Long-term fertilization altered microbial community structure in an aeolian sandy soil in northeast China

The effect of broadcast struvite fertilization on element soil content and microbial activity changes in winter wheat cultivation in southwest Poland

This study aimed to evaluate the potential of struvite as a phosphorus fertilizer in winter wheat cultivation in southwest Poland. The field experiment was conducted at Wroclaw University of Environmental and Life Sciences in Swojec in 2022/2023. The studied factors were two cultivars of winter wheat (Activus and Chevignon) and two phosphorus fertilization methods (traditional superphosphate and struvite). Aditionally, the study attempted to develop a reasonable phosphorus testing method to analyze phosphorus content in soil. Three phosphorus extraction methods were used to determine P, Mg and K content where Mehlich 3 and Yanai seem to be most appropriate. The following traits in the study were estimated: grain yield, content of P, Mg and K in the grain, as well as soil microbial activity expressed as enzyme activity (acid and alkaline phosphatase, dehydrogenase), metabolic activity (Biolog EcoPlates™) and phosphate solubilizing bacteria (PSB) abundance. An increase in the Mg content of wheat grain under the influence of struvite application was found. Phosphorus content in the soil depended primarily on the date of soil sampling followed by fertilization method and varieties based on the Egner-Rhiem method as well as Mehlich 3. Soil enzymatic activity depended mainly on the sampling date and then on fertilization. In the case of PSB, the dominant factor was the wheat cultivars. Biolog EcoPlate analysis showed that the most metabolically active microbial communities were recorded in samples collected at the second time of sampling (end of winter wheat vegetation) To see how the phosphorus content develops after the application of struvite under field conditions as well as its fraction, a long-term experiment should be conducted.

Recycled Phosphorus Bioamendments from Wastewater Impact Rhizomicrobiome and Benefit Crop Growth: Sustainability Implications at Water-Food Nexus

Phosphorus recovery through enhanced biological phosphorus removal (EBPR) processes from agricultural wastes holds promise in mitigating the impending global P shortage. However, the complex nutrient forms and the microbial augments, expected to exert a profound impact on crop rhizomicrobiome and thus crop health, remained unexplored. In this study, we investigated the impacts of EBPR biosolids on crops growth and rhizomicrobiome in comparison to chemical fertilizer and Vermont manure compost. Our findings revealed that EBPR biosolid augmentation promoted the best maize shoot growth traits with the least nutrient deficiency, evidencing its agricultural benefits. Biosolid augmentation significantly impacted the rhizomicrobiome with decreased biodiversity but higher activities with enriched taxa capable of utilizing various carbon sources. The novel single-cell Raman spectroscopy phenotyping technique uncovered the surprisingly high abundance (up to 30%) of polyphosphate-accumulating organisms (PAOs) in the rhizosphere and their distinctive variations in different biosolid amendments. Furthermore, the interactions between EBPR-derived PAOs such as Candidatus Accumulibacter phosphatis and soil native plant growth promoting rhizobacteria highlighted the previously overlooked status and yet-to-be-characterized functions of PAOs in P cycling. This study provides a novel perspective leveraging EBPR biosolids to facilitate plant growth with agronomic benefits, thereby contributing to more sustainable and ecologically responsible agricultural practices.

Adaptation of rhizobacterial and endophytic communities in Citrus Grandis Exocarpium to long-term organic and chemical fertilization

Introduction

Organic fertilizers (OF) are crucial for enhancing soil quality and fostering plant growth, offering a more eco-friendly and enduring solution compared to chemical fertilizers (CF). However, few studies have systematically analyzed the effects of OF/CF on root microbiome of medicinal plants, especially in combination with active ingredients.

Methods

In this study, we investigated the composition and function of bacteria and fungi in the rhizosphere or within the root of traditional Chinese medicinal plants, Citri Grandis Exocarpium (Huajuhong), which were treated with OF or CF over 1, 3, and 5 years (starting from 2018). Additionally, we conducted metabolome analysis to evaluate the effects of different fertilizers on the medicinal properties of Huajuhong.

Results

The results indicated that extended fertilization could enhance the microbial population and function in plant roots. Notably, OF demonstrated a stronger influence on bacteria, whereas CF enhanced the cohesion of fungal networks and the number of fungal functional enzymes, and even potentially reduced the proliferation of harmful rhizosphere pathogens. By adopting distancebased redundancy analysis, we identified the key physicochemical characteristics that significantly influence the distribution of endophytes, particularly in the case of OF. In contrast, CF was found to exert a more pronounced impact on the composition of the rhizosphere microbiome. Although the application of OF resulted in a broader spectrum of compounds in Huajuhong peel, CF proved to be more efficacious in elevating the concentrations of flavonoids and polysaccharides in the fruit.

Discussion

Consequently, the effects of long-term application of OF or CF on medicinal plants is different in many ways. This research provides a guide for OF/CF selection from the perspective of soil microecology and aids us to critically assess and understand the effects of both fertilizers on the soil environment, and promotes sustainable development of organic agriculture.

Assessing the influence of diverse phosphorus sources on bacterial communities and the abundance of phosphorus cycle genes in acidic paddy soils

The impact of chemical fertilizers on soil microbial communities is well acknowledged. This study assesses the influence of various phosphorus sources on soil bacterial composition, abundance, and Phosphorus Cycle Gene Abundance. Three phosphorus sources (natural phosphate rock, triple super phosphate (TSP), and chemical fertilizer NPK) were field tested following two rice cultivation cycles. Soil samples were subsequently collected and analyzed for bacterial groups and phosphorus cycle genes. Results indicated that the bacterial community composition remained consistent, comprising five main phyla: Firmicutes, Actinobacteria, Proteobacteria, Halobacterota, and Chloroflexia, regardless of fertilizer type. NPK fertilizer significantly reduced the relative abundance of Chloroflexia by 19% and Firmicutes by 16.4%, while increasing Actinobacteria and Proteobacteria by 27.5 and 58.8%, respectively. TSP fertilizer increased Actinobacteria by 27.1% and Halobacterota by 24.8%, but reduced Chloroflexia by 8.6%, Firmicutes by 12.6%, and Proteobacteria by 0.6%. Phosphate rock application resulted in reductions of Chloroflexia by 27.1%, Halobacterota by 22.9%, and Firmicutes by 6.2%, alongside increases in Actinobacteria by 46.6% and Proteobacteria by 23.8%. Combined application of TSP, NPK, and phosphate rock led to increases in Proteobacteria (24-40%) and Actinobacteria (13-39%), and decreases in Chloroflexia (5.2-22%) and Firmicutes (6-12.3%) compared to the control (T0). While the different phosphorus sources did not alter the composition of phosphorus cycle genes, they did modulate their abundance. NPK fertilizer did not significantly affect ppK genes (57-59%) but reduced gcd (100 to 69%), 3-phytase (74 to 34%), appA (91 to 63%), and phoD (83 to 67%). Phosphate rock reduced appA and gcd by 27 and 15%, respectively, while increasing 3-phytase by 19%. TSP decreased ppK and phoD by 42 and 40%, respectively, and gcd and appA by 34 and 56%, respectively. Combined fertilizers reduced appA (49 to 34%), 3-phytase (10 to 0%), and gcd (27 to 6%), while increasing ppK (72 to 100%). Among tested phosphorus sources, natural phosphate rock was best, causing moderate changes in bacterial composition and phosphorus genes, supporting balanced soil microbial activity. These findings highlight the complex interactions between fertilizers and soil microbial communities, underscoring the need for tailored fertilization strategies to maintain soil health and optimize agricultural productivity.

Continuous cropping system altered soil microbial communities and nutrient cycles

Understanding the response of microbial communities and their potential functions is essential for sustainability of agroecosystems under long-term continuous cropping. However, limited research has focused on investigating the interaction between soil physicochemical factors and microbial community dynamics in agroecosystems under long-term continuous cropping. This study probed into the physicochemical properties, metabolites, and microbial diversity of tobacco rhizosphere soils cropped continuously for 0, 5, and 20 years. The relative abundance of bacterial genera associated with nutrient cycling (e.g., Sphingomonas) increased while potential plant pathogenic fungi and beneficial microorganisms showed synergistic increases with the duration of continuous cropping. Variations in soil pH, alkeline nitrogen (AN) content, and soil organic carbon (SOC) content drove the shifts in soil microbial composition. Metabolites such as palmitic acid, 3-hydroxypropionic acid, stearic acid, and hippuric acid may play a key role in soil acidification. Those results enhance our ability to predict shifts in soil microbial community structure associated with anthropogenic continuous cropping, which can have long-term implications for crop production.

Impact of nitrogen application and crop stage on epiphytic microbial communities on silage maize leaf surfaces

This study aimed to examine the impact of nitrogen (N) fertilization on phyllosphere microorganisms in silage maize (Zea mays) to enhance the production of high-quality silage. The effects of different N application rates (160, 240, and 320 kg ha-1) and maturity stages (flowering and dough stages) on microbial diversity, abundance and physiochemical properties of the leaf surfaces were evaluated in a field experiment. The results showed that N application rates did not significantly impact the abundance of lactic acid bacteria (LAB), aerobic bacteria (AB), yeasts, or molds on the leaf surfaces. However, these microbes were more abundant during the flowering stage compared to the dough stage. Furthermore, the N application rate had no significant impact on inorganic phosphorus, soluble sugar, free amino acids, total phenolic content, and soluble protein concentrations, or pH levels on the leaf surfaces. Notably, these chemical indices were lower during the dough stage. The abundance of Pantoea decreased with higher N application rates, while that of other microorganisms did not changes significantly. The abundance of AB, LAB, yeasts, and molds were positively correlated with soluble sugar, soluble protein, inorganic phosphorus, free amino acids, and total phenolic concentrations on leaf surfaces. Moreover, water loss was negatively correlated with the abundance of AB, LAB, yeasts, and molds, whereas water retention capacity and stomatal density were positively correlated with microbial abundance. We recommend applying an optimal N rate of 160 kg ha-1 to silage maize and harvesting at the flowering stage is recommended.