Inoculation Of Nitrogen-fixing Bacteria Research Articles

Vegetative Growth Response of Corn (Zea mays) Against Actinomycetes, Azospirillum, and Azotobacter from the Rhizosphere Neem (Azadirachta indica)

This research is an experimental study that aims to determine the effect of the application of N2-fixing bacteria Actinomycetes, Azospirillum, and Azotobacter on the vegetative growth parameters of corn plants and on the nitrogen content of corn plants. Parameters for measuring the growth of corn plants include: formation rate of radicle length, plant height, number of leaves, leaf length, fresh weight of plants, fresh weight of plant roots, dry weight of plants, dry weight of plant roots, total N content in plants, as well as physical and chemical qualities of the ground. Experiments on the application of N2 -fixing bacteria on corn plants on a laboratory scale were carried out to determine the in vitro effect of microbes on corn seeds. The pot test was carried out to determine the effect of N2-fixing bacteria on the vegetative growth of corn plants in vivo. Data were analyzed using ANOVA with Duncan's test. The results showed that corn plants inoculated with Actinomycetes, Azospirillum and Azotobacter showed a significant different growth from corn plants without nitrogen fixing bacteria, namely formation rate of radicle length, plant height, number of leaves, leaf length, fresh weight, dry weight, total N content (%) of crops, and soil physical and chemical quality. It can be concluded that the inoculation of nitrogen-fixing bacteria in corn plants has a significant effect on plant vegetative growth parameters and plant nitrogen content.Keywords: Nitrogen fixing bacteria, Actinomycetes, Azospirillum, Azotobacter, Plant vegetative growth.

Vegetative growth response of upland rice to Actinomycetes, Azospirillum and Azotobacter

The research aims is to determine the suitability of nitrogen fixing bacteria, namely Actinomycetes, Azospirillum and Azotobacter with upland rice seeds to the speed of radicle formation and growth of upland rice plants. Upland rice plant growth measurement parameters include; speed of formation of radicle length, upland rice plant height, number of upland rice tillers, dry weight of the top of upland rice plants and roots of upland rice plants, wet weight of upland rice plants and roots of upland rice plants, and total N of upland rice plants and upland roots Testing the application of N2 fixing bacteria on upland rice plants on a laboratory scale was carried out to determine the suitability of microbes with upland rice plant seeds in vitro. The pot test was carried out to determine the suitability of the N2 fixing bacteria with the vegetative growth of upland rice plants in vivo. Data were analyzed using ANOVA with Duncan’s advanced test. The results showed that upland rice plants inoculated with Actinomycetes, Azospirillum and Azotobacter showed significantly different growth from upland rice plants without nitrogen fixing bacteria treatment, namely the radicle formation speed and radicle length, plant height, number of tillers, wet weight, dry weight, and total N (%) plants. It can be concluded that the inoculation of nitrogen-fixing bacteria on upland rice plants has a significant effect on plant vegetative growth parameters and plant nitrogen content.

Inoculation of nitrogen fixing bacteria in conjugation with integrated nitrogen sources induced changes in phenology, growth, nitrogen assimilation and productivity of wheat crop

Numerous strains of plant growth-promoting bacteria are used as biofertilizers to minimize the utilization of synthetic fertilizers, improve nutrients use efficiency, crop productivity and to reduce environmental pollution. This study was planned with the aims to assess the effects of seeds inoculation with different strains of nitrogen (N)-fixing bacteria in conjugation with N fertilization from various combinations of farmyard manure (FYM) and urea on days to anthesis, days to physiological maturity, leaf area duration (LAD), crop growth rate (CGR), net assimilation rate (NAR), physiological N use efficiency (PNUE), apparent N re-translocation (ANR), relative N accumulation rate (RN), N harvest index (NHI) and grain yield of wheat crop under the environmental conditions of Northern Pakistan. The experiment was carried out in RCB design with a factorial arrangement of treatments. Wheat seeds were inoculated with N-fixing bacterial strains viz. Azotobacter sp., Azospirillum ER-20, Rhizobium SK-8 and Pseudomonas K-1, and N were applied from three different combinations of FYM and urea i.e. 100% urea, 75% FYM and 25% urea, and 50% FYM and 50% urea. The results showed that days to anthesis (122), days to physiological maturity (162), CGR (10.31 g. m −1 . day −1 ), grain yield (4016 kg ha −1 ), PNUE (43.1 kg grain kg −1 N uptake), ANR (9.1 g kg −1 DM), NHI (79.4) and RN (0.1046 day −1 ) were increased (P < 0.05) by Azospirillum Er-20 and Pseudomonas K-1 inoculation, while maximum (P < 0.05) LAD (76 m. day −1 ) and NAR (0.19 g. m −1 . day −1 ) were attained on Rhizobium SK-8 inoculation with N from 50% FYM and 50% urea, as compared to control. The grain yield revealed a significant (P < 0.001) correlation with CGR (0.76), NHI (0.72) and PNUE (0.68). The regression analysis exhibited a good estimate for grain yield (R 2 = 0.83) and CGR (R 2 = 0.57) in response to soil mineral N content. In conclusion, bacterial inoculation in conjugation with an equal ratio of N from the integrated sources improved the phenological and growth traits as well as N assimilation and grain yield of wheat crop. Therefore, it is suggested to plan long-term experiments to explore the potential of N-fixing bacteria in conjugation with integrated N-sources under different agronomic conditions for attaining sustainability in the wheat cropping systems.

Co-inoculations with rhizobia and arbuscular mycorrhizal fungi alters mycorrhizal composition and lead to synergistic growth effects in cowpea that are fungal combination-dependent

Cowpea can effectively form tripartite symbiotic associations with nitrogen-fixing bacteria (NFB) and arbuscular mycorrhizal fungi (AMF) although the selection of compatible AMF species and rhizobial strains which are promoting cowpea growth remains a challenge. The aims of the current study were 1) to evaluate the response of cowpea plants to a symbiotic NFB and a multi-AMF inoculum and 2) to explore any interaction between the symbiotic NFB and the different AMF isolates. In a pot gnotobiotic trial, cowpea plants grown under limited N supply, were inoculated with or without a symbiotic nitrogen-fixing bacterium, Sinorhizobium meliloti, and combinations of three different AMF species namely Dominikia disticha, Claroideoglomus etunicatum and Rhizophagus irregularis. Experimental evaluation was determined through the measurement of above ground biomass, nutrient content and AMF root colonization. The presence of AMF species on cowpea roots was also determined with cloning and sequencing. Inoculation with both AMF and S. meliloti led to increased cowpea biomass production compared to inoculation with AMF only, but the presence of a positive effect depended on the specific AMF partners used. Inoculation with AMF alone had a highly positive impact on the growth and P uptake of cowpea, but the NFB inoculation was needed to address N deficiency in planta. The presence of both symbionts generally led to increased AMF colonization of the cowpea roots, however, plant colonization depended on the AMF species, and became even negative, when all three AMF inocula were used together. The AMF composition in plant roots was also altered in the presence of the S. meliloti. Plant nitrogen content of cowpea plants significantly increased under the presence of both symbionts compared to AMF alone, while phosphorus content was hardly affected by dual inoculations. The results show positive synergistic effects of the different AMF species and S.meliloti. Inoculation with all AMF isolates and S. meliloti led to high above ground biomass production and accumulation of N. The presence of S. meliloti increased P content in plants not inoculated with AMF. Finally, the efficiency of synergism depends on the specific AMF partners used and it is not related to their colonization levels.

Different methods of inoculation of nitrogen-fixing bacteria (Azospirillum) specific of grasses in sorghum

Sorghum is one of the crops of great relevance in the production of grains in the cerrado region. Its main use for animal feeding and is considered a great alternative for human food in the form of grains. A promising alternative is the use of nitrogen-fixing bacteria (N) in the sorghum crop. Inoculation with N-fixing bacteria, such as Azospirillum, is an alternative to reduce costs by replacing the high cost of production due to nitrogen fertilization. The objective of this work was to evaluate different methods of inoculating nitrogen - fixing bacteria (Azospirilum) in sorghum culture. The experiment was carried out in the city of Goianésia, Goiás, Brazil. The experimental design was randomized blocks with five treatments, using 4 replicates per treatment, arranged in different methods of inoculation of Azospirillun brasilense in sorghum: control inoculation, seed treatment, application in furrow, application in cover after sowing and application 10 days after emergence. To determine growth and development, the following evaluations were made: stem thickness, root length, root volume, number of nodes, fresh shoot mass and shoot dry mass. Seed inoculation presented superiority in relation to other treatments regarding root length, number of nodes, green mass and dry mass. The inoculation with Azospirillum promoted positive effects on shoot thickness and root length, obtaining significant amounts and seed inoculation with the best results.

The effect of nitrogen-fixing bacteria towards upland rice plant growth and nitrogen content

This study was performed to observe the associative effect of Nitrogen-fixing bacteria and combination of each with nitrogen dosage on Nitrogen content and upland rice plant growth. Klebsiella pneumonia and Azospirillum brasilense were applied, while urea used as fertilizer on 0, 25, 50, and 75 kg N/Ha. The result revealed that inoculation of nitrogen-fixing bacteria to upland rice can increase tiller formation, shoot and root dry weight and plant N Total production. The effect of A. brasilense on increase tiller formation, biomass dry weight (shoot and root) and N total production revealed to tendency to increase compare to K. pneumonia. Differences in nitrogen fertilizer did not cause a significant effect on all parametric measured, except plant N content. Bacteria and nitrogen fertilizer interaction did not cause a significant effect on all parametric measured. From the regression analysis, there was a correlation between root dry weight with shoot dry weight; and the correlation between root dry weight with plant N total production.

Potential of Boehmia nivea as phytoremediator for petroleum-contaminated soil following nitrogen-fixing bacteria inoculation

Phytoremediation is one of an alternative technology to overcome a petroleum-contaminated soil. Boehmia nivea or Ramie has the potential to be used as a phytoremediatoragent to degrade petroleum hydrocarbons. The effort to improve the performance of Ramie in degrading petroleum hydrocarbons is through the concept of phytostimulant inoculation in biological fertilizer. The objective of pot experiment was to investigate the performance of Ramie as a phytoremediator of petrolleum waste. The research was designed in a randomized block design and consisted of Ramie treatment without inoulation, Ramie inoculated with 2% Azotobacter vinelandii, 2% Azospirillum sp., and 2% consortia of both inoculants. Experimental result showed that Ramie plants removed petroleum hydrocarbons up to 83.22% after 13 week of inoculation. The efficacy of hydrocarbon degradation increased significantly if Ramie plants was inoculated by N-fixing bacteria, but the biodegradation efficiency in biofertilizer treatments was not significantly different.

English

The inoculation of nitrogen-fixing bacteria in soybean crops allows the achievement of high crop yield by reducing or eliminating the application of nitrogen fertilizers. Pre-inoculation of seeds can reduce costs and increase the efficacy of this agricultural practice. The objective of this study was to assess the efficacy of pre-inoculation of soybean seeds with a commercial inoculant of Bradyrhizobium (RIZOLIQ LLI&reg; manufactured by Rizobacter do Brasil) at 60, 45, and 30 days before sowing using a cell protector and different chemical treatments. The study was conducted in four municipalities in the state of Paran&aacute; (Londrina, Pato Branco, Ponta Grossa, and Santa Tereza do Oeste) and included 14 treatments, a negative control, standard inoculation of the recommended bacterial strains on the day of sowing, and pre-inoculation at 30, 45, and 60 days before sowing using the commercial inoculant RIZOLIQ LLI&reg; together with the cell protector and chemical treatment of seeds with Imidacloprid (Rocks&reg;), Fipronil+Thiophanate-methyl+Pyraclostrobin+ (Standack&reg;Top), Metalaxyl-M+Fludioxonil (Maxim&reg;XL), and Metalaxyl-M+Fludioxonil+Thiabendazole with Thiamethoxam (Maxim&reg;Advanced+Cruiser&reg;). The nodulation, plant biomass, nitrogen concentration in shoot and grain, and grain yield were evaluated. The cell protector was efficient in maintaining the bacterial inoculant viable in the seed for up to 60 days. All treatments of pre-inoculation of soybean chemically-treated seeds up to 60 days before sowing could be performed without impairment of nodulation, plant biomass, nitrogen concentration in shoot and grain, and grain yield. Therefore, pre-inoculation of soybean seeds up to 60 days before sowing is an efficient and practical inoculation strategy for sowing soybean crops. Key words: Inocula, pre-sowing inoculation, rhizobia, symbiosis.

Nitrogen source contribution in sugarcane-inoculated plants with diazotrophic bacterias under urea-N fertigation management

Although Brazilian sugarcane crops use lower nitrogen rates when compared to other producing countries, the biological nitrogen fixation (BFN) could be performed aiming to reduce costs, since almost all nitrogen fertilization used in Brazil is imported. BFN can occur in sugarcane; however, its role in non-leguminous plants is controversial. Therefore, this study aimed to assess the nitrogen source contribution (using N isotope 15N technique) along a growing period in sugarcane plants under different management (diazotrophic bacteria inoculation and N fertigation rates). The natural abundance of nitrogen isotope (15N) abundance in + 1 leaves of fourth ratoon cultivar SP 80-3280 was used to indicate the comparative importance of N sources, including BFN for sugarcane nutrition. The treatments were irrigated with two levels of nitrogen fertilizer 50 and 100 kg ha−1 (urea source), including a control without fertilizer, with (I) and without (NI) inoculation of nitrogen-fixing bacterias. The bacteria cocktail used consisted of five strains: Gluconacetobacter diazotrophicus, Herbaspirillum seropedicae, H. rubrisubalbicans, Burkholderia tropica and Azospirillum amazonense. Although the nitrogen content in + 1 leaves, the above ground dry matter, cane yield and stalk sugar content expanded by increasing nitrogen fertilizer rates, no significant interactions between nitrogen-fixing bacteria inoculation and nitrogen fertilizer rates were observed. In the treatment without N fertilizer application, no differences in δ15N‰ (per thousand) values between sugarcane-inoculated and sugarcane-non-inoculated sugarcane leaves was found. The temporal variation of δ15N‰ in sugarcane + 1 leaves indicated that nitrogen content and δ15N‰ values decreased during the phenological development stages and that the main sources of nitrogen for sugarcane were from synthetic fertilizer and mineralization of nitrogen from soil organic matter.

Improvement of Indigofera zollingeriana Production and Methionine Content through Inoculation of Nitrogen-Fixing Bacteria.

Indigofera zollingeriana is a tremendous potential as a forage plant due to its high protein content. This experiment was conducted to increase production and nutrient quality of I. zollingeriana biomass, especially methionine content through inoculation of nitrogen fixing bacteria. Nine isolates obtained from nodule of I. zollingeriana were screened for 37 days in greenhouse, resulting in three desirable isolates. These three selected isolates at density of 105 cfu/mL and 107 cfu/mL were inoculated as much as 1 mL per seedling. Uninoculated plants were also grown as control treatment, i.e., positive (+ 0.05% KNO3 (w/v)) and negative. The experiment was laid out in a completely randomized design with four replicates and carried out for three months. Plant biomass was analyzed for amino acid and other nutrient contents. Moreover, nodulation activity was also observed by counting and weighting the nodules. The results showed that Bradyrhizobium sp. P8 828, Bradyrhizobium sp. PZS_A08, and Roseomonas sp. CMS4Y-2-2 significantly increased shoot production. Subsequent experiment showed that plant inoculation with Bradyrhizobium sp. PZS_A08 at 105 cfu/mL significantly increased dry matter content. Inoculation with Bradyrhizobium sp. PZS_A08 and Roseomonas sp. CMS4Y-2-2 at 107 cfu/mL produced higher crude protein contents that were better than the application of nitrogen fertilizer. Inoculation treatment with Bradyrhizobium sp. P8 828 at 105 cfu/mL was the most effective in improving methionine content. It is concluded that production and quality of biomass obtained from inoculation treatments were comparable to the application of inorganic N-fertilizer.

Suppression of an invasive legume by a native grass — High impact of priority effects

Nitrogen-limited ecosystems are threatened by extensive spread of broom (Cytisus scoparius (L.) Link), a European leguminous shrub that is invasive in several countries. The establishment of invading species may, however, be suppressed by competition from native vegetation. The neighbor impact of the grass Festuca rubra subsp. commutata Gaudin on the performance of C. scoparius was studied in a greenhouse experiment with different arrival order, under low and high nitrogen supply, and with or without inoculation of nitrogen-fixing bacteria. Aboveground biomass of both species was measured after a six-months establishment period, and after a five-months regrowth period. In both periods, presence of F. rubra reduced the performance of C. scoparius as indicated by negative neighbor-effect intensity indices (NIntA).During the establishment period the competitive impact of F. rubra was highest, when planted before C. scoparius, followed by synchronous and late planting. Inoculation with rhizobia and low fertilization decreased the competitive impact of F. rubra. After cutting and regrowth priority effects of F. rubra were still visible. Interaction between the two study species was not affected anymore by inoculation, but strongly by fertilization, with highest competitive impact of F. rubra on C. scoparius under high nitrogen fertilization. In both study periods biomass of C. scoparius was negatively correlated with biomass of F. rubra. Our study provides knowledge about competition processes, which help to improve conservation and restoration measures regarding the spread of C. scoparius. Early sowing of a native grass can help to suppress the invasive species at an early stage. Competitive impact of the grass might be strengthened by high nitrogen availability.

Change of Polysaccharide Content and Its Relation with Nitrogen Level in Sugarcane Leaves Under Nitrogen-Fixing Bacteria Inoculation and Nitrogen Supply

In order to investigate polysaccharide accumulation in sugarcane leaves under azotobacter inoculation and nitrogen supply, a pot culture experiment was conducted in 2012. The plants of sugarcane varieties B8 and ROC22 were inoculated either with or without endogenous nitrogen fixation bacteria at two levels of nitrogen supply, that is, 0 and 1/2 N (5 mM N) application. The polysaccharide and total nitrogen in leaves were determined at different growth stages of sugarcane. The results showed that the polysaccharide content in sugarcane leaves changed in a single-peak curve for the whole growth duration, and reached the peak in September. Azotobacter inoculation and nitrogen fertilizer application resulted in 2 months advanced the polysaccharide peak in variety B8, but not in ROC22 compared to the non-inoculation treatment. For the non-nitrogen treatment, the azotobacter inoculation significantly increased the polysaccharide content in variety B8 from July to September. Treatment with 1/2 N dose showed decreased polysaccharide content by 39.8 and 29.0 %, respectively, in both B8 and ROC22 that were inoculated with azotobacter. The nitrogen fertilizer application increased the total nitrogen content in sugarcane leaf regardless of with or without azotobacter inoculation. The polynomial regression model fitting showed that the polysaccharide content in sugarcane leaf first increased and then decreased with the increasing of total nitrogen level, showing a parabola relationship between them.

RECYCLING OF OIL PALM EMPTY FRUIT BUNCH AS POTENTIAL CARRIER FOR BIOFERTILIZER FORMULATION

The palm oil industry generates large amount of biomass waste such as oil palm empty fruit bunch (EFB) and palm oil mill effluent (POME). This biomass would be typically recycled to produce EFB compost that is a valuable agricultural input. This study was conducted to evaluate the suitability of using EFB compost as carrier for nitrogen fixing bacteria (NFB) and phosphate solubilizing bacteria (PSB). Mixture (50-60% moisture) between EFB (shredded short fibres) and POME (anaerobic pond) were added with Effective Microorganisms (EM) to accelerate the composting process. The EFB compost reached thermophilic phase after 4-6 weeks with consistent temperature between 50-60oC. After 7 weeks of composting, EFB compost reached the mesophilic phase with continuous reduction of temperature to 35-40oC at week 8. The maturity of the compost is supported from the reduction of the C/N ratio from 36 (initial) to 20 (after 6 weeks). Mature EFB compost was sun-dried and ground into fine particle size (1 mm) prior to be used as carrier. Dried EFB compost carrier has the following characteristics (dry weight); average pH at 7.5, C/N ratio - 13.5, moisture - 17.4%, organic matter – 74.5%, total N - 3.06%, P - 0.37%, K - 4.74%, Ca - 3.32% and Mg - 0.79%. The inoculation of NFB and PSB into the EFB compost carrier from single cultures of Serratia marcescens and Enterobacter cloacae showed high viable cell count at 4.05 x 109 CFU/g and 2.75 x 108 CFU/g respectively at day three after inoculation. Meanwhile, the mixed culture of Burkholderia cenocepacia with Serratia marcescens showed 2.45 x 108 CFU/g and 4.31 x 109 CFU/g respectively. This clearly indicates the potential of using EFB as a useful alternative for bacterial immobilization prior to application in the oil palm industries.

Pengaruh Bakteri Pelarut Fosfat Dan Bakteri Penambat Nitrogen terhadap Pertumbuhan Tanaman Tomat pada Tanah Masam

Acid soil is the dried soil which has great potential for growing of agriculture commodity but this kind of soil has not been used optimally. The acid soil which has acidity reaction at pH<5,0 has Al poisonous potency, less of organic material and sensitivity toward erosion, and also less of nitrogen (N) and phosphor (P). Those problems can be solved by doing phosphate-solubilizing bacteria and nitrogen fixing bacteria inoculation. The aims of this study were to know the effect of phosphate-solubilizing bacteria, nitrogen fixing bacteria, and the mixture of both of them to the wet weight, height, level of nitrogen and phosphor of tomato plants. This research was conducted experimentally for six weeks by using completely randomized design (CRD) with 4 treatments. One treatment is a treatment without bacteria inoculation and the other treatments used bacteria inoculations which were phosphate-solubilizing bacteria inoculation, nitrogen fixing bacteria inoculation, and the mixture of both of them inoculations. Data were analyzed by using analysis of variance (ANOVA) at the 95% and 99% confidence level. The result proved the mixture of phosphate-solubilizing bacteria and nitrogen fixing bacteria is the most effective inoculation to improve the wet weight, height, level of nitrogen, and level of phosphor of tomato plant in acid soil.

THE FUNCTIONING OF ASSOCIATIVE SYSTEM OF NITROGEN-FIXING BACTERIA-WINTER RYE ACCORDING TO PLANT SORT FEATURES

The associative nitrogen fixation of different winter rye sorts has been studied. It has been shown that such sorts as Charkovskoe 79, Struna, Novozibkovskoe 150, Borba, Verchniachskoe 32 have high N2- fixing potential. The mentioned sorts were noted by their high sensitivity to inoculation of nitrogen fixing bacteria from Azospirillum, Azotobacter, Bacillus, Pseudomonas genuses and ability to supply with effective functioning of N2-fixing bacteria – winter rye associative system.