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Network visualization of co-occurring bacteria and fungi per treatment. Control: unamended soil; CL: soil amended with a low dose of compost (3.8 ton/ha); CH: soil amended with a high dose of compost (9.5 ton/ha); BL: soil amended with a low dose of bokashi (9.7 ton/ha); BH: soil amended with a high dose of bokashi (24.25 ton/ha).
Source publication
The living soil harbors a significant number and diversity of bacteria and fungi, which are essential in sustaining soil ecosystem functions. Most studies focus on soil bacteria or fungi, ignoring potential interrelationships between kingdoms that coevolve and synergistically provide ecosystem functions. In a seven-year agricultural field, we explo...
Contexts in source publication
Context 1
... fertilization did not influence the richness and composition of the soil microbial community ( Fig. S2; Table S3; Table S4). Therefore, we assessed the effects of OAs and doses on soil microbial networks and co-occurrence patterns without distinguishing between the two chemical fertilizer ...
Context 2
... correlation analysis revealed that OA amended soils retained more nodes (OTUs) and edges than control soil ( Fig. 2 and Table 2). Higher C-scores were observed in the amended soils, indicating that the addition of either compost or bokashi increased the network structure of the soil microbial community. The control soil community network had a C-score of 13.8 (p < 0.001), which also indicated a non-random structure. The addition of a low dose of ...
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Citations
... Soil microorganisms, including bacteria, fungi, archaea, and viruses, survive in the same soil environment and have complex interactions (e.g., commensalism, mutualism, competition, predation, and parasitism), which reflect material and information transport and energy transfer among microorganisms (Deng et al. 2012;Huang et al. 2021a;Luo et al. 2022). In addition, the co-occurrence networks hold keystone taxa that profoundly impact microbial community structure and function Wang et al. 2021). ...
... This result implied that labile C addition broadened niches, thus alleviating competition and creating positive co-occurrence patterns (Banerjee et al. 2016;Wang et al. 2021). Studies have reported that introducing organic amendments increased the multiple trophic levels in the food web, which was beneficial in facilitating more efficient energy utilization (Coyte et al. 2015;Luo et al. 2022). However, negative interactions could enhance network stability against species invasion and environmental change (Coyte et al. 2015;Palmer and Foster 2022). ...
Purpose
Organic carbon (C) application can improve soil C sequestration, but little is known about the impact of organic C-driven microbial community alteration on phosphorus (P) availability in soils with different tillage regimes.
Materials and methods
A 30-day incubation experiment was carried out in this study to explore the response of labile inorganic P content, organic P fraction, phosphatase activity, and phoD-harboring bacterial and fungal community structure and co-occurrence network to glucose (500 mg C kg⁻¹ dry soil) addition in 13-year continuous-tilled (CT) and no-tilled (NT) soils.
Results
The results showed that glucose addition significantly decreased the labile inorganic P content to the lowest value on Day 3 and then gradually increased by 13.1% and 25.9% in CT and NT from Day 3 to Day 30, respectively. On Day 30, the labile inorganic P content in CT was notably lower than that in NT, mainly due to the lower pH and higher phosphatase activity in NT. The labile organic C input shifted phoD-harboring bacteria from Actinobacteria (oligotrophic) to Proteobacteria (copiotrophic) and phoD-harboring fungi from Ascomycota to Basidiomycota. After glucose addition, Ensifer and Bradyrhizobium emerged as the dominant bacterial species in CT and NT soils, respectively, while Solicoccozyma became the dominant fungal species in both CT and NT soils. Regarding the combined bacterial and fungal co-occurrence network, stronger positive interactions among phosphate solubilizing microorganisms (PSMs), especially between bacteria and fungi, were detected in the glucose-amended treatment. This phenomenon was more evident in NT than in CT.
Conclusion
Overall, incorporating exogenous labile organic C could affect P availability by altering soil pH, phosphatase activity and the microbial community composition, and increasing the complexity of co-occurrence network topological patterns; more importantly, NT was more sensitive to labile organic C addition than CT.
... They may indicate a strong cooperation among microorganisms in the transformation of organic matter. Similar conclusions were also drawn by other authors who observed similar relationships between microorganisms under the influence of organic corrections (Luo et al., 2022). ...
... The relationship between the type of organic amendment and soil suppressiveness is likely a combined result of organic amendment quality and the local composition of the microbiome (Clocchiatti et al., 2021(Clocchiatti et al., , 2020Luo et al., 2018;Mayerhofer et al., 2021). For example, when making compost, the aerobic process leads to an end product with a more recalcitrant stabilized organic fraction compared to fresh material because of the release of labile carbon during composting (Luo et al., 2022;Mondini et al., 2003;Neher et al., 2013). This could create different effects on soil suppressiveness between fresh organic material and compost because the decomposability of an organic material is a major factor influencing the soil microbes (Bonanomi et al., 2010;Clocchiatti et al., 2020;Mayerhofer et al., 2021;Stone et al., 2001;Widmer et al., 1998). ...
... The organic material serves as an energy source for the soil microbiome and the easier the material can be decomposed, the quicker the boost in the activity in the soil microbiome occurs. Bokashi is mentioned to be a more easily decomposable organic amendment compared to the fresh material due to the fermentation process the organic material has been through which makes the plant cells weaker that in the fresh material (Luo et al., 2022;Shin et al., 2017). Additionally, Bokashi is a fairly new processing method for organic materials with a high potential in increasing soil suppressiveness due to the high decomposability. ...
... The maturity of our used compost was not tested extensively but the composting process took eight weeks and was believed to be finished when the compost did not have an elevated temperature above 40 • C. This practice ensured a matured compost which could explain the lack of soil suppressiveness after application since the availability of easily degradable carbon sources at this stage of composting is low (Mondini et al., 2003) which does not activate or increase the soil microbiome in the short and long term as well as other amendments would (Bonanomi et al., 2010;Luo et al., 2022;Neher et al., 2013). ...
... Although there is a considerable amount of nutrients in the composition of bokashi [9], the advantages of using this plant soil conditioner are extensive. When compared to the control, the use of bokashi resulted in significant increases in microbial biomass carbon [40,42,44], changing and regulating the pattern of microorganisms in the soil [45]. An increase in fungi diversity, mostly of the Penicillium genus, was observed when chemical fertilizer was replaced by bokashi [44]. ...
... An increase in fungi diversity, mostly of the Penicillium genus, was observed when chemical fertilizer was replaced by bokashi [44]. When applying bokashi, an increase of non-random microorganisms was observed in addition to an increase of positive correlation between microbes [45]. This suggests a reduction in resource competition, making the soil microbiota more stable and resilient to disturbance [45]. ...
... When applying bokashi, an increase of non-random microorganisms was observed in addition to an increase of positive correlation between microbes [45]. This suggests a reduction in resource competition, making the soil microbiota more stable and resilient to disturbance [45]. ...
Productive traits, total polyphenols (TPC), and antioxidant activity (DPPH) of arugula submitted to the combination (or not) of cow urine and doses of bokashi were evaluated in two experimental areas. Arugula was planted in cultivation bags with 55 dm3 of capacity in protected cultivation. The treatments were bokashi doses (0, 10, 20, and 30 g) and use (or not) of cow urine diluted 1% in water. The variables evaluated were fresh leaf biomass (FLB), dry leaf biomass (DLM), plant height (PH), chlorophyll index, TPC, and DPPH. In area 1, all agronomic variables were increased at 30 g and 20 g bokashi doses. FLB was increased by 87 and 76% with 30 g of bokashi. Cow urine only increased PH. In area 2, the use of bokashi + cow urine increased FLB, DLB, and PH with a positive quadratic response. At the maximum point, the FLB was increased by 159% with 28.92 g of bokashi. Bokashi increased FLB and DLB in the two areas in all evaluated doses. For TPC, with the use of cow urine, 10 g of bokashi increased TPC by 14%. Without the use of cow urine, increases of 17 and 33% with 10 and 30 g of bokashi were observed. The 30 g of bokashi is recommended because of increased productive traits and TPC.
Most agricultural soils in the Global South have inherently poor soil fertility status due to the old nature of soils. Coupled with this, high erosion and nutrient depletion lead to biological, chemical, and physical soil degradation. Furthermore, the low organic matter content in many soils in the Global South results in soils having poor structure, reduced soil moisture, low microbial activity, low cation exchange capacity, and soil nutrient pools, and thus poor soil health. Soil health comprises the biological, physical, and chemical properties of the soil that enable it to function as a living system and provide ecosystem services under current and changing conditions. To restore soil health and its associated functions, it is of prime importance to characterize and alleviate the main pressures that cause soil health decline. This can be achieved by using soil health indicators and their mechanistic links to each other and the functions they underpin. Next, interventions in soil management practices can be performed and the changes in soil health can be monitored. Farmers in the Global South are already employing various practices to enhance soil health which we discuss in more detail from an applied and soil health mechanism perspective. One such method is liming, which effectively raises soil pH and neutralizes soil exchangeable acidity. Another strategy is shifting cultivation, where farmers abandon a field and move to a new one, allowing the previous field to remain fallow and regenerate. Organic matter management has recently emerged as a crucial practice to improve soil health in the Global South. There has been a growing emphasis on shifting from conventional farming methods to conservation farming methods which help to bolster soil organic matter and improve various soil properties. Conservation farming principles such as minimum tillage, crop rotation, and growing of cover crops have proven to be effective in improving soil health. In order to further promote the improvement of soil health amidst the challenges faced in the Global South, a better understanding of suitable practices that conserve the soil and improve crop yields is needed.
Oil pollution in intertidal zones is an important environmental issue that has serious adverse effects on coastal ecosystems. This study investigated the efficacy of a bacterial consortium constructed from petroleum degraders and biosurfactant producers in the bioremediation of oil-polluted sediment. Inoculation of the constructed consortium significantly enhanced the removal of C8-C40n-alkanes (80.2 ± 2.8% removal efficiency) and aromatic compounds (34.4 ± 10.8% removal efficiency) within 10 weeks. The consortium played dual functions of petroleum degradation and biosurfactant production, greatly improving microbial growth and metabolic activities. Real-time quantitative polymerase chain reaction (PCR) showed that the consortium markedly increased the proportions of indigenous alkane-degrading populations (up to 3.88-times higher than that of the control treatment). Microbial community analysis demonstrated that the exogenous consortium activated the degradation functions of indigenous microflora and promoted synergistic cooperation among microorganisms. Our findings indicated that supplementation of a bacterial consortium of petroleum degraders and biosurfactant producers is a promising bioremediation strategy for oil-polluted sediments.
