Effects of Nature-Derived Biostimulants on Wheat Rhizosphere Microbial Biomass, Diversity, and Networks

Environmental and agronomic drivers of bacterial and fungal alpha diversity in crop rhizosphere: a multifactorial field study

Diversity of Fungal and Bacterial Communities in Bioinputs from Chiapas Mountains and Soils from Maize Agroecosystems

The increasing demand for food has driven intensive agricultural practices, which negatively impact soil health and ecosystem stability; therefore, it is necessary to adopt sustainable alternatives that enhance crop productivity while minimizing environmental damage. The aim of this study was to characterize the bacterial and fungal microbiota present in bioinputs derived from mountain soil microorganisms used in maize cultivation, as well as the microbial communities in agricultural soils at the end of the cultivation stage across different plots in the Frailesca region, Chiapas, Mexico. Bacterial communities showed differences among bioinputs depending on their origin, while soil samples showed relatively similar bacterial distribution patterns across plots. Conversely, fungal communities displayed heterogeneous distribution patterns in both bioinputs and soils. Several microbial groups related to beneficial functions for plants and soil, such as nitrogen fixation, phosphate solubilization, and the production of phytohormones and siderophores were identified; those belonging to the genera Acetobacter, Klebsiella, Meyerozyma, Saccharomyces, and Paecilomyces were found in bioinputs, while those belonging to the genera Bradyrhizobium, Sphingomonas, Penicillium, Talaromyces, Humicola, and Metarhizium were identified in soil samples. The results demonstrate that bioinputs contain microbial communities with potential plant growth-promoting functions and can serve as strategies for improving soil health through sustainable agricultural production.

The Effects of Biofertilizer Derived from Fermentation Effluent on the Structure and Function of Microbial Communities in Maize Soils, Northeastern China

To investigate the associations of a biofertiliser derived from fermentation effluent with microbial community composition and soil physicochemical properties in northern maize cropping systems, we conducted a field trial with three fertilisation treatments (macronutrients only, T1; macronutrients plus micronutrients, T2; and fermentation effluent combined with nutrients, T3) and one conventional control (CK) in continuously cropped maize soils. Soil physicochemical properties, microbial diversity and community composition, and predicted functional potential were analysed using high-throughput amplicon sequencing and standard soil assays. The results indicated that, compared with other treatments, the biofertiliser treatment (T3) was associated with significantly higher soil electrical conductivity, available phosphorus and alkali-hydrolysable nitrogen, but showed no significant effect on total organic carbon or organic matter. Bacterial community diversity did not differ significantly among treatments, whereas the fungal community appeared more sensitive to fertilisation. Principal coordinate analysis (PCoA) supported by PERMANOVA tests revealed that the treatments significantly altered fungal community structure. The phyla Acidobacteriota, Actinobacteriota and Firmicutes (including the genus Bacillus) were relatively enriched in the T3 treatment, while Ascomycota and Mortierellomycota were the dominant fungal phyla across all treatments. Redundancy analysis (RDA) indicated that available potassium, available phosphorus, and pH were key factors associated with microbial community structure. Functional gene inference, based on taxonomic annotation, suggested that the biofertiliser was correlated with predicted functional potential related to soil carbon and nitrogen cycling. In conclusion, the biofertiliser derived from fermentation effluent was correlated with improved soil nutrient availability and with putative shifts in microbial community composition in northern maize fields, thereby providing technical support for the resource utilisation of agricultural waste and the conservation of black soil.

Plant Exposure to Agrochemicals in the Soil Has Transgenerational Impact on the Seed Microbiota in Tomato

Seed-associated bacterial communities are crucial for plant health, yet the impact of agrochemicals on them remains largely unexplored. This study investigated the effects of repeated soil applications of nine different agrochemicals (four synthetic and five biopesticides) on the seed microbiome of tomato (Solanum lycopersicum L.) plants. They represent major plant protectant categories in current agricultural use. The results showed that abamectin (R² = 21.9%), chitosan (R² = 24.7%), fosthiazate (R² = 11.8%), imidacloprid (R² = 27.2%), ningnanmycin (R² = 19.3%), and wuyiencin (R² = 22.1%) significantly (P < 0.05) altered the composition, diversity, and abundance of seed-associated microbial communities comprising 33 bacterial phyla and 445 genera. Among these, abamectin increased bacterial richness while simultaneously reducing key beneficial taxa such as Streptomyces and Rhizobium, which are known to be crucial for plant health. In contrast, kasugamycin, moroxydine hydrochloride, and sodium nitrophenolate exhibited negligible impacts, likely due to their non-bacterial targets or rapid degradation. Our study suggests that pesticide-induced microbiome shifts extend beyond direct effects and are associated with influencing seed endophyte selection by the host, as indicated by the depletion of Streptomyces and Rhizobium under specific treatments. Other treatments promoted taxa such as Pseudomonas, suggesting ecological trade-offs. These findings highlight the need to incorporate seed microbiome considerations into pesticide risk assessments and to develop agrochemical strategies that protect the functional integrity of plant-associated microbial communities.

Characterization of Microbiome in Natural Farming Inputs and their Effect on In Vitro Phosphorus Solubilization by Mixed Rhizosphere Microbial Community

Beejamrit (BJ), Jeevamrit (JV) and Ghanajeevamrit (GV) the core inputs for practicing natural farming in India have been characterized for the plant nutrient content and microbial composition using cultural and metabarcoding techniques. Also, Phosphorus (P) solubilization efficiency of rhizosphere microbes receiving these natural farming inputs has been compared with organic, integrated and inorganically managed soils microbes. Chemical analysis revealed higher total NP and K (2.04, 0.3 and 1.3% respectively) in GV. Metabarcoding revealed dominance of Bacillota (87.5%) in JV, whereas Beejamrit and Ghanajeevamrit had abundance of Pseudomonadota with 49.67% and 46.77% OTU respectively. Higher abundance of Lactococcus, Clostridium, Lacticaseibacillus, Lactiplantibacillus and Acetobacter was found in JV. GV had higher diversity of bacteria and Flavobacterium, Hydrogenophaga, Pseudomonas and Arenimonas was dominant genera. Highest solubilization of phosphorus was observed by mixed microbial community in Control soil (CONT) 92.75 µg/mL and natural farming (NF) soil 90.56 µg/mL on 21 days of incubation (DAI) while P solubilization by bacterial flora was recorded highest in NF 40.77 µg/mL on 21 DAI followed by integrated crop management (ICM) 38.76 µg/mL and organic farming (OF) soil 34.12 µg/mL on 14 DAI. P solubilization by bacterial flora ranged from 34.36% in CONT to 67.63% in ICM. It can be concluded that organic and low input management system supported more efficient microbes in P solubilization while bacterial contribution was more where nutrient source was added exogenously.

Sustainable bioformulation of Trichoderma asperellum, Pseudomonas fluorescens, and Bacillus subtilis enhances agricultural productivity in different Brazilian states

ABSTRACT The use of plant growth-promoting microorganisms (PGPM) is a promising strategy to enhance crop productivity while improving soil functionality. This study evaluated the efficacy of fungal-bacterial consortium of Trichoderma asperellum, Pseudomonas fluorescens, and Bacillus subtilis, for promoting the growth of soybean and maize cultivated under distinct edaphoclimatic conditions across Brazil. Field trials were conducted in five locations within Rio Grande do Sul, Santa Catarina, São Paulo, and Minas Gerais. Treatments consisted of a fungal-bacterial consortium (200 g ha-¹, in-furrow at planting) combined with 50% or 100% of the recommended nitrogen rate. Shoot dry biomass, foliar nitrogen (N) and phosphorus (P) concentrations, grain yield, and soil microbial activity determined by fluorescein diacetate hydrolysis were assessed. The fungal-bacterial consortium significantly improved all variables in both crops. In soybean, shoot biomass increased by 10.7-13.4% and grain yield by 9.2-9.9%, while foliar N and P rose by 10.2-12.4%, and soil enzymatic activity increased up to 11.0%. In maize, biomass increased by 10.4-11.8% and grain yield by 13.1-13.9%, with foliar N and P increasing by 9.5-14.1% and soil enzymatic activity by up to 12.5%. Notably, positive responses were maintained under 50% nitrogen fertilization. These findings demonstrate that fungal-bacterial consortium enhances nutrient acquisition and soil microbial activity, improving crop performance under variable environmental conditions and reduced N input, supporting its potential as a biological tool for sustainable nutrient management in soybean and maize systems.