Liquid Inoculum Research Articles

English

The present study refers to the results obtained in four experiments carried out in the 2015/2016 crop: Toledo/PR; Palotina/PR; Cascavel/PR; and São Miguel do Iguaçu/PR. The objective of the present study was to evaluate the agronomic efficiency of Azospirillum brasilense (pest strains Ab-V5 and Ab-V6) in four distinct rice culture regions (Oryza sativa L.). The tests were performed to meet the requirements of the Ministry of Agriculture, Livestock and Supply regarding the registration of the product. The experiments were conducted in a randomized block design with seven treatments and four replications, totaling 28 plots each. Rice cultivar IAC 201 was used in all four experiments. At stage R7, 10 plants were collected to measure morphobiometric variables and nitrogen content in grains (N grains). The results showed that in all evaluated sites the use of liquid inoculation with A. brasilense increased rice crop development as well as productivity. Thus, inoculation of rice seeds with A. brasilense strains Ab-V5 and Ab-V6 based inoculant in the liquid formulations increased the yield and yield components of rice crop in different regions. The inoculant based on A. brasilense strains Ab-V5 and Ab-V6, using the liquid vehicle, presented higher agronomic efficiency for rice cultivation. The inoculant based on A. brasilense strains Ab-V5 and Ab-V6 using the peat medium has good agronomic efficiency similar to the standard inoculant. These results were satisfactory contributing also to the sustainability in the agriculture. Key words: Diazotrophic bacteria, plant growth promoting bacteria, nitrogen fertilization, seed inoculation, Oryza sativa L. &nbsp

Impacts of rumen fluid, refrigerated or reconstituted from a refrigerated pellet, on gas production measured at 24h of fermentation

Rumen fluid is used as fresh inoculum for gas production fermentations to predict the nutritional value of feeds and rations for ruminants. However, collection of rumen fluid from animal donors is invasive, expensive, time consuming and results in fluids of variable quality. The general aim was to identify a procedure to manipulate rumen inoculum in order to facilitate its storage and transfer between laboratories. This strategy would also limit fluid collections from animals. Two experiments were completed based on gas production from graduated 100 mL glass syringe with five feeds as substrates.In experiment 1, the gas production and some fermentation parameters of fresh rumen fluids were compared with those preserved at 4 °C for 24, 48, 72 and 96 h. Refrigeration did not modify concentration of volatile fatty acids and pH, but ammonia in liquids refrigerated for 48–96 h was higher (P < 0.05) compared to fresh. In contrast, rumen fluid refrigeration for 24, 48 or 72 h did not depress gas production at 24 h, but it was lower at 96 h. In experiment 2, the rumen fluid was centrifugated at 13,000 x g and sedimented material (i.e., pellet) was refrigerated for 48 h at 4 °C. The asymptote of gas production kinetics from rumen fluid regenerated from the pellet was 8 % lower (P < 0.05) than that from fresh. However for 24 h gas production, the correlation between fresh liquid and pellet inoculum, calculated for five ingredients, was high (R2 = 0.94). Results support the use of rumen fluid preserved by refrigeration for up to 72 h, and rumen fluid reconstituted from refrigerated pellet, as an alternative to fresh. This would reduce the need for laboratories to maintain animal donors and/or frequently collect rumen fluid.

Formulation of Bacillus and Azotobacter Consortia in Liquid Cultures: Preliminary Research on Microbes-Coated Urea

The spore-forming Bacillus and cysts forming Azotobacter are Plant Growth Promoting Rhizobacteria which has been used as biofertilizer in sustainable agriculture since they tolerant to dried soil. Drought resistant microbes will be useful to coat urea in order to reduce the lost of nitrogen. The objectives of this preliminary study were to study the effect of molasse based liquid media on the population of Bacillus spore and Azotobacter vegetative cell and to determine the composition of four bacterial species in liquid formula. In the first experiment The Bacillus subtilis, B. megaterium, A. chroococcum and A. vinelandii were grown separately in 1% cane molasses enriched with 0.1% NH4Cl. As control treatment, The Bacillus and Azotobacter were grown in Nutrient Broth and Ashby’s mannitol broth respectively. In the second experiment, different composition of said Bacillus and Azotobacter were grown in molasses based liquid media prior to count the spore and vegetative cell. The results showed that molasses-based media supported bacterial growth and initial ratio 1:1:1:1 of liquid inoculant was effective to increase bacterial growth. This experiment suggested that the use of organic based media was useful practice of liquid biofertilizer formulation for granule urea coating.

Impacts of test methods on the assessment of insulation materials’ resistance against moulds

Bio-based insulation materials have been increasing in the construction market, however, these materials must prove their resistance to moulds. This research project aimed to compare two test methods to assess the resistance against moulds of two bio-based insulation panels and a mineral conventional panel artificially contaminated with Aspergillus niger spores. Test specimens were assessed applying a reference test method and a method developed in this work. The two methods consisted in four steps: 1) preconditioning of test specimens at 26 °C and 85 ± 5% of relative humidity during 1 week, 2) inoculation of test specimens, 3) incubation of test specimens at 26 °C and 85 ± 5% of relative humidity during four weeks and, 4) growth assessment by visual inspection and CFU counting. The difference between the methods is the contamination technique, which is a liquid inoculum for the reference method and a dry aerosolization of fungal spores for the new method. A dry aerosol was used because is a more realistic way on how materials get contaminated in realistic conditions and avoids the introduction of water into the system and in consequence, the modification of water activity (Aw). Materials presented different behaviours concerning visual and quantitative assessments according the test method employed, highlighting the difficulty establishing a standard test method to assess bio-based materials resistance to mould growth. The results showed that an evaluation only by a visual inspection may lead to misinterpretations of the results. Variability in the results may have been due to the differences in the inoculation techniques of the test methods and the heterogeneity of the materials composition and the anti-fungal product distribution within them.

Production of Conidia by Entomopathogenic Fungi and Their Pathogenicity Against Coptotermes sp.

Entomopathogenic fungi have the potential to infect most arthropods including termites which are economically important major insects pest of wood, wood products and building structures. However, the application of this fungus in the field has not shown satisfactory results yet, one of which is constrained in mass production of conidia. The purpose of this study was to evaluate 16 types of biodegradable products and waste as substrates for mass production of conidia using solid state fermentation method and two types of inoculum namely solid and liquid inoculum. Toxicity tests were carried out on subterranean termites (Coptotermes sp.) based on JIS K 1571, 2010. The parameters observed were the number and dry weight of the conidia produced, conidial viability, nutrient content of the substrate, and percentage of termite mortality. The results showed that rice, sorghum and corn were the best media for the growth of entomopathogenic fungi based on the number of conidia and dry weight of the conidia produced. Metarhizium sp. T4.B23 produced the highest number of conidia, 1.12 x 1011 conidia/100 g substrate and yielded 180.9 ± 0.623 g dry conidia/kg of rice; followed by Metarhizium sp. B2.2 grown on sorghum that resulted in 1.11 x 1010 conidia/100 g substrates and 8 ± 0.570 g /kg sorghum; and B. bassiana produced 8.3 x 109 conidia/100 g substrate and 31.24 ± 0.407 gr/ kg sorghum. Metarhizium sp. B2.2 showed the highest toxicity to termites with 100% mortality was observed within the second day of testing. Therefore the conidia of Metahizium sp. B2.2 is potential to be developed as a biopesticide using rice or sorghum substrate as a carrier.

O tipo de exposição interfere na compatibilidade de herbicidas com Metarhizium rileyi?

O presente trabalho teve por objetivo avaliar o efeito direto e indireto de alguns herbicidas utilizados no manejo da soja com o fungo entomopatogênico M. rileyi. Os herbicidas utilizados nos ensaios foram: Aramo®, Basagran®, Flex® e Glifosato®, em doses mínimas e máximas, quando possível. Os tratamentos foram aplicados seguindo duas metodologias distintas. Primeiro os produtos foram misturados ao meio de cultura Batata-Dextrose-Ágar (BDA) ainda liquefeito e posteriormente foi feita a inoculação do fungo. Da segunda forma, após o meio nutritivo vertido e solidificado, foram feitas as aplicações dos herbicidas com auxílio da torre de Potter e inoculação do patógeno, o qual ocorreu de duas formas: primeiramente o produto em suas respectivas doses e posteriormente o patógeno; e o patógeno e depois os produtos. Avaliou-se o crescimento vegetativo, a produção de conídios e a germinação. Apenas os produtos Basagran® (dose mínima) e Flex® foram compatíveis com M. rileyi; o produto Basagran® na dose máxima foi moderadamente tóxico e os demais produtos e doses foram tóxicos. Não houve diferenças entre as metodologias ao classificar a toxicologia do produto.

Inoculation of Wheat Plants with Pseudomonas spp. and Azospirillum brasilense under Drought Stress

Aims: To investigate the effect of inoculation and co-inoculation of Pseudomonas spp. and Azospirillum brasilense on the morphophysiological characters of wheat (Triticum aestivum L.) under drought stress conditions.&#x0D; Study Design: A randomized complete block design was used in a split plot scheme with four replicates. The plots consisted of irrigated and drought conditions. The subplots consisted of control (without inoculation), inoculation of Pseudomonas spp., inoculation of A. brasilense and co-inoculation of Pseudomonas spp. + A. brasilense. Liquid inoculant was used for two bacteria.&#x0D; Place and Duration of Study: Agricultural Experimental Area of the Federal University of Santa Catarina, Campus of Curitibanos, SC, Brazil, between July and October 2018.&#x0D; Methodology: Inoculation was performed at the time of sowing. Water deficit was characterized by irrigation suppression after plant emergence, considering a 25-day period without significant rainfall. At the end of the water restriction period, SPAD (Soil Plant Analysis Development) index and morphologic parameters of wheat plants was determined.&#x0D; Results: Drought stress decreased dry matter accumulation of wheat plants, in terms of number of tillers, above ground dry matter and root-shoot ratio. Inoculation or co-inoculation with Pseudomonas spp. and A. brasilense did not affect plant growth. Under drought stress, SPAD index was higher in plants co-inoculated with Pseudomonas spp. and A. brasilense.&#x0D; Conclusion: Although maintains SPAD index of wheat plants under drought stress, inoculation and co-inoculation with Pseudomonas spp. and A. brasilense do not influence the morphological characters of wheat plants.

Effectiveness of Azospirillum brasilense Inoculants to Wheat (Triticum aestivum) in the Micro-region of Curitibanos (SC)

Aims: This work aimed to evaluate the effectiveness of A. brasilense inoculants to the development of wheat at the southern part of Brazil.&#x0D; Study Design: The experimental design was randomized block with twelve treatments, containing two liquid inoculants with the A. brasilense strains Ab-V5 and Ab-V6, with or without nitrogen fertilization and five replicates. The plot area was 4m per 6m and thirty-two rows. The seeds inoculation was performed according to the manufacturer's recommendation, and manual sowing. The top-dressing N fertilization was Urea (Super N- 45%N) at 20 days after emergence (DAE), at 120 kg ha-1 (full dosage) or 60 kg ha-1 (half dosage).&#x0D; Place and Duration of Study: The experiment was performed in a farm in Curitibanos county in Santa Catarina state, Brazil. The experiment was carried out on July to November 2016.&#x0D; Methodology: At 45 DAE, it was performed flag leaves N content Tedesco, et al. [1]. At 115 DAE, it was performed dry shoot weight, plant height, ear sizes, grain N contents and grain yield. The results were submitted to variance analysis (ANOVA) and media compared by Scott-Knot's test at 5% of significance.&#x0D; Results: There was no statistical difference for shoot dry weight, plant height, ear size and yield. The N leaf content was greater with Ab-V5 inoculation and half N dosage (HC5 - 109% higher than the control). The N grain content was greater with the two strains (inoculant B) without, half and full N dosage (WC56 - 51%, HCB56 - 76% and CB56 - 65%, respectively).&#x0D; Conclusion: A. brasilense strains had the ability to increase wheat N accumulation with lower N fertilizing, suggesting their potential as growth inducers, emphasizing the importance of further studies to confirm and understand the mechanisms involved.

Influence of Rhizobium inoculation on dry bean yield and symbiotic nitrogen fixation potential

Inoculation of dry bean (Phaseolus vulgaris L.) might have potential to increase symbiotic nitrogen fixation (SNF) and to reduce dependency on chemical fertilizers. Peat based inoculant can cause clogging of air seeder and therefore, the potential of liquid inoculant was compared to peat based- and without inoculant during 2016 and 2017 growing seasons in the Red River Valley of ND and MN. Seed yield and SNF, using 15N isotope enrichment, response to inoculation were studied for four pinto and four kidney bean cultivars. Inoculation did not increase seed yield; moreover, both liquid and peat inoculation reduced kidney cultivars’ seed yield by 47% and 62% over control (without inoculation) treatment, respectively in 2016. In 2017, percent N derived from the atmosphere (%Ndfa) was significantly reduced by peat inoculation (61.2%) over control (76.7%). On average, pinto cultivars fixed 90.5 and 73.7 kg N ha−1 and kidney cultivars fixed 73.8 and 65.1 kg N ha−1, respectively in 2016 and 2017. The interaction between inoculation and cultivar influenced the quantity of SNF, specifically for kidney cultivars in 2017. Rather than inoculation, selection of cultivars had a more pronounced effect on seed yield and SNF.

The Growth Of White Oyster Mushroom Mycelium (Pleurotus ostreatus) (Jacq) (P. Kumm) From Liquid And Solid Inoculum

The study about the growth of white oyster mushroom mycelium (Pleurotus ostreatus) (Jacq) (P. Kumm) from liquid and solid inoculum conducted on January until July 2018 in Biotechnology laboratory, Biology Department, Faculty of Math and Science, Tadulako University. This study was aimed to find out the mycelium growth of source of stem inoculum and hood in liquid and solid media. This study was designed by Complete Randomized Design (CRD) which consisted of four treatments and five replications. The treatment were M1 (source of stem inoculum in liquid medium), M2 (source of stem inoculum in solid medium), M3 (source of hood inoculum in liquid medium), and M4 (source of hood inoculum in solid medium). The parameters were (a) incubation time till mycelium fills medium, (b) CFU, and (c) the viability of inoculum on producing medium. The result showed that the faster incubation were M1 and M3 (for 2 days, higher CFU was M3 with an average number 8,2 x 10 10 CFU /ml. The faster viability of mycelium growth were M3 with an average growth of mycelium 6,97 cm/days.

Dry batch anaerobic digestion of food waste in a box-type reactor system: Inoculum preparation and reactor performance

Abstract A box-type reactor system with liquid inoculum has been studied for the dry anaerobic digestion of food waste. The food waste was processed without any pre-treatment to remove physical impurities, neither water addition to dilute and slurry the feedstock. The experiment was carried out with inoculum to substrate ratios of 1:1 (w/w) and 0.08:1 (VS basis). Previous acclimation of liquid inoculum enhanced the process, assuring a fast start up of the box digester and preventing from process failure by volatile fatty acids accumulation. The percolate recirculation strategy was shown to have a relevant effect on the progress of the process. The results suggest that the process can be optimized by providing low percolate recirculation rate during the start-up of the box digester followed by an increase in the percolate recirculation rate when volatile fatty acids decrease and methane content in the biogas increases. The methane yield obtained in the box digester from the food waste was in the range 460–477 L CH4 kg−1 VS, being the VS removal efficiency between 91.1 and 91.4%. Globally, the process operated at an organic loading rate of 2.5 kg VS m−3 d−1 and yielded a volumetric methane production rate of 1.0 m3 CH4 m3 d−1. These results show the high potential of food waste for its conversion in renewable energy by using the dry batch anaerobic technology.

Chemical characteristics of organic-based liquid inoculant of Bacillus spp

Bacillus is an important soil rhizobacteria of many food crops and utilized as active substance in biofertilizer due to plant growth promoting activity. The objective of this research was to identify nutrient’s profiles and composition of primary and secondary metabolites in organic-based liquid inoculant of Bacillus spp. Proximate and molecular analysis had been carried out in laboratory by using standard method. The results verified that liquid inoculant contained organic carbon of 2.02%; small quantity of nitrogen, phosphor, potassium; and micronutrients iron and zinc. Heavy metals included lead, cadmium and chromium were detected in small amount, under the threshold level of heavy metal in organic fertilizer. The composition of primary metabolites in liquid inoculant was 0.31% of carbohydrate, 0.17% of protein, and 0.08% of lipid. The phytohormone of Indole Acetic Acid, gibberellin and cytokinin; as well as organic acids were detected in significant amount. This study suggests that consortia of Bacillus spp. enabled to synthesize phytohormone, organic acid, and exopolysaccharide which are important to promote plant growth.

STUDIES ON PEANUT BRADYRHIZOBIUM BROTH INOCULA AS AFFECTED BY IRRIGATION WATER QUALITY IN NEWLY RECLAIMED DESERT SOILS.

Peanut being a leguminous crop is capable of fixing atmospheric nitrogen. The present investigation had been carried out in order to study and evaluate the efficiency of both liquid and solid inoculum of Bradyrhizobium ssp (N2-fixing bacteria) alone or with plant growth promoting rhizobacteria (PGPR); Azotobacter chroococcum DSM 2286, as co-inoculation to reduce the negative impact of salinity of irrigation water (Nile Water (563 mg L-1) (W1), Groundwater artesian well, about 1000 mgL-1 (W2) and Groundwater artesian well about 2000 mgL-1 (W3), were collected from cultivated regions of Sadat city.) on peanut plants grown in cultivated sandy soils. Nodulation, fresh and dry weights of the growing plants and their elemental composition, mainly contents of nitrogen, phosphorus, potassium, manganese, zinc and Iron, yield, yield components as well as quality traits of the seed and oil of two peanut cultivars grown in sandy soils were determined. The biofertilizers inoculation treatments as follows: 1-Control treatments (without any biofertilizers inoculation). 2- Inoculation by solid Bradyrhizobium alone. 3-Inoculation by liquid Bradyrhizobium alone. 4- Co-inoculation: by solid Bradyrhizobium + PGPR (Azotobacter chrococoum), and 5- Co-inoculation: by liquid Bradyrhizobium fertilization + PGPR (Azotobacter chrococoum). It could be concluded that inoculation by liquid Bradyrhizobium + Azotobacter chroococcum seems to be the recommended treatment for producing optimum seed and straw yield and other parameters studied. Likewise it achieved the least production costs, also reducing the harmful effects of salinity of soil and/or irrigation water. These in turn reflect an increase in dry matter yield and after that pod, seed and straw yield. However, this approach could be explored as an effective strategy with least production costs to improve salt tolerance index in peanut plants under drip irrigation system in newly reclaimed soils in Egypt.

Antagonistic and plant-growth promoting novel Bacillus species from long-term organic farming soils from Sikkim, India.

Three bacteria namely Bacillus luciferensis K2, Bacillus amyloliquefaciens K12 and Bacillus subtilis BioCWB possessing plant growth promotion and biocontrol potential against phytopathogens and rice leaf folder were identified from organic soils of Sikkim, India. The results revealed significant higher production of phytohormones IAA (97.1μgmL-1) and GA3 (10.6μgmL-1) was found in K2, whereas BioCWB had higher phosphate solubilization (570.0μgmL-1) efficacy and also possessed nitrogen fixation ability (5.34 log copy number mL-1 culture). All these bacteria had higher antagonistic activities against phytopathogens viz. Rhizoctonia solani, Fusarium proliferatum, Athelia rolfsii and Colletotrichum gloeosporioides and also had higher larvicidal activity against rice leaf folder Cnaphalocrocis medinalis (Guenne) under in vitro conditions. Molecular insights into the antagonistic mechanisms of Bacillus strains deciphered the presence of several antimicrobial peptides (ericin, subtilin, surfactin, iturin, bacilysin, subtilosin, fengycin and bacillomycin), volatiles (dimethyl disulphide, methyl-Furan, acetic acid, Z-1,3-pentadiene and 3-hexyn-2-ol) and soluble metabolites (9-octadecenamide, E-15-heptadecenal, E-3-eicosene and 5-octadecene). Furthermore, liquid microbial inoculum prepared using the bacterial strains (K2, K12 and BioCWB) were evaluated under glass house (rice) and field condition (capsicum), which significantly enhanced plant growth in rice and yield in capsicum compared to control. The present study revealed the combination of Bacillus spp. (K2, K12 and BioCWB) can be used as bio-inoculants for improving agricultural production in Sikkim. Moreover, for the first time, we demonstrated plant growth promoting (PGP) traits, antifungal and insecticidal properties of B. luciferensis.

Biological incising of lodgepole pine and white spruce lumber with Dichomitus squalens

Deep penetration into wood is necessary for wood preservatives to provide long-term durability and for some wood modification agents to enhance wood properties. Bioincising was investigated as a means to enhance chemical penetration. Candidate fungi were screened for bioincising on pine and spruce samples. Dichomitus squalens dramatically improved wood permeability. Full preservative penetration was reached in spruce samples exposed to D. squalens isolate 78A for 6 weeks. No loss in compression stiffness was detected in small-scale bioincised samples. Optimum growth conditions, inoculation methods, and the practicality of bioincising were investigated on full size lumber. The optimal temperature for bioincising with D. squalens was around 30 °C. Bioincising was most effective using grain or liquid inoculum. Using liquid inoculum, spruce samples exposed for 6 weeks reached an average penetration of 10 mm through the heartwood face and 22 mm through the edge; and using grain inoculum average penetration was 10 mm through the heartwood face and 25 mm through the edge. On full-size lumber, bioincising was highly variable. Less than 50% of the bioincised samples achieved a minimum preservative uptake of 200 kg/m3. However, samples that met a minimum uptake of 200 kg/m3 of preservative and achieved 5 mm penetration on both edge and heartwood faces were within an acceptable range for strength loss, comparable to mechanical incising. The biggest barrier to commercialization of bioincising is the difficulty in achieving consistent fungal colonization of commercial size wood using a simple application method and the high variability in success.

Pepper (Capsicum ssp.) as a feed additive in sheep rations using two types of inoculum: Effects on in vitro digestibility and fermentation parameters

The influence of pepper (Capsicum ssp.) as a feed additive to balanced sheep rations on the in vitro digestibility coefficient of nutrients and their fermentation parameters was evaluated in two different inocula: rumen liquid and sheep feces. Four inclusion levels of pepper (0.0%, 0.2%, 0.4% and 0.6% of DM) and two types of inoculum were arranged in a 4 x 2 factorial arrangement, in a completely randomized design. Experimental rations were balanced to include 0.0%; 0.2%; 0.4% and 0.6% Capsicum ssp., with 13.5% crude protein and 70.0% total digestible nutrients (TDN). A basal diet of 60% bulk (corn silage) and 40% of the concentrate containing 0.0% Capsicum ssp. was given to the inoculant donor animals. Two sheep with a mean bodyweight of 27.6 + 1.6 kg were used as inoculum donors (ruminal fluid and feces) for the determination of the IVDC of nutrients. The variables studied were submitted for analysis of variance and the inclusion levels of pepper. Regression analysis was performed at 5% of probability and for the different inocula, a Tukey test was performed at 5% significance. The different levels of inclusion of pepper (0.0%, 0.2%, 0.4%, and 0.6%) in the balanced sheep rations were not altered (P &gt; 0.05) the IVDC of DM; OM; CP and NDF for both inocula (ruminal fluid and sheep feces). However, the use of the different inocula resulted in a change (P &lt; 0.05) in the IVDC value of DM, OM, CP, and NDF, in which the ruminal liquid inoculum presented higher (P &lt; 0.05) values of IVDC for the ration nutrients in relation to sheep feces. The levels of 0, 0%; 0.2%; 0.4% and 0.6% of pepper in ruminant feeds did not change the pH value of the fermented content after a 24-hour in vitro incubation (P &gt; 0.05). However, the use of ruminal liquid as inoculum for the in vitro fermentation of the experimental rations provided a lower value (P &lt; 0.05) for the pH of the fermented content in relation to the sheep feces. The inclusion of this phytogenic additive in ruminant feeds and the use of inoculum based on rumen fluid or sheep feces did not cause changes in the concentration of ammoniacal nitrogen (N-NH3) in the fermented rations after incubation (P &gt; 0.05) for 24 hours in vitro. Thus, the inclusion of up to 0.6% Capsicum ssp. (pepper) in balanced rations for ruminants does not alter the in vitro digestibility coefficient of dry matter, organic matter, crude protein, and neutral detergent fiber, or the in vitro fermentation parameters. However, the use of ruminal fluid as inoculum for the in vitro fermentation presented values of a higher degree of confidence in relation to feces to determine the in vitro digestion coefficient of the nutrients.

EVALUTION EFFICENCY OF LIQUID BRADRHIZOBIUM AND AZOTOBACTER CHROOCOCCUM DSM 2286 AS CO-INOCULATION AFFECTED BY SALINITY LEVEL OF IRRIGATION WATER ON PEANUT IN SANDY SOILS OF EGYPT

Peanut being a leguminous crop is capable of fixing atmospheric nitrogen. The present investigation had been carried out in order to study and evaluate the efficiency of both liquid and solid inoculum of Bradyrhizobium ssp (N2-fixing bacteria) and plant growth promoting rhizobacteria (PGPR); Azotobacter chroococcum DSM 2286, as co-inoculation to decrease the negative impact of salinity levels of irrigation water on peanut plants grown in cultivated sandy soils, as well as to comparatively evaluate the responses of two peanut cultivars to the studied treatments. A pot experiment peanut seeds were inoculated with solid or liquid inoculum of Bradyrhizobium and Azotobacter chroococcum DSM 2286 (PGPR) as co-inoculation, and planted in the sandy soils. Dry weights of the growing plants yield components and oil of two peanut cultivars were determined. It was clear that the rhizospheric soil of Gregory peanut cultivar plants achieved higher values of dehydrogenase activity compared with the Giza 6 peanut cultivar plants, with the assigned experimental treatments. The inoculation treatments with Azotobacter chroococcum, as Co-inoculation, with liquid Bradyrhizobium spp of Gregory cultivar peanut plants attained a higher seed protein and oil content (%), as compared to the other inoculation treatments.

Root Nodule Preparation as a Low-Cost Inoculant for Cowpea

Widely grown in diverse regions of Brazil, cowpea has high nutritional value, is easily cultivated, and can fix nitrogen (N) symbiotically. Although there are commercial inoculants for cowpea, it is difficult for small producers to acquire them. A nodule preparation is an inexpensive and easily prepared option for small farmers. The aim of this study was to test a nodule preparation as a low-cost inoculant, increasing cowpea seed grain production. Thus, different cowpea cultivars were compared in two locations, the municipalities of Crato and Madalena, both in Cear&amp;aacute;. Two field experiments were performed to evaluate gain derived from this inoculation method. The nodule preparation was created from nodules removed from roots of cowpea grown in the experimental locations. The nodules were macerated and added to water, obtaining a liquid (inoculant) that was applied to the seeds. The experiment was conducted following a randomized block design with four replicates and a 4 &amp;times; 3 factorial arrangement (N sources &amp;times; cultivars). Results indicate little interaction between the sources of N and the cultivars because only the shoot dry matter (Crato experiment) exhibited interaction between both. The differences provided by the nodule preparation were more notable among cultivars and between the environments, Crato and Madalena. The nodule preparation differed little from the commercial inoculant; they were comparable. However, gain in relation to the zero control also proved to be reduced, indicating little contribution of the nodule preparation to cowpea under the conditions tested.

Liquid Inoculation with Rhizobia in the Planting Furrow of Common Bean under No‐Till Is Feasible under Different Soil and Climatic Conditions

Common bean (Phaseolus vulgaris L.) producers that have adopted a high level of technology have shown interest in the use of liquid inoculant in the planting furrow, especially because of the practicality of this operation in large‐scale planting operations. However, consistent information on this practice is lacking for common bean, which requires studies to assist the producer in the choice of the inoculation method to be adopted and in determination of the application rates adequate for good performance of biological N2 fixation. To that end, two field experiments were conducted under the no‐till system under different soil and climatic conditions, both of them in irrigated areas. A randomized block experimental design was used, with four replications and seven treatments (three rates of liquid inoculation in the planting furrow; peat‐based or liquid inoculation on the seed; and two control treatments without inoculation, without and with N‐urea). The cultivar used was BRSMG Madrepérola and the rhizobial strain was CIAT 899 (±109 cells of Rhizobium tropici per milliliter or gram). Inoculation on the seed was performed shortly before sowing. Inoculation in the planting furrow at the rate of 3.5 L ha−1 not only leads to higher yields than inoculations on the seed but also ensures bean seed yields equivalent to those of the treatment with mineral N. Therefore, due to operational practicality, inoculation in the planting furrow is the most advantageous of the inoculations tested, regardless of the soil and climatic conditions in this study.

Paper-based inoculum of &lt;i&gt;Bacillus megaterium &lt;/i&gt;and its practical application for simple culture preparation

The bacterium Bacillus megaterium can be used to biologically control sheath blight and grain discoloration in rice. Large-scale inoculations using liquid cultures are cumbersome so the efficacy of an alternative, paper-based system was examined. Bacterial endospores were embedded on filter papers and multiplied using a simple culture technique. The resulting suspension was used to pre-soak yardlong bean and cucumber seeds before sowing to assess its effect on seed germination and weight. The efficacy of the bacterium in protecting cucumber seeds from pre-emergent damping-off was also examined. The population of bacteria embedded in paper declined initially but remained stable for 150 days at room temperature. Bacterial culture reduced seed germination of cucumber and seedling weight of yardlong beans. Dilution with water either increased or reduced germination of cucumber seeds depending on concentration. A 1:10 v/v dilution increased cucumber-seed germination in a pre-emergent damping-off pot test but all seedlings later died, irrespective of treatment. Paper-based inoculum has the potential to replace liquid inoculum but further work is required to optimise the concentrations of the bacterial culture to achieve disease control without adversely affecting the host plant.