Desert Soil Research Articles

THE MELIORATIVE CONDITION OF FOREST BROWN SOILS AND THE EFFECTIVENESS OF THE APPLICATION OF ANTI-EROSION COMPLEX MEASURES

Land degradation and desertification are the greatest scourges threatening human society. Global climate change and gaps in the culture of agriculture significantly increase the negative impact of these processes. The article presents the direction of degradation processes in the eroded forest brown soils of the Lori region, the qualitative characteristics of these soils, the thickness, the degree of humus content and the availability of nutrients. To mitigate erosion processes, degradation and desertification of soils, on the basis of the conducted research, it is proposed to introduce new technologies and methods of resource-saving tillage and plant care into the agricultural system. In particular, it is necessary to cultivate the soil along the contours of the slope, apply effective crop rotation schemes and fertilize the soil with high rates of organic fertilizers (25-30 t/ha). On heavily eroded and uncultivated arable lands, it is necessary to cultivate a grass mixture of legumes and cereal grasses, which will significantly reduce erosion processes.

Agrochemical and Ecological Conditions of Brown Forest Soils Determined by Degradation Factors by the Example of Bazum Community of Lori Region

The article presents the direction of degradation processes in eroded forest brown soils based on the example of the Bazum community of the Lori region. It also shows the qualitative characteristics of these soils, the thickness, the degree of humus content, and the availability of nutrients. New technologies and methods of resource-saving tillage and plant care are proposed to mitigate erosion processes, degradation, and desertification of soils based on the research conducted.

The mechanical composition of irrigated sandy desert soils in the Jondor district of Bukhara region, and the amount of nutrients in them

The article presents information about the genesis of sandy desert soils of Bukhara region (on the example of the Jondor district), distribution, mechanical (granulometric) composition of the soil, humus in the composition of the soil, the amount and levels of availability of common and mobile nutrients, the level of salinity, the type of these soils, as well as about the usage of these soils in agriculture.

The characteristics of actinomyces strptomyces griseorubiginosus 83 – the effective biosorbent of silver

The bacteria bound about the same amount of silver at the time of inoculation and when added after 24 hours Fourier transform infrared spectroscopy (FT-IR) and measurements of the ζ- potential showed that several groups, mainly carboxy groups are involved in the binding and biotransformation of silver cations. Also, volatile organic compounds profiling for L. lactis, demonstrated the presence of many compounds in the free space of bacteria, which were typical products of bacterial metabolism. Finally, it can be stated that the combination of various instrumental methods used has opened up new possibilities for the interpretation of physicochemical phenomena occurring at the interface between bacteria-bacteria and bacteria-metals- bacteria. The ability of the biomass of cultures of various taxonomic groups to sorb metals is used both for purification of wastewater from metals and in the additional separation of valuable and environmentally significant metals from various wastes. In this work 48 strains of actinomycetes were isolated from various samples of desert soils of Uzbekistan under agricultural crops. As a result of screening, a strain of Streptomyces sp. 83, efficiently absorbs silver from solutions. The morphological-cultural and physiological-biochemical characteristics of the selected

Effect of Compost on Some Soil Physical Properties and Yield of Forage Sorghum (Sorghum bicolor L.) in Desert Soil of Northern State of Sudan

Effect of Compost on Some Soil Physical Properties and Yield of Forage Sorghum (Sorghum bicolor L.) in Desert Soil of Northern State of Sudan

Soil microbial community shifts explain habitat heterogeneity in two Haloxylon species from a nutrient perspective.

Haloxylon ammodendron and Haloxylon persicum (as sister taxa) are dominant shrubs in the Gurbantunggut Desert. The former grows in inter-dune lowlands while the latter in sand dunes. However, little information is available regarding the possible role of soil microorganisms in the habitat heterogeneity in the two Haloxylon species from a nutrient perspective. Rhizosphere is the interface of plant-microbe-soil interactions and fertile islands usually occur around the roots of desert shrubs. Given this, we applied quantitative real-time PCR combined with MiSeq amplicon sequencing to compare their rhizosphere effects on microbial abundance and community structures at three soil depths (0-20, 20-40, and 40-60 cm). The rhizosphere effects on microbial activity (respiration) and soil properties had also been estimated. The rhizospheres of both shrubs exerted significant positive effects on microbial activity and abundance (e.g., eukarya, bacteria, and nitrogen-fixing microbes). The rhizosphere effect of H.ammodendron on microbial activity and abundance of bacteria and nitrogen-fixing microbes was greater than that of H.persicum. However, the fertile island effect of H.ammodendron was weaker than that of H.persicum. Moreover, there existed distinct differences in microbial community structure between the two rhizosphere soils. Soil available nitrogen, especially nitrate nitrogen, was shown to be a driver of microbial community differentiation among rhizosphere and non-rhizosphere soils in the desert. In general, the rhizosphere of H.ammodendron recruited more copiotrophs (e.g., Firmicutes, Bacteroidetes, and Proteobacteria), nitrogen-fixing microbes and ammonia-oxidizing bacteria, and with stronger microbial activities. This helps it maintain a competitive advantage in relatively nutrient-rich lowlands. Haloxylon persicum relied more on fungi, actinomycetes, archaea (including ammonia-oxidizing archaea), and eukarya, with higher nutrient use efficiency, which help it adapt to the harsher dune crests. This study provides insights into the microbial mechanisms of habitat heterogeneity in two Haloxylon species in the poor desert soil.

Desert plants to stop desertification: To succeed, reforestation projects to reclaim once fertile lands need to consider the local abiotic, biotic, and social factors: To succeed, reforestation projects to reclaim once fertile lands need to consider the local abiotic, biotic, and social factors.

Understanding the intricate relationship between plants, desert soils, and desert-specific microbiomes would increase the success chances for reforestation projects to reclaim lands lost to desertification.

Natural degradation process of Salix psammophila sand barriers regulates desert soil microbial biomass C:N:P stoichiometry and homeostasis

The Salix psammophila sand barrier is widely used to control wind-sand disasters in desert areas. Importantly, the means through which the natural degradation of the sand-buried section of these sand barriers contributes to the community-level microbial elemental homeostasis of desert soils remains elusive. In this study, we conducted long-term field in situ sampling experiments over a nine-year period in a typical study area in the desert region of northwest China. Chloroform fumigation and high-throughput sequencing were used to determine soil microbial biomass and the diversity of fungi and bacteria. Combined with sand barrier decay characteristics, soil physicochemical factors, and extracellular enzyme activities, we explored the dynamic balance of soil microbial element ratios and key driving factors. The results show that natural degradation of S. psammophila sand barriers increased microbial biomass C and N contents in desert soil, with seven years being the most important turning point. The consistent increase in the soil microbial C:N:P stoichiometry ratios was primarily directly caused by an increase in the mass loss and changes in the fungal diversity. Microbial C:N and N:P ratios were well limited over time, suggesting homeostatic regulation of microorganisms, but the C:P ratio was not homogenized at the community level. The higher microbial C:P and N:P ratios indicated that microorganisms were limited by P after five years of sand barrier degradation. This was primarily related to a decrease in the soil alkaline phosphatase activity. However, microorganisms mitigated P limitation by altering the fungal community structure. These results constitute new evidence in our understanding of the relationships between S. psammophila sand barriers and soil element stoichiometry and the subsequent effects on microorganisms and community-level elemental homeostasis. This work advances the current understanding of artificial interventions in ecological restoration and desertification control.

Actinotalea soli sp. nov., isolated from Kubuqi Desert soil.

A Gram-stain positive, facultatively anaerobic, motile rod-shaped strain, BY-33T, was isolated from a soil sample obtained from the Kubuqi Desert, PR China. Phylogenetic analysis based on 16S rRNA gene sequence similarity revealed that strain BY-33T was most closely related to the genus Actinotalea, including Actinotalea ferrariae CF5-4T (98.2 % similarity), 'Actinotalea subterranea' HO-Ch2T (98.0 %), Actinotalea solisilvae THG-T121T (97.6 %), 'Actinotalea bogoriensis' 69B4T (97.5 %), Actinotalea fermentans MT (97.3 %) and 'Actinotalea carbonis' T26T (97.0 %). The strain grew at 0‒37 °C (optimum, 28-30 °C) and pH 6.0-11.0 (optimum, pH 9.0-10.0) and with 0‒8.0 % (w/v) NaCl (optimum, 3.0%) on tryptic soy agar. It had catalase activity, but no oxidase activity. The polar lipids of strain BY-33T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannosides. The major respiratory quinone of strain BY-33T was MK-10 (H4). Its major fatty acids were anteiso-C15 : 0, anteiso-C15 : 1 A and C16 : 0. The genomic DNA G+C content of strain BY-33T was 73.0 mol% based on total genome calculations. The average nucleotide identity scores between the genomic sequences of strain BY-33T and the other species of the genus Actinotalea were found to be low (ANIm <85.0 %, ANIb <77.0 % and OrthoANIu <78.0 %). Furthermore, the digital DNA-DNA hybridization and average amino acid identity values between strain BY-33T and the closely related species ranged from 20.5 to 21.0% and from 62.2 to 72.2 %, respectively. Based on the results of phylogenetic, phenotypic, genotypic and chemotaxonomic analyses, it is concluded that strain BY-33T represents a novel species within the genus Actinotalea, for which the name Actinotalea soli sp. nov. is proposed. The type strain is BY-33T (=CGMCC 1.17460T=KCTC 49362T).

Abundant culturable diazotrophs within Actinomycetia rather than rare taxa are underlying inoculants for nitrogen promotion in desert soil

Desert soil may harbor various culturable diazotrophs that can endure multiple environmental stresses and promote ecological restoration. To explore nitrogen-fixing microorganisms that can be potential inoculants for nutrition improvement in nitrogen-limited ecosystems and disclose whether rare taxa contribute to the nitrogen incorporation process, we collected soil from the Mu Us Desert and combined 16S rRNA high-throughput sequencing, functional gene arrays (GeoChip) method, and culture-dependent approaches to observe the composition and key groups of culturable diazotrophs. Proteobacteria was the most dominant phylum, accounting for 73.07 % of the 823 operational taxonomic units (OTUs), grown in nitrogen-free media. Among all the valid assigned putative nitrogen-fixing OTUs, 53.21 % were identified as rare taxa in the soil. Among all the rare OTUs that could be effectively enriched as abundant taxa in the medium, over 58 % were also affiliated with Proteobacteria. Despite the predominance of Proteobacteria, the ordinary least squares regression model implied that less abundant Actinomycetia was significantly related to the nifH gene signal intensity generated by GeoChip, while rare culturable diazotrophic categories had no relationship with the nifH gene. The random forest analyses further confirmed that the most important indicator of the nitrogen-fixing process was Actinomycetia. The two stably generated pure cultures, classified as Streptomyces sp. (Actinomycetia) and Bacillus pumilus (Firmicutes) by Sanger sequencing and BLAST were inoculated into sterilized desert soil. Available nitrogen, total dissolved nitrogen (TDN), and total nitrogen (TN) were measured, and the two strains significantly increased the soil ammonium content, nitrate content, and TDN content. Our findings provide genomic and solid evidence that rare taxa within Proteobacteria maintain the biodiversity of culturable nitrogen fixers, whereas abundant Actinomycetia possess potential value as nitrogen-fixing inoculants in drylands.

Remediation of Diesel-contaminated soil using zero-valent nano-nickel and zero-valent nano copper particles-stabilized Tween 80 surfactant foam

This paper uniquely reports the remediation of diesel-contaminated desert soil by aqueous Tween 80 (TW80) surfactant foams stabilized by zero–valent nickel (Ni0) and zero–valent copper (Cu0) nanoparticles (NPs). The sizes of synthesized nanoparticles, ∼21 nm (Cu0), ∼20 nm (Ni0), are determined by XRD and FE-SEM. The impact of these NPs (1 mg, 2 mg concentrations) on foaming characteristics, remediation of diesel-contaminated soils is explored at 2 vol% TW80 surfactant concentration. With 2 mg concentration of Ni0, Cu0 NPs and 2 vol% TW80 surfactant, it is found that 98.73 and 99.38 % diesel contaminants are removed.

Study of water productivity of wheat and moisture distribution under the influence of center pivot irrigation and different tillage systems for desert soils

A field experiment was conducted to grow the wheat crop during the fall season 2020 in Karbala province, north of Ain Al-Tamr District in two locations of different textures and parent materials. The first site (calcareous soil) with a sandy loam texture, is located at (44° 40′ 37′) east longitude and (32° 41′ 34′) north latitude, at an altitude of 32 m above sea level, and an area of 20 hectares. As for the second location (gypsum soil) with a loam texture, it is located at a longitude (45° 41′ 39′) east and a latitude (33° 43′ 34′ north) and at an altitude of 33 m above sea level and an area of 20 hectares. To find out the effect of different tillage systems on water productivity and wheat yield under center pivot irrigation system. Two treatments were used in the experiment, The first treatment: four-level tillage systems: zero tillage (T1), Spike pin harrows (T2), disc harrows (T3), and Moldboard plows (T4). As for the second treatment: Soil type with two levels: gypsum soil (G) and calcareous soil (C). The experiment was designed according to a randomized complete block design with three replications. The highest yield of crop and field water was with treatment C with the productivity of 10.40 and 9.82 kg m-3, respectively and with T1 treatment with yields of 10.10 and 9.50 kg m-3, respectively. And with the GT1 bi-interaction treatment with yields of 9.30 and 8.80 kg m-3, respectively and with CT2 treatment with yields of 11.70 and 11.10 kg m-3, respectively. The treatment of calcareous soil (C) gave the highest value of grain yield, biological yield and 7657 kg ha-1, 18167 kg ha-1, respectively. Tillage treatment T1 gave the highest value of grain yield and biological yield of 7735 kg ha-1 and 18475 kg ha-1, respectively. The bi- interaction treatment GT1 gave the highest value for grain yield, biological yield 7520 kg ha-1, 17,980 kg ha-, respectively. The interaction CT2 treatment gave the highest value for grain yield, biological yield 8660 kg ha-1, 19270 kg ha-1, respectively. The T1 and T2 tillage system under center pivot irrigation is better in terms of moisture content at all depths and time periods.

Community distribution of rhizosphere and endophytic bacteria of ephemeral plants in desert‐oasis ecotone and analysis of environmental driving factors

AbstractEphemeral plants are important part of the vegetation maintaining Gurbantünggüt Desert‐oasis ecotone stability. Studying the response characteristics of root‐associated bacteria of ephemeral plants to soil habitats is of great significance for understanding the adaptability of plants and maintaining ecotone stability. In this study, physicochemical analysis and 16 S sequencing technology were used to analyse the diversity, structure, function, and driving factors of rhizosphere and root‐endophytic bacteria of ephemeral plants in aeolian soil and grey desert soil. The results showed differences in the rhizosphere soil properties and root nutrient content between the two habitat soils. The Shannon index of the rhizosphere bacteria in the grey desert soil was higher than that in the aeolian soil, whereas the Shannon and ACE indices of the endophytic bacteria were lower than those in the aeolian soil. Soil type caused evident changes in the relative abundance and community structure of the rhizosphere and endophytic bacteria. PICRUSt function prediction showed that energy metabolism, carbohydrate metabolism, amino acid metabolism, replication and repair, and membrane transport were the main functional categories of rhizosphere and endophytic bacteria in the two soils. The rhizosphere and endophytic bacteria of ephemeral plants were closely related to soil factors. Soil water content, electrical conductivity (EC), total phosphorus, total potassium, and nitrogen/phosphorus ratio were the key factors affecting the rhizosphere bacterial community structure and function. The key factors affecting the root‐endophytic bacterial community structure and function were the pH, EC, total phosphorus, ammonium nitrogen, available potassium, carbon/phosphorus ratio, and root phosphorus. This study revealed the community structure, functions and driving factors of root‐associated bacteria in ephemeral plants grown in different soils. These findings have significance for future studies on the bacterial metabolic function of ephemeral plants and provide references for vegetation protection and restoration in different soils of the ecotone.

The Impact of Viticulture on Soil Characteristics and Microbial Communities in the Ningxia Region of Northwest China

Winegrape cultivation has become increasingly common throughout northwest China over the past 20 years, and such viticulture can profoundly impact the properties of the utilized soil and the associated soil microbial communities. To explore these effects in the present study, samples of soil were collected from control desert soil and from vineyards planted in different years: Cabernet Sauvignon (CS, 2014), Merlot (M, 2012), and Italian Riesling (IR, 2008). The properties of this soil and the microbial communities therein were assessed through a series of physicochemical, enzymatic, and high-throughput sequencing analyses. Compared to the control soil, respective 1033.06 U/g, 398.28 U/g, and 240.56 U/g increases in alkaline phosphatase activity levels were observed in the CS, M, and IR soil samples. Stable soil bacterial richness was observed in the control, CS, and M samples, but decreased in the 11-years old IR soil, whereas no noticeable changes in soil fungi were observed across these samples. The network analyses highlighted correlations among soil microbes, and soil organic carbon and microbial biomass carbon were found to strongly influence variability in these soil microbial communities. Overall, these findings thus provide strong evidence that the prolonged monoculture of winegrapes can contribute to the deterioration of soil quality.

Organic fertilizer substitution promotes soil organic carbon sequestration by regulating permanganate oxidizable carbon fractions transformation in oasis wheat fields

Organic fertilizer substitution (OFS) technology effectively mitigates the adverse effects of excessive synthetic fertilizer application while promoting soil organic carbon (SOC) sequestration in farmlands. However, how the permanganate oxidizable carbon fractions (KOCs) transformation affects SOC under OFS remains unknown. In this study, two typical farmland soils (grey desert soil, GS; meadow soil, MS) were selected for a 3-year field fertilization experiment (no fertilization, NF; synthetic fertilizer alone, SCF; and organic fertilizer substituted 20% synthetic N fertilizer, OFS). Field experiments conducted from 2018 to 2020 showed that SOC could be used to evaluate wheat yield and soil quality, so further study the effects of OFS on SOC and KOCs and their corresponding C pool management index (CPMIs). The results showed that OFS in GS and MS increased SOC (by 3.37%–15.62%, 4.92%–20.28%) and its fractions content (except low-activity KOC, LKOC) and CPMIs (except CPMI-L) year by year compared to SCF and NF. The recalcitrant organic C (ROC), KOC, high-activity KOC (HKOC), and medium-activity KOC (MKOC) were the key fractions affecting SOC. Moreover, HKOC and MKOC and their corresponding CPMIs (CPMI-H and CPMI-M) showed higher sensitivity. Structural equation modeling revealed that OFS in GS and MS increased SOC by increasing ROC and KOC (by regulating KOCs transformation) content, and increased CPMI-H and CPMI-M by increasing HKOC and MKOC content. Overall, the process of OFS promoted SOC sequestration and improved soil C pool in two soils were revealed from the perspective of KOCs transformation. Also, we proposed corresponding fertilization recommendations and showed that HKOC and MKOC could be used to evaluate and monitor soil quality and SOC. This study provides guidance for SOC sequestration, crop yield, and soil quality improvement in oasis wheat fields, contributing to the sustainable development of farmland.

Bioremediation of Petroleum-Contaminated Soils with Biosurfactant-Producing Degraders Isolated from the Native Desert Soils.

A crude oil spill in 2014 resulted in extensive soil contamination of the hyper arid Evrona Nature Reserve in Israel's Negev Desert. The contaminated soils became highly hydrophobic, threatening the existence of plants in the habitat. We hypothesized that bioaugmenting the soil with indigenous biosurfactant-producing, hydrocarbon-degrading bacteria (HDB) would accelerate the reduction in the soil's hydrophobicity. We aimed to isolate and characterize biosurfactant-producing HDBs from the desert-contaminated soil and test if they can be used for augmenting the soil. Twelve hydrocarbon-degrading strains were isolated, identified as Pseudomonas, and classified as biosurfactants "producing" and "nonproducing". Inoculating 109 CFU/g of "producing" strains into the polluted soil resulted in a 99.2% reduction in soil hydrophobicity within seven days. At the same time, nonproducing strains reduced hydrophobicity by only 17%, while no change was observed in the untreated control. The microbial community in the inoculated soil was dominated by the introduced strains over 28 days, pointing to their persistence. Rhamnolipid biosynthesis gene rhlAB remained persistent in soil inoculated with biosurfactants, indicating in situ production. We propose that the success of the treatment is due to the use of inoculum enriched from the polluted soil.

Fertirrigation in coffee: agronomic and sustainable aspects

The present work aims to relate the positive effects of irrigation and mineral nutrition on coffee productivity, considering that the various existing methods and techniques involve a wide variation of dosage and nutrient splitting, due to the interaction between soil, water, climate, plant and area where the crop is located. Thus, through the methodology of literature review, a survey of research and theoretical notes of issues related to the benefits of irrigation and mineral nutrition was carried out, culminating in the focus of the fertigation technique. The study took into account aspects related to the rational use of water, the prevention of soil desertification and the Sustainable Development Goals of the UN 2030 Agenda. The analysis of the works and authors consulted made it possible to bring to the academic-scientific scope approaches that highlighted the fundamental role of fertigation in coffee farming.

Physicochemical analyses and mycoflora of desert soils in Upper Egypt

Most of the desert lands contain sandy soils, which include large areas in the world. The sandy or loam soils in Upper Egypt were placed under investigate of soil texture, and moisture content –in addition some chemical analyses. Where, had very low organic matter (mean= 0.28) with available total dissolved salts (mean= 0.53) and alkaline pH-value (mean= 9.00). The moisture content of samples was very low (mean= 2.59). All of desert soil samples (100% of the samples) proved to be contaminated by filamentous fungi. A total of 121 fungal species + 7 varieties of 32 genera were isolated and identified on the isolation medium (1% glucose Czapek’s agar) at 28°C, based on dilution plate method. The gross fungal count was 94.36 colonies/mg dry soil. Aspergillus (36 sp. + 4 var.) was the most dominant genus based on frequency (95% of the samples) and count (55.34% of total fungal counts). Penicillium (28 sp. + 1 var.) had the second place (70% of the sample and 26.83% of grass count). Ulocladium occupied the third place (22.5% and 3.18%). Acremonium was one of the dominant genera (4th place). It occurred in 20% of the samples examined and 1.61% of gross fungal counts. The dematiaceous hyphomycetes, in addition ascospore-forming fungi were dominant in rare frequency. Whereas, sterile mycelia were high in frequency (52.5% of the samples) and low count (1.99% of gross fungal count).

ITS3/ITS4 outperforms other ITS region and 18S rRNA gene primer sets for amplicon sequencing of soil fungi

AbstractThe primer sets of 18S rRNA genes and Internal Transcribed Spacer (ITS) regions are universal primers for amplicon sequencing in soil fungal diversity studies. The selection of proper primer sets has been identified as one of the main drivers affecting effective cross‐study comparisons in various types of soils. However, few studies have provided guidance for the selection of fungal primers in soil fungal biodiversity studies. The aim of this study was to evaluate and optimise fungal sequencing methods with three primer sets in desert, forest, grassland and farmland soils. Melting curve analyses were used to evaluate the specificity of each primer set in different soil ecosystems. The quality of fungal sequencing with three primer sets was assessed with the same conditions on the Illumina platform. The melting curve analysis showed that both the FR1/FF390 and the ITS3/ITS4 primer sets have better specificity than the ITS1/ITS primer set. 18S rRNA amplicon sequencing produced less fungal phylotypes compared to the amplicon sequencing data of the ITS1/ITS2 and ITS3/ITS4 primer sets. Our study suggests that the ITS3/ITS4 primer set was more suitable for the analysis of soil fungal biodiversity in desert, forest, grassland and farmland soils on the Illumina sequencing platform.Highlights Comparison of three existing primer sets for soil fungal amplicon sequencing. ITS region has better performance than 18S rRNA gene in amplicon sequencing. ITS3/ITS4 primer set is more suitable for the analysis of soil fungal biodiversity.

Screening of osmotic stress-tolerant bacteria for plant growth promotion in wheat (Triticum aestivum L.) and brinjal (Solanum melongena L.) under drought conditions.

Drought stress adversely affects plant growth and productivity. Therefore, the application of plant growth-promoting bacteria is a viable option for combating drought resistance in crops. In this study, 144 bacteria were isolated from the Kutch desert soil in Gujarat. Based on osmotic stress tolerance and PGP properties, two strains, Bacillus tequilensis (KS5B) and Pseudomonas stutzeri (KS5C) were tested for their effect on wheat (Triticum aestivum L.) and brinjal (Solanum melongena L.) under drought stress conditions. Inoculation with osmotic stress-tolerant bacteria showed 15·15-29·27% enhancement in root length of wheat and 15·27-32·59% in brinjal plants. Similarly, the enhancement of shoot length ranged from 14·72 to 37·70% for wheat and 59·39-95·94% for brinjal plants. Furthermore, the inoculated plants showed significant improvement in chlorophyll content and antioxidant properties such as proline, peroxidase and polyphenol oxidase activity compared to the control. Therefore, the bacterial strains identified in this study can be used to mitigate drought stress and enhance plant biomass.