zone Research Articles

Predicting habitat suitability for the endangered species Hedysarum criniferum Boiss. using a fuzzy model in the semi-arid zone in Iran

The present study explored the habitat suitability for an endangered species, Hedysarum criniferum, in Iran using fuzzy logic. We measured 24 environmental variables including soil, climate, and physiographic variables of eight natural habitats of H. criniferum as the predictive variables and the percent cover of the species as the response variable. The most important environmental factors influencing species distribution and the species response curves were determined by principal component analysis (PCA) and the generalized linear model, respectively. The tolerance range and the optimal growth point of the studied species with respect to the environmental factors were specified, the ranges were divided into 11 classes by fuzzy value, and the fuzzy functions of the environmental factors were calculated. The species habitats were classified by the developed fuzzy model. Three regions with no H. criniferum occurrence were selected to determine their fuzzy suitability. The success in germination and shoot growth length of H. criniferum were used as the metrics of the habitat suitability in these regions. Based on the PCA, H. criniferum occurrence was most strongly affected by soil Mg, K, and Ca content, soil pH, wind speed, annual minimum temperature, slope, and altitude. The results revealed that the seedling length and germination percentage in the site with the fuzzy suitability of 0.6 differed from those in the two other sites with the fuzzy suitability of 0.5 and 0.3 significantly. The method used in this study can be employed in predicting optimal habitats for other endangered species in different ecosystems.

Sensitivity of the land surface hydrological cycle to human activities in China

While many studies have focused on the sensitivity of the water cycle to climate change, few have investigated this sensitivity to human activities. We don't know how sensitive the surface hydrological system is to human activity and which component of the water balance is most sensitive. This study performed model simulations to quantify the sensitivity of China’s land surface water cycle to the human activity intensity (HAI). The results indicate that lateral flow to streamflow (LATQ) was the most sensitive to HAI (0.679), followed by base flow (GW, 0.291), actual evapotranspiration (ET, 0.203), and surface runoff (SURQ, 0.174), while the percolation amount (PERC) and water yield (WYLD) sensitivities were 0.172 and 0.081, respectively. Hotspots of the ET sensitivity to HAI occurred mainly in Western and Northeast China. The spatial sensitivity patterns of GW and PERC were similar, i.e., lower in the south than elsewhere. Notably, SURQ was insensitive to HAI changes in the urban areas of South China (sensitivity: 0–0.06). Although the HAI variation was the lowest in semiarid regions during 1980–2018 (0.07–0.82%), their water cycle sensitivity to HAI was the highest among all four climatic zones. The ET, SURQ, LATQ, PERC, GW and WYLD sensitivity coefficients to the HAI in the semiarid zone were 20.441, 41.292, 5.276, 24.431, 52.06 and 1.032, respectively. Hydrologically, semiarid areas, the Qinghai-Tibet Plateau and the region near the Karamay oilfield should be prioritized. Specifically, LATQ should receive the most attention.

The effect of formation processes on the frequency of palaeolithic cave sites in semiarid zones: Insights from Kazakhstan

AbstractCentral Asian caves with Palaeolithic deposits are few, but they provide a rich record of human fossils and cultural assemblages that has been used to model Late Pleistocene hominin dispersals. However, previous research has not yet systematically evaluated the formation processes that influence the frequency of Palaeolithic cave sites in the region. To address this deficiency, we combined field survey and micromorphological analyses in the piedmont zone of south Kazakhstan. Here, we present our preliminary results focusing on selected sites of the Qaratau mountains. Sediment cover varies among the surveyed caves, and loess‐like sediments dominate the cave sequences. The preservation of cave deposits is influenced by reworking of cave sediments within the caves but also by the broader erosional processes that shape semiarid landscapes. Ultimately, deposits of potentially Pleistocene age are scarce. Our study provides new data in the geoarchaeologically neglected region of Central Asia and demonstrates that micromorphology has great analytical potential even within the limitations of rigorous survey projects. We outline some of the processes that influence the formation and preservation of cave deposits in Kazakhstan, as well as broader implications for the distribution of Palaeolithic cave sites in Central Asia and other semiarid environments.

Morphological and molecular characterization of ticks infesting cattle and buffaloes in different agro-climatic zones in Andhra Pradesh, India, and factors associated with high tick prevalence

ABSTRACT A study was carried out to characterize the hard tick species and risk factors associated with tick prevalence in bovines in Andhra Pradesh, India on 3720 animals (1942 cattle and 1778 water buffaloes) in 344 livestock farms covering the tropical wet and dry zone and the tropical semi-arid zone . Overall, 10,371 ticks were collected from 947 animals reared on 216 farms. Analysis of morphology, 16S r RNA, andCOI gene sequences identified four tick species, namely Haemaphysalis bispinosa, Rhipicephalus (Boophilus) microplus (clade C), Hyalomma anatolicum, and Hyalomma isaaci. Haemaphysalis bispinosa was the predominant species in two zones, and the occurrence of Hy. anatolicum was restricted to the semi-arid zone. The overall prevalence of tick infestation was 25.5% and was 25.8% and 25.0% in cattle and buffaloes, respectively. The prevalence of tick infestation did not vary (P>0.05) between the two zones. The overall median tick burden per animal differed (P<0.01) between the two zones; but not among cattle and buffaloes. Age, sex, and breed (P<0.001) the overall prevalence of tick infestation. The conventional housing system, absence of rural poultry, soft floor, presence of a boundary wall, and rearing multiple ruminant species were observed to be potential risk factors associated with higher tick prevalence in livestock farms.

Evaluation of WRF Cumulus Parameterization Schemes for the Hot Climate of Sudan Emphasizing Crop Growing Seasons

High spatiotemporal resolution climate data are essential for climate-related impact studies. The Weather Research and Forecasting (WRF) model is widely used to downscale climate data for different regions with regional-specific physics configurations. This study aimed to identify robust configurations of the WRF model, especially cumulus parameterization schemes, for different climatic zones of Sudan. We focused on wet season (June–September) rainfall and dry season (November–February) temperature, which are determinants of summer crop and irrigated wheat yields, respectively. Downscaling experiments were carried out to compare the following schemes: Betts–Miller–Janjic (BMJ), improved Kain–Fritch (KFT), modified Tiedtke (TDK), and Grell–Freitas (GF). Results revealed that the BMJ performed better for wet season rainfall in the hyper-arid and arid zones; KFT performed better for rainfall in July and August in the semi-arid zone where most summer crops are cultivated. For dry season temperature, the BMJ and TDK outperformed the other schemes in all three zones, except that the GF performed best for the minimum temperature in December and January in the arid zone, where irrigated wheat is produced, and in the semi-arid zone. Specific parameterization schemes therefore need to be selected for specific seasons and climatic zones of Sudan.

Arbuscular mycorrhizal fungus and organics substrates effect on bean plant morphology and minerals

Arbuscular mycorrhizal fungi (AMF) are obligate symbionts that require a host plant (tramp) and support (substrates) to be applied as bio-fertilizers in agriculture. The objective of this study is to assess eight native AMF consortia of semi-arid zones (C1-ART, C2-GEC, C3-PAR, C4-VIE, C5-CUC, C6-SAC, C7-SAB, and C8-MUZ) and their reproduction response in three organic substrates: coffee pulp (CP), bovine manure (BM) and sugarcane bagasse (SB) on bean Phaseolus vulgaris. Plant height, stem diameter, number of leaves, root length, fresh and dry biomass, and mineral content in root were measured. The organic substrates (CP and BM) and C5-CUC and C8-MUZ consortia increased plant height, root length, and total fresh and dry biomass considerably. After day 75 of inoculation, root colonization oscillated from 5.7% in C8-MUZ to 46.1% in C2-GEC and C4-VIE; the greatest number of spores (201) was obtained in CP substrate in a 100-g sample. N, P, K, Ca, Mg, Fe, Zn, Cu, and Mn contents in root and leaves were signif icantly high (P ≤ 0.001). To conclude, native AMF inoculation and substrates had positive effects on biomass content and nutrient levels in leaf and root with the C2-GEC and C3-PAR consortia and CP and BM substrates, which produced better effects in beans, making them a biofertilization alternative in agricultural crops.

Effect of Sowing Date on Grain Yield, its Components and Some Morpho-Phenological Traits of Durum Wheat (Triticum durum Desf.) In Semi-Arid Zone in Algeria

This study was conducted at Setif Agricultural Experimental Station in 2017−2018 crop season, the experimental material used in this study consisted of 5 cultivars (Triticum durum Desf.) based on their difference between early and late cultivation. The genotypes tested were sowing in in a random block design with three replications, each plot consisted of 2 rows of 2.5 m long spaced of 20 cm. The aim of this study is to assess the impact of the choice of sowing date on grain yield, these components as well as some morpho-phenological traits in order to have an idea on the best sowing date. Two-way analysis of variance showed that the effect of sowing date was significant (p&lt;0.001−0.05) with the variables above ground biomass (BIO), spike weight (SW), Thousand kernels weight (TKW), Flag leaf area (LA), plant height (PH), number of days to heading (DH) and canopy temperature (CT), this effect caused the decrease of major parameters studied and mainly grain yield (GY), accompanied by decrease of BIO, SW, TKW, relative Water contents RWC, LA, PH and DH. Ofanto is shown to be the most suitable genotype for the late sowing date (January). The correlation analysis show that GY was significantly, strongly and positively correlated (p&lt;0.001) under both sowing date with BIO and SW. CT was negatively correlated with GY, BIO, SW and HI (p&lt;0.05) who suggest that our plants underwent water stress during the second sowing date.

English

African rosewood (Pterocarpus erinaceus) is an endemic, highly exploited and endangered tree species in arid and semi-arid zones of West Africa. Identifying optimum conditions for seed propagation and storage is critical for its conservation. This study assessed the effects of four pretreatments on seed germination and seedling vigour. Varying temperature, duration and packaging on storage deterioration were also evaluated for 12-months. Moisture sorption isotherms at 20, 25 and 30&deg;C were characterized by equilibrating seed samples on series of lithium chloride (LiCl) solutions, generating relative humidity (RH) range of 3-95%. Data were fitted to four mathematical models; Chung Pfost, Halsey, Henderson and Oswin to determine the most suitable for describing the water activity (aw), equilibrium moisture content (EMC) and temperature relationship. Results indicate that whole fruit sowing reduced germination capacity by more than 50% compared with extracted seeds at 5% probability level. Seeds stored at -10&deg;C recorded the lowest rate of seed deterioration compared with ambient storage, regardless of packaging. Moisture sorption isotherms for rosewood showed a sigmoid (S-shaped) profile characteristic of orthodox seeds, and best described by the Henderson equation. Our findings highlight the need for adopting improved seed extraction technology and orthodox seed storage protocols for P. erinaceus conservation. Key words: seed germination, storability, African rosewood, sorption isotherms.

A Modified Richard’s Equation for Assessing the Impact of Drought and Salinity in Arid and Semi-Arid Zones

A Modified Richard’s Equation for Assessing the Impact of Drought and Salinity in Arid and Semi-Arid Zones

Grazing intensity and its impact on plant performance at semi-arid zone of Sudan

Grazing intensity and its impact on plant performance at semi-arid zone of Sudan

Grazing intensity and its impact on plant performance at semi-arid zone of Sudan

Livestock grazing can affect the herbaceous composition by making changes to the vegetation coverage. Plant species contribute to the largest proportion of the fodder. Despite the profound benefits obtained, anthropogenic disturbances are hindering its development. The study was carried at Umkaddada locality, North Darfur State, for years 2017 and 2018 to investigate the effect of grazing intensity on plant density and species. A total of twenty random line transects in unprotected area were conducted, quadrats of 1×1 m2 size were laid down at 50 m intervals along every transect, and data were analyzed by t-test to compare data. The result showed the higher number of plants subjected to grazing was at level (III) with the percentage of 52.9% at the late of first season, and showed that there was 39.4% at level (I) at early of the second season. Also the result showed that the higher number of species not subjected to grazing was 100% at early of the first season, and the result showed there was 100% grazing at level (III) at the late of second season. The study concluded that grazing intensity of level (II) and more may have significant effect on plant growth.

Effect of copper mining on vegetation disturbances in and out of Oyu Tolgoi mining site

Since 2005, the mining sector has been a vital part of Mongolia's economy. This sector is one of Mongolia's most important sources of revenue. Primary outputs of Mongolia's mining industry are copper, gold, and coal. On the other hand, mining has a negative impact on the environment causing soil erosion, noise pollution, water pollution, and biodiversity loss. The Oyu Tolgoi copper mine is located in a semi-arid zone in the Mongolian Gobi. The impact of mining was investigated by sampling eight plots both in and out of this giant mining site. Vegetative cover, species richness, biomass, and basal gap of perennial plants were compared within and outside the perimeter of the Oyu Tolgoi mining site. The mining sites have a harmful impact on the environment. According to our findings vegetation cover, species richness, biomass, and perennial plant gaps were not different between the paired plots outside and inside of the mining site. Mining activities had little effect on vegetation, according to the findings.

Comparative study and genetic diversity of Salicornia persica (Chenopodiaceae) using SCOT molecular markers

Salicornia is a cosmopolitan genus having a high complicate taxonomy even described as a nightmare. Morphologically members of Salicornia are halophyte, annual, articulated, and succulent herbs with cortical palisade, opposite decussate scale-leaves, thyrsoid cymes, flowers packed in cauline depressions and the diaspore composed of l-seeded utricle. Salicornia is a priceless edible vegetable, considered as a favourable resource for cultivation in arid and semiarid coastal zones. Concerning the molecular data, although various studies were published, the situation is still quite obscure, at least for some taxa. Also, no DNA markers were used to analyses the genomic variability of the populations, up to date. In the present study, the genetic diversity of 102 individuals of S. persica (15 populations) were studied using 10 Start Codon Targeted (SCoT) markers. High polymorphic bands (94.18%), polymorphic information content (0.27), and allele number (1.38) showed SCoT as a reliable marker system for genetic analysis of this species. We used SCoT molecular marker for our genetic investigation with the following aims: 1) investigate genetic diversity both among and with date S. persica, 2) identify genetic groups within the 15 populations studied, and 3) produce data on the genetic structure of S. persica populations. The results obtained revealed a high within-population genetic variability.

Tufa associated with karst features in a fracture-system fed by meteoric water, Araripe basin, NE Brazil

Karstic tufa from the Brazilian semi-arid zone offers a key opportunity to study the depositional evolution, unveiling the past climate history with examples generated outside of the phreatic zone. Morpho-petrological identification, in addition to a structural survey, petrographic analysis, X-ray diffractometry (XRD), scanning electronic microscopy (SEM), and measurements of δ18O and δ13C, provided elements to explain the occurrence of tufa associated with a fracture system. Three sedimentary facies were identified, one allochthonous (detrital) and two autochthonous (in situ). Field recognition and structural analysis showed that tufa occurs only in the deformed portion of the Crato Formation, at the Triunfo Fault splay sector. Facies formed in an open fracture-controlled hydrological system during rainfall periods. The infiltration of meteoric water into the limestones of the Crato Formation facilitated the dissolution of the parent rock through time, with the percolation controlled by open fractures in tilted blocks. Breccia tufa developed in the early stage of the karstification by carbonate clast forming from the limestone, previously collapsed from the walls and later cemented by percolation of solutions enriched in calcium carbonate within fractures. The two autochthonous facies developed in later stages through continuous percolation of water, rock dissolution, bryophyte-microbial growth, soil development, and calcium carbonate precipitation in progressively more humid conditions. Thin section analyses and SEM imaging revealed calcite crystals closely related with organic structures. The association between tufa and microbial filamentous organisms (likely cyanobacteria) indicates an active biogenic role for the tufa origin. Calcite stable-isotopes analyses indicated tufa as a product of meteoric water as supported by δ18O isotope. Changes of the carbon ratios through time indicated influence of soil development and probably C3–C4 photosynthetic activity. An integrated structural, sedimentological, petrological, and geochemical approach provided elements to define these tufa deposits as formed in a fracture-system fed by meteoric water, as result of the post-Mesozoic denudation process that affected the Araripe Basin.

A Geospatial Approach for Analysis of Drought Impacts on Vegetation Cover and Land Surface Temperature in the Kurdistan Region of Iraq

Drought is a common event in Iraq’s climate, and the country has severely suffered from drought episodes in the last two decades. The Kurdistan Region of Iraq (KRI) is geographically situated in the semi-arid zone in Iraq, whose water resources have been limited in the last decades and mostly shared with other neighboring countries. To analyze drought impacts on the vegetation cover and the land surface temperature in the KRI for a span of 20 years from 1998 to 2017, remote sensing (RS) and Geographical Information Systems (GIS) have been adopted in this study. For this study, 120 Landsat satellite images were downloaded and utilized, whereas six images covering the entire study area were used for each year of the study period. The Normalized Difference Vegetation Index (NDVI) and Land Surfaces Temperature Index (LST) were applied to produce multi-temporal classified drought maps. Changes in the area and values of the classified NDVI and LST were calculated and mapped. Mann–Kendall and Sen’s Slope statistical tests were used to assess the variability of drought indices variation in 60 locations in the study area. The results revealed increases in severity and frequency of drought over the study period, particularly in the years 2000 and 2008, which were characterized by an increase in land surface temperatures, a decrease in vegetation area cover, and a lack of precipitation averages. Climate conditions affect the increase/decrease of the vegetated cover area, and geographical variability is also one factor that significantly influences the distribution of vegetation. It can be concluded that the southeast and southwestern parts of the KRI were subjected to the most severe droughts over the past 20 years.

Estimation of water erosion in abandoned quarries sites using the combination of RUSLE model and geostatistical method

Worldwide, water erosion is one of the most severe hazards to soil degradation. This study aims to estimate and map water erosion in abandoned quarries in the semi-arid zone of Morocco with the Revised Universal Soil Loss Equation (RUSLE) model coupled to a Geographic Information System (GIS). This study used the RUSLE model to assess water erosion risk in abandoned open-pit quarries. This equation necessitates data collection from many sources in various formats and scales. The GIS program (ArcGIS 10.5) facilitated data processing and management. It was used to spatially process the different layers and evaluate the input data's effect on the soil erosion mapping. The average annual soil loss was calculated by multiplying the five erosion factors: rainfall erosivity, soil erodibility, slope length and steepness, vegetation cover and erosion control practices. The results show that: (i) three quarries (Q3=0.574 t/ha/year, Q4=3.772 t/ha/year and Q5=1.096 t/ha/year) have low soil loss rate, two quarries (Q1=7. 495 t/ha/year and Q2=6.104 t/ha/year) have medium soil loss rate, and (ii) LS and R factors have the most influence on these results. Finally, these results can be an important tool for locating erosion hotspots and help decision-makers make sustainable decisions regarding soil and water conservation.

Abundance and distribution of plant-parasitic nematodes in tomatoes grown in a semi-arid agro-ecological zone in Tanzania

The abundance and distribution of plant-parasitic nematodes (PPN) on tomato plants grown in nine villages in the semi-arid zones of Singida and Dodoma in Tanzania were assessed in December 2020. Samples from soil and plant roots were evaluated for abundance, genera and distribution of PPN. Nematodes were extracted, counted and identified based on morphological descriptors. Ten genera of PPN were identified in both root and soil samples, with root-knot nematodes (RKN) being the most common PPN in all nine villages surveyed. The results showed that the abundance of RKN was significantly higher (p = 0.002) in soil than in tomato roots. Tutu and Chamkoroma villages had a significantly (p = 0.001) higher population density of RKN compared to other villages. In addition, RKN was associated with Penicillium and Aspergillus fungi, while the nematode genera Helicotylenchus, Aphelenchus, Scutellonema and Pratylenchus exhibited relationships with Alternaria and Fusarium fungi. The results also indicated that the abundance of RKN was significantly higher (p = 0.001) in sandy soil as compared to other types of soils. Inappropriate agronomical practices (e.g., no fallow, rotation of tomato plant with related crops) and poor phytosanitary measures were the major factors associated with high levels of abundance and distribution of RKN in soil.

Agrobiodiversity and Sustainability of Oasis Agrosystems in Palm Groves of Sahara and Sahel in Chad

The cultivation of date palm, a pillar of oasis agrosystem constitutes a real source of development in arid and semi-arid zones because of its fruit&amp;rsquo;s rich in sugars and various products, essential to daily life of the populations. In Chad, date production has experienced a decline since the sixties, in relation to diseases, pests and poorly performing cultivation techniques, environmental factors are major causes of the degradation of phoeniculture as well as insecurity and the phenomenon of rural exodus. In order to assess the potential of oasis agroecosystems based on the date palm in Chad, an ethnobotanical survey was carried out among date farmers of Sahara and Sahel. The cultivars of date palm is mainly cultivated in Sahara in the North of the country where it allows a rich and diversified subsistence agriculture (market gardening, fruit trees, cereals and fodder), which excludes the use of chemical inputs in production. Our study made it possible to highlight an important genetic diversity with more than 200 cultivars, resulting from empirical selection and multiplied by offshoot. In Sahara, date palms cultivars have only one fruit production season per year with satisfactory productivity, an acceptable price and farmers have a good knowledge of cultivation practises. In central part of the country corresponding to the Sahelian zone, oasis agrosystems are also found in basins. The climatic conditions favour two production seasons and the income from the sale of dates from the first fruit production season (April and May) is greater than those from the second production season (June to September). The strengthening of the local knowledge and the extension of palm groves made it possible to increase production and income and would contribute to food security and the maintenance of populations in Chad and more generally in Sahel&amp;rsquo;s countries.

A review on the application of the DRASTIC method in the assessment of groundwater vulnerability

AbstractIndustrial and municipal wastes, agricultural contamination owing to pesticides and chemical hazards, seawater intrusion in coastal areas, and other factors damage groundwater. In several towns and industrial clusters across India, this is becoming a rising subject of concern. Groundwater is difficult to contaminate, but once contaminated, it is difficult to clean up. It is critical to attain this goal using a variety of aquifer vulnerability assessment approaches. All of these strategies rely on process models as well as statistical or overlay index methodologies. Groundwater vulnerability is a major topic of discussion due to declining groundwater levels and rising contamination, posing a serious threat to the environment and water sources. To identify the risk and to assess the vulnerability, extensive research has been carried out among all the methods based on different parameters and different indexes. The DRASTIC method is one of the most important and accurate of the overlay and index methods for the assessment of groundwater vulnerability. This research study is a systematic analysis of the available research articles on the applications of the DRASTIC and Modified DRASTIC (DRASTIC-L) performance management process on Geographical Information Systems (GIS). This research also reveals research gaps in the various groundwater vulnerability assessment approaches, as well as their limits and hypotheses. This study discovered that integrating GIS with DRASTIC is the most effective and accurate way for determining groundwater vulnerability. In agricultural, arid, semi-arid, and basaltic zones, the modified DRASTIC model also outperforms the traditional DRASTIC model.

Multiscale and multifactor sea-groundwater interactions in southwestern Mauritania

Coastal aquifers in semi-arid zones are particularly exposed to environmental changes because of their low annual recharge and the increasing anthropogenic pressure. This is particularly the case in the Trarza phreatic aquifer (SW Mauritania), which is the uppermost northern part of the great Senegalese-Mauritanian sedimentary basin. The interactions between the Atlantic Ocean and the Tertiary-Quaternary aquifer have evolved considerably during the last millennia and these continuous changes concern the nature and location of processes at work, their intensity and their current consequences. In this vast region with a very flat topography, hydrodynamic and geochemical observations are still rare and currently allow only the main features of recent history to be reconstructed. The analysis of old and recent data reveals that eustatic variations and the annual flood of the Senegal River were in the past the most important factors of equilibrium between fresh water and sea water, even very far from the present coastline. Today, anthropization, in particular hydraulic developments and urbanisation, adds to the complexity of the system. At a more local scale, denser observations in the Nouakchott urban area or in the Diawling natural park provide a better understanding of current dynamics.