Phosphate Solubilizing Bacteria Research Articles

Phosphorus Release from Nano-Hydroxyapatite Derived from Biowastes in the Presence of Phosphate-Solubilizing Bacteria: A Soil Column Experiment.

Phosphorus applications in agriculture can lead to significant environmental impacts, necessitating a revolution in current agricultural practices. This study explores the potential of hydroxyapatite nanoparticles (nHAPs) synthesized from poultry bones as P fertilizers. nHAPs were produced at 300 °C (nHAP300) and 700 °C (nHAP700), and their effectiveness was evaluated. An in vitro solubilization test with Pseudomonas alloputida evaluated the bacterium's ability to solubilize the nanoparticles, assessing dissolved P and organic acids produced. Additionally, a soil leaching test measured P losses and bioavailable P in soil compared to a conventional fertilizer, the triple superphosphate (TSP). nHAP300 displayed heterogeneous sizes, while nHAP700 were approximately 100 nm in size, with a P content of 8.8% and 19.4%, respectively. Pseudomonas alloputida successfully solubilized both types of nanoparticles, with nHAP700 demonstrating a higher solubility than nHAP300. The TSP treatment resulted in higher P losses (6.35 mg) compared with nHAP treatments (nHAP300 0.32 mg; nHAP700 0.28 mg), indicating the potential of nHAP for recycling P from waste. Our findings indicate that nHAP700 are more efficient in P release than nHAP300 but less prone to leaching compared to conventional fertilizers. Utilizing these nanoparticles enables phosphorus recovery from waste and holds significant potential for sustainable agricultural applications.

Transcriptomic and metabolomic analysis of recalcitrant phosphorus solubilization mechanisms in Trametes gibbosa

IntroductionPhosphorus (P) is a crucial growth-limiting nutrient in soil, much of which remains challenging for plants to absorb and use. Unlike chemical phosphate fertilizers, phosphate-solubilizing microorganisms (PSMs) offer a means to address available phosphorus deficiency without causing environmental harm. PSMs possess multiple mechanisms for phosphorus solubilization. Although the phosphorus-solubilizing mechanisms of phosphate-solubilizing bacteria (PSB) have been well characterized, the mechanisms utilized by phosphate-solubilizing fungi (PSF) remain largely unexplored.MethodsThis study isolated a PSF strain, Trametes gibbosa T-41, from soil and evaluated its phosphorus solubilizing capacity with organic (calcium phytin; Phytin-P) and inorganic (tricalcium phosphate; Ca-P) phosphorus sources. The phosphorus solubilization, enzyme activity, and organic acid production of T-41 were measured. And the P-solubilizing mechanism conducted by transcriptomic and metabolomic analyses.Results and discussionT-41 exhibited varying phosphorus solubilizing capacity when grown with organic (calcium phytin; Phytin-P) and inorganic (tricalcium phosphate; Ca-P) phosphorus sources (109.80 ± 8.9 mg/L vs. 57.5 ± 7.9 mg/L, p < 0.05). Compared with the Ca-P treatment, T-41 demonstrated a stronger alkaline phosphatase (ALP) production capacity under Phytin-P treatment (34.5 ± 1.2 μmol/L/h vs. 19.8 ± 0.8 μmol/L/h, p < 0.05). Meanwhile, the production of oxalic acid, maleic acid, and succinic acid was higher under Phytin-P treatment (p < 0.05). Transcriptomic and metabolomic analysis revealed that different phosphorus sources altered metabolic pathways such as galactose metabolism, glyoxylate and dicarboxylic acid metabolism, and ascorbate and aldolate metabolism. Key metabolites like myo-inositol, 2-oxoglutarate, and pyruvate were found to impact the performance of T. gibbosa T-41 differently under the two P sources. Notably, synthesis in Ca-P vs. Pytin-P, T-41 upregulated genes involved in myo-inositol synthesis, potentially enhancing its P-solubilizing ability. These results provide new insights into the molecular mechanisms of PSF at the transcriptomic and metabolomic levels, laying a theoretical foundation for the broader application of PSF as bio-phosphorus fertilizers in the future.

Stabilization effect and mechanism of heavy metals by microbial consortium of phosphate-solubilizing bacteria and urease-producing bacteria

IntroductionStabilization of heavy metals through phosphate-solubilizing bacteria (PSB) induced phosphate precipitation and urease-producing bacteria (UPB) induced carbonate precipitation are promising bioremediation methods. However, little attention has been conducted on the combined action of the above two bioremediations to stabilize heavy metals.MethodsPSB and UPB were isolated from the environment and their growth characteristics and antagonistic properties were studied. A simulated solution of acidic leachate was prepared based on heavy metal contaminated soil. Microbial consortium of PSB and UPB were constructed for the stabilization of heavy metals by optimizing carbon and nitrogen sources. The microstructural and compositional changes during the biostabilization process were more deeply analyzed using XRD, FT-IR and SEM-EDS.Results and discussionThe precipitation of heavy metals could be promoted effectively when soluble starch (10.2 g/L) was used as carbon source and urea (7.8 g/L) as nitrogen source. The stabilization rates for Cu, Zn, Cd, and Pb were 98.35, 99.78, 99.09, and 92.26%, respectively. The stabilization rates of the combined action of PSB and UPB were significantly higher than that of the two microorganisms alone. An in-depth analysis showed that the composite metals were precipitated as dense precipitate encased in carbonate and phosphate, and additionally could be stabilized in the form of biosorption. Finally, the stabilization mechanism of heavy metals based on biomineralization and biosorption is proposed. These findings provide new theoretical support for sustainable remediation and management strategies for composite heavy metal polluted areas.

Unraveling the microecological mechanisms of phosphate-solubilizing Pseudomonas asiatica JP233 through metagenomics: insights into the roles of rhizosphere microbiota and predatory bacteria

The effects of phosphate-solubilizing bacteria (PSB) on plant productivity are high variable under field conditions. Soil phosphorus (P) levels are proposed to impact PSB performance. Furthermore, the effect of exogenous PSB on rhizosphere microbial community and their functions are largely unexplored. Our study examined how different P background and fertilization affected the performance of PSB Pseudomonas asiatica JP233. We further conducted metagenomic sequencing to assess its impact on rhizosphere microbiota and functions, with a focus on genes related to soil P cycling. We found that JP233 could enhance P solubilization and tomato growth to different extent in both high and low P soils, irrespective of P fertilization. It was particularly effective in high P soil without extra fertilization. JP233 altered the rhizosphere microbial community, boosting taxa known for plant growth promotion. It also changed soil gene profiling, enriching pathways related to secondary metabolite biosynthesis, amino acids, carbon metabolism, and other key processes. Particularly, JP233 increased the abundance of most P cycle genes and strengthened their interconnections. Populations of certain predatory bacteria increased after JP233 inoculation. Our findings provide valuable insights into PSB’s mechanisms for P solubilization and plant growth promotion, as well as potential adverse impacts of resident microbes on bioinoculants.

Phosphate solubilization by rhizobacteria isolated from the rhizosphere of <i>Mimosa pudica</i>: an investigation into microbial mobilization of phosphorus

Phosphorus (P), in addition to nitrogen (N) and potassium (K), makes up the essential macronutrients needed by plants for growth and development. P is also one of the most abundant elements present in the Earth’s crust, and it occurs in both organic and inorganic forms. Although present in high concentrations, only a very minute amount is bioavailable to plants because of its poor solubility due to its high binding affinity to calcium, aluminium, and iron in the soil, forming insoluble calcium phosphate, aluminium phosphate, and ferrous phosphate, thereby becoming recalcitrant for plant utilization. In this study, bacteria isolated from the rhizosphere of Mimosa pudica from different locations at Nnamdi Azikiwe University, Awka, were screened for their ability to solubilize phosphate using point inoculation on Pikovskaya (PVK) media agar plates with tricalcium phosphate (Ca3(PO4)2) as a source of phosphate. The result showed that of the twenty-one (21) rhizobacteria screened, four (4) were able to solubilize phosphate with varying phosphate solubilizing index (PSI). The degrees of PSI were in the following order: isolate SVM5 and UBG13 > isolate UBG14> isolate FEA6. Isolate SVM5 and UBG13 had the highest PSI of 4.0, while isolate FEA6 had the lowest PSI of 3.1. The biochemical tests of the isolates revealed that the phosphate-solubilizing bacteria were members of Klebsiella spp. (FEA6, SVM5, and UBG14) and Pseudomonas sp. (UBG13). This study, therefore, suggests the need to include rhizobacteria as part of biofertilizer formulations to improve plant yield via the solubilization of phosphate into forms that are bioavailable for plant growth.

Development of Optimized Liquid Formulations of Azospirillum, Phosphate-Solubilizing Bacteria, and Rhizobium Strains for Enhanced Viability and Shelf Life

The aim of this study was to evaluate the stability and shelf-life of Rhizobium, Azospirillum, and Pseudomonas striata a Phosphate Solubilizing Bacterium (PSB) in liquid formulations under ambient conditions, with a focus on the impact of various additives on the viability of these microbes over a 12-month period. Liquid formulations of Rhizobium strains NC-92, Sb-120, and Gr-2, Azospirillum, and PSB were prepared with different combinations of additives such as polyethylene glycol (PEG), gum arabic (GA), polyvinylpyrrolidone (PVP), and glycerol. The formulations were stored under ambient conditions, and colony-forming unit (CFU) counts were assessed at regular intervals over the year. The results revealed that formulations with higher concentrations of PVP, GA, and PEG maintained significantly higher CFU counts. Azospirillum formulations, particularly F20, exhibited superior viability, maintaining 2.2 × 10⁷ CFU after 12 months compared to rapid declines in other formulations such as F2, F8, and F16. Rhizobium NC-92 in basal medium + 1% PVP (F1) retained 5.2 × 10⁸ CFU after 12 months, while Sb-120 in basal medium + 1% PVP (T1) demonstrated high stability, maintaining 6.9 × 10⁸ CFU over six months. PSB formulations containing combinations of glycerol, PEG, and PVP also performed better, with the best formulation retaining 6.2 × 10⁸ CFU after 12 months. The study highlights the importance of certain additives such as PVP, GA, and PEG in improving the stability and shelf life of microbial compositions. Optimized formulations significantly increased viability, laying the groundwork for the development of robust biofertilizer solutions.

Mutual Relations Between Arbuscular Mycorrhizal Fungi and Ralstonia solanacearum in Potato Brown Rot Disease

Abstract Potato brown rot disease can devastate potato production. Arbuscular mycorrhizal fungi (AMFs) are known to boost crop output. This study examines the interaction between AMFs and Ralstonia solanacearum, focusing on their effects on tuber yield and brown rot incidence. AMF increased the tuber yield by 68% (P = 0.03) in sandy soil and 30% (P = 0.047) in clay soil, along with an increase in HCO₃⁻ in sandy soil by 56% (P = 0.001) and a 24% increase in clay soil (P = 0.002). A 12% decrease in soil organic matter from 1.37 to 1.20% (P = 0.044) was recorded in sandy soil. AMF increased the pathogen populations in the rhizosphere from 3.2 to 7.8 (log CFU/g, P = 0.02) in sandy soil without a significant increase in Area Under the Disease Progression Curve. The pathogen decreased AMF colonization by 47% in sandy soil and 48% in clay soil, as well as sporulation by 63% in sandy and 57% in clay soils respectively (P < 0.05 for all). It decreased the densities of phosphate-solubilizing bacteria from 6.19 up to 5.39 (P = 0.001) in sandy soil and from 6.04 to 5.16 (P = 0.008) in clay soil. Additionally, the pathogen decreased the silicate-solubilizing bacteria from 6.94 to 5.32 (P < 0.001) in sandy and from 6.82 up to 6.17 (P = 0.04) in clay soils respectively. In conclusion, while AMF significantly increased potato yield, it is not recommended for soils infested with R. solanacearum due to the potential increase in disease risk. Graphical Abstract

Application of Biochar-Immobilized Bacillus megaterium for Enhancing Phosphorus Uptake and Growth in Rice.

Phosphorus (P) is an essential nutrient for rice growth, and the presence of phosphate-solubilizing bacteria (PSB) is an effective means to increase soil P content. However, the direct application of PSB may have minimal significance due to their low survival in soil. Biochar serves as a carrier that enhances microbial survival, and its porous structure and surface characteristics ensure the adsorption of Bacillus megaterium. Inoculating rice husk biochar-immobilized with Bacillus megaterium (BMB) resulted in dissolved inorganic and organic P levels of 39.55 and 31.97 mL L-1, respectively. Subsequently, rice pot experiments were conducted to investigate the response of soil microbial P mobilization and P uptake in rice to fertilizer inputs. The organic fertilizer (OF) combined with BMB treatment (MOF) showed the highest soil available phosphorus (AP) at 38 days, with a value of 7.83 mg kg-1, as well as increased the pqqC abundance while decreasing the abundance of phoD bacterial communities compared with the control. Furthermore, the bioavailable P reservoir (H2O-Pi and NaHCO3-Pi) in soil was greatly increased through the fertilizer input and microbial turnover, with the highest H2O-Pi (3.66 mg kg-1) in OF treatment and the highest NaHCO3-Pi (52.65 mg kg-1) in MOF treatment. Additionally, carbon utilization analysis was applied using the commercial Biolog system, revealing that the MOF treatment significantly increased the utilization of carbohydrates, polymers, and amino acid carbon sources. Moreover, compared to the control, MOF treatment significantly increased the shoot (0.469%) and root P (0.516%) content while promoting root development and thereby supporting rice growth. Our study demonstrates that the MOF treatment displayed higher P levels in both soil and rice plants, providing a theoretical basis for further understanding the role of biochar-based bacterial agents in rice P management.

Oxidized alkaline biochar and phosphate solubilizing bacteria mixture enhances direct seeded maize yield in an acid soil

Maize is an important cereal in many developed and developing countries of the world. One of the primary challenges for maize cultivation is soil acidity. Acidic soil is a major constrain in achieving food security requiring sustainable solutions. Biochar, a pyrogenic carbon-rich material, carries reactive surfaces (i.e., high surface area and variable surface charges). Therefore, it facilitates nutrient retention in soil and gradual release to plants, thereby supporting crop growth. However, the combine effects of functionalized biochar with microbes on phosphorus (P) bioavailability and plant performance remain unclear. This study investigates the application of different oxidized biochars (i.e.,fresh rice husk biochar (RHB), pH adjusted oxidized RHB and control) and phosphate solubilizing bacteria (i.e., <em>Pseudomonas aeruginosa</em>, and control) on soil properties including phosphorus dynamics and the performance of maize grown in an acid soil. Biochar was oxidized using 10% hydrogen peroxide while the pH was adjusted to 8.5. Maize was grown in pots having 20 kg of soil or soil-biochar mixture. Overall, biochar and microbes treatments increased soil phosphorus bioavailability and maize yield with a greater effects in the oxidized biochar giving a significant biochar × microbes interactions. Specifically, oxidized biochar when applied with <em>Pseudomonas aeruginosa</em> increased P availability by 380 % which then contributed to yield increment (291%). We also observed a significant reduction in available aluminum (Al) concentration (40% ) compare to the control. These improvement in yield might have occurred due to an increase soil pH, P bioavailability (r<sup>2</sup>= 0.74), and a reduction in Al toxicity (r<sup>2</sup>= 0.36).Findings of this study could have significant implications for crop production in acidic soil.

Co-inoculation effect of AM fungi and phosphate solubilizing bacteria in growth and morphological character of chilli (Capsicum annuum L.)

Co-inoculation effect of AM fungi and phosphate solubilizing bacteria in growth and morphological character of chilli (Capsicum annuum L.)

Organic acid release and microbial community assembly driven by phosphate-solubilizing bacteria enhance Pb, Cd, and As immobilization in soils remediated with iron-doped hydroxyapatite.

Although iron-doped hydroxyapatite (Fe-HAP) and its composites have been reported to immobilize arsenic (As), lead (Pb), and cadmium (Cd), its practical application is limited by the inefficient release of iron and phosphate. In this study, Ochrobactrum anthropic, a phosphate-solubilizing bacterium isolated from a lead-zinc smelting site, was employed to enhance multi-heavy metal immobilization in Fe-HAP-amended soils. O. anthropic secreted low-molecular-weight organic acids, promoted phosphate (25.6 mg/L) and iron (14.2 mg/L) release from Fe-HAP, and minimally disrupted native bacteria. Compared to CK, the combination of 2 % O. anthropic (v/w) and Fe-HAP (Fe-to-HAP ratio of 1:1) significantly increased the residual fractions of Cd, Pb, and As by 109.09 %, 49.21 %, and 25.00 %, respectively. The combined treatment also improved available phosphorus, available nitrogen, and acid phosphatase activity by 233.24 %, 196.55 %, and 246.45 %, respectively. Furthermore, O. anthropic facilitated the recruitment of phylum Firmicutes and genera Acidovorax, Sedimentibacter, and Brevundimonas, shifting the bacterial community from specialists to generalists. Positive correlations were observed between residual fractions of Pb, Cd, As, well-crystallized As, and the abundance of Firmicutes, Acidovorax, and Sedimentibacte. These findings demonstrate the potential of an O. anthropic-driven Fe-HAP remediation strategy for the eco-friendly restoration of barren and polymetallic-contaminated soils.

Optimizing Integrated Nutrient Management (INM) for Enhanced Growth and Yield of Chickpea (Cicer arietinum L.) Under Irrigated Conditions

A field experiment was conducted during the Rabi season of 2021-22 at the Agronomy Research Farm, CCS Haryana Agricultural University, Hisar, Haryana. The experiment followed a randomized complete block design with three replications. This study attempts to examine how Integrated Nutrient Management (INM) affects chickpea growth, yield and productivity. Integrated Nutrient Management (INM) is a sustainable farming method that improves soil fertility, crop output, and quality by combining biofertilizers, organic and inorganic fertilisers, and other nutrient sources. In addition to providing the necessary plant nutrients, the use of vermicompost as an organic source and biofertilizers such as Rhizobium and PSB (Phosphate Solubilising Bacteria) as living sources in conjunction with inorganic fertilisers has improved the physical, chemical, and biological characteristics of the soil and contributed to environmental and soil sustainability. The treatments were as follows: T1: control, T2: 100% RDF (18:48:0 kg ha⁻¹), T3: 100% vermicompost (3.00 t ha⁻¹), T4: 75% RDF + 25% vermicompost (0.75 t ha⁻¹), T5: 50% RDF + 50% vermicompost (1.5 t ha⁻¹), T6: 25% RDF + 75% vermicompost (2.25 t ha⁻¹), T7: 75% RDF + 25% vermicompost (0.75 t ha⁻¹) + biofertilizers (Rhizobium + PSB), T8: 50% RDF + 50% vermicompost (1.5 t ha⁻¹) + biofertilizers (Rhizobium + PSB), and T9: 25% RDF + 75% vermicompost (2.25 t ha⁻¹) + biofertilizers (Rhizobium + PSB). The results indicated that the application of 75% RDF + 25% vermicompost (0.75 t ha⁻¹) combined with biofertilizers (Rhizobium + PSB) yielded the highest growth attributes, such as plant height (37.5 cm and 77.5 cm at 60 and 120 DAS, respectively) and dry matter accumulation (2.6 g/plant and 21.7 g/plant at 60 and 120 DAS, respectively). This treatment also showed the highest yield attributes, including the number of branches per plant (7.4), number of pods per branch (53.8), number of seeds per pod (2.0), and test weight (14.8 g). The highest grain yield, biological yield, straw yield, gross return and B:C ratio were recorded under the 75% RDF + 25% vermicompost (0.75 t ha⁻¹) + biofertilizers (Rhizobium + PSB) treatment, followed by the 75% RDF + 25% vermicompost (0.75 t ha⁻¹) and 100% RDF (18:48:0 kg ha⁻¹) treatments. The control treatment produced the lowest grain yield (1395 kg ha⁻¹). The maximum harvest index (45%) was observed in the treatment with 100% vermicompost (3.00 t ha⁻¹). The study highlights that the treatment of 75% RDF + 25% vermicompost (0.75 t ha⁻¹) combined with biofertilizers significantly improved growth attributes and yield components of chickpea. This finding underscores the role of INM in sustainable intensification of chickpea production. (*RDF; Recommended Dose of Fertilizer, *PSB; Phosphate Solubilizing Bacteria.).

Effect of varying levels of phosphorus and bio-fertilizers on growth and yield of chickpea under sub-tropical condition

A field experiment was conducted at the Crop Research Centre of School of Agriculture, ITM University, Gwalior, Madhya Pradesh during rabi 2021–22 and 2022–23 to study the influence of phosphorus and bio-fertilizers on growth and yield of chickpea under sub-tropical condition of Madhya Pradesh. The experiment was laid out in randomized complete block design (factorial experiment) by taking four levels of phosphorus, viz. 0 kg P2 O5 /ha, 30 kg P2 O5 /ha, 40 kg P2 O5 /ha, 50 kg P2 O5 /ha and bio-fertilizers (No inoculation, PSB (B. thuringiensis) @ 20 g/kg of seed, Rhizobium (Mesorhizobium) @ 20 g/kg of seed PSB (B. thuringiensis) + Rhizobium (Mesorhizobium) which were replicated thrice. The chickpea variety “JG-16” was uniformly fertilized by 20 kg N/ ha through Urea. However, phosphorus and bio-fertilizers were applied as per the requirement of the treatments. The crop was managed as per the recommended package and practices. The experimental study revealed that among the phosphorus levels, the application of 50 kg P/ha recorded significantly highest plant height, number of nodules, shoot dry matter accumulation, number of primary and secondary branches. Further, it also produced highest seed, stover, biological yield and harvest index. Similar, result showed in N, P, K uptake. However, among the bio-fertilizers, application of Phosphate solubilizing bacteria (B. thuringiensis) + Rhizobium Mesorhizobium resulted in highest plant height, number of nodules, shoot dry matter accumulation, number of primary and secondary branches, seed and stover yield, biological yield and harvest index of chickpea. Application of 50 kg ha-1 phosphorus and combined treatment of Phosphate solubilizing bacteria (B. thuringiensis) + Rhizobium (Mesorhizobium) resulted in highest gross return, net return and Benefit: cost ratio.

Effect of varying levels of phosphorus and bio-fertilizers on growth and yield of chickpea under sub-tropical condition

A field experiment was conducted at the Crop Research Centre of School of Agriculture, ITM University, Gwalior, Madhya Pradesh during rabi 2021–22 and 2022–23 to study the influence of phosphorus and bio-fertilizers on growth and yield of chickpea under sub-tropical condition of Madhya Pradesh. The experiment was laid out in randomized complete block design (factorial experiment) by taking four levels of phosphorus, viz. 0 kg P2 O5 /ha, 30 kg P2 O5 /ha, 40 kg P2 O5 /ha, 50 kg P2 O5 /ha and bio-fertilizers (No inoculation, PSB (B. thuringiensis) @ 20 g/kg of seed, Rhizobium (Mesorhizobium) @ 20 g/kg of seed PSB (B. thuringiensis) + Rhizobium (Mesorhizobium) which were replicated thrice. The chickpea variety “JG-16” was uniformly fertilized by 20 kg N/ ha through Urea. However, phosphorus and bio-fertilizers were applied as per the requirement of the treatments. The crop was managed as per the recommended package and practices. The experimental study revealed that among the phosphorus levels, the application of 50 kg P/ha recorded significantly highest plant height, number of nodules, shoot dry matter accumulation, number of primary and secondary branches. Further, it also produced highest seed, stover, biological yield and harvest index. Similar, result showed in N, P, K uptake. However, among the bio-fertilizers, application of Phosphate solubilizing bacteria (B. thuringiensis) + Rhizobium Mesorhizobium resulted in highest plant height, number of nodules, shoot dry matter accumulation, number of primary and secondary branches, seed and stover yield, biological yield and harvest index of chickpea. Application of 50 kg ha-1 phosphorus and combined treatment of Phosphate solubilizing bacteria (B. thuringiensis) + Rhizobium (Mesorhizobium) resulted in highest gross return, net return and Benefit: cost ratio.

Counseling of How to Make Organic Fertilizer Enriched with Phosphate Solubilizing Bacteria to the Community in Tanjung Raja Sub-District

The village of Talang Balai Baru 1, located in the sub-district of Tanjung Raja in the Ogan Ilir Regency, is characterized by a type of land known as lowland, locally called “lebak” land, which is characterized by low soil fertility. This factor, among others, contributes to a decrease in crop productivity. To address this challenge, it is imperative to employ organic fertilizer in optimal amounts. Specifically, the harvested straw is primarily incinerated, with a limited portion being utilized as chicken manure fertilizer. Despite the abundance of local resources like chicken manure and straw, they are underutilized. Therefore, there is a need to harness these resources for the production of organic fertilizers enriched with phosphate-solubilizing bacteria (PSB). This enriched organic fertilizer is expected to provide essential nutrients to plants and improve soil fertility, thereby boosting soil and crop productivity. The project, conducted from July 29, 2024, to August 27, 2024. The method employed in this study is counseling and socialization regarding the production of BPF-enriched organic fertilizer and its subsequent application by partner farmers. The results of this counseling and socialization demonstrate the high level of support among the residents of Talang Balai Baru 1 Village for this program, as evidenced by their ability to utilize BPF-enriched organic fertilizer on their respective fields. This will contribute to an enhancement in soil and plant productivity.

Antagonistic Potential of a Phosphate Solubilizing Bacteria (B. cereus PS1.1, B. cereus PS1.2, B. cereus PS1.4) Against the Patogent Fungus Ganoderma sp. Isolated from Basal Stem of Oil Palm (Elaeis guineensis Jacq.) with Rot Disease

Ganoderma sp. is a pathogenic fungus whose attack can cause basal stem rot disease of oil palm (Elaeis guineensis Jacq.). Disease control using phosphate solubilizing bacteria (PSB), namely Bacillus cereus can be an alternative to biological control. The purpose of this study was to determine the antagonistic ability of PSB (B. cereus PS1.1, B. cereus PS1.2, B. cereus PS1.4) in inhibiting the growth of Ganoderma sp. BP1 and changes in hyphal morphology of Ganoderma sp. BP1 after antagonistic testing. The research was conducted from January to May 2023 at the Microbiology Laboratory, Department of Biology, Faculty of Mathematics and Natural Sciences, Tanjungpura University, Pontianak. Antagonist testing used a completely randomized design (CRD) with the treatments consisted of Ganoderma sp. BP1 (negative control), 1% hexaconazole fungicide (positive control), PSB isolates PS1.1, PS1.2 and PS1.4. The test method used the dual culture on Sabouraud Dextrose Agar (SDA) media with each treatment repeated four times so that 20 experimental units were obtained. The results showed that PSB isolate PS1.4 had strong inhibition with an inhibition zone diameter of 11.01 mm, while isolates PS1.1 and PS1.2 had moderate inhibition with inhibition zone diameters of 9.43 mm and 9.45 mm, respectively, against Ganoderma sp. BP1. Hyphal morphology changes in of Ganoderma sp. BP1 that occurred after the antagonist test consist of lysed hyphae, twisted hyphae, hook-like hyphal tips, curly hyphae, bulbous hyphae, branched hyphae and bent hyphal ends.

Influence of Phosphorus and Phosphate-solubilizing Bacteria on Soil Microbial Dynamics in Mustard under Gmelina-Based Agroforestry

The impact of phosphorus (P) levels and phosphate-solubilizing bacterium (PSB) inoculation techniques on soil microbial dynamics in mustard (Brassica juncea) grown in agroforestry systems based on Gmelina arborea is examined in this study. Three phosphorus levels (30, 40, and 50 kg/ha) and three PSB inoculation techniques (soil, seedling, and combination soil + seedling) were used in the split-plot design experiment, which was carried out at the Jawaharlal Nehru Krishi Vishwa Vidyalaya Research Farm in Jabalpur. Azotobacter, Rhizobium, total bacteria, and fungi were among the soil microbial communities that were examined after harvest. The findings showed that phosphorus levels had no discernible impact on the number of microorganisms. Nonetheless, PSB inoculation techniques showed notable results; in every category, the soil + seedling inoculation combination consistently produced the greatest microbial populations. For instance, the populations of Azotobacter, Rhizobium, and fungi were 28.55 CFU × 10⁵ g⁻¹, 20.58 CFU × 10⁶ g⁻¹, 45.15 CFU × 10⁶ g⁻¹, and 7.72 CFU × 10⁵ g⁻¹, respectively. These results highlight how PSB inoculation and agroforestry systems can work together to improve soil health and nutrient dynamics, which will support sustainable mustard farming methods.

The role of nutrient solutions on Phosphate-solubilizing bacteria population, Phosphorus availability, Phosphorus uptake, growth and yield of Red Chili (Capsicum annuum L.)

Red chili consumption in Indonesia has increased every year. However, with large chili production to meet large consumption, land conversion for various purposes has reduced the harvested area. The efforts to increase the harvested area of chili using Inceptisols soil by providing nutrient solutions to overcome the infertility of the soil using its nutrients. This experiment aims to determine the effect of nutrient solution application on the population of phosphate-solubilizing bacteria, phosphorus availability, phosphorus uptake, growth, and yield of Red Chili (Capsicum annuum L.) in Inceptisols. The experiment was conducted from August 2023 to February 2024 at Ciparanje Experimental Field, Faculty of Agriculture, Padjadjaran University, and the analysis process was conducted at the Laboratory of Soil Biology and Soil Chemistry and Plant Nutrition, Department of Soil Science and Land Resources, Faculty of Agriculture, Universitas Padjadjaran., using a factorial randomized block design with two factors, nutrient solutions concentrates (1200, 1600, 2000 ppm) and nutrient solutions doses (200, 400, 600 mL), resulting in nine treatments and three replications. The results showed that the treatment of nutrient solution concentration and dose increased the number of fruits per plant, fruit weight per plant, and yield of chili with grade A. Treatment with 2000 ppm concentrate + 600 mL dose gave the best results on the number of fruits per plant (44.7 fruits), fruit weight per plant (725g), and grade A chili yield (73 fruits).

Growth and yield of bok choy (Brassica rapa L.) plants in post-rock excavation soils provided with phosphate-solubilizing bacteria and manure

Elevated sand and gravel mining to meet market needs causes negative impacts on the environment, soil, and biodiversity. The government issued a regulation that requires revegetation as reclamation of mineral and coal mining. The conversion needs to overcome the physical and chemical characteristics of post-rock excavation soil that can be utilized by economic value plants such as bok choy. This experiment aimed to determine the growth and yield of bok choy on post-rock excavation soil by providing phosphate solubilizing bacteria (PSB) and various manure types. The study was conducted in Margasari Village, Buah Batu District, Bandung at an altitude of 671 m above sea level and at the Soil Biotechnology Laboratory, Faculty of Science and Technology, UIN Sunan Gunung Djati Bandung from April to June 2023. The experimental design used was a factorial Randomized Block Design (RBD) with two factors and repeated three times. The first factor was PSB isolate dose (without PSB; 5 mL polybag-1; 10 mL polybag-1; 15 mL polybag-1, and 20 mL polybag-1). The second factor was manure variety (cow, goat, and laying hen manure, each of 15 t ha-1). The parameters observed comprised the soil and plant parameters. The results showed that there was no interaction between the dose of PSB isolate and various types of manure on the growth and yield of bok choy plants. The PSB isolate and manure had not been able yet to increase the growth and yield of Bok Choy (Brassica rapa L.) plants on post-rock excavation soil, mainly due to the soil nature.

Biochar promotes the dissolution of inorganic inactive phosphorus by mediating the bacterial community during corn stover and cattle manure composting.

Phosphorus (P) is a macroelement primarily found in insoluble forms in nature. Enhancing the effectiveness of P is crucial for sustainable agricultural development and ecosystems. The research employed a combination of sequential extraction methods, high-throughput sequencing techniques, microbial culturing, and ecological network analysis of bacterial communities, along with module comparison, to explore the dynamics of different P fractions in calcareous soils. The objective of incorporating biochar into the composting of maize stover and cattle dung was to uncover potential microbial processes that could facilitate the activation of inorganic non-labile P. Findings revealed that during the composting process with biochar, bacterial populations played three distinct roles in the transformation of inorganic non-labile P compounds (such as occluded P and Ca10-P). Primarily, the introduction of biochar significantly increased both the diversity and abundance of bacterial communities. Additionally, it enhanced the ability of phosphate-solubilizing bacteria to maintain the structure of bacterial ecological networks by boosting their complexity, interconnectedness, and stability. Moreover, the incorporation of biochar stimulated the P-related metabolic activities within the bacterial community, significantly enriching key metabolic pathways such as the citrate (TCA) cycle, glycolysis/gluconeogenesis, the pentose phosphate pathway, galactose metabolism, starch, and sucrose metabolism, as well as the metabolism of amino and nucleotide sugars. Moreover, biochar addition intensified the connections between key operational taxonomic units (OTUs) and non-labile P while simultaneously increasing the total organic carbon concentration and enhancing alkaline phosphatase activity. This study provides valuable insights for enhancing P effectiveness in calcareous soils.