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Bioorganic fertilizer (BOF) represents favorable potential for agricultural production, but the safe and residual effects of BOF application in heavy-metal-contaminated soils still remain unclear. A two-year field experiment of four rice-growing cycles were conducted to study the effects of the one-time addition of BOF (low and high dosages, 0.45 and 0.9 kg/m2, namely, BOF1 and BOF2, respectively) on the lead (Pb) and arsenic (As) accumulations in brown rice, rice yield, and soil properties in an acidic and Pb-As-contaminated paddy field. The results show that BOF application enhanced the rice yields by 7.9–25.5% and increased the soil pH, organic carbon contents, and fluorescein diacetate hydrolase activity in the former two rice-growing cycles, while these attributes declined gradually and were not significant in the last two cycles. The soil bulk density decreased marginally due to the BOF. Furthermore, the BOF1 treatment barely affected the rice Pb and As concentrations during all cycles, whereas the BOF2 treatment clearly increased the Pb concentrations in brown rice, exceeding the food quality standard limit of 0.2 mg/kg in the last three cycles, and slightly increased the rice As in the former three cycles. The BOF effects on Pb and As in brown rice were due to the changes in the available soil Pb and As, respectively. Our results indicate that a one-time application of BOF could ameliorate the soil conditions of rice growth in two rice-growing cycles, while the high-dose BOF seemed undesirable in toxic-metal-contaminated soils. BOF application at the rate of 0.45 kg/m2 per annum may be a potential strategy for safe rice production in Pb-As-contaminated fields. [ABSTRACT FROM AUTHOR]

Bioorganic fertilizer (BOF) represents favorable potential for agricultural production, but the safe and residual effects of BOF application in heavy-metal-contaminated soils still remain unclear. A two-year field experiment of four rice-growing cycles were conducted to study the effects of the one-time addition of BOF (low and high dosages, 0.45 and 0.9 kg/m2, namely, BOF1 and BOF2, respectively) on the lead (Pb) and arsenic (As) accumulations in brown rice, rice yield, and soil properties in an acidic and Pb-As-contaminated paddy field. The results show that BOF application enhanced the rice yields by 7.9–25.5% and increased the soil pH, organic carbon contents, and fluorescein diacetate hydrolase activity in the former two rice-growing cycles, while these attributes declined gradually and were not significant in the last two cycles. The soil bulk density decreased marginally due to the BOF. Furthermore, the BOF1 treatment barely affected the rice Pb and As concentrations during all cycles, whereas the BOF2 treatment clearly increased the Pb concentrations in brown rice, exceeding the food quality standard limit of 0.2 mg/kg in the last three cycles, and slightly increased the rice As in the former three cycles. The BOF effects on Pb and As in brown rice were due to the changes in the available soil Pb and As, respectively. Our results indicate that a one-time application of BOF could ameliorate the soil conditions of rice growth in two rice-growing cycles, while the high-dose BOF seemed undesirable in toxic-metal-contaminated soils. BOF application at the rate of 0.45 kg/m2 per annum may be a potential strategy for safe rice production in Pb-As-contaminated fields.

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Introduction: Biochar and bioorganic fertilizer (BOF) application in agriculture has garnered increasing interest recently. However, the effects of biochar and BOF on rhizosphere soil microecology, especially in a region with saline-alkaline soil, remain largely unexplored. Methods: In this study, we performed Illumina-based 16S rRNA sequencing to investigate the effects of biochar with or without BOF addition, as well as at different addition rates and particles sizes, on the microecology of saline-alkaline rhizosphere soil. Results: In the field experiment, biochar and BOF application altered the rhizosphere soil microecology. Actinobacteriota, Proteobacteria, and Chloroflexi accounted for >60% of the total bacterial population in each treatment. In the different treatments, Actinobacteria and Alphaproteobacteria were the predominant classes; Micromonosporales and Vicinamibacterales were the dominant orders; norank_f__ Geminicoccaceae and Micromonosporaceae were the most abundant families; and Micromonospora and norank_f_Geminicoccaceae were the predominant genera. Application of biochar with or without BOF decreased soil electrical conductivity (EC) by 7% -11.58% only at the depth of 10 cm below the surface, again, soil EC can be significantly reduced by an average of 4% at 10 cm depth soil after planting Sesbania cannabina. Soil organic carbon, organic matter, available potassium, and available phosphorus contents had significant effects on the soil bacterial community structure. Conclusion: Co-application of biochar and BOF resulted in the greatest improvement of rhizosphere soil microecology, either by promoting plant growth or improving the nutrition and physicochemical properties of soil, followed by BOF alone and biochar alone. Additionally, higher application rate of biochar was better than lower application rate, and fine biochar had a stronger effect than coarse biochar. These results provide guidance for the development of new saline-alkaline soil remediation strategies. [ABSTRACT FROM AUTHOR]

To encourage the use of biological organic fertilizer in tobacco planting, a three-year field experiment was undertaken to examine the impact of a single kind of biological organic fertilizer on the microecosystems of tobacco rhizosphere. The soil physicochemical index, trace element index, and enzyme and microbial amount index were used to quantify the impact. Compared to traditional fertilization, biological organic fertilizer increased the level of organic matter, alkali-hydro nitrogen, and accessible phosphorus in all physical and chemical soil indexes, whereas the pH remained the same and the rapidly available potassium content decreased somewhat. In the soil trace element indexes, the contents of Mg, Cu, Mn, and Fe were increased annually by 4.53% to 9.42%, 1.45% to 14.12%, 5.22% to 11.07%, and 5.34% to 16.98%, respectively. In the soil enzyme indexes, the activity of urease, catalase, and sucrose invertase were increased, while acid phosphatase activity was decreased. Significant increases were observed in soil microbial carbon (MBC), soil microbial nitrogen (MBN), and soil microbiological phosphorus (MBP) in soil microbial biomass indexes. According to principal component analysis, the contribution rates of the aforementioned indexes to the micro-ecosystem of soil applying biological organic fertilizer were as follows: urease > organic matter > MBN > MBC > Mg > Cu > catalase > Mn > alkali-hydro nitrogen > invertase > Fe > acid phosphatase > rapidly available potassium (K) > available phosphorus (P) > pH > MBP. This study provided a significant scientific approach and theoretical foundation for the advancement of bio-organic fertilizer in the future. [ABSTRACT FROM AUTHOR]

Biochar and bioorganic fertilizers (BOF) that are used in agriculture can, both directly and indirectly, impact rhizosphere soil microorganisms. However, changes to the halophyte rhizosphere bacterial community after applying biochar and BOF to saline–alkali soil have not been thoroughly described. This study has investigated the bacterial communities of halophytes in saline–alkali soil through the addition of different biochar and BOF formulas using Illumina-based sequencing of the 16S rRNA gene fragment. B_BOF (biochar and BOF combined application) had the best effect, either by promoting the plant growth or by improving the physical and chemical properties of the soil. The concentration of the rhizosphere bacterial communities correlated with the changes in soil organic matter (OM) and organic carbon (OC). Proteobacteria, Actinobacteria, Chloroflexi, and Acidobacteria accounted for >80% of the total bacteria in each treatment. In addition, the abundance of Micromonospora was much higher in response to B_BOF than to the other treatments. BOF, with or without biochar, significantly influenced the bacterial community composition in the saline–alkali soil. The OC, OM, total nitrogen, and the available phosphorus had significant effects on the bacterial structure of this soil. The complex correlation of the bacterial communities between CK and B_BOF was higher compared to that between CK and FB or between CK and BOF. These findings suggested that the plant growth, the soil characteristics, and the diversity or community composition of the rhizosphere bacteria in saline–alkali soil were significantly influenced by B_BOF, followed by BOF, and then biochar; fine biochar had a stronger effect than medium or coarse biochar. This study provides an insight into the complex microbial compositions that emerge in response to biochar and BOF. [ABSTRACT FROM AUTHOR]

Abstract Severe early defoliation has become an important factor restricting the development of the pear industry in southern China. However, the assembly patterns of microbial communities and their functional activities in response to the application of bioorganic fertilizer (BIO) or humic acid (HA) in southern China’s pear orchards remain poorly understood, particularly the impact on the early defoliation of the trees. We conducted a 3-year field experiment (2017–2019) in an 18-year-old ‘Cuiguan’ pear orchard. Four fertilization schemes were tested: local custom fertilization as control (CK), CK plus HA (CK-HA), BIO, and BIO plus HA (BIO-HA). Results showed that BIO and BIO-HA application decreased the early defoliation rate by 50–60%, and increased pear yield by 40% compared with the CK and CK-HA treatments. The BIO and BIO-HA application significantly improved soil pH, available nutrient content, total enzyme activity and ecosystem multifunctionality, and also changed the structure of soil bacterial and fungal communities. The genus Acidothermus was positively correlated with the early defoliation rate, while the genus Rhodanobacter was negatively correlated. Additionally, random forest models revealed that the early defoliation rate could be best explained by soil pH, ammonium content, available phosphorus, and total enzyme activity. In conclusion, application of BIO or BIO mixed with HA could have assembled distinct microbial communities and increased total enzyme activity, leading to significant improvement of soil physicochemical traits. The increased availability of soil nutrient thus changed leaf nutrient concentrations and alleviated the early defoliation rate of pear trees in acid red soil in southern China.

A controlled fermentation was conducted to develop and design a bioorganic fertilizer based on three wastes generated by the food industry: olive mill wastewater (OMW), molasses and rice hulls by inoculation with selected strains of lactic acid bacteria (LAB), of the species “Lactiplantibacillus plantarum” and “Levilactobacillus brevis” and of the yeast of the species “candida famata”. The fermentation with commercial yeasts and particularly the species of “saccharomyces” produced an unstable fertilizer with a high pH value (6.14).Whereas, the fermentation test with an inoculum composed of 20% yeast and 80% lactic acid bacteria showed a decrease in pH at 4.66 and a maximum enzymatic activity of 43.900 IU/l after 30 h. This combination allowed an appropriate morphological and microbiological quality of the bioorganic fertilizer. To determine with precision, the optimum conditions of this fermentation an optimization design was applied. As a result of experiments and statistical validation of the fitted model, the bioorganic fertilizer with the lowest pH value was achieved after fermentation of 53.2% OMW, 19.1% molasses, 21.3% rice hulls and 6.4% inoculum content. The final pH was able to reach a value of 4.07 with desirability of the order of 99.7%. A fertilizer with the lowest possible pH allowed farmers longer storage periods and required no special storage conditions.

[Objectives] This study was conducted to promote the rational use of bioorganic fertilizers. % Methods] Stanley bioorganic fertilizer was selected to in-vestigate the laws and characteristics of the eefects of bioorganic fertilizer on spinach growth with different application rates in a short term and found out the precise application rate. [Results] As the application rate of bioorganic fertilizer increasing, the emergence rate of spinach decreased. The total weights and leaf areas of spinach plants treated with diferent application rates of bioorganic fertilizers were all higher than those of the control check (CK). The total weights and leaf areas of spinach plants applied with bioorganic fertilizer at diferent rates were all higher than those of the CK. The total weight of spinach plants increased linearly with the application rate of bioorganic fertilizer increasing among treatments, while the leaf area fluctuated with the increase of bioorganic fertilizer concentration among various treatments. The average root volumes and average diameters of treatments applied with bioorganic fertilizer at diferent rates were all higher than those in the CK, but the average root length showed a diferent trend. The average root length was higher in the CK than in various bioorganic fertilizer treatments in the early growth period, but the diferences of various treatments from the CK graduHy decreased in the middle period, and in the later period, the root length of spinach treated with organic fertilizer graduaUy exceeded the CK. [Conclusions] This study provides a theoretical basis for the rational application of bioorganic fertilizers in spinach production. [ABSTRACT FROM AUTHOR]

As a functional probiotic, Bacillus subtilis can promote crop growth and improve nutrient utilization by various mechanisms, so it has been made into bioorganic fertilizer as a replacement for chemical fertilizer. However, the effects of B. subtilis bioorganic fertilizer application on the yield and quality of commercial crops of Brassica chinensis L., the soil physicochemical properties and the microflora have not been clarified. In this study, pot experiments were conducted using Brassica chinensis L. plants with four fertilization treatments: control without fertilization (CK), chemical fertilizer (CF), organic fertilizer (OF), and bioorganic fertilizer containing B. subtilis (BF). After 30 days of pot experiment, the results showed that BF efficiently improved plant height and biomass (1.20- and 1.93-fold, respectively); as well as significantly increasing soil available potassium and pH value. Using high-throughput sequencing, we examined the bacterial and fungal communities in the soil, and found that their diversity was remarkablely reduced in the BF treatment compared to CK group. A principal coordinate analysis also showed a clear separation of bacterial and fungal communities in the BF and CK groups. After application of B. subtilis bioorganic fertilizer, some beneficial bacteria (such as Bacillus and Ammoniphilus) and fungi (Trichoderma and Mortierella) were enriched. A network analysis indicated that bacteria were the dominant soil microbes and the presence of B. subtilis stimulated the colonization of beneficial microbial communities. In addition, predictive functional profiling demonstrated that the application of bioorganic fertilizer enhanced the function of mineral element metabolism and absorption and increased the relative abundance of saprotrophs. Overall, the application of bioorganic fertilizer effectively changed the soil microflora, improved the soil available potassium and pH value, and boosted the yield of Brassica chinensis L. This work has valuable implications for promoting the safe planting of facility vegetables and the sustainable development of green agriculture. [ABSTRACT FROM AUTHOR]

Abstract Application of a novel bioorganic fertilizer (BIO) has been effectively used to inhibit weeds in rice paddies. To identify changes in soil bacterial community and enzymes in response to BIO treatments, field experiments were carried out in five major rice-growing areas in China. The dominant phylogenetic groups recorded included Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Acidobacteria. Anaeromyxobacter, Bacteroides, Bifidobacterium, Escherichia- Shigella, Geobacter and Haliangium were significantly different between BIO-treatment and untreated control and aided in general function (R), amino acid transport, metabolism (E) and transcription (K) clusters. The soil chemical properties and enzyme activities were less affected by BIO at these study sites. RDA analysis showed that soil bacterial community had a significant positive correlations among northern latitude, eastern longitude, exchangeable K, total K, total P, soil pH, and total N, except for organic matter, hydrolytic N and extractable P. Overall, our work showed that application of BIO does not alter the main community structure and functional diversity of soil bacteria in rice paddies and should be encouraged for use as a sustainable weed management strategy.

This study was carried out to determine the effects of bioorganic fertilizer and high carbon base fertilizer on soil respiration (autotrophic and heterotrophic respiration) and some soil quality indexes in forage field, The dynamic changes of soil respiration (autotrophic respiration and heterotrophic respiration), soil temperature, soil moisture content and active organic carbon content (mass fraction) were studied by field experiments under three different treatments of chemical fertilizer (CK), chemical fertilizer + bio-organic fertilizer (T1) and chemical fertilizer + high-carbon base fertilizer (T2). The result of current study explored that the soil respiration rate varied from 0.99 µmol·m to 7.39 µmol·m under different fertilization treatments and the peak value of total soil respiration rate appeared about 90 days after transplanting. Total soil respiration rate in T1 and T2 treatments was significantly increased by 33.17% and 15.14%, respectively, and the autotrophic and heterotrophic respiration rates in T1 treatments were significantly increased by 34.66% and 32.08%, respectively. Results showed that combined application of organic fertilizer significantly increased soil active, medium active and high active organic carbon content and soil total respiration rate was positively correlated with soil temperature, active, medium active and high active organic carbon content, and negatively correlated with soil moisture content. Therefore, combined application of bioorganic fertilizer and high-carbon base fertilizer could increase soil total respiration rate and promote soil active organic carbon accumulation. [ABSTRACT FROM AUTHOR]

Severe early defoliation has become an important factor restricting the development of the pear industry in southern China. However, the assembly patterns of microbial communities and their functional activities in response to the application of bioorganic fertilizer (BIO) or humic acid (HA) in southern China's pear orchards remain poorly understood, particularly the impact on the early defoliation of the trees. We conducted a 3-year field experiment (2017–2019) in an 18-year-old 'Cuiguan' pear orchard. Four fertilization schemes were tested: local custom fertilization as control (CK), CK plus HA (CK-HA), BIO, and BIO plus HA (BIO-HA). Results showed that BIO and BIO-HA application decreased the early defoliation rate by 50–60%, and increased pear yield by 40% compared with the CK and CK-HA treatments. The BIO and BIO-HA application significantly improved soil pH, available nutrient content, total enzyme activity and ecosystem multifunctionality, and also changed the structure of soil bacterial and fungal communities. The genus Acidothermus was positively correlated with the early defoliation rate, while the genus Rhodanobacter was negatively correlated. Additionally, random forest models revealed that the early defoliation rate could be best explained by soil pH, ammonium content, available phosphorus, and total enzyme activity. In conclusion, application of BIO or BIO mixed with HA could have assembled distinct microbial communities and increased total enzyme activity, leading to significant improvement of soil physicochemical traits. The increased availability of soil nutrient thus changed leaf nutrient concentrations and alleviated the early defoliation rate of pear trees in acid red soil in southern China. [ABSTRACT FROM AUTHOR]

A controlled fermentation was conducted to develop and design a bioorganic fertilizer based on three wastes generated by the food industry: olive mill wastewater (OMW), molasses and rice hulls by inoculation with selected strains of lactic acid bacteria (LAB), of the species " Lactiplantibacillus plantarum" and " Levilactobacillus brevis " and of the yeast of the species " candida famata ". The fermentation with commercial yeasts and particularly the species of " saccharomyces " produced an unstable fertilizer with a high pH value (6.14).Whereas, the fermentation test with an inoculum composed of 20% yeast and 80% lactic acid bacteria showed a decrease in pH at 4.66 and a maximum enzymatic activity of 43.900 IU/l after 30 h. This combination allowed an appropriate morphological and microbiological quality of the bioorganic fertilizer. To determine with precision, the optimum conditions of this fermentation an optimization design was applied. As a result of experiments and statistical validation of the fitted model, the bioorganic fertilizer with the lowest pH value was achieved after fermentation of 53.2% OMW, 19.1% molasses, 21.3% rice hulls and 6.4% inoculum content. The final pH was able to reach a value of 4.07 with desirability of the order of 99.7%. A fertilizer with the lowest possible pH allowed farmers longer storage periods and required no special storage conditions. [ABSTRACT FROM AUTHOR]

Objectives: Evaluation of Streptomyces isolated from Udhagamandalam, The Nilgiris, Tamilnadu, India for the biocontrol potential against the phytopathogen Ralstonia solanacearum and its metabolite profiling. Methods: Streptomyces strains were screened for plant growth promotion and antagonistic activity against R. solanacearum in in-vitro. The metabolite profiling of strain UT4A49 was studied through gas chromatography coupled with mass spectroscopy (GC–MS) analysis. Further, the identified lead compound 2,4-Di-tert-butylphenol (2,4-DTBP) was analyzed for its mechanism of action through in-silico docking study. The bioorganic fertilizer (BOF) amended potential Streptomyces strain UT4A49 was studied for biocontrol activity against R. solanacearum on tomato seedlings through pot culture experiments. Results: The Streptomyces strain UT4A49 showed the promising production of indole acetic acid (IAA) (76.0 ± 2.0 µg/ml), siderophore, ammonia, amylase, protease, cellulase as well as it solubilized the phosphate in-vitro. The strain UT4A49 showed strong in vitro antagonistic activity against R. solanacearum with the inhibition zone of 19.83 ± 0.44 mm in diameter. The isolated major compound, 2,4-Di-tert-butylphenol was showed strong inhibition against R. solanacearum. In silico docking study revealed that the 2,4-DTBP showed lower binding energy score with all targeted proteins which found better protein–ligand binding stability. In the pot experiment, biocontrol activity of BOF amended Streptomyces strain UT4A49 showed significant biocontrol efficacy was 78.5% against R. solanacearum in tomato seedlings. The strain UT4A49 was identified as Streptomyces sp. based on its morphological and molecular properties. Conclusions: The detailed literature survey revealed that this is the first report on strong bioactive properties of 2,4-DTBP against R. solanacearum. This present study proved that bioorganic fertilizer amended with Streptomyces sp. UT4A49 is a promising biocontrol agent for tomato bacterial disease control.

Biochar and bioorganic fertilizers (BOF) that are used in agriculture can, both directly and indirectly, impact rhizosphere soil microorganisms. However, changes to the halophyte rhizosphere bacterial community after applying biochar and BOF to saline–alkali soil have not been thoroughly described. This study has investigated the bacterial communities of halophytes in saline–alkali soil through the addition of different biochar and BOF formulas using Illumina-based sequencing of the 16S rRNA gene fragment. B_BOF (biochar and BOF combined application) had the best effect, either by promoting the plant growth or by improving the physical and chemical properties of the soil. The concentration of the rhizosphere bacterial communities correlated with the changes in soil organic matter (OM) and organic carbon (OC). Proteobacteria, Actinobacteria, Chloroflexi, and Acidobacteria accounted for >80% of the total bacteria in each treatment. In addition, the abundance of Micromonospora was much higher in response to B_BOF than to the other treatments. BOF, with or without biochar, significantly influenced the bacterial community composition in the saline–alkali soil. The OC, OM, total nitrogen, and the available phosphorus had significant effects on the bacterial structure of this soil. The complex correlation of the bacterial communities between CK and B_BOF was higher compared to that between CK and FB or between CK and BOF. These findings suggested that the plant growth, the soil characteristics, and the diversity or community composition of the rhizosphere bacteria in saline–alkali soil were significantly influenced by B_BOF, followed by BOF, and then biochar; fine biochar had a stronger effect than medium or coarse biochar. This study provides an insight into the complex microbial compositions that emerge in response to biochar and BOF.

The effort to increase food production in tidal lowland areas was conducted by applying production technology through the use of superior varieties and organic fertilizer enriched with bacteria (bio organic fertilizer). This fertilizer was a formula that had been tested in swamp lowland area and proven capable to regain land fertility through action of beneficial microbia. Some microbia which used to produce bioorganic fertilizer are Azospirillium bacterium and phosphate solvent bacterium with carrier substance of chicken manure fertilizer. The reserach objective was to determine yield capacity of two rice varieties by using inorganic fertilizer and bioorganic fertilizer at tidal lowland area. This research was done at tidal lowland area of C-flooding type. The design used in this study was Factorial Randomized Block Design with 4 treatment combinations and 6 replications for each treatment. The first factor was varieties which consisted of Inpara 6 (V1) and Inpari I (V2), whereas the second factor was fertilizer types which consisted of inorganic fertilizer (P1) and bio-organic fertilizer (P2). The results showed that yield capacity of Inpari I rice variety treated with bio-organic fertilizer + 50% of recommended NPK fertilizer could increase the production of dry unhulled rice with magnitude of 165% (1.59 kg/plot or equal to 3.98 ton/ha) at tidal lowland of C flooding type. Through the provision of biofertilizers, chicken manure enriched with Azospirillum and bacteriophosphate biofertilizers contributes to sustainability agriculture, especially in tidal wetland

Application of a novel bioorganic fertilizer (BIO) has been effectively used to inhibit weeds in rice paddies. To identify changes in soil bacterial community and enzymes in response to BIO treatments, field experiments were carried out in five major rice-growing areas in China. The dominant phylogenetic groups recorded included Proteobacteria, Actinobacteria, Bacteroidetes, Firmicutes and Acidobacteria. Anaeromyxobacter, Bacteroides, Bifidobacterium, Escherichia- Shigella, Geobacter and Haliangium were significantly different between BIO-treatment and untreated control and aided in general function (R), amino acid transport, metabolism (E) and transcription (K) clusters. The soil chemical properties and enzyme activities were less affected by BIO at these study sites. RDA analysis showed that soil bacterial community had a significant positive correlations among northern latitude, eastern longitude, exchangeable K, total K, total P, soil pH, and total N, except for organic matter, hydrolytic N and extractable P. Overall, our work showed that application of BIO does not alter the main community structure and functional diversity of soil bacteria in rice paddies and should be encouraged for use as a sustainable weed management strategy. [ABSTRACT FROM AUTHOR]

Bioorganic fertilizers can alleviate (a) biotic stresses and sustainably increase crop yields. The effect of bioorganic fertilizers on the rhizosphere bacterial community of Panax notoginseng and soil metabolism remains unknown. Here, we tracked the changes in the soil physicochemical properties, bacterial microbiota responses, and soil metabolic functions after the addition of a bioorganic fertilizer in a P. notoginseng field. The application of a bioorganic fertilizer reduced the soil acidification, improved the organic matter, and increased the contents of the total/available soil nutrients. Soil amendment with a bioorganic fertilizer significantly affected the structure of the rhizosphere bacterial community, leading to the enrichment of specific bacterial consortia such as Rhodanobacter, Arthrobacter, Sphingomonas, Devosia, Pseudolabrys, Luteimonas, Lysobacter, Nitrosospira, and Nakamurella. Previously, many of these genera have been associated with nutrient cycling, plant productivity, and disease suppression. Metabolome analysis further highlighted that the bioorganic fertilizer treatment significantly reduced phenolic acids and flavonoids and enhanced organic acids, saccharides and alcohols, and amino acids. This result indicates a high survival of bacterial microbiota in the rhizosphere and an availability of nutrients for P. notoginseng growth. This work showed that the application of bioorganic fertilizers significantly improves soil health status, alters soil metabolic functions, and stimulates a specific subset of rhizosphere microbiota for nutrient cycling and disease protection in P. notoginseng.

Fusarium wilt caused by Fusarium oxysporum f. sp. fragariae is one of the most serious indigenous soil-borne fungal disease of strawberry. In this study, we have identified and investigated two sets of bacterial samples: Bacillus licheniformis (X-1) and Bacillus methylotrophicus (Z-1). Both of them were isolated from the rhizosphere soil of healthy strawberries which showed a strong inhibitory effect on Fusarium wilt caused by Fusarium oxysporum f. sp. fragariae. Bioorganic fertilizer developed by our team exhibiting a strong inhibition ability against the pathogen in comparison with the chemical and organic fertilizers. It allowed 80% disease free strawberry production together with improved physical and biochemical indexes in the pot experiments. The enzyme activity analysis of SOD, PPO, POD, and CAT in the bioorganic fertilizer (BOF) group showed significant increase with values; 48.8%, 68.7%, 85.9%, and 41.1% than that of the control group, respectively. The results of bacterial diversity showed that Bacillus in group BOF was almost three times as large as in the healthy soil control group (CK). Besides, the results of microbial diversity showed that Fusarium and Fusicolla of BOF was nearly five times less than that in CK and chemical fertilizer groups, where the Bacillus content reached to three times as much of the CK. Moreover, the enzymes activity and the content of beneficial microorganisms in the rhizosphere increased significantly. In this study, the bioorganic fertilizer developed by the isolated strains had significant effects on the control of strawberry Fusarium wilt disease. Our results demonstrate that BOF is a promising approach to control this disease in strawberry production. [ABSTRACT FROM AUTHOR]

Purpose: Traditional methods of composting are limited in timely production of good-quality compost due to recalcitrant nature of materials of plant origin. This study focused on evaluating the use chicken and donkey manure as starter cultures to biostimulate bioconversion of rice straw into bioorganic fertilizer. Use of starter cultures would enhance composting as a strategy for rice straw management to enhance soil fertilization and reduce environmental pollution. Methods: In this study, chicken manure and donkey manure were used as starter cultures to enhance bioconversion of recalcitrant and abundant rice straw in Mwea, the main rice-producing area in Kenya. Treatments of the study included rice straw co-composted with chicken manure (T1), rice straw co-composted with donkey manure (T2) and a control (T0) consisting of un-treated rice straw. Temperature, pH and electrical conductivity (EC) were monitored throughout the composting period. Resultant compost types were characterized in respect to their macro-nutrient concentrations, cation exchange capacity, pH and heavy metal content. Results: Levels of temperature, pH and EC among the treatments of the study revealed significant differences at 5% level of confidence using Tukey's test. The three resultant compost types obtained were also physicochemically different as revealed by analysis of variance of cation exchange capacity, phosphorus, nitrogen and carbon content. Conclusion: Results indicated that use of chicken and donkey manure significantly improved the composting process and the quality of resultant compost. [ABSTRACT FROM AUTHOR]

The effort to increase food production in tidal lowland areas was conducted by applying production technology through the use of superior varieties and organic fertilizer enriched with bacteria (bio organic fertilizer). This fertilizer was a formula that had been tested in swamp lowland area and proven capable to regain land fertility through action of beneficial microbia. Some microbia which used to produce bioorganic fertilizer are Azospirillium bacterium and phosphate solvent bacterium with carrier substance of chicken manure fertilizer. The reserach objective was to determine yield capacity of two rice varieties by using inorganic fertilizer and bioorganic fertilizer at tidal lowland area. This research was done at tidal lowland area of C-flooding type. The design used in this study was Factorial Randomized Block Design with 4 treatment combinations and 6 replications for each treatment. The first factor was varieties which consisted of Inpara 6 (V1) and Inpari I (V2), whereas the second factor was fertilizer types which consisted of inorganic fertilizer (P1) and bio-organic fertilizer (P2). The results showed that yield capacity of Inpari I rice variety treated with bio-organic fertilizer + 50% of recommended NPK fertilizer could increase the production of dry unhulled rice with magnitude of 165% (1.59 kg/plot or equal to 3.98 ton/ha) at tidal lowland of C flooding type. Through the provision of biofertilizers, chicken manure enriched with Azospirillum and bacteriophosphate biofertilizers contributes to sustainability agriculture, especially in tidal wetland. [ABSTRACT FROM AUTHOR]

Greenhouse soil salinization has received extensive attention, due to its serious impact on agricultural environment and crop production. A study regarding the effect of drip irrigation and bioorganic fertilizer application on the greenhouse soil and tomato crop was carried out from May to October in south China. The experiment included three irrigation quotas of 15, 18 and 21 mm, and three bioorganic fertilizer application amounts of 2800, 3600 and 4400 kg/ha. A conventional treatment (abbreviated as CK), applied with inorganic fertilizer (180 kg/ha N, 90 kg/ha P2O5, 54 kg/ha K2O) and drip irrigation (18 mm), was adopted for comparison. The tomato yield, the fruit quality indicators, as well as the soil physicochemical properties were observed. Results showed that, irrigation quota of 18 mm combined with bioorganicfertilizer application amount of 4400 kg/ha resulted in the highest tomato yield (132.6 t/ha) among the treatments, and increased it by 24.6% compared to yield of CK. Both irrigation and fertilization had extremely significant (p<0.01) effect on the tomato yield and the contents of soluble solid, total acid and vitamin C in tomato fruit. The salt decrease rate in plough layer was significantly (p<0.05) affected by irrigation or/and fertilization. The treatment, combined with 21 mm irrigation quota and 3600 kg/ha fertilizer application amount, had a significantly (p<0.05) higher salt decrease rate (22.4%), relative to the other treatments. With regards to soil properties, irrigation had significant (p<0.05) effect on the soil indicators including soil bulk density, total porosity, organic matter and field capacity, and fertilization had significant (p<0.01) effect on organic matter content and field capacity. Overall, the treatments reduced the soil bulk density by 2.9-12.8%, and increased the soil total porosity, organic matter content and field capacity by 2.9-10.3%, 0.4-18.9% and 3.3-17.3%, respectively, relative to CK. [ABSTRACT FROM AUTHOR]

Application of bioorganic fertilizers has been reported to improve crop yields and change soil bacterial community structure; however, little work has been done in apple orchard soils where the biological properties of the soils are being degraded due to long-term application of chemical fertilizers. In this study, we used Illumina-based sequencing approach to characterize the bacterial community in the 0-60-cm soil profile under different fertilizer regimes in the Loess Plateau. The experiment includes three treatments: (1) control without fertilization (CK); (2) application of chemical fertilizer (CF); and (3) application of bioorganic fertilizer and organic-inorganic mixed fertilizer (BOF). The results showed that the treatment BOF increased the apple yields by 114 and 67 % compared to the CK and CF treatments, respectively. The treatment BOF also increased the soil organic matter (SOM) by 22 and 16 % compared to the CK and CF treatments, respectively. The Illumina-based sequencing showed that Acidobacteria and Proteobacteria were the predominant phyla and Alphaproteobacteria and Gammaproteobacteria were the most abundant classes in the soil profile. The bacterial richness for ACE was increased after the addition of BOF. Compared to CK and CF treatments, BOF-treated soil revealed higher abundance of Proteobacteria, Alphaproteobacteria and Gammaproteobacteria, Rhizobiales, and Xanthomonadales while Acidobacteria, Gp7, Gp17, and Sphaerobacter were found in lower abundance throughout the soil profile. Bacterial community structure varied with soil depth under different fertilizer treatments, e.g., the bacterial richness, diversity, and the relative abundance of Verruccomicrobia, Candidatus Brocadiales, and Skermanella were decreased with the soil depth in all three treatments. Permutational multivariate analysis showed that the fertilizer regime was the major factor than soil depth in the variations of the bacterial community composition. Two groups, Lysobacter and Rhodospirillaceae, were found to be the significantly increased by the BOF addition and the genus Lysobacter may identify members of this group effective in biological control-based plant disease management and the members of family Rhodospirillaceae had an important role in fixing molecular nitrogen. These results strengthen the understanding of responses to the BOF and possible interactions within bacterial communities in soil that can be associated with disease suppression and the accumulation of carbon and nitrogen. The increase of apple yields after the application of BOF might be attributed to the fact that the application of BOF increased SOM, and soil total nitrogen, and changed the bacterial community by enriching Rhodospirillaceae, Alphaprotreobateria, and Proteobacteria. [ABSTRACT FROM AUTHOR]

Introduction: Biochar and bioorganic fertilizer (BOF) application in agriculture has garnered increasing interest recently. However, the effects of biochar and BOF on rhizosphere soil microecology, especially in a region with saline-alkaline soil, remain largely unexplored., Methods: In this study, we performed Illumina-based 16S rRNA sequencing to investigate the effects of biochar with or without BOF addition, as well as at different addition rates and particles sizes, on the microecology of saline-alkaline rhizosphere soil., Results: In the field experiment, biochar and BOF application altered the rhizosphere soil microecology. Actinobacteriota, Proteobacteria, and Chloroflexi accounted for >60% of the total bacterial population in each treatment. In the different treatments, Actinobacteria and Alphaproteobacteria were the predominant classes; Micromonosporales and Vicinamibacterales were the dominant orders; norank&#95;f&#95;&#95;Geminicoccaceae and Micromonosporaceae were the most abundant families; and Micromonospora and norank&#95;f&#95;Geminicoccaceae were the predominant genera. Application of biochar with or without BOF decreased soil electrical conductivity (EC) by 7% -11.58% only at the depth of 10 cm below the surface, again, soil EC can be significantly reduced by an average of 4% at 10 cm depth soil after planting Sesbania cannabina. Soil organic carbon, organic matter, available potassium, and available phosphorus contents had significant effects on the soil bacterial community structure., Conclusion: Co-application of biochar and BOF resulted in the greatest improvement of rhizosphere soil microecology, either by promoting plant growth or improving the nutrition and physicochemical properties of soil, followed by BOF alone and biochar alone. Additionally, higher application rate of biochar was better than lower application rate, and fine biochar had a stronger effect than coarse biochar. These results provide guidance for the development of new saline-alkaline soil remediation strategies., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Gu, Liang, Zhang, Fu, Li and Chen.)

Root rot is one of the major constraints on strawberry production worldwide, and no effective control measure is available yet. Therefore, the objective of this study was to develop a new bio-agent for controlling this disease. The antagonistic strain B04 was isolated from the rhizosphere soil of a healthy strawberry plant, and it strongly inhibited the growth of phytopathogenic fungi, especially that of Fusarium oxysporum . Strain B04 was identified as Streptomyces hygroscopicus by morphological and cultural traits and by 16S rRNA gene sequence analysis. Strain B04 could utilize numerous carbon sources and produce extracellular fungal cell wall-degrading enzymes including chitinase, β-1,3-glucanase, cellulase and protease. Agro-industrial waste materials, specifically wheat bran and vermicompost, were used for solid-state fermentation with strain B04 to produce bioorganic fertilizer. On the seventh day of fermentation, the spore number peaked at 5.3 × 10 10 CFU g −1 . Pot and field experiments were performed to evaluate the effects of bioorganic fertilizer B04 (BOF-B04) on the infested soils. Each experiment included three groups: (1) control treatment, (2) organic fertilizer, and (3) bioorganic fertilizer B04. BOF-B04 significantly increased the fresh weight of strawberry plants compared to the control and also decreased the incidence of root rot. The biocontrol efficiencies of BOF-B04 were 63.35% and 56.77% in pot and field experiments, respectively. Moreover, application of BOF-B04 also altered the microbial community structure of the rhizosphere soil. The number of fungi in rhizosphere soil decreased markedly, by 82.43% compared to the control. In contrast, bacterial and actinomycete densities were dramatically higher than in the control. Application of BOF-B04 decreased the levels of stress-related enzyme activity and of malondialdehyde compared to the control. Consequently, this study showed that bioorganic fertilizer B04 is a potential biocontrol agent for controlling strawberry root rot. [ABSTRACT FROM AUTHOR]

Tobacco bacterial wilt (TBW) caused by Ralstonia solanacearum (RS) is one of the most serious tobacco diseases worldwide and no effective control measures are available to date. This study investigated the potential of Trichoderma harzianum SQR-T037 amended bioorganic fertilizer (BOF) and the arbuscular mycorrhizal fungi (AMF) Glomus mosseae 171 (Gm) on the control of TBW and promotion of plant growth in pot experiments. The results showed that the disease incidence in plants treated with integrated application of G. mosseae 171 and T. harzianum SQR-T037 amended bioorganic fertilizer (Gm + BOF) was the lowest, with a control efficacy of 68.2%, which is greater than that of BOF or Gm alone (26.8% and 14.7%, respectively). The application of BOF or Gm alone significantly reduced the abundance of RS in rhizosphere soil, but the integrated treatment (Gm + BOF) showed the strongest inhibitory effect (with a 21.3% increase in inhibition). The root colonization of G. mosseae 171 in samples treated with Gm + BOF was higher than that in samples with solely Gm treatment, indicating that the BOF significantly promoted G. mosseae mycorrhizal colonization. The results showed that the G. mosseae also had a positive effect on SQR-T037 rhizospheric colonization. Denaturing gradient gel electrophoresis (DGGE) results showed that application of BOF and Gm alone or in combination changed the diversity of the rhizospheric microbial community. The integrated application of Gm + BOF to tobacco plants significantly increases the activity of polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), and peroxidase (POD), enzymes associated to systemic resistance. Additionally, the integrated application of Gm with BOF increased the tobacco plant height, shoot dry weight, and root dry weight. In conclusion, a synergistic biological approach integrating application of Gm and BOF for TBW protection seems promising. [ABSTRACT FROM AUTHOR]

Continuous applications of lignite bioorganic fertilizer (LBF) to the field have achieved substantial improvements in soil physicochemical properties and crop yields in multiple regions throughout China. However, the effects of LBF on crop growth, and water and fertilizer productivity in saline-sodic farmlands were scarcely understood. Thus, in this study, a two-year field experiment with six treatments including a control treatment without any organic fertilizer (CK), a treatment amended with 21 t ha−1sheep manure (SM), and four treatments amended with 1.5 (LBF1), 3 (LBF2), 4.5 (LBF3), and 7.5 t ha−1 (LBF4) LBF, was conducted in 2019 and 2020 in the Hetao Irrigation District (HID), an area known for its saline-sodic conditions located at the upper Yellow River basin, China. The results showed that the LBF2 and LBF3 treatments improved plant height, leaf area index, and dry biomass by 8–76.7 cm, 0.3–2.4, and 309–402 g plant−1, respectively, in comparison with the CK treatment. The root length, root surface area, and root volume in the LBF2 and LBF3 treatment was 18.3–99.7 m, 464.6–2022.6 cm2, and 7.6–46.4 cm3 larger than that in the CK treatment, respectively. Average yield, water productivity, partial nitrogen productivity, and economical gain in the LBF treatments were up to 2.2 t ha−1, 0.4 kg m−3, 23.6 kg kg−1, and 6100 Chinese Yuan ha−1, respectively, substantially higher than those of the CK treatment. In addition, compared with SM treatment, the LBF2 and LBF3 treatments also significantly improved sunflower growth and water and nitrogen productivity. The results of structural equation model analysis and linear regression analysis showed that LBF2 and LBF3 treatments improved sunflower root growth mainly through improving absorption of soil nitrogen. Furthermore, the root indices had a significant positive relation with the sunflower yield, water productivity, and partial nitrogen productivity. The partial nitrogen productivity, water productivity, yield, and economic profits showed a quadratic relationship with the application rate of LBF. A comprehensive assessment of the partial nitrogen productivity, water productivity, yield, and cost versus economic suggested that an application rate of 3.0–4.0 t ha−1 of the lignite bioorganic fertilizer is optimal for achieving a sustainable improvement of crop yield, water productivity, and partial nitrogen productivity in saline-sodic farmlands. • Sunflower growth in saline-sodic soil was improved by lignite bioorganic fertilizer. • Application of lignite bioorganic fertilizer increased sunflower nitrogen absorption. • Water and nitrogen productivity of sunflower increased by lignite bioorganic fertilizer. • 3.0–4.0 t ha−1 is the optimal application rate of lignite bioorganic fertilizer in the study area. [ABSTRACT FROM AUTHOR]

Abstract: The application method for a novel bioorganic fertilizer (BIO) was developed to improve its biocontrol efficacy of Fusarium wilt (Ling et al. 2010). However, its efficacy on controlling Fusarium wilt and the variations of microbial community after long-term application for watermelon production had not been elucidated. To clarify, a 4-years pot experiment of mono-cropping watermelon was conducted. The results revealed that though the disease incidences were increased in all treatments with the increase of continuous cropping years, the treatment of BIO application both in nursery and pot soil always maintained the lowest disease incidence. The real-time PCR results showed that the population of Paenibacillus polymyxa was decreased with continuous cropping years, but in all seasons, the treatment with BIO application both in nursery and pot soil had a highest population of P. polymyxa than the other treatments. On the other hand, the abundance of the pathogen FON was increased with the increase of continuous cropping years and the lowest rate of increase was found by BIO application in both nursery and pot soil. DGGE patterns showed that the bacterial diversity was weakened after mono-cropping of watermelon for 4 years, but the consecutive applications of BIO at nursery and transplanting stage resulted in the minimal change of bacterial diversity. More detailed differences on bacterial diversity between control and double application of BIO treatment after 4-years monoculture were analyzed by 454 pyrosequencing, which showed the dominant phyla found in both samples were Firmicutes, Proteobacteria and Actinobacteria, and the consecutive applications of BIO recruited more beneficial bacteria than control, such as Bacillus, Paenibacillus, Haliangium, Streptomyces. Overall, these results, to a certain extent, approved that the consecutive applications of BIO at nursery and transplanting stage could effectively suppress watermelon Fusarium wilt by regulating the rhizosphere bacterial diversity. These results could give some clues that how to regulate the soil microbial community to an appropriate level which can keep the plant healthy and thus control the soil-borne diseases. [Copyright &y& Elsevier]

Highlights: [•] The application of BOFs delayed wilt development and effectively decreased the disease incidence. [•] Application of BOF7 achieved 58.0% and 56.2% control efficacies in two years field experiments. [•] Application of BOFs could significantly repressed the pathogen in both pot and field experiments. [•] The density of SQR-7 and SQR-29 remained at a high level in later tobacco growth stages. [•] Application of BOFs promoted tobacco growth and increased the tobacco leaf yields. [Copyright &y& Elsevier]

As a functional probiotic, Bacillus subtilis can promote crop growth and improve nutrient utilization by various mechanisms, so it has been made into bioorganic fertilizer as a replacement for chemical fertilizer. However, the effects of B. subtilis bioorganic fertilizer application on the yield and quality of commercial crops of Brassica chinensis L., the soil physicochemical properties and the microflora have not been clarified. In this study, pot experiments were conducted using Brassica chinensis L. plants with four fertilization treatments: control without fertilization (CK), chemical fertilizer (CF), organic fertilizer (OF), and bioorganic fertilizer containing B. subtilis (BF). After 30 days of pot experiment, the results showed that BF efficiently improved plant height and biomass (1.20- and 1.93-fold, respectively); as well as significantly increasing soil available potassium and pH value. Using high-throughput sequencing, we examined the bacterial and fungal communities in the soil, and found that their diversity was remarkablely reduced in the BF treatment compared to CK group. A principal coordinate analysis also showed a clear separation of bacterial and fungal communities in the BF and CK groups. After application of B. subtilis bioorganic fertilizer, some beneficial bacteria (such as Bacillus and Ammoniphilus ) and fungi ( Trichoderma and Mortierella ) were enriched. A network analysis indicated that bacteria were the dominant soil microbes and the presence of B. subtilis stimulated the colonization of beneficial microbial communities. In addition, predictive functional profiling demonstrated that the application of bioorganic fertilizer enhanced the function of mineral element metabolism and absorption and increased the relative abundance of saprotrophs. Overall, the application of bioorganic fertilizer effectively changed the soil microflora, improved the soil available potassium and pH value, and boosted the yield of Brassica chinensis L. This work has valuable implications for promoting the safe planting of facility vegetables and the sustainable development of green agriculture., Competing Interests: Authors XH, PM and ZW are employed by Shenzhen Batian Ecological Engineering Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wang, Cheng, Huo, Meng, Cai, Wang and Zhou.)

Pear trees with severe early defoliation usually suffer from weakened aboveground growth and a serious decrease of fruit quality and yield. Soil fertility and its microbial community and functional activity are significant factors impacting plant growth and yield, which also might be the very factors that influence the early defoliation of pear trees. To address the problems caused by chemical fertilizers, bioorganic fertilizer (BIO) and silicon amendment (SOA) are increasingly used as amendments to improve soil microbial activity and increase soil nutrient availability. However, how effective BIO and SOA are at improving the health of soils and reducing early defoliation remains unclear. Here, we conducted a 4-year field experiment (2016–2019) in a 25-year-old 'Cuiguan' pear orchard in Jianning county, Fujian province, comparing local custom fertilization (CK), local custom fertilization supplemented with SOA (CK-SOA), BIO, and BIO supplemented with SOA (BIO-SOA). At the end of the 4-year study we found that BIO and BIO-SOA treatments resulted in reduced leaf nitrogen content and increased leaf potassium (K), calcium (Ca), silicon (Si), and manganese (Mn) content. BIO and BIO-SOA treatments also resulted in a 50% reduction of the early deciduous rate and a 47% increase in pear yield. Compared with CK treated soil, BIO and BIO-SOA treated soils had higher nitrate nitrogen content (NO 3 −-N), available Si, Fe, Mn, and Zn content, and significantly improved microbial biomass nitrogen content (MBN), geometric mean enzyme activity (GMEA) and ecosystem multifunctionality (EMF). Network analysis revealed that BIO and BIO-SOA treatments had significantly altered the bacterial and fungal community composition in the orchard soil. Redundancy analysis (RDA) and the Mantel test indicated that soil available K, exchangeable Ca and Mg, and available Si, Fe, Mn and Zn content were the main factors influencing bacterial and fungal communities. The increased nutrient availability (e.g., NO 3 −-N and microelement contents), MBN, GMEA and EMF had negative effects on the early defoliation rate. Random Forest model identified soil available Si content, microbial biomass nitrogen content, EMF, and GMEA as the main predictors of early defoliation rate. Overall, this study demonstrates that application of BIO or BIO mixed with SOA can alleviate the early defoliation rate of pear trees by increasing the availability of microelements, microbial functional activity, and changing the soil microbial community composition. [Display omitted] • BIO and BIO-SOA significantly reduced the early defoliation rate of pear trees, and improved the pear yield. • BIO and BIO-SOA significantly increased soil available Si, Fe, Mn and Zn concentrations in pear orchard. • Soil microelements (e.g. Mg, Si, Fe and Zn) availability strongly affects microbial communities. • Belowground interactions significantly affects the growth of aboveground parts of pear trees. [ABSTRACT FROM AUTHOR]

Bacterial wilt caused by Ralstonia solanacearum is one of the most serious tobacco diseases worldwide. Brevibacillus brevis (L-25) and Streptomyces rochei (L-9) with strong inhibitory effects on R. solanacearum in vitro were isolated from the rhizosphere of a healthy tobacco plant in a severely wilt-diseased field. Pot and field experiments were conducted to evaluate the biocontrol effect of the isolated antagonists alone and in combination with organic fertilizer. In pot experiment, the control efficacy was 92.3-100 % in the treatments applied with L-25 and L-9 alone or together with organic fertilizers. When bioorganic fertilizer containing L-9 and L-25 was applied to the soil in field condition, the control efficacies were 95.4 and 30.0 in the Anhui and Guizhou field plots, respectively. The counts of bacteria and actinomycetes in rhizosphere soil were significantly increased ( p ≤ 0.05) under all antagonist applications compared with CK (P). In contrast, fungal and R. solanacearum densities in the rhizosphere soil applied with antagonists were much lower than the CK (P) rhizosphere. Combined application of the two antagonists had better effect than single antagonist treatments. The antagonists were more effective when they were combined with organic fertilizer as compared with the antagonistic strains only. These results allow us to conclude that a combination of the biocontrol agents, L-25 and L-9, together with organic fertilizers can effectively control bacterial wilt by affecting soil microbial structure. [ABSTRACT FROM AUTHOR]

Banana production has been severely hindered by the long-term practice of monoculture agriculture. Fusarium wilt, caused by the Fusarium oxysporum f. sp. cubense (FOC), is one of the most destructive diseases that can afflict banana plants. It is both necessary and urgent to find an efficient method for protecting banana production worldwide. In this study, 57 antagonistic bacterial strains were isolated from the rhizospheres of healthy banana plants grown in a heavily wilt-diseased field; of the 57 strains, six strains with the best survival abilities were chosen for further study. Compared with the control and the other strains in the greenhouse experiment, W19 strain was found to observably decrease the incidence of Fusarium wilt and promote the growth of banana plants when combined with the organic fertilizer (OF). This strain was identified as Bacillus amyloliquefaciens based on its morphological, physiological, and biochemical properties, as well as 16S rRNA analysis. Two kinds of antifungal lipopeptides (iturin and bacillomycin D) produced by W19 strain were detected and identified using HPLC-ESI-MS. Another lipopeptide, called surfactin, was also produced by the thick biological film forming W19 strain. In addition to lipopeptides, 18 volatile antifungal compounds with significant antagonistic effect against F. oxysporum were detected and identified using gas chromatography-mass spectrometer (GC-MS). The work described herein not only highlights how the bioorganic fertilizer with B. amyloliquefaciens can be used to control Fusarium wilt of banana but also examines some of the potential mechanisms involved in the biocontrol of Fusarium wilt. [ABSTRACT FROM AUTHOR]

Abstract: We previously developed a method for the application of bioorganic fertilizer to improve the biocontrol efficacy of Fusarium wilt (). However, the detailed behavior of Fusarium oxysporum f. sp. niveum (FON) and its antagonistic bacterium, Paenibacillus polymyxa SQR-21 (SQR-21), in the rhizosphere of watermelon after application of the bioorganic fertilizer had not been elucidated. A rhizobox experiment was carried out to investigate the distribution of FON and its antagonistic bacterium, SQR-21, in the soil at different distances from the watermelon rhizoplane by real-time PCR. The results confirmed that the bioorganic fertilizer (BIO) significantly suppressed Fusarium wilt and promoted the growth of the watermelon plants. Furthermore, we found that the application of BIO significantly enhanced the abundance of SQR-21 and reduced the population of FON in the soil near the rhizoplane as compared to the control. A maximal quantity (7.14log10copies/g soil) of P. polymyxa SQR-21 was obtained in the rhizosphere under the BIO treatment, and this number was decreased with increasing distance from the rhizoplane. The population of FON in the rhizosphere of the control was 2 orders of magnitude higher than under the BIO treatment, and with increasing distance from the rhizoplane, the FON abundance increased in the SQR-21 inoculated treatments and decreased in the treatments without SQR-21. In the soil far from the rhizoplane (bulk soil), both FON and SQR-21 reached a level that was not statistically different between the treatments, which might be attributed to the background level of the infested soil. The localization and pattern of colonization of SQR-21 on the root surface was examined in an in vitro experiment by following green fluorescent protein (gfp)-labeled SQR-21. The colonization of P. polymyxa SQR-21 was found to occur at any site on the roots, yet it was preferentially found in defined regions of the root tip and root bend. These results revealed that the BIO applied with the developed method suppressed Fusarium wilt by the promotion of SQR-21 colonization in the rhizosphere, which largely reduced the population of the pathogen. The findings also indicated that the method of nursery application of BIO satisfies the ecological requirements of the biocontrol products. [Copyright &y& Elsevier]

Pot experiments were carried out over two growing periods to assay the biocontrol efficacy and rhizosphere colonization of Trichoderma harzianum SQR-T037 (SQR-T037) applied as SQR-T037 conidia suspension (TCS), SQR-T037 conidia suspension blended with organic fertilizer (TBF), or SQR-T037 fermented organic fertilizer (TFF). Each formulation had three T. harzianum numbers. In two experiments, Percent Disease Indexes (PDIs) decreased with the increase of SQR-T037 number added to soils. The TFF treatment consistently exhibited the lowest PDIs at same amendment rate of SQR-T037 and 0-8.9%, 25.6-78.9%, and 4.4-50.0% of PDIs were found in TFF, TCS, and TBF treatment, respectively. Soils treated with TFF showed the highest SQR-T037 population in rhizosphere and bulk soil. Decrease of Fusarium oxysporum population in both bulk and rhizosphere soils occurred in the treatment SQR-T037 at 10 and 10 cfug soil rate. The TFF treatment at the SQR-T037 rate of 10 cfug soil significantly ( p < 0.05) increased SQR-T037 population within the rhizoplane but had no effect on F. oxysporum population when compared to TCS and TBF. Generally, TFF treatments were superior to TCS and TBF treatments on disease control by sustaining colonization of SQR-T037 and decreasing F. oxysporum abundance in the rhizosphere soil. We propose that TFF treatment at SQR-T037 rate of 10 cfug (i.e., 10 cfug soil after applied to soil) was the best formulation for controlling Fusarium wilt of cucumber. [ABSTRACT FROM AUTHOR]

Indoor in vitro culture experiment and greenhouse pot experiment were conducted to evaluate the capabilities of three bacterial strains XZ鄄173 (Bacillus amyloliquefaciens), SL鄄25 (B. gib鄄sonii), and KS鄄62 (Paenibacillus polymyxa) that can hydrolyze collagen protein in controlling tomato root鄄knot nematode. In the in vitro culture experiment, suspensions of XZ鄄173, SL鄄25, and KS鄄62 induced a mortality rate of 75郾9%, 66郾7%, and 50郾0% to the second鄄stage junior nematode within 24 h, and decreased the egg hatching rate to 17郾8%, 28郾9% and 37郾6% after 7鄄day incubation, respectively, in contrast to the 17郾4% mortality rate and 53郾6% egg hatching rate in the control (sterilized water). In the greenhouse pot experiment, the bioorganic fertilizer mixed with equal parts of fermented XZ鄄173, SL鄄25, and KS鄄62 gained the best result, with the root鄄knot nematode population in rhizosphere soil decreased by 84郾0% as compared with the control. The bioorganic fertilizer also decreased the numbers of galls and eggs on tomato roots significantly, and increased the underground and aboveground biomass of tomato. Therefore, antagonist bioorganic fertilizer has promising potential in controlling root鄄knot nematode. [ABSTRACT FROM AUTHOR]

Bioorganic fertilizers can alleviate (a) biotic stresses and sustainably increase crop yields. The effect of bioorganic fertilizers on the rhizosphere bacterial community of Panax notoginseng and soil metabolism remains unknown. Here, we tracked the changes in the soil physicochemical properties, bacterial microbiota responses, and soil metabolic functions after the addition of a bioorganic fertilizer in a P. notoginseng field. The application of a bioorganic fertilizer reduced the soil acidification, improved the organic matter, and increased the contents of the total/available soil nutrients. Soil amendment with a bioorganic fertilizer significantly affected the structure of the rhizosphere bacterial community, leading to the enrichment of specific bacterial consortia such as Rhodanobacter, Arthrobacter, Sphingomonas, Devosia, Pseudolabrys, Luteimonas, Lysobacter, Nitrosospira, and Nakamurella. Previously, many of these genera have been associated with nutrient cycling, plant productivity, and disease suppression. Metabolome analysis further highlighted that the bioorganic fertilizer treatment significantly reduced phenolic acids and flavonoids and enhanced organic acids, saccharides and alcohols, and amino acids. This result indicates a high survival of bacterial microbiota in the rhizosphere and an availability of nutrients for P. notoginseng growth. This work showed that the application of bioorganic fertilizers significantly improves soil health status, alters soil metabolic functions, and stimulates a specific subset of rhizosphere microbiota for nutrient cycling and disease protection in P. notoginseng. [ABSTRACT FROM AUTHOR]

Evaluation of Streptomyces isolated from Udhagamandalam, The Nilgiris, Tamilnadu, India for the biocontrol potential against the phytopathogen Ralstonia solanacearum and its metabolite profiling. Streptomyces strains were screened for plant growth promotion and antagonistic activity against R. solanacearum in in-vitro. The metabolite profiling of strain UT4A49 was studied through gas chromatography coupled with mass spectroscopy (GC–MS) analysis. Further, the identified lead compound 2,4-Di- tert -butylphenol (2,4-DTBP) was analyzed for its mechanism of action through in-silico docking study. The bioorganic fertilizer (BOF) amended potential Streptomyces strain UT4A49 was studied for biocontrol activity against R. solanacearum on tomato seedlings through pot culture experiments. The Streptomyces strain UT4A49 showed the promising production of indole acetic acid (IAA) (76.0 ± 2.0 µg/ml), siderophore, ammonia, amylase, protease, cellulase as well as it solubilized the phosphate in-vitro. The strain UT4A49 showed strong in vitro antagonistic activity against R. solanacearum with the inhibition zone of 19.83 ± 0.44 mm in diameter. The isolated major compound, 2,4-Di- tert -butylphenol was showed strong inhibition against R. solanacearum. In silico docking study revealed that the 2,4-DTBP showed lower binding energy score with all targeted proteins which found better protein–ligand binding stability. In the pot experiment, biocontrol activity of BOF amended Streptomyces strain UT4A49 showed significant biocontrol efficacy was 78.5% against R. solanacearum in tomato seedlings. The strain UT4A49 was identified as Streptomyces sp. based on its morphological and molecular properties. The detailed literature survey revealed that this is the first report on strong bioactive properties of 2,4-DTBP against R. solanacearum. This present study proved that bioorganic fertilizer amended with Streptomyces sp. UT4A49 is a promising biocontrol agent for tomato bacterial disease control. [ABSTRACT FROM AUTHOR]

Tomato bacterial wilt caused by Ralstonia solanacearum is the most destructive disease impacting production. Application of bioorganic fertilizer (BOF) containing antagonistic microorganism to suppress tomato bacterial wilt disease may be a promising disease control strategy. Here, we used organic waste materials, specifically biogas residues, cattle manure and rice straw, in composting with antagonistic strain G33 isolated from the rhizosphere soil of a healthy tomato plant to produce BOF. Strain G33 was identified as Streptomyces microflavus by morphological and culturing traits and by 16S rRNA gene sequence analysis. We conducted a field experiment with control treatment, organic fertilizer and BOF-G33 to characterize suppression of tomato bacterial wilt disease. Our results indicate that the optimal combination containing (w/w) 40% biogas residues, 40% cattle manure and 20% rice straw can increase the nutrient contents of the compost product, prolong the thermophilic period and increase the decomposition rate of organic matter and the humification degree. A combination of strain G33 and mature compost produced under optimal conditions resulted in the spore number of 5.75 × 109 CFU/g on the sixth day of fermentation. Field experiments showed that BOF-G33 significantly decreased the incidence of tomato wilt; the disease biocontrol efficiency was 64.4%. In addition, application of the BOF-G33 significantly reduced the pathogenic R. solanacearum populations and increased the abundance of beneficial indigenous flora in the rhizosphere soil, which might have been the key factors in constraining the disease. In conclusion, this study showed that bioorganic fertilizer with Streptomyces microflavus G33 is a potential biocontrol agent for controlling tomato bacterial disease. • S. microflavus G33 showed strong antagonistic activity against R. solanacearum. • BOF-G33 application effectively controlled tomato bacterial wilt disease. • BOF-G33 application led to significant changes the rhizosphere microbial community. • Strain G33 had colonization capacity stably in rhizosphere soil. • The rhizosphere R. solanacearum was the key factor directly controlling the disease. [ABSTRACT FROM AUTHOR]

The application of Bacillus sp. in the biological control of plant soilborne diseases has been shown to be an environmentally friendly alternative to the use of chemical fungicides. In this study, the effects of bioorganic fertilizer (BOF) fortified with Bacillus amyloliquefaciens SQY 162 on the suppression of tomato bacterial wilt were investigated in pot experiments. The disease incidence of tomato wilt after the application of BOF was 65.18% and 41.62% lower at 10 and 20 days after transplantation, respectively, than in the control condition. BOF also promoted the plant growth. The SQY 162 populations efficiently colonized the tomato rhizosphere, which directly suppressed the number of Ralstonia solanacearum in the tomato rhizosphere soil. In the presence of BOF, the activities of defense-related enzymes in tomato were lower than in the presence of the control treatment, but the expression levels of the defense-related genes of the plants in the salicylic acid and jasmonic acid pathways were enhanced. It was also found that strain SQY 162 could secrete antibiotic surfactin, but not volatile organic compounds, to suppress Ralstonia . The strain could also produce plant growth promotion compounds such as siderophores and indole-3-acetic acid. Thus, owing to its innate multiple-functional traits and its broad biocontrol activities, we found that this antagonistic strain isolated from the tobacco rhizosphere could establish itself successfully in the tomato rhizosphere to control soilborne diseases.