Phosphate Solubilizing Microorganisms Research Articles

Study on the Effect of Trichoderma viride on Phosphate Solubilizing Microorganisms in Paddy Cultivation with the Combination of Chemical Fertilizer on soil Fertility Parameters

Trichoderma viride, biological control with Trichoderma viride is an eco-friendly and has potential approach for managing plant diseases. It also aids in phosphate solubilization. Phosphate Solubilizing Microorganisms are ubiquitous, whose number varies from soil to soil. The present work on, ‘Effect of Trichoderma viride on Phosphate Solubilizing Microorganism in Paddy cultivation” was conducted under lower gangetic alluvial region from 2016-2017(December to May) at Agricultural Experimental Station of Calcutta University, Baruipur, 24 Parganas (South), West Bengal. The Rice variety “Satabdi (IET-4786)” from the department of Genetics and Plant Breeding was sown and recommended fertilizer dose of 80:40:40 kg per hectare. The experiment was carried out with six treatments replicated four times. Out of the six treatments, T3 which received T.V and P.S showed highest Carbon, Phosphorus and Potassium content and T6 showed highest Nitrogen content in the soil

Response of green chiretta to different bio-fertilizers and their effect on phosphorus availability in the soil

When cultivating medicinal plants, the use of chemical substances such as pesticides and chemical fertilizers should be avoided, as these can be contaminated with hazardous substances. Bio-fertilizers are a good alternative for growing herbs, as they are produced from organic materials that contain fewer hazardous substances. The aim of this study was to investigate the effects of different bio-fertilizers on growth, yield, andrographolide content, nutrient accumulation, and different pigments in green chiretta. In addition, the effectiveness of bio-fertilizers on the convertible phosphorus content in the soil was investigated. The experimental design was a completely randomized design (CRD) with four treatments and four replicates. The details of the experiment were 1) control (no bio-fertilizer), 2) phosphate-solubilizing microorganisms (PSMs), 3) plant growth promoter, and 4) mycorrhiza. The findings revealed that the application of PSMs provided the highest leaf dry weight (yield) of green chiretta (20.8±3.58 g/plant). This treatment also gave the highest chlorophyll a, b and total chlorophyll content (699±70, 178±24, 880±94 mg/sqm, respectively) and andrographolide yield (0.38±0.06 g/plant). Regarding the phosphorus content in the soil, the PSMs application showed the highest available phosphorus and the highest phosphorus activation coefficient (PAC) in the soil, namely 52.0±4.76 mg/kg and 4.22±0.32 percent, respectively. These results indicate that the use of PSMs as a bio-fertilizer is most suitable for the cultivation of green chiretta, especially when this plant grows on acid sulfate soils.

Effect of Phosphate Solubilizing Microorganisms and Phosphorus Levels on Growth Yield and Quality of Chickpea (Cicer arietinum L.) in Inceptisol

A field study was conducted to know the “Effect of phosphate solubilizing microorganisms and phosphorus levels on growth, yield and quality of chickpea (Cicer arietinum L.) in inceptisol.” The experiment was laid in Factorial Randomized Block Design (FRBD) with sixteen treatments, replicated thrice during rabi season of 2019-20 at the Department Research Farm of SSAC, College of Agriculture, Latur. The treatments comprises four main (absolute control, Bacillus megaterium, Aspergillus niger and Aspergillus awamori @ 10 ml kg-1 seed treatment) and four sub treatments (0,45,60 and 75 P2O5 kg ha-1). The results indicated that, the incorporation of phosphate solubilizing microorganisms viz. Aspergillius awamori @ 10 ml kg-1 seed in combination with soil application of  75 P2O5 kg ha-1 found to be effective in improving growth and yield attributing characters viz. number of root nodules, fresh and dry weight, chlorophyll content , grain yield and straw yield  as compared to Aspergillus niger and Bacillus megaterium along with 60 P2O5 kg ha-1  and over control. Further results revealed that test weight and protein percentage was significantly influenced with the seed treatment of Aspergillius awamori @ 10 ml kg-1 seed in combination with application of 75 P2O5 kg ha-1.

Soil phosphorus transformation and plant uptake driven by phosphate-solubilizing microorganisms.

Phosphorus (P) is an important nutrient for plants, and a lack of available P greatly limits plant growth and development. Phosphate-solubilizing microorganisms (PSMs) significantly enhance the ability of plants to absorb and utilize P, which is important for improving plant nutrient turnover and yield. This article summarizes and analyzes how PSMs promote the absorption and utilization of P nutrients by plants from four perspectives: the types and functions of PSMs, phosphate-solubilizing mechanisms, main functional genes, and the impact of complex inoculation of PSMs on plant P acquisition. This article reviews the physiological and molecular mechanisms of phosphorus solubilization and growth promotion by PSMs, with a focus on analyzing the impact of PSMs on soil microbial communities and its interaction with root exudates. In order to better understand the ability of PSMs and their role in soil P transformation and to provide prospects for research on PSMs promoting plant P absorption. PSMs mainly activate insoluble P through the secretion of organic acids, phosphatase production, and mycorrhizal symbiosis, mycorrhizal symbiosis indirectly activates P via carbon exchange. PSMs can secrete organic acids and produce phosphatase, which plays a crucial role in soil P cycling, and related genes are involved in regulating the P-solubilization ability. This article reviews the mechanisms by which microorganisms promote plant uptake of soil P, which is of great significance for a deeper understanding of PSM-mediated soil P cycling, plant P uptake and utilization, and for improving the efficiency of P utilization in agriculture.

Phosphorus cycling in a subterranean estuary seepage face: A seasonal view on inventory composition and linkage with nitrate transformations

Seasonal field surveys (April 2018 to February 2019) were conducted in a subterranean estuary (STE) seepage face in Sanggou Bay (China) aiming to explore the transport and reactivity of phosphorus (P) and biogeochemical linkages with the cycling of nitrogen (N) prior to discharge. Porewater dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP) together with different fractions of sedimentary P were analyzed in the upper, middle and lower intertidal covering the top 20 cm of sediment (1–4 cm, 5–8 cm, 9–12 cm, 13–16 cm and 17–20 cm depth). The accumulation of sedimentary organic P stimulated the growth of phosphate-solubilizing microorganisms and led to porewater DOP enrichment during spring. During summer, total P (TP), porewater DIP and DOP concentrations decreased, potentially due to enhanced mineralization driven by high ambient temperature. From autumn to winter, pelagic organic matter into the STE lowered, triggering a drop of TP standing stocks. Compared with the significant seasonality, sedimentary P storage was statistically identical along the intertidal. Such spatial homogeneity likely results from the rebalance driven by P adsorption dynamics and pelagic organic matter delivered by tide and wave setup. The vertical distribution of DIP, DOP, and sedimentary TP were linked to nitrate transformations. In the sediment layer with active mineralization and nitrification, concentrations of DOP, sedimentary redox and clay P increased. In the layer with active nitrate removal (2–5 cm depth), both DIP and DOP concentrations decreased. The sedimentary loosely-bound and organic P were also lower there. Notably, a substantial quantity of soluble P seeped out, acting as an important contributor to the dissolved P pool of the receiving waters. The spatial and temporal overlap of high concentrations of N and P in STEs adds variabilities and uncertainties in P out-drainage fluxes and nutrient stoichiometry balances, which should draw attention from coastal researchers and stakeholders.

Effect of Graded Levels of Phosphorus & Phosphorus Solubilizing Microorganisms on Growth and Yield of Green Gram (Vigna radiata L.)

The present investigation entitled "Effect of Graded Levels of Phosphorus and Phosphorus Solubilizing Microorganisms on Growth and Yield of Green gram" during kharif season of the year, 2022-2023 at the research farm of the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Latur. The experiment was layout in FRBD with three replications and a recommended variety of green gram BM 2003-2 as a test crop along with twelve treatments. The results in nutshell indicated that the growth and yield were significantly influenced by the application of 125% RDP, combined with Aspergillus awamori. The growth parameters viz., plant height, number of leaves & no. of nodules plant-1, significantly increased with application of 125 % RDP, combined with Aspergillus awamori. The combined approach of incorporating phosphate-solubilizing microorganisms, particularly Aspergillus awamori, with the application of 125% RDP, resulted in a noteworthy increase in the availability of nitrogen (N), phosphorus (P), and potassium (K) in the soil. This improvement was attributed to the enhanced solubilization of inorganic phosphorus and the secretion of organic acids, which facilitated an increase in the content of other essential nutrients in the soil. The nutrient content in both grain and straw exhibited significant increases due to seed inoculation with Aspergillus awamori in conjunction with the application of 125%RDP. This approach outperformed treatments involving Tricoderma viridae and Bacillus megaterium in combination with 100% RDP, and the control. The incorporation of phosphate-solubilizing microorganisms, particularly Aspergillus awamori, alongside the application of 125% RDP, proved to be significantly more effective than treatments involving a Tricoderma viridae with 100% RDP, as well as the control.

Enhancing phosphate-solubilising microbial communities through artificial selection

Microbial communities, acting as key drivers of ecosystem processes, harbour immense potential for sustainable agriculture practices. Phosphate-solubilising microorganisms, for example, can partially replace conventional phosphate fertilisers, which rely on finite resources. However, understanding the mechanisms and engineering efficient communities poses a significant challenge. In this study, we employ two artificial selection methods, environmental perturbation, and propagation, to construct phosphate-solubilising microbial communities. To assess trait transferability, we investigate the community performance in different media and a hydroponic system with Chrysanthemum indicum. Our findings reveal a distinct subset of phosphate-solubilising bacteria primarily dominated by Klebsiella and Enterobacterales. The propagated communities consistently demonstrate elevated levels of phosphate solubilisation, surpassing the starting soil community by 24.2% in activity. The increased activity of propagated communities remains consistent upon introduction into the hydroponic system. This study shows the efficacy of community-level artificial selection, particularly through propagation, as a tool for successfully modifying microbial communities to enhance phosphate solubilisation.

The combined application of salt-alkali tolerant phosphate solubilizing microorganisms and phosphogypsum is an excellent measure for the future improvement of saline-alkali soils.

The combined application of salt-alkali tolerant phosphate solubilizing microorganisms and phosphogypsum is an excellent measure for the future improvement of saline-alkali soils.

Isolation of Phosphate Solubilizing Fungi from Soil and Their Application in Plant Growth Promotion

Phosphorus plays a significant role in numerous physiological and metabolic processes in plants. Soil phosphorus is immobilized due to the formation of insoluble complexes. The use of efficient phosphate-solubilizing microorganisms opens up a new prospect for better crop productivity and for greater yield performance without affecting the soil health. Phosphate-solubilizing fungi (PSF) enhance available phosphorus released from soil, which contributes to P requirement of plants. Hence, the present study was designed to evaluate the utilization of PSF as a biofertilizer. Pikovskaya's Agar medium was used to isolate fungal species from compost and open dumpsite soil. Isolated fungi were labelled as PSF-X, PSF-Y, and PSF-Z. A pot experiment was carried out to determine the effect of isolated fungal strains. The isolated fungal strain was introduced to the developed potting media which contained compost and soil at 1:1 ratio. Soya bean was selected as the experimental plant. Plant growth parameters (shoot length and root length) were measured to determine the effect of isolated fungal strains. Plant growth parameters were recorded after 21days. Fungi inoculated pots showed a significant increase in both shoot and root lengths in comparison to the control (n=9, p<0.05). Potting media consisting of PSF-X showed the best result. The highest root length (4.7±0.1 cm) and shoot length (35.8±1.2 cm) were recorded in pots inoculated with PSF-
 
 Hence, isolated PSF-X, PSF-Y, and PSF-Z are recommended as suitable biofertilizer strains for potting medium.
 
  
 Keywords: Fertilizer, Fungi strain, Phosphorus, Plant growth

Phosphate solubilizing microorganisms: a sustainability strategy to improve urban ecosystems.

Intensification of urban construction has gradually destroyed human habitat ecosystems. Plants, which serve as the foundation of ecosystems, require green, low-cost, and effective technologies to sustain their growth in stressful environments. A total of 286 keywords and 10 clusters from the bibliometric analysis of 529 articles (1999-2023) indicate the increasing importance of research on microbial functionality in landscape ecosystems. Phosphate solubilizing microorganisms (PSMs) also improve plant disease resistance, adaptability, and survival. PSMs are widely used to promote plant growth and improve ecological quality. They can increase the availability of phosphorus in the soil and reduce the dependence of plants on chemical fertilizers. Microorganisms regulate phosphorus as key tools in landscape ecosystems. Most importantly, in urban and rural landscape practices, PSMs can be applied to green spaces, residential landscapes, road greening, and nursery planting, which play significant roles in improving vegetation coverage, enhancing plant resistance, improving environmental quality, and mitigating the heat island effect. PSMs are also helpful in restoring the ecological environment and biodiversity of polluted areas, such as brownfields, to provide residents with a more liveable living environment. Therefore, the multiple efficacies of PSM are expected to play increasingly important roles in the construction of urban and rural landscape ecosystems.

Bibliometric analysis of soil phosphate solubilizing microorganisms research using VOSviewer

Bibliometric analysis of soil phosphate solubilizing microorganisms research using VOSviewer

Phosphate solubilization and plant growth properties are promoted by a lactic acid bacterium in calcareous soil.

On the basis of good phosphate solubilization ability of a lactic acid bacteria (LAB) strain Limosilactobacillus sp. LF-17, bacterial agent was prepared and applied to calcareous soil to solubilize phosphate and promote the growth of maize seedlings in this study. A pot experiment showed that the plant growth indicators, phosphorus content, and related enzyme activity of the maize rhizospheric soils in the LF treatment (treated with LAB) were the highest compared with those of the JP treatment (treated with phosphate solubilizing bacteria, PSB) and the blank control (CK). The types of organic acids in maize rhizospheric soil were determined through LC-MS, and 12 acids were detected in all the treatments. The abundant microbes belonged to the genera of Lysobacter, Massilia, Methylbacillus, Brevundimonas, and Limosilactobacillus, and they were beneficial to dissolving phosphate or secreting growth-promoting phytohormones, which were obviously higher in the LF and JP treatments than in CK as analyzed by high-throughput metagenomic sequencing methods. In addition, the abundance values of several enzymes, Kyoto Encyclopedia of Genes and Genomes (KEGG) orthology, and Carbohydrate-Active Enzymes (CAZys), which were related to substrate assimilation and metabolism, were the highest in the LF treatment. Therefore, aside from phosphate-solubilizing microorganisms, LAB can be used as environmentally friendly crop growth promoters in agriculture and provide another viable option for microbial fertilizers. KEY POINTS: • The inoculation of LAB strain effectively promoted the growth and chlorophyll synthesis of maize seedlings. • The inoculation of LAB strain significantly increased the TP content of maize seedlings and the AP concentration of the rhizosphere soil. • The inoculation of LAB strain increased the abundances of the dominant beneficial functional microbes in the rhizosphere soil.

Biofertilizer based on fish waste increases the yield of Vigna unguiculata L. Walp, Zea mays L., and the rhizospheric microbiota

Crops of Vigna unguiculata L. “cowpea” and Zea mays L. “corn” require chemical fertilizers for proper growth and development; however, its inadequate application contaminates the environment, creating the need to search new alternatives that reduce its impact. Due to this, the objective of this research was to determine the effect of a biofertilizer from fish wastes on the yield of cowpea and corn, and its effect on their rhizospheric microbiota. The physicochemical and biological characteristics of the biofertilizer were determined, and then was applied on the field under a completely randomized block design with six treatments: absolute control, chemical control, biofertilizer at 1%, 1.25%, 1.5% and 1.25% plus chemical fertilizer. The application of biofertilizer at 1, 1.25 and 1.5% increased the height, root length and yield of cowpea; however, the increase percentages were lower than those obtained with chemical fertilizer and the biofertilizer at 1.25% plus chemical fertilizer. In the case of corn, all treatments with biofertilizer increased the growth and yield of aerial biomass compared to the control, and the percentages of increase exceeded the chemical fertilizer in terms of the number of leaves, length and root biomass. In addition, the biofertilizer increased the microbial fertility of the soil expressed as the number of colony-forming units of nitrogen-fixing and phosphate-solubilizing microorganisms per gram of soil in both crops. In conclusion, a positive effect of the biofertilizer from fish wastes was evidenced, which increased the yield of cowpea and corn, as well as an increase in soil microbial fertility.

Using Bacillus megaterium as a bio-fertilizer alleviates salt stress, improves phosphorus nutrition, and increases cauliflower yield

The traditional crop production system involves the use of large amounts of chemical fertilizers, which negatively impacts the ecological environment by increasing soil degradation and salinity, threatening sustainable agricultural production. Therefore, there is an urgent need for agricultural practices that increase plant productivity and reduce negative impacts on the environment. Phosphate-solubilizing microorganisms can enhance nutrient availability and plant uptake. This study investigated the effect of Bacillus megaterium as a bio-fertilizer (inoculated and non-inoculated) combined with phosphorus fertilizer (40, 60, and 80 kg. ha−1) on the growth and yield of cauliflower grown under saline conditions, saline soil (9.68 dS.m−1) and saline irrigation water (7.12 dS.m−1). Salt-stressed cauliflower inoculated with Bacillus and fertilized with 60 or 80 kg. ha−1 P2O5 showed improved growth and higher yield compared to other treatments, without significant differences between them. However, Bacillus-treated plants fertilized with 60 P2O5 showed increases in superoxide dismutase (SOD) by 29.3%, catalase (CAT) by 13.9, chlorophyll by 10.4%, N by 7.8%, and P by 8.6%, while Na decreased by 7.8%, resulting in significant increases in cauliflower yield (head weight by 9.3%, and total yield by 8.3%) compared with the control treatment (recommended P fertilizer, 80 kg P2O5. ha−1). The results indicated that the inoculation of salt-stressed plants with Bacillus megaterium is a promising and feasible approach to reduce phosphorus fertilizer use by up to 25% and enhance membrane stability (MSI), relative water content (RWC), nutrient availability, and growth performance, thus mitigating the adverse effects of salt stress exacerbated by climate change.

Livestock movement driven phosphorus transitions as core drivers of grassland vegetation dynamics

The Banni grasslands, located in the Kachchh district of India, have experienced significant degradation and a decrease in grassland productivity. Phosphorus is a crucial nutrient for grassland productivity, and its availability is often limited in these ecosystems. The study is a maiden attempt to understand the link between phosphorus availability, measured by the phosphorus activation coefficient (PAC), phosphate solubilizing microorganisms (PSM), vegetation patterns, indicated by normalized difference vegetation index (NDVI) and its relationship with livestock movement. Soil samples were collected from 45 locations spread across the three divisions of Banni grassland, and various soil parameters including phosphorus content, organic carbon, and microbial activity were analyzed. The results showed that the concentration of available phosphorus (AP) varied significantly among different divisions of the grassland, with division 1 having the highest AP concentration. The phosphorus activation coefficient (PAC) was also highest in division 2. Additionally, PSM diversity was significantly different among divisions, with division 2 exhibiting the highest PSM values. The NDVI values, representing vegetation density, varied across divisions, with division 1 having the highest overall NDVI. Statistical analysis revealed significant positive correlations between PAC, PSM, and NDVI. The research emphasizes the significance of PSM driven phosphorus availability in influencing vegetation dynamics within the Banni grassland ecosystem. The movement of livestock emerges as a key factor in introducing organic matter and phosphate solubilizing microorganisms, thereby facilitating the conversion of total phosphorus (TP) into forms accessible to plants. The study indicates that implementing effective phosphorus management practices, taking into account livestock movement and organic contributions, could enhance grassland productivity and ensure the long-term sustainability of the ecosystem. These findings offer valuable insights for more holistic and nuanced understanding of the complex relationships between phosphorus availability, phosphate solubilizing microorganisms, vegetation patterns, and sustainable management in the Banni grasslands and potentially in other ecosystems facing similar challenges.

Phosphorus Solubilizing Microbes: Propitious Strategy For Biofertilization

Phosphorus (P) is crucial for plant growth and development, it is a macroelement that is required for plants to function physiologically. Even though there are a lot of P-containing organic and inorganic molecules in soil, most of them are inert, making them unavailable to plants. Phosphorus (P) deficiency is widely acknowledged as a critical constraining factor in agricultural production, primarily due to its essential role in various biochemical pathways, including ATP synthesis, nucleic acid formation, and energy transfer processes within plant cells. In rhizosphere soil a diverse community of plant-growth-promoting rhizobacteria (PGPR), particularly phosphate-solubilizing bacteria (PSB) are present, by increasing nutrient bioavailability—especially in the case of phosphate—these bacteria have a beneficial effect on plant growth, increasing total plant productivity and yield. Phosphate-solubilizing microorganisms (PSMs) aid in the hydrolysis of resistant organic and inorganic phosphate (P) forms into soluble forms that are easily absorbed by plants. Despite decades of research on PSMs, the practical implementation of PSM-based strategies to enhance soil phosphorus fixation and improve crop yields at the field scale remains largely undeveloped. This review aims to deepen our comprehension of the pivotal role played by PSMs as biofertilizers in the context of crop production.

Uranium bioprecipitation mediated by a phosphate-solubilizing Enterobacter sp. N1-10 and remediation of uranium-contaminated soil

Uranium (U) pollution in soils is prevalent worldwide and poses a significant health risk that will require remediation approaches. However, traditional U bioreduction by sulfate reducing bacteria (SRB) are sensitive to oxygen and are not suitable for treating aerobic topsoil. Bioprecipitation of U into uranyl phosphate (UP) mediated by phosphate-solubilizing microorganism (PSM) is not affected by oxygen. In this study, PSM strains were isolated and used for U-contaminated soil remediation. Microbial metabolites and the mechanism of PSM bioprecipitation were revealed. The results showed that strain Enterobacter sp. N1-10 had the highest phosphate-solubilizing capacity (dissolved P was 409.51 ± 8.48 mg/L). Uranium bioprecipitation was investigated by culturing the bacterium in the presence of 50 mg/L U and in the cell-free culture supernatant. The results showed that strain N1–10 had a high U removal rate (99.45 ± 0.43 %) after adding 50 mg/L U to the culture medium. A yellow precipitate was immediately formed when uranyl nitrate solution was added to the cell-free culture supernatant. The analysis indicated that bacterium produced lactic acid (37.58 mg/L), citric acid (4.76 mg/L), succinic acid (2.03 mg/L), and D-glucuronic acid (1.94 mg/L); the four organic acids solubilized Ca3(PO4)2 to form stable uranyl phosphate precipitate. The application of strain N1-10 and Ca3(PO4)2 significantly decreased the bioavailability of soil U (43.54 ± 0.52 %). In addition, pot experiments showed that PSM N1-10 and Ca3(PO4)2 promoted plant growth and markedly reduced U accumulation by pakchoi. These results demonstrate that PSM N1-10 and Ca3(PO4)2 exhibit a great potential for U bioremediation.

Effect of ammonium stress on phosphorus solubilization of a novel marine mangrove microorganism Bacillus aryabhattai NM1-A2 as revealed by integrated omics analysis

BackgroundPhosphorus is one of the essential nutrients for plant growth. Phosphate-solubilizing microorganisms (PSMs) can alleviate available P deficiency and enhance plant growth in an eco-friendly way. Although ammonium toxicity is widespread, there is little understanding about the effect of ammonium stress on phosphorus solubilization (PS) of PSMs.ResultsIn this study, seven PSMs were isolated from mangrove sediments. The soluble phosphate concentration in culture supernatant of Bacillus aryabhattai NM1-A2 reached a maximum of 196.96 mg/L at 250 mM (NH4)2SO4. Whole-genome analysis showed that B. aryabhattai NM1-A2 contained various genes related to ammonium transporter (amt), ammonium assimilation (i.e., gdhA, gltB, and gltD), organic acid synthesis (i.e., ackA, fdhD, and idh), and phosphate transport (i.e., pstB and pstS). Transcriptome data showed that the expression levels of amt, gltB, gltD, ackA and idh were downregulated, while gdhA and fdhD were upregulated. The inhibition of ammonium transporter and glutamine synthetase/glutamate synthase (GS/GOGAT) pathway contributed to reducing energy loss. For ammonium assimilation under ammonium stress, accompanied by protons efflux, the glutamate dehydrogenase pathway was the main approach. More 2-oxoglutarate (2-OG) was induced to provide abundant carbon skeletons. The downregulation of formate dehydrogenase and high glycolytic rate resulted in the accumulation of formic acid and acetic acid, which played key roles in PS under ammonium stress.ConclusionsThe accumulation of 2-OG and the inhibition of GS/GOGAT pathway played a key role in ammonium detoxification. The secretion of protons, formic acid and acetic acid was related to PS. Our work provides new insights into the PS mechanism, which will provide theoretical guidance for the application of PSMs.

The Role of Phosphate-Solubilizing Microorganisms in Soil Health and Phosphorus Cycle: A Review

The role of phosphate-solubilizing microorganisms (PSM) in soil health and Phosphorus (P) cycle is a crucial aspect of agricultural productivity. Recent research has emphasized the importance of microorganisms in maintaining soil health. Phosphorus is an essential macronutrient for plant growth and development and significantly affects crop productivity. The PSM solubilize phosphate by producing metabolites such as organic acids, inorganic acids, hydrogen sulphide, exopolysaccharide, and siderophore. Studies have shown that the combination of PSM with phosphate fertilizers increase the efficiency of the fertilizers in soils. The efforts have been made to integrate exogenous soil microorganisms into P cycling models. This review highlights the critical role of microorganisms in maintaining soil health and promoting P cycle, emphasizing the importance of incorporating them into soil management practices.

Organic and natural farming improve microbial diversity and dehydrogenase activity in clusterbean-tomato cropping sequence

ABSTRACT Organic (OF) and natural farming (NF) may help to overcome drawbacks of chemical farming. A field experiment was conducted to investigate the microbial diversity and dehydrogenase activity in clusterbean-tomato cropping sequence with different farming systems over 3 years. An increase in bacterial population in OF (73.6%) and NF (55.4%) over conventional farming practice (PoP) and 90.8% (OF) and 62.1% (NF) over farmers’ practice (FP) was recorded. Fungal population in OF and NF increased by 32.8% and 12%, respectively over PoP and 76.8% (OF) and 47% (NF) over FP. Increase in actinomycetes population of 34% (OF) and 18.1% (NF) over PoP and 60.9% (OF) and 41.8% (NF) over FP was observed. Phosphate solubilizing microorganisms (PSM) population increased to 62.8% (OF) and 33.4% (NF) over PoP and 103.1% (OF) and 66.4% (NF) over FP. Population of N-Fixers also found enhanced in OF (31.4%) and NF (9.7%) compared to PoP and FP (OF: 97.4% and NF: 58%). The higher dehydrogenase activity of 41.4% (OF) and 25.5% (NF) was recorded over PoP and OF (62%) and NF (43.8%) over FP. It can be concluded that OF and NF enhanced microbial diversities and dehydrogenase activity.