Rhizobium Inoculation Research Articles

Soil P-stimulating bacterial communities: response and effect assessment of long-term fertilizer and rhizobium inoculant application

BackgroundPhosphorus (P) plays a vital role in plant growth. The pqqC and phoD genes serve as molecular markers for inorganic and organic P breakdown, respectively. However, the understanding of how P-mobilizing bacteria in soil respond to long-term fertilization and rhizobium application is limited. Herein, soil that had been treated with fertilizer and rhizobium for 10 years was collected to investigate the characteristics of P-mobilizing bacterial communities. Five treatments were included: no fertilization (CK), phosphorus fertilizer (P), urea + potassium fertilizer (NK), NPK, and PK + Bradyrhizobium japonicum 5821 (PK + R).ResultsThe soybean nodule dry weight was highest in the P treatment (1.93 g), while the soybean yield peaked in the PK + R treatment (3025.33 kg ha− 1). The abundance of the pqqC gene increased in the rhizosphere soil at the flowering-podding stage and in the bulk soil at the maturity stage under the P treatment, while its abundance increased in the bulk soil at the flowering-podding stage and in the rhizosphere soil at the maturity stage under the PK + R treatment. The abundance of the phoD gene was enhanced in the bulk soil at the flowering-podding stage under the PK + R treatment. The Shannon and Ace indexes of pqqC- and phoD-harboring bacteria were higher in the rhizosphere soil at maturity under the PK + R treatment compared to other treatments. Furthermore, a comprehensive analysis of the neutral community model and co-occurrence pattern demonstrated that the application of P fertilizer alone led to an increase in the distribution and dynamic movement of pqqC-harboring bacteria, but resulted in a decrease in complexity of network structure. On the other hand, rhizobium inoculation enhanced the distribution and dynamic movement of phoD-harboring bacteria, as well as the stability and complexity of the network structure. Pseudomonas and Nitrobacter, as well as Steptomyces, Stella, and Nonomuraea, may be crucial genera regulating the composition and function of pqqC- and phoD-harboring communities, respectively.ConclusionsThese findings affirm the crucial role of fertilization and rhizobium inoculation in regulating pqqC- and phoD-harboring bacterial communities, and highlight the significance of long-term phosphate-only fertilization and rhizobium inoculation in enhancing dissolved inorganic phosphorus and mineralized organophosphorus, respectively.

Assessing the Zinc, Boron and Rhizobium Inoculation on Yield and Economics of Kharif Mungbean (Vigna radiata L.)

The present experiment was carried out during kharif season of 2021 and 2022 at Instructional farm, Kamla Nehru Institute of Physical and Social Sciences Sultanpur, U.P. India. Four levels of zinc (0, 2.5, 5.0 and 7.5 Kg Zn ha-1), three levels of boron (0, 0.5 and 1.0 Kg B ha-1) and two levels of rhizobium i.e. Uninoculated (Control) and inoculated. A split-split plot design with three replications was used. Zinc levels were allocated to the main plots, boron levels in the sub-plot, while Rhizobium inoculation in the sub-sub plot. Results revealed that dry weight and seed and stover yield was observed that Rhizobium inoculation with application of zinc 7.5 kg ha-1 and Application of boron 1.0 kg ha-1. Obtaining seed yield from Rhizobium inoculation (8.53 and 8.71 q/ha-1) with application of zinc (8.53 and 8.79 q/ha-1) and Application of boron (8.45 and 8.70 q/ha-1). The highest net return (Rs. 58211.0 and 65488.50 ha-1) and benefit cost ratio (1.75 and 1.97) were obtained with 7.5kg Zn ha-1 + 1 kg B ha-1 + seed inoculation with rhizobium. It could be recommended for cultivation of mungbean.

Analyzing the Role of Different Molybdenum doses and Rhizobium Inoculation in Optimizing Nutrient Absorption and Yield in Vegetable Cowpea [Vigna unguiculata (L.) Walp.] cv. AVCP 1

Legumes, along with cereals, can be considered a main plant source of energy and quality proteins. A versatile legume crop, cowpeas offer economic, agronomic, environmental, and nutritional advantages. Cowpeas have a high total protein level and a relatively low fat content, making them nutritionally similar to other pulses. The study aimed to evaluate the effects of different rates of ammonium molybdate and Rhizobium inoculation on the yield and nutrient uptake of vegetable cowpea. There were 12 treatment combinations comprising six concentrations of molybdenum i.e. M0:control, M1: soil application of molybdenum @ 200 g ha-1, M2: soil application of molybdenum @ 300 g ha-1, M3: seed treatment of molybdenum 25 g ha-1 seeds, M4: seed treatment of molybdenum 50 g ha-1 seeds and M5: seed treatment of molybdenum 6 ml kg-1 seeds and two levels of Rhizobium i.e. R0: without Rhizobium seed treatment, R1: with Rhizobium (10 ml kg-1 seed) seed treatment in a Randomized Block Design (Factorial) with three replications. Results indicated that the application of ammonium molybdate and Rhizobium inoculation significantly improved total cowpea yield. The highest yield was observed with the treatment combination of 300 g ha⁻¹ ammonium molybdate (M₂) and Rhizobium inoculation (R₁). Nutrient analysis revealed that phosphorus, potassium and iron content in cowpea pods significantly increased with ammonium molybdate and Rhizobium treatments. The highest phosphorus and potassium contents were recorded with M₂ treatment, while the maximum iron content was found in M₃ treatment. Rhizobium treated seeds (R₁) also enhanced phosphorus, potassium and iron content in the pods. In terms of nutrient uptake, the highest nitrogen and phosphorus uptake were observed with the combined M₂R₁ treatment. Similarly, the highest potassium uptake in pods and total potassium uptake were recorded with M₂R₁ treatment, respectively. The interaction between ammonium molybdate and Rhizobium inoculation showed significant effects on nitrogen, phosphorus and potassium uptake, highlighting the importance of these treatments in enhancing cowpea nutrient absorption and yield. The use of biofertilizers can be highly successful in restoring agricultural soil, and this study highlights the possibility of combining Rhizobium inoculation with ammonium molybdate treatment to maximize nutrient uptake and enhance cowpea yield in sustainable agriculture production.

The Effect of Rhizobium Inoculation on the Nutritional Value of Crops in the Legume–Cereal Intercropping System in Northern Kazakhstan

In this study, the changes in yield, nutrient content, and amino acid levels in legume–cereal grass mixtures were qualitatively evaluated depending on the legume–cereal combination and inoculation with preparations based on Rhizobium. This study, taking into account the biological characteristics of legume forage crops, used inoculations with strains of nodule bacteria and associative nitrogen fixers to enhance the process of the nitrogen fixation of mixed crops of legumes and cereal. The aim of this study was to compare the yields and nutritional values of monocultures and mixed crops, as well as to determine the effects of preparations based on strains of nodule bacteria and the associated nitrogen fixer on the photosynthetic activity and yield of combined annual legume–grain crops. A comparative study of forage crop biomass was conducted to analyze crude protein, fiber, carotene, and amino acid content in monocultures and legume–cereal mixtures, with and without the use of nodule-bacteria-based preparations (Rhizotorphin, Mizorine, Flavobactrin, and Azolene). The combined effect of crop mixtures and biological products led to increased green mass yield, protein content, and feed productivity. Notably, two-component mixtures with Rhizotorphin inoculation increased green mass yield by 8.79%, while three-component mixtures saw a 16.49% increase. The oat–pea mixture showed the most significant amino acid improvements, with lysine increasing by 6.26% and tyrosine by 3.24%. The general conclusion reached by the two-year experiment of 2022–2023 in the hill–plain zone of northern Kazakhstan is that double grass mixtures treated with nodule bacteria are more productive than monoculture crops in this area. These results suggest that inoculation with bacterial strains can effectively enhance the productivity of forage crops in northern Kazakhstan, providing a basis for future recommendations on optimizing herbaceous crop combinations. It is recommended to grow annual forage crops in mixtures with legumes to produce highly nutritious feeds with high metabolic energy in terms of biochemical composition.

Effects of Biochar and Bradyrhizobium Inoculation on Nodulation, Growth, and Grain Yield of Soybean in the Guinea Savanna Agroecological Zone of Ghana

ABSTRACT Soybeans are a vital crop globally, significantly contributing to food security, soil fertility, and economic development. However, soil conditions can constrain their productivity, including nutrient deficiencies and acidity. This study explores the combined effects of biochar (BC) and Rhizobium inoculation (RI) on soybean growth, nodulation, and yield. The experiment was conducted over two growing seasons and employed a split-plot design with five BC application rates (0, 2, 4, 6, and 8 t ha− 1) and two RI levels (uninoculated and inoculated) across four replications. The results demonstrated that the integration of BC and RI significantly improved various growth parameters, including nodulation, biomass accumulation, pod number, and grain yield. The highest grain yield was observed at 8 t ha−1 BC with RI, yielding 3394 kg ha−1 in 2021 and 2542 kg ha−1 in 2022. This was identical to the yield attained with the 6 t ha−1 BC rate paired with RI in both years. The inoculated control treatment consistently demonstrated the lowest grain yield. Additionally, it showed a significant (p < .05) impact on the weight of one hundred seeds. The study also revealed significant and consistent relationships among soybeans’ growth and yield features. In conclusion, the findings suggest that the combined application of BC and RI has a positive impact on soybean yield and its key components.

Response of Mungbean (Vigna radiata L. Wilczek) to Rhizobium inoculation and Irrigation Schedule in Siraha, Nepal

Mungbean (Vigna radiata L.) productivity in Nepal is indeed lower compared to its potential yield due to inadequate nutrient management and soil moisture depletion. Use of effective plant growth promoting bacteria and proper irrigation scheduling in mungbean can enhance its production and productivity. To study the response of Rhizobium inoculation and irrigation schedule on growth and yield of mungbean, a field experiment was conducted in a split-plot field layout at a farmers' field in Dhangadimai Municipality, Siraha, Nepal from March 2023 to June 2023. The treatments consisted of four levels of irrigation (i.e. Rainfed, Irrigation at vegetative stage (V), irrigation at reproductive stage (R) and irrigation at both (V and R) in main plots and two levels of biofertilizer (with and without Rhizobium inoculation) in sub plots which was replicated three times. Plant height, leaf numbers, number of effective branches, pod length, and grain per pod were recorded highest in mungbean inoculated with rhizobium, and irrigation at both V and R stages. The highest grain yield (1.81 Mtha-1) was obtained from the treatment having irrigation at both V and R stages, followed by irrigation scheduled at R (1.56 Mtha-1), V (1.47 Mtha-1), and rainfed condition (1.34 Mtha-1). The grain yield was higher in inoculated (1.58 Mtha-1) than in non-inoculated mungbean (1.50 Mtha-1). Rhizobium inoculated crops irrigated during V stage only, irrigated during R stage only and irrigated at both V and R stages increased grain yield by 6.32%, 5% and 17% respectively as compared to rainfed conditions. Number of effective nodules per plant was 79 % higher in inoculated (15.72) than in non-inoculated plots (4). The best combination was found in the treatment where irrigation was applied in both V and R stages with Rhizobium inoculation. Thus, application of rhizobium inoculation and irrigation at V and R stages showed a positive response to growth parameters, yield attributing characters, and yield.

Enhanced biochemical properties of soybean root nodule asparaginase through plant molecular farming compared to bacterial enzyme for cancer treatment

Asparaginase is a therapeutic enzyme used as an anticancer agent and is typically produced through microbial fermentation using organisms such as Escherichia coli and Erwinia chrysanthemi. However, this method faces challenges, including potential enzyme contamination during production, allergic reactions to the enzyme, and stability issues requiring stringent control measures. An innovative solution is the application of plant molecular farming, utilizing Rhizobium root symbiosis for asparaginase production. The objective is to optimize nodule development for asparaginase yield, characterize the enzyme's properties, and evaluate its anticancer efficacy against microbial enzyme. In our study, we established soybean root cultures and inoculated them with Bradyrhizobium japonicum to form root nodules. We evaluated eukaryotic asparaginase production at different incubation times. We purified asparaginase from the root nodule cultures and compared its physicochemical properties and anticancer activity with microbial asparaginase. Results showed that asparaginase reached maximum activity in root nodule cultures 10 days after rhizobium inoculation in the culture media. The root nodule asparaginase exhibited a high content of alpha helices and beta sheets and a low random coil. It demonstrated higher stability and activity across different pH levels and temperatures than Escherichia coli asparaginase. Additionally, root nodule asparaginase displayed better catalytic parameters and stability over time than E. coli asparaginase. Thus, root nodule asparaginase is superior to E. coli asparaginase as an anticancer agent. This ensures the root nodule asparaginase can effectively target cancer cells, enhancing the overall therapeutic outcome. This provides a renewable, cost-effective, and environmentally friendly alternative to traditional enzyme production methods.

Isolation and characterization of mung bean (Vigna radiata L.) rhizobia in Myanmar

AbstractWe collected soil samples from six major mung bean cropping regions in Myanmar: Sagaing, Mandalay, Nay Pyi Taw, and Magway in the tropical savanna climate zone and Bago and Yangon in the tropical monsoon climate zone. All fields grew mung bean for at least 5 years and had no history of rhizobial inoculation. Mung bean ‘Yezin-11’, a popular cultivar in Myanmar, was inoculated with soil suspensions. From the nodules formed on the roots, we isolated 55 rhizobial strains. Identification of the isolates revealed the dominant species of indigenous rhizobia in each region. We identified 53 Bradyrhizobium strains and 2 Ensifer strains. Bradyrhizobium yuanmingense was dominant in the tropical savanna zone and Bradyrhizobium sp. (B. liaoningense or B. diversitatis) and B. centrosematis were dominant in the tropical monsoon zone. Principal component analysis indicates that the dominance of B. yuanmingense in the tropical savanna zone might be due to high concentration of NO3-N and P2O5 in the soil. It also indicates that the dominance of B. centrosematis in the tropical monsoon zone might be caused by drastically low pH and high concentration of NH4 in the soil. Bradyrhizobium centrosematis YGN-M9, B. yuanmingense SGG-M3, and Bradyrhizobium sp. BGO-M5 significantly increased nodulation (nodule number and nodule dry weight), acetylene reduction activity, and shoot dry weight, respectively, relative to Ensifer terangae MDY-M6. Co-inoculation with these three strains increased nodulation significantly compared with single inoculation of BGO-M5. The characterization of mung bean rhizobia and selection of microbial inoculant candidates will be useful for the development of microbial inoculants in Myanmar.

Impacts of Rhizobium inoculation and Fe3O4 nanoparticles on common beans plants: a magnetic study of absorption, translocation, and accumulation processes

Impacts of Rhizobium inoculation and Fe3O4 nanoparticles on common beans plants: a magnetic study of absorption, translocation, and accumulation processes

Effects of integrated fertilizer application on selected soil properties and yield attributes of common bean (Phaseolus vulgaris L.) on different soil types

In Ethiopia, common bean (Phaseolus vulgaris L.) productivity remains low because of low soil fertility. However, both plant production and soil fertility benefit from integrated application of fertilizers. Thus, this study investigates the effect of integrated application of inorganic, organic and biofertilizers on selected soil properties and yield components of common bean. A field experiment was conducted at three sites in southern Ethiopia, under two consecutive cropping season (2021 and 2022). The experiment was conducted using a randomized complete block design (RCBD) with three replications. The treatments included three levels of inorganic fertilizer (Triple Superphosphate, TSP), applied at 0, 42.5, and 85 kg TSP ha⁻1 for Kokate; 0, 29, and 58 kg TSP ha⁻1 for Hawassa; and 0, 35.5, and 71 kg TSP ha⁻1 for Alage, tailored to the specific conditions of each site. Additionally, the experiment incorporated three levels of organic inputs 0, 5 t biochar ha⁻1, and 5 t compost ha⁻1 as well as Rhizobium inoculation (HB-429) applied at 500 g ha⁻1. These treatments were designed to assess the combined effects of inorganic, organic and biofertilizers on soil health and crop performance. Results showed that the integrated application of inorganic, and organic fertilizers significantly (p ≤ 0.05) improved soil pH, soil organic carbon, and available P compared with the sole fertilizer application plots. Similarly, the integrated use of inorganic, organic and biofertilizers increased nodule numbers, seed weight, grain yield, and biomass yield. We also found that 23 and 24 % higher grain yield were achieved with integrated applications of TSP fertilizer with compost on Hawassa and Alage sites than sole inorganic fertilizer application. On the other hand, the integrated application of TSP fertilizer with biochar increased by 18 % grain yield on Kokate over the sole application of inorganic fertilizer. The highest economic benefit of 69,460 and 63,250 ETB was obtained from the integrated application of TSP fertilizer with compost at Hawassa and Alage sites, respectively. The highest economic benefit for the Kokate site was 53,583 ETB at TSP fertilizer with biochar application. Overall, the study confirms that site-specific integrated soil fertility management appears to be a prerequisite for sustainable and profitable common bean production over sole fertilizer application in southern Ethiopia.

Crop diversity significantly enhances soil carbon sequestration via alleviating soil inorganic carbon decline caused by rhizobium inoculation

Increasing crop diversity and nitrogen (N) fertilizer application have been identified as effective strategies for enhancing productivity and soil organic carbon (SOC) storage in agroecosystems. However, the impact of these management practices on soil inorganic carbon (SIC) in agroecosystems remains unclear. At present, we evaluated the effects of maize/faba bean intercropping, N application rates, and inoculation rhizobia of faba bean on SIC in the top 20 cm of soil depth using a 13-year crop diversity field experiment. Our results showed that the soil total carbon (TC) content increased significantly by 5.9 % and 7.0 % compared to faba bean monoculture and maize monoculture, respectively, after 13 years of continuous intercropping. Intercropping increased the pedogenic carbonate (PIC) content by 36.7 %, resulting in an 8.9 % higher SIC content compared to faba bean monoculture. Additionally, intercropping significantly reduced the dissolution of lithogenic carbonate (LIC) by 17.5 %, leading to a 7.6 % higher SIC content compared to maize monoculture. The formation of PIC was associated with an increase in soil available cations especially Ca2+ in intercropping. The conservation of LIC was related to the higher soil available Mg2+ in intercropping than monoculture. Faba bean inoculated with rhizobia significantly decreased SIC content due to soil acidification after 13 years of continuous cropping. Intercropping also significantly increased SOC and C3-derived SOC content compared to maize monoculture and increased C4-derived SOC content compared with faba bean monoculture. Soil organic carbon showed a positive correlation with SIC across all cropping systems, and the SOC fractions could affect the neoformation of PIC and dissolution of LIC. Our results demonstrate that intercropping can increase SIC content, which further promotes soil carbon sequestration. This study highlights the significance of increasing crop diversity on cropland carbon sequestration and provides practical implications for mitigating carbon emissions.

Isolation of Rhizobium from Moisture Stress Imposed Groundnut Nodules

Groundnut is an important oil seed crop accounts for a less than half of the major oilseeds produced in the country. Oil content of Groundnut varies from 44 % to 50 % depending upon the varieties and agronomic practices. It is also called as ‘king of oil seeds’ More than 85 % of the crop Is grown under rainfed conditions in low fertile soils. Rhizobium is a well-known symbiotic nitrogen fixing bacteria. Inoculation of Rhizobium improves plant growth, pod kernel and Oil yield. Rhizobium species help in improving root nodulation and nitrogen fixation, enhancing plant growth and yield of leguminous plants including groundnut under moisture stress conditions. Hence the present study is to isolate Rhizobium species from groundnut nodules by following method given by Vincent (1970) after growing them on Yeast Mannitol Agar Media morphological characteristics were studied, which can be further used for improving nodulation efficiency and plant growth promotion under moisture stress conditions.

Exploring the role of rhizobium inoculation in sustainable pulse farming: A comprehensive review

Exploring the role of rhizobium inoculation in sustainable pulse farming: A comprehensive review

Optimizing Growth and Yield of Cluster Bean (Cyamopsis tetragonoloba L.) Var. Neelam-61 through Integrated Use of Inorganic Fertilizers, Organic Manure and Rhizobium Inoculation

Organic matter decomposition is beneficial to plant growth and development. However, the overuse of chemical fertilizers poses risks to environmental sustainability and long-term soil health. The integration of organic fertilizers, such as poultry manure, offers a promising solution to reduce dependency on chemical inputs while maintaining crop productivity. The field experiment was conducted at Research Farm of the Department of Soil Science, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj U.P during Kharif season of 2023. An experiment was conducted in Factorial Randomized Block Design (FRBD) with three levels of N:P:K, Poultry manure and two levels of Rhizobium inoculation. The seeds were treated with Rhizobium. Based on the experimental data, the application of 100% Recommended Dose of Fertilizer (RDF), 100% Poultry manure and 100% Rhizobium inoculation not only resulted in maximum growth and yield attributes but also proved to be significantly superior to all other treatments.

Assessing the Effect of Phosphorus, Molybdenum and Rhizobium Inoculation on Growth, Yield and Yield Attributes of Mungbean. (Vigna radiata L.) under Rainfed Conditions

Assessing the Effect of Phosphorus, Molybdenum and Rhizobium Inoculation on Growth, Yield and Yield Attributes of Mungbean. (Vigna radiata L.) under Rainfed Conditions

Synergistic impact of Rhizobium and arbuscular mycorrhizal fungi on lentil plant tolerance to heavy metal-rich fly ash amended soil

The purpose of the study was to investigate the impact of microbes [symbiotic bacteria viz. Rhizobium (Frank) and the arbuscular mycorrhizal fungi (AMF) viz. Funneliformis caledonius (Nicolson & Gerd.) and Glomus bagyarajii Mehrotra] on the growth and physiology of lentil (Lens culinaris Medik.) cultivated in soil alone and soil amended with fly ash. The experiment had twenty-four treatments, twelve in sterilized soil and twelve in unsterilized soil (with six treatments in soil alone and six in soil amended with fly ash in both the sets). Amendment of soil with 25% fly ash significantly increased plant growth. Microbial inoculation further increased the plant growth and physiological parameters studied (plant length, fresh and dry weight, chlorophyll and protein content, and nitrate reductase activity). Microbial parameters like nodule number and fresh weight, mycorrhizal root colonization and spore numbers were also significantly higher in plants inoculated with Rhizobium + AMF. Soil amendment with 25% fly ash together with inoculation of Rhizobium + AMF further improved the growth of lentil. Plant heavy metal (Cd, Pb, Zn) content was significantly more in soil amended with fly ash, but microbial inoculation significantly decreased heavy metal uptake. Of the two AM fungus studied F. caledonius proved to be better, resulting in higher plant growth and physiological parameters studied with reduced heavy metal uptake.

Numerical Variables Analysis and Improving Phosphorus Use Efficiency in Groundnut with Microbial Cultures in Coastal Zone of Puducherry

Background: The precise application of phosphorus fertilizer is pivotal in determining Groundnut (Arachis hypogaea L.) productivity. The high demand of phosphorus for energy transfer molecules involved in nitrogen fixation makes it essential for leguminous crop. A field experiment was conducted at Perunthalaivar Kamaraj Krishi Vigyan Kendra, Puducherry during 2021 to 2023 to explore the performance of groundnut by employing an optimal combination of microbial culture alongside varying levels of phosphorus. Methods: The experiment was laid out in randomized block design with 10 treatments and replicated thrice. The treatments consisted of different doses of phosphorus (@ 20, 40 and 60 kg/ha) with and without seed treatment with DGRC culture. Result: The experiment results of the three years study revealed that a variable response of groundnut to P fertilizer rates and rhizobium inoculant on sandy loam soil in puducherry. P fertilizer rates combined with DGRC inoculant had a significant influence on growth, root nodule, nodule dry weight, pod and kernel yield. From this study, it may concluded that combined application of P fertilizer @ 60 kg/ha and seed treatment of DGRC culture inoculants @ 20 g/kg seed have the potential to increase the productivity and profitability of groundnut. Correlation and Regression analysis also indicated that the yield attributes had a positive impact on groundnut yield.

Rhizobium Inoculant and Seed-Applied Fungicide Effects Improve the Drought Tolerance of Soybean Plants as an Effective Agroecological Solution under Climate Change Conditions.

Rhizobial inoculation in combination with fungicidal seed treatment is an effective solution for improving soybean resistance to modern climate changes due to the maximum implementation of the plant's stress-protective antioxidant properties and their nitrogen-fixing potential, which will contribute to the preservation of the environment. Model ecosystems at different stages of legume-rhizobial symbiosis formation, created by treatment before sowing soybean seeds with a fungicide (fludioxonil, 25 g/L) and inoculation with an active strain of Bradyrhizobium japonicum (titer 109 cells per mL), were subjected to microbiological, biochemical, and physiological testing methods in controlled and field conditions. Seed treatment with fungicide and rhizobia showed different patterns in the dynamics of key antioxidant enzymes in soybean nodules under drought conditions. Superoxide dismutase activity increased by 32.7% under moderate stress, while catalase increased by 90.6% under long-term stress. An increase in the antioxidant enzyme activity induced the regulation of lipoperoxidation processes during drought and after the restoration of irrigation. Regeneration after stress was evident in soybean plants with a combination of fungicide seed treatment and rhizobial inoculant, where enzyme levels and lipoperoxidation processes returned to control plant levels. Applying seed treatment with fungicide and Rhizobium led to the preservation of the symbiotic apparatus functioning in drought conditions. As proof of this, molecular nitrogen fixation by nodules has a higher efficiency of 25.6% compared to soybeans without fungicide treatment. In the field, fungicidal treatment of seeds in a complex with rhizobia inoculant induced prolongation of the symbiotic apparatus functioning in the reproductive period of soybean ontogenesis. This positively affected the nitrogen-fixing activity of soybeans during the pod formation stage by more than 71.7%, as well as increasing soybean yield by 12.7% in the field. The application of Rhizobium inoculant and fungicide to seeds contributed to the development of antioxidant protection of soybean plants during droughts due to the activation of key enzymatic complexes and regulation of lipoperoxidation processes, which have a positive effect on nitrogen fixation and productivity of soybeans. This is a necessary element in soybean agrotechnologies to improve plant adaptation and resilience in the context of modern climate change.

Changes in root and nutrient uptake of chickpea affected by organic fertilizers and inoculation with arbuscular mycorrhizal fungi and Rhizobium

AbstractAlthough humans have studied biological nitrogen (N) fixation for nearly two centuries, our understanding of how legumes–microbiome interactions impact agroecosystem function is still evolving. To understand the effects of organic fertilizers and dual inoculation with Rhizobium and arbuscular mycorrhizal fungi (AMF) on root activity, N fixation and nutrient uptake of chickpea (Cicer arietinum), a two‐year greenhouse study was conducted in 2020–2021 at the research station of Ferdowsi University of Mashhad, Iran. The experiment design was a randomized complete blocks in the factorial arrangement with three replications. The first factor consisted of two seedbeds including S1 (field soil) and S2 (soil + humic acid + 40 ton ha−1 cattle manure). The second factor included inoculation with Rhizobium alone, mycorrhiza alone, both Rhizobium and mycorrhiza and non‐inoculated treatment. The results showed that the application of organic fertilizers increased the number of nodules, nodule weight, AMF colonization, leaf N content, leaf P content, root volume, root biomass and N uptake of chickpea, significantly. Also, the effect of seed inoculation was significant on all studied parameters where the highest root biomass (2 g), root volume (3.6 cm3) and leaf phosphorus (0.54%) were obtained in co‐inoculated treatments. There was no significant difference between the effect of single inoculation of Rhizobium and dual inoculation of mycorrhiza and Rhizobium on nodule number, nodule weight, leaf N and N uptake of chickpea. Generally, rhizobia and AMF can benefit nutrient uptake and root activity of chickpea, potentially leading to higher crop production.

Effect of Rhizobium Inoculation with Zinc and Boron Fertilizers on Growth and Yield of Mungbean (Vigna radiata L.)

Mungbean is considered as an extremely nutritious crop possessing a high level of micronutrients. The field experiment was conducted to evaluate the response of growth and yield of Mungbean to zinc, boron and rhizobium inoculation. The experiment was laid out in split-plot design with tree replications during kharif season of 2021 and 2022 at Instructional farm, Kamla Nehru Institute of Physical and Social Sciences Sultanpur, U.P. India. Four levels of zinc (0, 2.5, 5.0 and 7.5 Kg Zn ha-1), three levels of boron (0, 0.5 and 1.0 Kg B ha-1) and two levels of rhizobium i.e. Uninoculated (Control) and inoculated were used in this study. Zinc levels were allocated to the main plots, boron levels in the sub-plot, while Rhizobium inoculation in the sub-sub plot. The results revealed that plant height, number of branches per plant, dry weight, number of nodules and seed and stover yield were higher in mungbean inoculated with Rhizobium inoculation with application of zinc 7.5 kg ha-1 and Application of boron 1.0 kg ha-1. The findings of the current study would improve the growth and yield of mungbean.