Effect Of Microbial Inoculation Research Articles

Effects of laboratory ensiling method, microbial inoculation, and storage length on the fermentation profile and nutrient composition of whole-plant corn silage and high-moisture corn

The objectives of this experiment were to compare the effects of laboratory ensiling methods (plastic buckets or vacuum-sealed plastic bags) and microbial inoculation (Lentilactobacillus buchneri AHLB02 and Pediococcus pentosaceus AHPP02; LBPP or the same amount of distilled water; CON) on the fermentation profile and nutrient composition of WPCS and HMC. Moreover, this study aimed to evaluate the effects of microbial inoculation on aerobic stability of WPCS and HMC ensiled in buckets. Whole-plant corn was packed into 20 L plastic buckets to a density of 195 kg of DM/m3 or 900 g of sample material placed in nylon-polyethylene standard barrier vacuum pouches and inoculated with 300,000 CFU of LBPP/g of fresh forage or CON. High-moisture corn was packed into 3.785 L plastic buckets to a density of 792.5 kg of DM/m3 or 1300 g of sample material placed in nylon-polyethylene standard barrier vacuum pouches and inoculated with 450,000 CFU of LBPP/g of fresh material or CON. Silos were randomly assigned to 30 or 90 d of storage. Data were analyzed as a completely randomized block design with field location as a blocking factor in a 2 × 2 × 2 factorial arrangement of treatments using PROC GLIMMIX of SAS with fixed effects of ensiling method, microbial inoculation, storage length, and all their interactions with significance at P ≤ 0.05. Whole-plant corn silage had greatest (P = 0.001) pH for LBPP silage ensiled in bucket, intermediate for LBPP silage fermented in bag, and lowest for CON silage ensiled in bucket. The 1,2-PD concentration was greatest (P = 0.001) for LBPP silage fermented in bag, intermediate for LBPP silage fermented in bucket, and lowest for CON silage. High-moisture corn had greater (P = 0.04) lactic acid concentration for silage ensiled in bucket for 30 d than 90 d. Acetic acid concentration was greater (P = 0.01) for inoculated HMC ensiled in bucket compared with other treatments at 90 d. Moreover, lactic acid concentration was lower (P = 0.001) for LBPP than CON in both silages. Total acids concentration was greater (P = 0.001) for 90 d than 30 d in both silages. High-moisture corn had greater (P = 0.01) acetic acid concentration for LBPP than CON at 30 d. The 1,2-PD concentration was greatest (P = 0.001) for LBPP at 90 d, intermediate for LBPP at 30 d, and lowest for CON. Both ensiling methods are comparable and suitable for laboratory silage research. Microbial inoculation improved fermentation of both WPCS and HMC but this response was more pronounced at 90 d.

Effects of microbial inoculant on chemical compositions and in vitro digestibility of elephant grass-based silage

Probiotic microbial inoculants have been used to improve fermentation quality of green forage feed in pig farming This study aimed to formulate and evaluate effects of microbial inoculants on quality and digestibility of elephant grass-based silage. Green forage formula was made based on economical and agro ingredients resulting in 36% of cost reduction in comparison to the basal diet. The additive containing 1% microbial mixture of Lactobacillus plantarum LCN13, Bacillus velezensis VTX9 and Saccharomyces cerevisiae MCN9 as starter cultures significantly reduced crude fiber (12.39 ± 1.01% Dry Matter (DM)) and neutral detergent fiber concentrations (28.49 ± 0.93% DM) after 120 h (p < 0.05). In contrast, remarkable increases (p < 0.05) were determined in metabolizable energy (2972 ± 18.18% DM) and crude protein (16.32±1.15% DM). These results indicated that metabolic activities by microbial inoculants contributed considerably to the nutritive value of the elephant grass-based diet. The experiment along ensiling time revealed that significant changes in nutritive compositions were observed at 120 h and 168 h (p < 0.05). In support of these results, in vitro digestibility indexes including dry matter, organic matter, and crude protein showed an increasing trend corresponding to ensiling times. Since there were no significant differences between 120 h and 168 h, fermentation time of 120 h was sufficient to obtain desired outcomes. These findings emphasized that elephant grass-based forage fermented with microbial inoculant could be a promising cost-effective and high-quality feed for pig production. Further investigations are required to evaluate safety, growth performance, and pig intestinal microbiota.

Combination effects of microbial inoculation and N fertilization on maize yield: A field study from southern Brazil

The use of inoculants based on diazotrophic microorganisms is an alternative to decrease the dosage and increase the efficiency of nitrogen fertilizers, especially in grains that are demanding and nutrient-responsive crops. Cyanobacteria is photosynthetic and nitrogen fixing prokaryote; however, there has been little focus on Anabaena cylindrica and Nostoc muscorum as biofertilizers in the presence of added nitrogen sources. The purpose of this study was to explore the maize yield in two crop seasons in Londrina, Brazil under different nitrogen rates (topdress, 0–130 kg ha−1; sowing, 20–150 kg ha−1) and microbial inoculants (A. cylindrica, N. muscorum and Azospirillum brasilense), in randomized block design with factorial arrangement 4 × 4. Different phytometric characteristics (e.g. height of plant and spike insertion; stem diameter; area idex and chlorophyll content of leaf; Nitrogen (N), Phosphorous (P) and Potassium (K) contents in leaf) and grain yield (such as quantity of rows ear−1, grains row−1, grains ear−1, ear plant−1, grain N content, weight 1000 grains−1, grain yield) were evaluated. The phytometric characteristics and maize yield were not altered by the interaction between N rates and inoculants, demonstrating that N rates do not interfere with cyanobacteria performance. The inoculation with A. cylindrica favored the development and yield performance of maize and resulted in an increase in grain biomass of 912 kg ha−1 (20.46%) in the crop season 1 and 1020 kg ha−1 (21.11%) in season 2 crop, related to the control. The use of above inoculants was favorable in the responses of maize growth and yield components, particularly when combined with an adequate dose of N. The results demonstrated the potential of microbial inoculants in the improvement of maize crop yield.

Microbial inoculants enhance the persistence of antibiotic resistance genes in aerobic compost of food waste mainly by altering interspecific relationships

The effects of microbial inoculants on ARG removal in composting are poorly understood. Here, a co-composting method for food waste and sawdust amended with different microbial agents (MAs) was designed. The results show that the compost without MA unexpectedly achieved the best ARG removal. The addition of MAs markedly increased the abundance of tet, sul and multidrug resistance genes (p < 0.05). Structural equation modeling demonstrated that MAs can enhance the contribution of the microbial community to ARG changes by reshaping community structure and altering the ecological niche, causing the proliferation of individual ARGs, an effect related to the MA component. Network analysis revealed that inoculants weakened the correlation between ARGs and community but increased the linkage between ARGs and core species, suggesting that inoculant-induced ARG proliferation may correspond with gene exchange occurring mainly between core species. The outcome provides new insights into MA application for ARG removal in waste treatment.

Effects of microbial inoculants on agronomic characters, physicochemical properties and nutritional qualities of lettuce and celery in hydroponic cultivation

Leafy vegetables are rich in nutrients such as vitamins and dietary fiber, which are essential to people's daily diet. Microbial inoculants play an important role in promoting plant growth and nutritional qualities. In this study, two combined microbial inoculants of Arthrobacter pascens BUAYN-122 and Bacillus subtilis BUABN-01 were applied in the hydroponic system for lettuce (Lactuca sativa L.) and celery (Apium graveolens L.) cultivation. After harvesting, the agronomic characters, physicochemical properties and nutritional qualities of lettuce and celery were determined. The paper aimed to evaluate the application of the combined microbial inoculants on hydroponic cultivation of lettuce and celery. The results showed that the microbial inoculants significantly improved the aboveground fresh weight, underground fresh weight, root length, leaf length and leaf number of both lettuce and celery. The root dehydrogenase activity, net photosynthetic rate, stomatal conductance and total chlorophyll content of the two vegetables were significantly improved, indicating that the microbial inoculation can promote the root nutrient uptake and leaf photosynthesis. Furthermore, the microbial inoculants could significantly increase the total protein, vitamin C and total phenol contents of lettuce and celery, anthocyanin and total flavonoid contents of lettuce, and soluble sugar and total dietary fiber contents of celery. The results of this study confirmed that the application of microbial inoculants in hydroponics systems can promote the yield and the quality of lettuce and celery.

Effects of Microbial Inoculants and Organic Amendments on Wheat Nutrition and Development in a Variety of Soils

Manipulation of soil microbial communities through inoculants or amendments can improve crop nutrition. However, to what extent these benefits vary depending on soil properties is not yet understood. Thus, here we studied the effects of microbial inoculants and the application of labile organic C on the yield and uptake of micronutrients and P in wheat (Triticum durum) in different soils. The application of Bacillus subtilis QST713, Trichoderma asperellum strain T34, and cellulose was tested in ten soils varying greatly in properties in a pot experiment. Microbial inoculants and cellulose increased dry matter (between 5 and 10%) and grain yield (between 15 and 20%), regardless of the soil. Some treatments triggered nutrient mobilization mechanisms such as phosphatase and oxalate production. However, total Zn and P in plants did not increase with treatments, and their effect on Fe and Mn varied depending on soils. The effect of B. subtilis and T. asperellum improving Fe uptake by plants decreased with increasing pH and also with decreased microbial activity in soil. Inoculants and cellulose increased the Zn harvest index and decreased the P-to-Zn ratio in grains independently of the soil. This was probably ascribable to changes in the distribution of phytohormones in plants. Microorganisms and cellulose improved wheat yield, the portion of absorbed Zn accumulated in grains, and grain quality. These effects did not depend on the soil. However, the effect on Fe and Mn nutrition was affected by soil pH and microbial activity.

PRECURSOR-INOCULUM INTERACTION FOR THE GROWTH PROMOTION OF COTTON UNDER FIELD CONDITIONS

The present experiment was conducted during 2019-2021 at Agricultural Biotechnology Research Institute, Ayub Agricultural Research Institute, Faisalabad, Pakistan. The yield of local BT cotton variety FH-142 was evaluated using different combinations of rhizobacteria (free living diazotroph and phosphate solubilizer) with auxin precursor L-tryptophan (L-TRP). The experiment was comprised of seven treatments under Randomized Complete Block Design (RCBD) replicated thrice. The experiment was repeated for consecutive three years to find the effect of microbial inoculants with auxin precursor L-TRP and mean of three years was reported in the manuscript. The microbial inoculants were applied as seed coating. The bacterial inoculation showed promising results as compared to control. However, the consortium of PGPR and P-solubilizer with precursor had the significant effects on cotton yield during all three years of experiment. The consortium increased the yield parameters of cotton i.e., 1810 kg/ha in comparison with un-inoculated control i.e., 1672 kg/ha. Individual applications of PGPR and P-solubilizer also had significant effect on the yield compared to control. Hence, it was concluded that the interaction of bacterial consortium and precursor (precursor inoculum interaction) proved to be the best to improve the cotton yield.

Unraveling the effect of added microbial inoculants on ammonia emissions during co-composting of kitchen waste and sawdust: Core microorganisms and functional genes

Despite the role of microorganisms in nitrogen biotransformation has been extensively explored, how microorganisms mitigate NH3 emissions in the transformation of nitrogen throughout the composting system is rarely addressed. The present study explored the effect of microbial inoculants (MIs) and the contribution of different composted phases (solid, leachate, and gas) on NH3 emissions by constructing a co-composting system of kitchen waste and sawdust with and without the addition of MI. The results showed that NH3 emissions increased markedly after adding MIs, in which the contribution of leachate ammonia volatilization to NH3 emissions was most prominent. The core microorganisms of NH3 emission had a clear proliferation owing to the MIs reshaping community stochastic process. Also, MIs can strengthen the co-occurrence between microorganisms and functional genes of nitrogen to promote nitrogen metabolism. In particular, the abundances of nrfA, nrfH, and nirB genes, which could augment the dissimilatory nitrate reduction process, were increased, thus enhancing NH3 emissions. This study bolsters the fundamental, community-level understanding of nitrogen reduction treatments for agricultural.

Plant and Native Microorganisms Amplify the Positive Effects of Microbial Inoculant.

Microbial inoculants can be used to restore abandoned mines because of their positive effects on plant growth and soil nutrients. Currently, soils in greenhouse pot studies are routinely sterilized to eradicate microorganisms, allowing for better inoculant colonization. Large-scale field sterilization of abandoned mining site soils for restoration is difficult, though. In addition, microbial inoculants have an impact on plants. Plants also have an impact on local microbes. The interactions among microbial inoculants, native microorganisms, and plants, however, have not been studied. We created a pot experiment utilizing the soil and microbial inoculant from a previous experiment because it promoted plant growth in that experiment. To evaluate the effects of the plants, native microorganisms, and microbial inoculants, we assessed several indicators related to soil elemental cycling and integrated them into the soil multifunctionality index. The addition of the microbial inoculant and sterilizing treatment had a significant impact on alfalfa growth. When exposed to microbial inoculant treatments, the plant and sterilization treatments displayed radically different functional characteristics, where most of the unsterilized plant treatment indices were higher than those of the others. The addition of microbial inoculant significantly increased soil multifunctionality in plant treatments, particularly in the unsterilized plant treatment, where the increase in soil multifunctionality was 260%. The effect size result shows that the positive effect of microbial inoculant on soil multifunctionality and unsterilized plant treatment had the most significant promotion effect. Plant and native microorganisms amplify the positive effects of microbial inoculant.

Integrative effects of microbial inoculation and amendments on improved crop safety in industrial soils co-contaminated with organic and inorganic pollutants

Soils co-contaminated by organic and inorganic pollutants usually pose major ecological risks to soil ecosystems including plants. Thus, effective strategies are needed to alleviate the phytotoxicity caused by such co-contamination. In this study, microbial agents (a mixture of Bacillus subtilis, Sphingobacterium multivorum, and a commercial microbial product named OBT) and soil amendments (β-cyclodextrin, rice husk, biochar, calcium magnesium phosphate fertilizer, and organic fertilizer) were evaluated to determine their applicability in alleviating toxicity to crops (maize and soybean) posed by polycyclic aromatic hydrocarbon (PAHs) and potentially toxic metals co-contaminated soils. The results showed that peroxidase, catalase, and superoxide dismutase activity levels in maize or soybean grown in severely or mildly contaminated soils were significantly enhanced by the integrative effects of amendments and microbial agents, compared with those in single plant treatments. The removal rates of Zn, Pb, and Cd in severely contaminated soils were 49 %, 47 %, and 51 % and 46 %, 45 %, and 48 %, for soybean and maize, respectively. The total contents of Cd, Pb, Zn, and PAHs in soil decreased by day 90. Soil organic matter content, levels of nutrient elements, and enzyme activity (catalase, urease, and dehydrogenase) increased after the amendments and application of microbial agents. Moreover, the amendments and microbial agents also increased the diversity and distribution of bacterial species in the soil. These results suggest that the amendments and microbial agents were beneficial for pollutant purification, improving the soil environment and enhancing both plant resistance to pollutants and immune systems of plants.

Effect of microbial inoculant on the oviposition and completion of life cycle of Chrysomya megacephala(Fabricius) and Chrysomya rufifacies(Macquart) infest-ing rabbit carcasses

This research was conducted to assess the influence of microbial inoculant (EM.1®) on the initial oviposition and developmental pattern of two prevalent necrophagous flies (Chrysomya megacephala and Chrysomya rufifacies) in Malaysia. Nine rabbit carcasses were equally divided into control and two treated groups. The control carcasses were sprayed with deionized water (about 100 mL), whereas the two other treated groups were individually sprayed with two concentrations of EM.1® at 1:500 and 1:100, respectively. Results revealed that the single application of EM.1® on both treated carcasses did not statistically impede oviposition by both necrophagous species, as well as their subsequent developmental patterns (P &gt; 0.05) when compared with that of controls. Therefore, estimating the minimum post-mortem interval (mPMI) using empirical baseline data for the control animal model would remain appropriate for estimating mPMI in cases involving carcasses with a single application of EM.1®

The co-inoculation of Pseudomonas chlororaphis H1 and Bacillus altitudinis Y1 promoted soybean [Glycine max (L.) Merrill] growth and increased the relative abundance of beneficial microorganisms in rhizosphere and root.

Currently, plant growth-promoting rhizobacteria (PGPR) microbial inoculants are heavily used in agricultural production among which Pseudomonas sp. and Bacillus sp. are two excellent inoculum strains, which are widely used in plant growth promotion and disease control. However, few studies have been conducted on the combined use of the two bacteria. The aim of this study was to investigate the effects of co-inoculation of these two bacteria on soybean [Glycine max (L.) Merrill] growth and physiological indexes and further study the effect of microbial inoculants on native soil bacterial communities and plant endophyte microbiota, especially microorganisms in rhizosphere and root. A pot experiment was conducted and four treatments were designed: group without any strain inoculant (CK); group inoculated with Pseudomonas chlororaphis H1 inoculant (J); group inoculated with Bacillus altitudinis Y1 inoculant (Y) and group inoculated with equal volume of P. chlororaphis H1 inoculant and B. altitudinis Y1 inoculant (H). Compared with CK, the three inoculant groups J, Y, and H exhibited improved soybean growth and physiological indexes, and group H was the most significant (p < 0.05). In terms of rhizosphere bacterial community structure, the relative abundance of native Luteimonas (9.31%) was higher in the H group than in the J (6.07%), Y (3.40%), and CK (5.69%) groups, which has potential value of disease suppression. Besides, compared with bacterial communities of the other three groups in soybean roots, group H increased the abundance of beneficial bacterial community for the contents of Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Devosia, and Methylobacillus significantly increased (p < 0.05). In conclusion, we found that the composite inoculum of Pseudomonas chlororaphis H1 and Bacillus altitudinis Y1 could effectively promote soybean growth, increase yield and improve the beneficial bacterial community in root and rhizosphere and have certain value for soil improvement.

Effects of microbial inoculant and additives on pile composting of cow manure.

Composting is an effective method of recycling organic solid waste, and it is the key process linking planting with recycling. To explore the reuse of agricultural organic solid waste as a resource in the Yellow River Delta, the effects of microbial inoculant and different additives (calcium superphosphate, biochar, tomato straw, rice husk, and sugar residue) on pile composting of cow dung were studied to obtain the best composting conditions. The results showed that microbial inoculant and additives all played positive roles in the process of aerobic composting, and the experimental groups outperformed the control groups without any additives. For discussion, the microbial inoculant promoted rapid pile body heating more than the recovery materials alone, and the effects on aerobic composting were related to the organic matter of substrates and biochar. After being composted, all the materials were satisfactorily decomposed. Degradation of additives into humic acid might serve as electron shuttles to promote thorough organic matter decomposition. These results provide a scientific basis data for industrial composting of organic solid waste processed by on-site stacking, and provide a reference for researcher and practitioners for studying the applications of microbial inoculant on aerobic composting.

Impact of Microbial Inoculants and Fertilizers on Nutrient Uptake and Yield of Sugarcane Short Crop

A field experiment was conducted at Agricultural Research Station, Perumallapalle, Tirupati, Acharya N. G. Ranga Agricultural University, Andhra Pradesh, India during 2021-22 to study the effect of microbial inoculants and fertilizers on nutrient uptake and yield of sugarcane short crop. The experiment was laid out in randomized block design with ten treatments and replicated thrice. The treatments consist of 75%, 100% and 125% RDF in combination of solid and liquid microbial inoculants (Gluconacetobacter, PSB and KSB). Data on N, P, K and S uptake by plant at different stages and yield were recorded. Results revealed that application of 100% RDF along with sett treatment with liquid Gluconacetobacter @ 1 lit ha-1, PSB @ 1 lit ha-1 and KSB @ 1 lit ha-1 resulted significantly the highest N, P, K and S uptake by plant and seed cane yield followed by 100% RDF + sett treatment with solid Gluconacetobacter @ 10 kg ha-1, PSB @ 1.25 kg ha-1 and KSB @ 1.25 kg ha-1.

Six complex microbial inoculants for removing ammonia nitrogen from waters.

To determine the effect of microbial inoculants on the removal of ammonia nitrogen (NH4 + -N), six different complex microbial inoculants were studied. In this study, their effectiveness on NH4 + -N removal was compared, and their microbial community composition was determined. High-throughput sequencing results showed that Proteobacteria and Firmicutes were the dominant phyla in six samples. Before the reaction, Bacillus, Cyanobacteria, and Mitochondria genera were the dominant genera. The dominant genera were significantly different after the reaction with the addition of bacterial agents. The six water samples were Massilia, Escherichia-Shigella, Brevibacillus, Mitsuaria, Bacillus, and Ralstonia. Among the six complex microbial inoculants, "Gandu nitrifying bacteria (NR4 )" have the best removal effect on NH4 + -N. In addition, the removal effect of six different bacterial agents on chemical oxygen demand (COD) was compared. The results showed that "Bilaiqing ammonia nitrogen removal bacteria agent (NR5 )" has the best removal effect on COD. Single-factor experiments suggested that the optimal conditions for NR4 bacteria were pH7, 30°C, 1.0g/L of bacterial agent dosage and a wide range of NH4 + -N from 30 to 300 mg/L. PRACTITIONER POINTS: The nitrogen removal effects of six different microbial agents were compared. High-throughput sequencing provides important insights into the study of ammonia nitrogen removal by microbial communities. Analysis of six different complex bacterial agents by high-throughput sequencing. The relative abundance of microorganisms is not proportional to the ability to remove NH4 + -N Good application effect in urban landscape water body.

The rhizosphere microbiome and host plant glucosinolates exhibit feedback cycles in Brassica rapa.

The rhizosphere microbiome influences many aspects of plant fitness, including production of secondary compounds and defence against insect herbivores. Plants also modulate the composition of the microbial community in the rhizosphere via secretion of root exudates. We tested both the effect of the rhizosphere microbiome on plant traits, and host plant effects on rhizosphere microbes using recombinant inbred lines (RILs) of Brassica rapa that differ in production of glucosinolates (GLS), secondary metabolites that contribute to defence against insect herbivores. First, we investigated the effect of genetic variation in GLS production on the composition of the rhizosphere microbiome. Using a Bayesian Dirichlet-multinomial regression model (DMBVS), we identified both negative and positive associations between bacteria from six genera and the concentration of five GLS compounds produced in plant roots. Additionally, we tested the effects of microbial inoculation (an intact vs. disrupted soil microbiome) on GLS production and insect damage in these RILs. We found a significant microbial treatment × genotype interaction, in which total GLS was higher in the intact relative to the disrupted microbiome treatment in some RILs. However, despite differences in GLS production between microbial treatments, we observed no difference in insect damage between treatments. Together, these results provide evidence for a full feedback cycle of plant-microbe interactions mediated by GLS; that is, GLS compounds produced by the host plant "feed-down" to influence rhizosphere microbial community and rhizosphere microbes "feed-up" to influence GLS production.

Microbial inoculants improve nutrients uptake and yield of durum wheat in calcareous soils under drought stress in the Mediterranean region

ABSTRACT Despite some evidence in greenhouse experiments, the benefits of Bacillus subtilis and Trichoderma asperellum on nutrients uptake by plants under field conditions are unknown. This work aims to study the effect of these microbial inoculants on durum wheat nutrition and yield under Mediterranean conditions where soils may lead to micronutrients and phosphorus deficiencies and where drought may promote low use efficiencies of applied fertilizers. To this end, three experiments were performed in two growing seasons. B. subtilis increased the uptake of nitrogen, phosphorus, and manganese relative to other treatments in the experiment carried out in the first growing season involving two experimental sites. The increased phosphorus uptake was attributed to the increased activity of alkaline phosphatase. In this first season, T. asperellum increased acid phosphatase activity without effect on P uptake and decreased the P to Zn molar ratio in grains, thus improving grain quality for human consumption. In the second season, the effects of microbial inoculants were less evident possibly due to favourable environmental conditions for crops (higher water availability) or phosphate fertilization. Results evidenced that B. subtilis can be effective improving the development and nutrient uptake of durum wheat under more stressful conditions, such as drought stress.

Effects of Two Bacillus Velezensis Microbial Inoculants on the Growth and Rhizosphere Soil Environment of Prunus davidiana.

Microbial inoculants, as harmless, efficient, and environmentally friendly plant growth promoters and soil conditioners, are attracting increasing attention. In this study, the effects of Bacillus velezensis YH-18 and B. velezensis YH-20 on Prunus davidiana growth and rhizosphere soil bacterial community in continuously cropped soil were investigated by inoculation tests. The results showed that in a pot seedling experiment, inoculation with YH-18 and YH-20 resulted in a certain degree of increase in diameter growth, plant height, and leaf area at different time periods of 180 days compared with the control. Moreover, after 30 and 90 days of inoculation, the available nutrients in the soil were effectively improved, which protected the continuously cropped soil from acidification. In addition, high-throughput sequencing showed that inoculation with microbial inoculants effectively slowed the decrease in soil microbial richness and diversity over a one-month period. At the phylum level, Proteobacteria and Bacteroidetes were significantly enriched on the 30th day. At the genus level, Sphingomonas and Pseudomonas were significantly enriched at 15 and 30 days, respectively. These bacterial phyla and genera can effectively improve the soil nutrient utilization rate, antagonize plant pathogenic bacteria, and benefit the growth of plants. Furthermore, inoculation with YH-18 and inoculation with YH-20 resulted in similar changes in the rhizosphere microbiome. This study provides a basis for the short-term effect of microbial inoculants on the P. davidiana rhizosphere microbiome and has application value for promoting the cultivation and production of high-quality fruit trees.

Microbial community response to drought depends on crop

Growing season drought can be devastating to crop yields. Soil microbial communities have the potential to buffer yield loss under drought through increasing plant drought tolerance and soil water retention. Microbial inoculation on agricultural fields has been shown to increase plant growth, but few studies have examined the impact of microbial inoculation on plant and soil microbial drought tolerance. We conducted a rainout shelter experiment and subsequent greenhouse experiment to explore 3 objectives. First, we evaluated the performance of a large rainout shelter design for studying drought in agricultural fields. Second, we tested how crop (corn vs. soybean) and microbial inoculation alter the response of soil microbial composition, diversity, and biomass to drought. Third, we tested whether field inoculation treatments and drought exposure altered microbial communities in ways that promote plant drought tolerance in future generations. In our field experiment, the effects of drought on soil bacterial composition depended on crop type, while drought decreased bacterial diversity in corn plots and drought decreased microbial biomass carbon in soybean plots. Microbial inoculation did not alter overall microbial community composition, plant growth, or drought tolerance despite our efforts to address common barriers to inoculation success. Still, a history of inoculation affected growth of future plant generations in the greenhouse. Our study demonstrates the importance of plant species in shaping microbial community responses to drought and the importance of legacy effects of microbial inoculation.

Production of plant growth substances by asymbiotic nitrogen fixers

Modern agriculture faces challenges such as loss of soil fertility fluctuating climatic factors and increase in pathogen and pest attacks. The sustainability and environmental safety in agriculture production needs eco-friendly approach like use of biofertilizers, bio pesticide and green manuring etc. The multiple beneficial effects of microbial inoculants apart of nitrogen fixation needs further research and their use in modern agriculture. This review summarises the plant growth substances related research and its benefits from asymbiotic bacteria.