Co-inoculation Of Bradyrhizobium Research Articles

Sulfur fertilization and inoculation of soybean with Azospirillum brasilense and Bradyrhizobium spp. can improve grain yield and quality.

The success of biological nitrogen fixation (BNF) in soybean depends on two crucial factors, viz., seed inoculation and soil nutritional balance. The macronutrient sulfur (S) is vital to the formation of ferredoxin, a common source of electrons that controls the proper functioning of the subunits of the enzyme nitrogenase, responsible for the conversion of atmospheric nitrogen (N2) to ammonia (NH3+). However, as the S dynamics is a complex process in soil, it may cause to the plants to be sulfur limited. This study aims at assessing the relationship between S fertilization through the use of elemental-S, and bacterial inoculation (Bradyrhizobium spp.) and co-inoculation (Bradyrhizobium spp. and Azospirillum brasilense) on nodulation, production and quality of soybean. The study was performed on the 2017/2018 and 2018/2019 crop seasons, involving four experiments where two were carried out in Santa Maria and two in Augusto Pestana, Rio Grande do Sul, Brazil. Adopting the randomized experimental block design, the treatments included a 3 × 4 factorial design, with three inoculations (Non-inoculated control, Inoculation and Co-inoculation) together with four doses of S (0, 20, 40 and 60kg ha- 1). Evaluations were done of the plant nodulation, accumulation of shoot dry matter, yield constituents, and quality of the soybean grain. S fertilization and co-inoculation promote an increase in plant nodulation, proving to be an important strategy to support nitrogen supply to soybean crops. The application of elemental sulfur in doses between 20 and 40kg ha- 1 promotes nodulation, the accumulation of dry mass of plants, the productivity and quality of soybeans, in addition to benefiting nodulation when combined with co-inoculation of Bradyrhizobium ssp. and Azospirillum brasilense.

Soybean production in SEALBA: inoculation, co-inoculation, and starter nitrogen fertilization

The grain production area in the Brazilian agricultural region known as SEALBA, especially in Alagoas State, has seen significant growth in recent years. This study aims to contribute to sustainable regional development by evaluating the effects of inoculation, co-inoculation, and the application of starter mineral nitrogen (N), either individually or in combination, on soybean growth and yield. Eight field experiments were conducted from 2018 to 2021 in two municipalities within Alagoas, covering soybean cultivation areas ranging from the first to the fourth year. The experiments followed a randomized complete block design with four replications, employing a factorial arrangement of treatments. The first factor encompassed five levels related to inoculation technologies and N management: 1) Inoculation with Bradyrhizobium; 2) Inoculation with Bradyrhizobium combined with N basal fertilization; 3) Co-inoculation of Bradyrhizobium + Azospirillum; 4) Co-inoculation of Bradyrhizobium + Azospirillum + N fertilization at the base; and 5) Control treatment without microbiological inputs or nitrogen fertilizers. The second factor involved the evaluation of different soybean cultivars, with two materials assessed in 2018 and three cultivars in 2019, 2020, and 2021. Results demonstrated that seed inoculation with Bradyrhizobium led to increased soybean grain yield in first-year cultivation areas. However, N basal fertilization, commonly known as starter fertilization, did not result in yield improvements compared to the use of microbiological inputs alone. Soybean cultivars BRS 9383 IPRO and FTR 3191 IPRO exhibited greater responsiveness to seed inoculation with Bradyrhizobium.

How did the coinoculation of Bradyrhizobium and Azospirillum become indispensable for soybean production in Brazil?

How did the coinoculation of Bradyrhizobium and Azospirillum become indispensable for soybean production in Brazil?

Effect of different methods of inoculation and co-inoculation of Bradyrhizobium spp. and Azospirillum brasilense on soybean agronomic performance in fields with a history of inoculation

ABSTRACT The yield gain of soybean inoculated with Bradyrhizobium spp. or co-inoculated with Bradyrhizobium spp. and Azospirillum brasilense is variable. Inoculants can be applied in the sowing furrow or via seed treatment. There is a gap in our understanding of the efficacy of different inoculation methods. This study aimed to assess the agronomic efficiency of soybean inoculated and co-inoculated with Bradyrhizobium spp. and A. brasilense by different methods. The study was conducted in Paraná State, Brazil, in two seasons. Five treatments were tested: control; seed treatment with Bradyrhizobium spp. (SBr), seed treatment with Bradyrhizobium spp. + A. brasilense (SBr+Az), in-furrow treatment with Bradyrhizobium spp. (FBr), and in-furrow treatment with Bradyrhizobium spp. + A. brasilense (FBr+Az). Shoot dry weight, grain nitrogen content and grain yield were lower in 2018/19. In 2017/18, FBr+Az increased nodule number and dry weight compared with SBr. FBr+Az promoted a 47% increase in pods per plant compared with the control in both seasons. Regardless of season, grain nitrogen content was higher with FBr+Az (mean relative increase of 27%). FBr+Az was superior to SBr+Az in 2017/18, with a 12% increase in yield. Inoculation and co-inoculation improve morphological traits and soybean yield. In-furrow inoculation is more efficient than seed treatment.

Coinoculação com Bradyrhizobium ssp. e Azospirillum brasilense em feijão caupi sob estresse salino

ABSTRACT Plants grown under salinity are subject to many morphological and physiological disorders. In this context, practices that can enable the use of saline water are essential. The deleterious effects of salinity can be mitigated by using beneficial microorganisms, especially diazotrophic bacteria. In this context, this study aimed to evaluate the effect of bacterial inoculation and co-inoculation using Bradyrhizobium spp. and Azospirillum brasilense on the growth, nodulation and production of cowpea under salt stress. The experiment was conducted using a randomized block design, in a 4 × 5 factorial arrangement, corresponding to four nitrogen sources (N1 - without nitrogen and without inoculant; N2 - fertilization with mineral nitrogen and without inoculant; N3 - inoculation of Bradyrhizobium spp.; and N4 - co-inoculation of Bradyrhizobium spp. and Azospirillum brasilense) and five values of electrical conductivity of irrigation water - ECw (0.4, 1.9, 3.4, 4.9 and 6.4 dS m-1), with five replicates. Co-inoculation with Azospirillum brasilense and Bradyrhizobium spp. favors the growth, production and nodulation of cowpea plants up to ECw of 0.4 dS m-1. Increase in the electrical conductivity of irrigation water negatively affects the growth, production and nodulation of cowpea plants in Corujinha variety, regardless of the nitrogen source used.

Co-Inoculation of Bradyrhizobium spp. and Bacillus sp. on Tarwi (Lupinus mutabilis Sweet) in the High Andean Region of Peru

Tarwi (Lupinus mutabilis Sweet) is an Andean legume that has attracted international interest due to its high nutritional value. This has resulted in an increase in its conventional production, which leads to an ecological imbalance. In this context, the application of biotechnologies, based on the use of bacterial inoculants, is of utmost importance. This work aimed to evaluate the effects of a consortium of 2 strains of Bradyrhizobium spp. (BR) and 1 strain of Bacillus sp. (BA) on tarwi var. Andenes. The treatments tested were BR + BA, BR + Organic Matter, BR + Agrochemical (Azoxystrobin y Difenoconazole), and the control (without application). The crop was located in Marcara-Ancash (altitude 3254 masl), Peru. The experiment involved the inoculation of BR in the seeds and a re-inoculation 30 days later. BA was inoculated every 30 days in the neck of the plant and aerial part, 5 times during plant development. The inoculation with BR + BA significantly increased the aerial fresh weight (413.2%), plant height (13.5%), and diminished the anthracnose (38.4%) of plants 110 DAS (days after the sowing). Also, this treatment produced the best-harvested emergence percentage (97.9%), morpho-agronomic characteristics, and an increase in the yield (171%) compared to the control. In conclusion, the application of the Bacillus sp. strain and the Bradyrhizobium spp. consortia improved the productivity of tarwi var. Andenes. The interaction of these strains have the potential to be used in tarwi field planting programs.

Co-Inoculation with Azospirillum brasilense and Bradyrhizobium sp. Enhances Nitrogen Uptake and Yield in Field-Grown Cowpea and Did Not Change N-Fertilizer Recovery

This study was designed to investigate the effects of Azospirillum brasilense and Bradyrhizobium sp. co-inoculation coupled with N application on soil N levels and N in plants (total N, nitrate N-NO3− and ammonium N-NH4+), photosynthetic pigments, cowpea plant biomass and grain yield. An isotopic technique was employed to evaluate 15N fertilizer recovery and derivation. Field trials involved two inoculations—(i) single Bradyrhizobium sp. and (ii) Bradyrhizobium sp. + A. brasilense co-inoculation—and four N fertilizer rates (0, 20, 40 and 80 kg ha−1). The co-inoculation of Bradyrhizobium sp. + A. brasilense increased cowpea N uptake (an increase from 10 to 14%) and grain yield (an average increase of 8%) compared to the standard inoculation with Bradyrhizobium sp. specifically derived from soil and other sources without affecting 15N fertilizer recovery. There is no need for the supplementation of N via mineral fertilizers when A. brasilense co-inoculation is performed in a cowpea crop. However, even in the case of an NPK basal fertilization, applied N rates should remain below 20 kg N ha−1 when co-inoculation with Bradyrhizobium sp. and A. brasilense is performed.

Changes in 137cs Translocation to Soybean Root Nodules by Co-Inoculation of Bradyrhizobium and Am Fungi

Changes in 137cs Translocation to Soybean Root Nodules by Co-Inoculation of Bradyrhizobium and Am Fungi

Co-inoculation of two symbiotically efficient Bradyrhizobium strainsimproves cowpea development better than a single bacterium application.

The co-inoculation of Bradyrhizobium with other non-bradyrhizobial strains was already assessed on cowpea, but the co-inoculation of two Bradyrhizobium strains was not tested up to now. This study aimed to evaluate the cowpea growth, N accumulation, and Bradyrhizobium competitiveness of the elite strain B. pachyrhizi BR 3262 when co-inoculated with other efficient Bradyrhizobium from the Brazilian semiarid region. Three potted-plant experiments were carried out. In the first assay, 35 efficient Bradyrhizobium isolates obtained from the semiarid region of Brazil were co-inoculated with the elite strains B. pachyrhizi BR 3262. The experiment was conducted in gnotobiotic conditions. The plant growth, nodulation, N nutritional variables, and nodular occupation were assessed. Under gnotobiotic and non-sterile soil conditions, ten selected bacteria plus the elite strain B. yuanmingense BR 3267 were used at the second and third experiments, respectively. The cowpea was inoculated with the 11 bacteria individually or co-inoculated with BR 3262. The plant growth and N nutritional variables were assessed. A double-layer medium spot method experiment was conducted to evaluate the interaction among the co-inoculated strains in standard and diluted YMA media. The co-inoculation treatments showed the best efficiency when compared to the treatments inoculated solely with BR 3262. This strain occupied a low amount of cowpea nodules ranging from 5 to 67.5%. The treatments with lower BR 3262 nodule occupancy showed the best results for the shoot nitrogen accumulation. The culture experiment showed that four bacteria inhibited the growth of BR 3262. In contrast, seven strains from the soils of Brazilian semiarid region were benefited by the previous inoculation of this strain. In the second and third experiments, the results indicated that all 11 co-inoculated treatments were more efficient than the single inoculation, proofing the best performance of the dual inoculation of Bradyrhizobium on cowpea.

Changes in root morphological traits in soybean co-inoculated with Bradyrhizobium spp. and Azospirillum brasilense or treated with A. brasilense exudates

We assessed the effects of co-inoculation with Azospirillum brasilense or the application of its exudates via seeds or leaf spray on root morphological traits and nodulation, as well as on shoot development and grain yield of soybean inoculated with Bradyrhizobium. Two experiments were performed in sterile substrate under greenhouse, and two were performed at field conditions in sandy soils in a crop season with episodes of drought. The treatments in the greenhouse experiments comprised the non-inoculated control, sole inoculation with Bradyrhizobium, co-inoculation of Bradyrhizobium and A. brasilense, and inoculation of Bradyrhizobium with the application of Azospirillum exudates via seeds or leaf spray. Field treatments included non-inoculated controls without and with N-fertilizer and inoculation of Bradyrhizobium and co-inoculation with A. brasilense. Plants were assessed for root weight, total and specific lengths, volume, diameter, tissue density, branches number, root-hair length and incidence, nodule number and dry weight, shoot dry weight and N content, and grain yield. Co-inoculation of Bradyrhizobium and A. brasilense and seed application of A. brasilense exudates increased the number of root branches and nodules compared with the sole inoculation of Bradyrhizobium. However, leaf spray application of exudates was less effective. Co-inoculation also increased specific root length, root length density in soil, root-hair incidence and length, and total N content in shoot, altogether resulting in increases in grain yield. Co-inoculation of soybean with Bradyrhizobium and A. brasilense improved several root morphological traits, increasing the plant capacity to overcome moderate drought stress episodes in sandy soils, allowing to reach higher yields.

The Co-inoculation of Rhizobium and Bradyrhizobium Increases the Early Nodulation and Development of Common Beans

It has recently been shown that the co-inoculation of Rhizobium tropici and Bradyrhizobium spp. can benefit the nodulation, development, and biological nitrogen fixation of common beans (Phaseolus vulgaris L.). Here, we compared this type of co-inoculation with the co-inoculation of Azospirillum brasilense on two common bean cultivars and evaluated whether they can stimulate the early nodulation of this crop, aiming at anticipating the contribution of biological nitrogen fixation to plant nutrition. The co-inoculation with B. elkanii 29w increased the number of nodules in the V3 and V4 stages. Both co-inoculations stimulated a larger mass of nodules and larger shoot biomass during the V4 stage. The co-inoculation of Bradyrhizobium also stimulated root growth. The co-inoculation effects were consistent for the two tested cultivars, but some differences in response indicate a possible genotype effect. We can conclude that the co-inoculation of B. elkanii benefits the common bean during the early stages of its cycle. These effects are comparable with the effects of the co-inoculation with Azospirillum brasilense Sp 245.

Can co-inoculation of Bradyrhizobium and Azospirillum alleviate adverse effects of drought stress on soybean (Glycine max L. Merrill.)?

Harnessing the beneficial potential of plant growth-promoting rhizobacteria may be an alternative strategy to improve plant tolerance to drought stress. The effect of inoculation with Bradyrhizobium japonicum and Azospirillum brasilense either alone or in combination on the plant growth and drought tolerance of soybean [Glycine max (L.) Merrill.] was investigated in this study in greenhouse conditions. Treatments were arranged in a randomized block design in a 3 × 4 factorial: three irrigation regimes [100% of pot capacity-PC (well-watered control), 50% of PC (moderate stress) and 25% of PC (severe stress)] and four inoculation treatments [control (non-inoculated), inoculation with B. japonicum, inoculation with A. brasilense, and co-inoculation with B. japonicum and A. brasilense]. Leaf relative water content, cell membrane stability, root nodulation, plant growth, and morphophysiological indexes were recorded. The inoculation of soybean plants with B. japonicum and A.brasilense either alone or in combination improved leaf membrane stability under drought stress conditions when compared to non-inoculated plants; however, this lower damage to cell membranes was not sufficient to maintain the leaf water content of the plant under drought stress. Plants co-inoculated with B. japonicum and A.brasilense improved the root nodulation under severe drought conditions. Inoculation of B. japonicum and A. brasilense either alone or in combination reduced the pod abortion rate under moderate drought stress, but had no effect under severe drought stress. In summary, the co-inoculation of A. brasilense and B. japonicum alleviate adverse effects limited by drought stress to the growth of soybeans.Author: Please check and confirm that the authors [Elijanara Raissa Silva, Carlos Eduardo Silva Oliveira, Alan Mario Zuffo, Eduardo Pradi Vendruscolo] and their initials have been correctly identified and amend if necessary.The authors were correctly identified.

RESPONSE OF SOYBEAN PLANTS TO INOCULATION WITH RHIZOBIA AND CYANOBACTERIA

Field experiments were carried out on a clayey alluvial soil to evaluate the effect of (Bradyrhizobium japonicum (B.j), ,Nostoc muscorum, Anabaena oryzae, B.j. +Nostc, B.j.+Anabaena, and B.j.+Nostc+Anabaena , on soybean (Glycine max L.) vegetative growth, root nodulation status , yield and its components. Also, microbial activity in soybean rhizosphere soil and technology characters of seeds (protein, oil, and carbohydrate content) were determined. Results indicated that, inoculation with Brady rhizobium or cyanobacteria improved plant growth parameters, i.e., plant height, number of branches, number and dry weight of pods above the control (60kgN) . However, co-inoculation of Brady rhizobium with the two cyanobacteria significantly enhanced those parameters, where they scored significant increases in number and dry weight of root nodules, as well as nitrogenase activity of the root system, as compared with the single inoculation with Brady rhizobium alone or the control. The mixed inoculation improved dehydrogenase activity in the rhizosphere soil, as well as the seed content of oil, protein and carbohydrate were achieved. Also, the highest yield and its components were also recorded with the mixed inoculation.

English

The continuous development of soybean cultivars aiming at higher yields can result in a demand of N supply higher than the standard inoculation with Bradyrhizobium species. In this context, Azospirillum species, a nitrogen-fixing microorganism found in the rhizosphere of various plant species, may be studied as a way of providing soybean crop with the part of the N it needs. Employing a completely randomized design with four replicates, this study aimed to evaluate the agronomic performance of two different methods of standard inoculation of Bradyrhizobium spp. associated with the co-inoculation with Azospirillum spp. The tested treatments consisted of the absence of N fertilizer and inoculant, full N recommendation, two single inoculations with Bradyrhizobium spp. (in-furrow and seed-applied) combined with an in-furrow application of Azospirillum spp. At R2 growth stage, the nodule number, nodule dry weight, shoot dry biomass and shoot N content were the variables evaluated, whereas at R8 the grain yield, thousand seed weight and grain N content were assessed. The results demonstrated that the co-inoculation of Bradyrhizobium spp. with Azospirillum brasilense is beneficial to soybean yield, mainly using the in-furrow method of application for Bradyrhizobium spp., associated to the in-furrow co-inoculation with Azospirillum spp. Key words: Glycine max, inoculation, nitrogen content, yield.

Strategies to promote early nodulation in soybean under drought

Biological nitrogen fixation (BNF) is a sustainable process that dismisses the use of supplemental N-fertilizers in soybean [Glycine max (L.) Merrill]. Strategies to provide early nodulation may increase the effectiveness of BNF under stressing conditions like drought. We assessed the effects of inoculation of Bradyhizobium, co-inoculation of Bradyrhizobium and Azospirillum, and addition of microbial secondary metabolites (MSM) on nodulation parameters and soybean yield in four field experiments in two growing seasons, 2013/14 and 2014/15, in Southern Brazil. The treatments were: non-inoculated (Ni) control; Ni+N-fertilizer (100kgha−1 at sowing and 100kgha−1 at full flowering, as urea); Inoculated with Bradyrhizobium (I); Co-inoculated with Bradyrhizobium+Azospirillum brasilense (Co-I); Co-I+microbial secondary metabolites (MSM) and I+MSM. All trials were rainfed and the second trial in 2014/15 was severely affected by drought and high temperatures. The co-inoculation with Azospirillum increased the soybean nodulation at early developmental stages and resulted in higher shoot N accumulation and plant growth, especially under drought. The addition of MSM attenuated the effect of drought on nodulation and in one trial increased the grain yield by 15% and 7% in relation to the N-fertilizer and sole inoculation with Bradyrhizobium, respectively. The strategy of co-inoculation stimulates an early nodulation and helps the maintenance of nodulation under drought; moreover, the addition of MSM improves nodulation and may increase the grain yield.

Higher soybean yield by inoculation with N-fixing and P-solubilizing bacteria

Phosphorus availability for soybean growth is frequently low because P reacts with iron, aluminum and calcium in soil to form insoluble phosphates. The increasing price of phosphatic fertilizers is a major obstacle faced by farmers for application of recommended P doses. Low yield of soybean in Pakistan is also lowering adoption by farmers of this oilseed crop. These issues could be solved by inoculation of beneficial microorganisms that enhance the availability of N and P to the plant. Here, we tested the effect of inoculation of Bradyrhizobium or Pseudomonas, or both, in the presence and absence of P2O5 fertilizer, on soybean yield. Experiments were carried out in pots and the field during 2004 and 2005 under natural conditions. The bacterial strains were applied in broth culture in the pots at the seedling stage or as a seed treatment in the field. Our results showed that co-inoculation of Bradyrhizobium and Pseudomonas strains with the P2O5 treatment resulted in increased grain yield of 38% in pot experiments and 12% in the field experiment, compared with the P2O5 treatment alone. Bradyrhizobium japonicum strain TAL 377 produced 74.64 μg/mL indole acetic acid and 261.2 μg/mL gibberellic acid. Similarly, Pseudomonas strain 54RB produced 8.034 μg/mL indole acetic acid and 1766 μg/mL gibberellic acid. The survival efficiency of Bradyrhizobium was up to 46% higher due to co-inoculation and P2O5 as compared with its single inoculation. On the other hand, Pseudomonas survival efficiency was up to 33% higher with added P2O5 as compared with its single inoculation.

Nodulation, yield and quality of soybean as influenced by integrated nutrient management

A field experiment was conducted at the Horticultural Farm of Bangladesh Agricultural University, Mymensingh during the period from November 2007 to March 2008 to study the effect of integrated nutrient management on nodulation and sustainable soybean production. There were significant differences among the different treatment combinations in terms of yield and yield contributing characters. Integrated nutrient management with application of 50% of the recommended doses of urea, TSP, MOP, gypsum and biofertilizer (Bradyrhizobium) at the rate of 1 kg ha-1 significantly increased most of the parameters, such as the highest plant height, number of nodule per plant, nodule dry weight per plant, pods per plant, grains per pod, grain yield, oil and protein contents. Coinoculation of Bradyrhizobium seemed to help reduce the NPKS requirement in soybean cultivation. Overall results indicate that the application of integrated nutrient management of biofertilizer (Bradyrhizobium) with ½ NPKS of the recommended dose would produce the best quality of soybean with higher nodulation and yield. Keywords: Nodulation; Integrated nutrient management; Inoculation DOI: 10.3329/jbau.v7i2.4723 J. Bangladesh Agril. Univ. 7(2): 229-234, 2009