Search Results (128)

The study examined seasonal variability in soil enzymatic activity and microbial abundance across five grassland vegetation units: Molinietum caeruleae, Alopecuretum pratensis, Arrhenatheretum elatioris, Lolio–Cynosuretum, and com. Poa pratensis–Festuca rubra. Soils under Molinietum caeruleae showed higher fungal abundance and greater plant diversity, while Lolio–Cynosuretum was notable for elevated Azotobacter spp. populations. Actinobacteria preferred soils with more organic matter, whereas Azotobacter spp. favored higher pH. A negative correlation was observed between the Shannon diversity index (H′) and heterotrophic bacterial abundance in Arrhenatheretum elatioris and with fungal abundance in com. Poa pratensis–Festuca rubra. Acid and alkaline phosphatase and catalase activities were also negatively correlated with H′. Redundancy analysis showed these enzymes were related to total nitrogen content, and enzyme activity decreased with rising soil pH. In autumn 2022, high fungal abundance coincided with a reduction in other microorganisms. Seasonal trends were evident: catalase and urease activities peaked in autumn 2023, while other enzymes were more active in spring 2022. The results emphasize the significance of seasonal shifts in shaping microbial and enzymatic soil processes, which are vital for nutrient cycling, carbon sequestration, and climate regulation. Further research is essential to guide sustainable grassland soil management. Full article

Despite growing interest in improving soil health on cocoa farms, applied research on the impacts of specific amendments on soil and plant outcomes is lacking. An integrated assessment of the impacts of two different organic amendments (compost and vermicompost) and a microbial biofertilizer on soil physical, chemical, and biological properties, as well as cocoa flowering, fruit set, and yield, was conducted in Guayaquil, Ecuador. Complementary culture-dependent and culture-independent methods were used to assess the impacts of amendments on microbial diversity, community composition, and specific taxa. Compost or vermicompost application affected soil chemical properties, including potassium, phosphorus, and sodium, and had small but significant effects on fungal beta diversity. Biofertilizer application slightly lowered soil pH and altered the total abundance of specific taxonomic groups including Azotobacter sp. and Trichoderma sp., with borderline significant effects on Azospirillum sp., Lactobacillus sp., Pseudomonas sp., calcium-solubilizing bacteria, and phosphorus-solubilizing bacteria. Amplicon sequencing (16S, ITS) identified 15 prokaryotic and 68 fungal taxa whose relative abundance was influenced by organic amendments or biofertilizer. Biofertilizer application increased cherelle formation by 19% and monthly harvestable pod counts by 11% despite no impact on flowering index or annual pod totals. This study highlights the tangible potential of microbiome optimization to simultaneously improve on-farm yield and achieve soil health goals on cocoa farms. Full article

Intensive research has been conducted for many years to develop environmentally friendly techniques for plant cultivation that optimize the fertilization process. One of the most promising areas within the fertilizer industry is using microbiologically enriched fertilizers, which incorporate beneficial bacteria or fungi. Biofertilizers are the focus of studies on both their production technologies and their effects on crop growth and yield, presenting a potential alternative to conventional mineral fertilizers. The prolonged and improper use of mineral fertilizers, along with inadequate plant protection, a lack of organic fertilization, and poor crop rotation practices, negatively impact soil health, disrupting microbial populations and ultimately diminishing yield quality and quantity. Microorganisms, particularly specific groups known as plant growth -promoting rhizobacteria (PGPR) and beneficial fungi, are estimated to make up 85% of the total soil biomass and play a crucial role in soil fertility by mineralizing organic matter, suppressing pests and pathogens, forming humus, and maintaining proper soil structure. They also provide optimal conditions for plant growth. Soil microorganisms can be categorized as either autochthonous, naturally present in the soil, or zymogenic, which develop when easily assimilable organic matter is added. Key microorganisms such as Micrococcus, Bacillus, Azotobacter, and nitrogen-fixing bacteria like Rhizobium and Bradyrhizobium significantly contribute to soil health and plant growth. Microbially enhanced fertilizers not only supply essential macro- and micronutrients but also improve soil quality, enhance nutrient use efficiency, protect plants against pathogens, and restore natural soil fertility, fostering a balanced biological environment for sustainable agriculture. Full article

Commercial tomato hybrids exhibit robust performance in modern high-input agricultural systems. However, their suitability for low-input farming remains uncertain. With the goal that by 2030, 25% of European agricultural production must be organic as part of the European Green Deal, this study aims to assess whether existing commercial tomato hybrids can offer a viable solution for low-input farming. Additionally, the impact of beneficial microorganisms such as plant growth-promoting rhizobacteria (PGPR), in relation to the growth and productivity of tomato hybrids under low-input cultivation is assessed. For this purpose, a well-defined microbial consortium, including Azotobacter chroococcum, Clostridium pasteurianum, Lactobacillus plantarum, Bacillus subtilis, and Acetobacter diazotrophicus, was applied as a liquid suspension to enhance root colonization and promote plant growth. Seven commercial tomatoes (Solanum lycopersicum L.) hybrids—the most popular in the Greek market—were evaluated for their performance under high-input (hydroponic) and low-input cultivation systems (with and without the use of PGPR). Several parameters related to yield, fruit quality, nutritional value, descriptive traits, and leaf elemental concentration were evaluated. In addition, a techno-economic analysis was conducted to assess whether hybrids developed under high-input conditions and intended for such cultivation environments suit low-input farming systems. The results indicated that such hybrids are not a viable, efficient, or profitable strategy for low-input cultivation. These findings underscore the importance of breeding tomato varieties, specifically adapted to low-input farming, highlighting the need for targeted breeding strategies to enhance sustainability and resilience in future agricultural systems. Notably, this study is among the first to comprehensively assess the response of commercial tomato hybrids under low-input conditions, addressing a critical gap in the current literature. Full article

Qinghai Lake, the largest inland saline lake in China, plays a vital role in wetland carbon cycling. However, the structure and function of soil bacterial communities in its estuarine and nearshore estuarine wetlands remain unclear. This study examined the effects of wetland type and soil depth on bacterial diversity, community composition, and functional potential in the Shaliu, Heima, and Daotang River wetlands using high-throughput sequencing. The results showed that wetland type and soil depth significantly influenced bacterial communities. Nearshore wetlands exhibited lower bacterial diversity in the 0–10 cm layer, while deeper soils (10–20 cm) showed greater regional differentiation. Estuarine wetlands were enriched with Proteobacteria, Actinobacteriota, and Chloroflexi, whereas nearshore wetlands were dominated by Actinobacteriota and Cyanobacteria. Functionally, estuarine wetlands had higher sulfate reduction and anaerobic decomposition potential, with Desulfovibrio, Desulfobacter, and Desulfotomaculum regulating sulfur cycling and carbon decomposition. In contrast, nearshore wetlands showed greater nitrogen fixation and organic matter degradation, facilitated by Rhizobium, Azotobacter, Clostridium, and nitrogen-fixing Cyanobacteria (e.g., Anabaena, Nostoc). Microbial metabolic functions varied by depth: surface soils (0–10 cm) favored environmental adaptation and organic degradation, whereas deeper soils (10–20 cm) exhibited lipid metabolism and DNA repair strategies for low-oxygen adaptation. These findings highlight the spatial heterogeneity of bacterial communities and their role in biogeochemical cycles, providing insights into wetland carbon dynamics and informing conservation strategies. Full article

A field trial was conducted on eight-year-old ‘Anna’ apple (Malus domestica) trees from 2021 to 2023 in northern Egypt. The objective of this study was to determine the effects of replacing mineral fertilizer with compost and microorganism applications. Treatments were prepared using combinations of three mineral fertilizer NPK (nitrogen (N), phosphorus (P) and potassium (K)) levels (75% recommended NPK rate, 50% and 25% recommended rate), with two compost levels (with/without) and two bacteria/fungi biological blend (PGPM) levels (with/without). This design resulted in 12 treatments in addition to a control treatment consisting of the full NPK recommended rate (100% NPK). Leaf nutrient concentrations, vegetative growth, fruit set percentage, fruit drop percentage, yield and fruit quality were measured in 2022 and 2023. Our results indicated that vegetative growth parameters were significantly influenced by the fertilizer treatments in both seasons. The application of 75% NPK + compost + PGPM or 50% NPK + compost + PGPM significantly increased shoot length, shoot diameter, leaf area and leaf-specific weight compared with the control (100% NPK). The greatest values of leaf nutrients and production and quality parameters were obtained with treatments 75% NPK + compost + PGPM or 50% NPK + compost + PGPM. Applying 75% NPK + compost + PGPM or 50%NPK + compost + PGPM increased total soluble solids and anthocyanin concentrations but reduced fruit nitrate and nitrite levels compared with the control (100% NPK). This study shows that it is possible to reduce mineral fertilizer application by 25–50% while improving the yield if compost and microbial inoculants are applied. Full article

Insect-based (silkworm cocoons) and plant-based (cotton wool pads and gauzes) fiber substrates were used to support and ameliorate seed germination originating from trifoliate orange (Poncirus trifoliata) and pomegranate (Punica granatum) trees. Three different commercial formulations of beneficial microorganisms (Bacillus spp.-Azotobacter spp., Saccharomyces boulardii, and Saccharomyces cerevisiae) were administered to seeds in order to evaluate their contribution to germination and growth. The silkworm cocoons provided better germination rates for P. trifoliata seeds (83.33%) among the tested media without any microbial supplementation. These rates increased towards the absolute maximum (100%) when Bacillus spp.-Azotobacter spp., S. boulardii and S. cerevisiae were applied. Furthermore, inoculums of Bacillus spp.-Azotobacter spp. 2 mL and S. cerevisiae 3 g raised the pomegranate seed germination ability by 30–33.33% and 50–67.7%, respectively, on silkworm cocoon substrates when compared to plant-derived, cellulosic fiber substrates under the same biotic exposure. On increasing the size of applied microbial inoculums, seed germination moved from optimum to suboptimum for all germination media. Examination of multipartite pH compatibility (between seeds, microorganisms, and germination media) was beneficial and of functional value. In conclusion, the germination rates of both tree species can be raised using bacterial and yeast supplementation, including medical-grade S. boulardii, on environmentally friendly materials such as insect- and plant-based fiber substrates. Full article

This study explores agroecological practices designed to improve soil quality and crop yield in small-scale agriculture, focusing on soil inoculation with beneficial bacteria over conventional fertilizers. Conducted at the SZIA Agroecological Garden MATE in Gödöllő, Hungary, the research utilizes 12 plots to evaluate different conservation tillage methods, including minimum and no-tillage, with and without microbial inoculation. Commenced in 2022, this study centers on potato cultivation (Solanum tuberosum L.) and includes comprehensive chemical and physical analyses of soil and harvested potatoes, alongside continuous monitoring of growth. Statistical analysis using One-way Anova in R revealed p-values predominantly above 0.05, indicating no significant differences across most parameters, though variations in soil plasticity and pH (KCl) were noted. Results suggest that substantial treatmeent differences may require a longer observation period. Notably, plots with microbial inoculation exhibited higher harvest weights and tuber sizes compared to control plots. Additionally, trends and interactions were found between weed abundance, total harvest, and plant height. The findings indicate that the benefits of integrated agroecological practices, including conservation tillage, may take time to materialize, emphasizing the necessity for extended observation. This research lays the groundwork for future studies, underscoring the importance of patience in achieving improvements in soil health and crop quality through sustainable agricultural methods. Full article

(1) Background: The rapid growth in the number of nanoparticles today raises questions about studying their impact on the environment, including the soil, as the main absorber of nanoparticles. The purpose of our research was to study the effect of MoO₃ nanoparticles (NPs; 50, 100, 250, 500, and 1000 mg/kg of soil) on the physiological and biochemical parameters of Eisenia fetida, the number of certain ecologo-trophic groups of soil microorganisms, and enzymatic soil activity. (2) Methods: We used 92 ± 0.3 nm nanoparticles of MoO₃ at concentrations of 50, 100, 250, 500, and 1000 mg/kg dry soil. Texture-carbonate chernozem was used in the study. Eisenia fetida worms were used as test objects. (3) Results: The introduction of MoO₃ nanoparticles showed a weak toxic effect towards the animal and microbiological components of the soil at a concentration of 50–250 mg/kg, a medium toxic effect at 500 mg/kg, and a strong or unacceptable toxic effect at 1000 mg/kg. The oxidative stress response of E. fetida depended on the concentration of the NPs. MoO₃ NPs at a concentration of up to 100 mg/kg reduced the number of amylolytic bacteria, oligotrophs, and Azotobacter. In soil, urease and catalase showed mild activity, whereas the activity of invertase decreased by 34%. (4) Conclusions: The entry into the environment and the further deposition of nanoparticles of Mo and its oxides in the soil will lead to the suppression of the vital activity of beneficiary soil animals and the activity of soil enzymes. This phenomenon presents special kinds of ecological risks for the ecosystem. Full article

Oilseed rape is one of the most important oilseed crops, requiring high levels of nitrogen fertilization. Excessive nitrogen use, however, leads to numerous negative environmental impacts, spurring the search for sustainable, environmentally friendly alternatives to reduce reliance on mineral nitrogen fertilizers. One promising approach involves plant-growth-promoting bacteria (PGPB), which can support oilseed rape growth and lessen the need for traditional nitrogen fertilizers. This study evaluates a selected microbial consortium comprising bacterial isolates obtained from soil: Pseudomonas sp. G31 and Azotobacter sp. PBC2 (P1A). The applied PGPB significantly increased seed yield (a 27.12% increase) and, in the initial phase of the study, reduced the ammonium nitrogen content in the soil (a 20.18% decrease). Metataxonomic analyses were performed using Next-Generation Sequencing (NGS) technology by Illumina. Although P1A did not significantly affect alpha diversity, it altered the relative abundance of some dominant soil microorganisms. In the BBCH 75 phase, the P1A consortium increased the abundance of bacteria of Firmicutes phylum, including the genera Bacillus and Paenibacillus, which was considered a beneficial change. In summary, the Pseudomonas sp. G31 and Azotobacter sp. PBC2 consortium increased seed yield and was found to be part of the native rhizosphere community of oilseed rape, making it a promising candidate for commercialization. Full article

At present, there is growing consumer interest in Triticum spelta L., which has high nutritional value. This species is recommended for cultivation in organic farming. In this system of agriculture, biofertilizers are an alternative to mineral fertilization. Biofertilizers stimulate plant growth by providing nutrients through the biological fixation of molecular nitrogen from the air or by increasing the availability of insoluble nutrients in the soil and by synthesizing substances that stimulate plant growth. Green manure biomass and root secretions provide growth material for soil microorganisms, and microorganisms return nutrients to the soil and plants through nutrient decomposition and conversion. Considering the many benefits of using biofertilizers and growing cereals with cover crops for green manure in cereal rotations, field research was carried out on an organic farm to evaluate the soil microbes and the amount of biomass from green manures and their follow-up effect on Triticum spelta L. yields using biofertilizers. Two factors were researched: (I) biofertilizers: control object (no biofertilizer), Azotobacter chroococcum + Azospirillum lipoferum Br 17, Arthrobacter agilis + Bacillus megaterium var. phosphaticum, and combined application of atmospheric nitrogen-fixing bacteria with phosphate solubilizing bacteria; (II) green manures: control object (no green manure application), Trifolium pratense L., Trifolium pratense L. + Lolium multiflorum L., and Lolium multiflorum L. The results show that the most favorable abundance of microorganisms determined in the soil after harvesting Hordeum vulgare L. was recorded after the application of biofertilizers containing atmospheric nitrogen-fixing bacteria with phosphate-solubilizing bacteria under a mixture of Trifolium pratense L. with Lolium multiflorum L. Plowing green manure from a mixture of Trifolium pratense L. with Lolium multiflorum L. resulted in an average increase of 39% in grain yield of Triticum spelta L., while the application of a biofertilizer containing Azotobacter chroococcum + Azospirillum lipoferum Br 17 + Arthrobacter agilis + Bacillus megaterium var. phosphaticum resulted in an average increase of 63%. The proposed spelt wheat cultivation technique can be recommended for agricultural practice due to the positive response of grain yield, but it may also be an important direction for further research to reduce the negative impact of agriculture on the environment. Full article

In this research work, a main biopolymer group of polyhydroxyalkanoates (PHAs) in the form of polyhydroxybutyrate (PHB) was synthesised by a pure bacterial strain of Azotobacter vinelandii via repeated fed-batch fermentation. An agricultural crop, sugar cane, was used as the sole carbon source. Firstly, batch fermentation was investigated considering variations in incubation times (24 h, 48 h, and 96 h). The highest dry cell weight (DCW) and PHAs of 5.15 ± 0.04 g/L and 4.00 ± 0.04 g/L were obtained after 48 h of incubation time. The optimum time obtained was further varied to investigate the effect of the sugar concentrations in the medium. It was found that bacteria could grow very well and produced the highest DCW and PHAs (11.17 ± 0.15 g/L and 8.77 ± 0.06 g/L) when the culture medium with a 100 g/L sugar concentration was added. Later, repeated fed-batch fermentation was carried out to improve productivity. The results obtained revealed that PHA production was increased in the next cycle of the process. Furthermore, the final productivity (0.104 g/L·h) was increased 1.65-fold compared to the first cycle (0.063 g/L·h). Moreover, the culture strategy showed remarkable results, with reductions in both fermentation time and preparation cost. Full article

Sandy soils are widespread globally and are increasingly utilized to meet the demands of a growing population and urbanization for food, fiber, energy, and other essential services. However, their poor water and nutrient retention makes crop cultivation challenging. This study evaluated the effects of integrating compost and plant growth-promoting rhizobacteria (PGPR; Azospirillum brasilense SWERI 111 and Azotobacter chroococcum OR512393) on wheat (Triticum aestivum L. var. Misr 1) grown in sandy soil under varying levels of recommended NPK (50%, 75%, and 100%) fertilization. Conducted over two growing seasons, the experiment aimed to assess soil health, nutrient uptake, microbial activity, and plant productivity in response to compost and PGPR treatments. The results demonstrated that combining compost and PGPR significantly improved soil chemical properties, such as reducing soil pH, electrical conductivity (ECe), and sodium adsorption ratio (SAR), while enhancing soil organic matter (SOM). Additionally, compost and PGPR improved soil nutrient content (N, P, K) and boosted the total bacterial and fungal counts. The combined treatment also increased urease and phosphatase enzyme activities, contributing to enhanced nutrient availability. Notably, plant productivity was enhanced with compost and PGPR, reflected by increased chlorophyll and reduced proline content, along with improved grain and straw yields. Overall, the results underscore the potential of compost and PGPR as effective, sustainable soil amendments to support wheat growth under varying NPK levels. Full article

Hydroponic greenhouses and vertical farms provide an alternative crop production strategy in regions that experience low temperatures, suboptimal sunlight, or inadequate soil quality. However, hydroponic systems are soilless and, therefore, have vastly different bacterial microbiota than plants grown in soil. This review highlights some of the most prevalent plant growth-promoting bacteria (PGPB) and destructive phytopathogenic bacteria that dominate hydroponic systems. A complete understanding of which bacteria increase hydroponic crop yields and ways to mitigate crop loss from disease are critical to advancing microbiome research. The section focussing on plant growth-promoting bacteria highlights putative biological pathways for growth promotion and evidence of increased crop productivity in hydroponic systems by these organisms. Seven genera are examined in detail, including Pseudomonas, Bacillus, Azospirillum, Azotobacter, Rhizobium, Paenibacillus, and Paraburkholderia. In contrast, the review of hydroponic phytopathogens explores the mechanisms of disease, studies of disease incidence in greenhouse crops, and disease control strategies. Economically relevant diseases caused by Xanthomonas, Erwinia, Agrobacterium, Ralstonia, Clavibacter, Pectobacterium, and Pseudomonas are discussed. The conditions that make Pseudomonas both a friend and a foe, depending on the species, environment, and gene expression, provide insights into the complexity of plant–bacterial interactions. By amalgamating information on both beneficial and pathogenic bacteria in hydroponics, researchers and greenhouse growers can be better informed on how bacteria impact modern crop production systems. Full article