Peat Inoculant Research Articles

Pyrolysis temperature affects biochar suitability as an alternative rhizobial carrier

Biochars produced from different feedstocks and at different pyrolysis temperatures may have various chemical and physical properties, affecting their potential use as alternative microbial carrier materials. In this study, biochars were produced from pine wood and oak feedstocks at various temperatures (400°C, 500°C, 600°C, 700°C and 800°C), characterized, and assessed for their potential as carriers for Bradyrhizobium japonicum (CB1809) strain. The biochars were then stored at two different storage temperatures (28°C and 38°C) for up to 90 days. Furthermore, the study also explored the role of potentially ideal carriers as inoculants in the growth of Glycine max L. (soybean) under different moisture levels i.e., 55% water holding capacity (WHC) (D0), 30% WHC (D1) and, 15% WHC (D2) using a mixture of 50% garden soil and 50% sand. The results were compared to a control group (without inoculants) and a peat inoculant. Among all the materials derived from pine wood and oak, pine wood biochar pyrolyzed at 400℃ (P-BC400) exhibited the highest CFU count, with values of 10.34 and 9.74 Log 10 CFU g− 1 after 90 days of storage at 28℃ and 38℃, respectively. This was notably higher compared to other biochars and peat carriers. Significant (p < 0.05) increases in plant properties: shoot and root dry biomass (174% and 367%), shoot and root length (89% and 85%), number of leaves (71%), membrane stability index (27%), relative water content (26%), and total chlorophyll (140%) were observed in plants treated with P-BC400 carrier inoculant compared to the control at D2; however, lower enrichment of δ13C (37%) and δ15N (108%) with highest number of root nodules (8.3 ± 1.26) and nitrogenase activity (0.869 ± 0.04) were observed under D2, as evident through PCA analysis, showing more nitrogen (N) fixation and photosynthetic activity. Overall, this experiment concluded that biochar pyrolyzed at lower temperatures, especially P-BC400, was the most suitable candidate for rhizobial inoculum and promoted soybean growth.

Effectiveness of Rhizobium tropici sp. Strain UD5 Peat Biofertilizer Inoculant on Growth, Yield, and Nitrogen Concentration of Common Bean

Common bean (Phaseolus vulgaris L.) ranks among the most produced and consumed legume crops and contains essential macro- and micronutrients. Grain yield of the food crop is markedly decreased by poor management, especially a lack of additional essential nutrient elements through the application of fertilizers. In addition to the application of fertilizers, scholarly research and crop farmers have shown that the use of biofertilizer inoculants improves the yield of legume crops. The objective of this research study was to assess the effectiveness of peat-based Rhizobium tropici sp. UD5 on the growth, yield, and nitrogen concentration of common bean. The peat inoculant contained 6.5 × 109 viable cells/g. The experiment was conducted in two climatic zones, as described by the Koppen–Gieger climatic classification system. Treatments involved the peat-based inoculant Rhizobium tropici (T0 = 0 g without inoculation, T1 = 250 g of peat inoculant of strain UD5 for 50 kg seeds, T2 = 500 g of inoculant of strain UD5, and T3 = 200 g of comparative peat inoculant). The results indicated that common-bean-inoculated formulation of R. tropici sp. strain UD5 increased the following parameters compared to the controls: plant height (T1 = 18.22%, T2 = 20.41%, and T3 = 19.93% for bioclimatic zone 1; T1 = 16.78%, T2 = 20.71%, and T3 = 19.93% for bioclimatic zone 2), root length (T1 = 13.26%, T2 = 21.28%, and T3 = 19.38% for zone 1; T1 = 15.06%, T2 = 23.70%, and T3 = 19.20% for zone 2), number of nodules (T1 = 1162.57%, T2 = 1166.36%, and T3 = 1180.30% for zone 1; T1 = 1575%, T2 = 1616.5%, and T3 = 1608.25% for zone 2), size of nodules (T1 = 224.07%, T2 = 224.07%, and T3 = 208.33% for zone 1; T1 = 166.4%, T2 = 180%, and T3 = 140% for zone 2), and yield (T1 = 40.49%, T2 = 47.10%, and T3 = 45.45% for zone 1; T1 = 62.16%, T2 = 54.05%, and T3 = 58.55% for zone 2). R. tropici sp. UD5 peat inoculant formulation also increased the nitrogen concentration in leaves compared to the control (T1 = 3.75%, T2 = 1.12%, and T3 = 8.72%) in both bioclimatic zones. The findings of this study provide significant information on the positive effect of R. tropic UD5 strain peat inoculant application in the improvement of plant growth, development, and yield through the formation of nodules.

Eficiencia de diferentes tipos de inoculantes en el cultivo de soja

The inoculation of Bradyrhizobium specific for the soybean crop is an indispensable practice in the cultivation of this leguminous plant. In this study, traditional inoculation via seed was chosen. The experiment was carried out in a soil classified as red oxisol with medium texture in a completely randomized design (DIC), with 4 treatments and 7 repetitions. Each experimental unit was comprised of a 1m² plot, and the treatments analyzed were: Liquid inoculant (T1); Peat inoculant (T2); Liquid + peat inoculant (T3) and no inoculant (T4). The objective proposed in this study was to verify the need to use inoculants in soybean planting in areas where the crop has been cultivated for more than six years. According to the F test, there was a significant difference between the treatments, with T3 standing from among the others for root length, number of nodules and nitrogen concentration on the leaf. T2, although inferior to T3, showed better results than treatments T1 and T4. In the experimental conditions using the Brasmax Bônus8579IPRO cultivar, there was a significant difference in the use of the products, with emphasis on the liquid inoculation + peat (T3), presenting a higher frequency concentration in the plant leaf, obtaining an even greater number of nodules and root length. As the value of the F statistic for the variables average root length, average number of nodes and average leaf transmit nitrogen content exceeds the critical value at the 1% probability level (4.72), they are represented at this level (P &lt; 0 ,01). As the calculated F values were greater than the tabulated F values for the three analyzed variables, we rejected the null hypothesis (H0), and concluded that the determining variables have different effects. Therefore, we can conclude that the most recommended for inoculation would be the use both products.

Identification of Ensifer meliloti genes required for survival during peat-based bioinoculant maturation by STM-seq

Rhizobial inoculants are sold either as rhizobia within a liquid matrix; or as rhizobia adhered to granules composed of peat prill or finely ground peat moss. During the production of peat-based inoculants, a series of physiological changes occur that result in an increased capability of the rhizobia to survive on the seeds. The number of viable rhizobia on preinoculated seeds at the point of sale, however, is often a limiting factor, as is the inefficiency of the inoculant bacteria to compete with the local rhizobia for the host colonization. In the present work, we used STM-seq for the genome-wide screening of Ensifer meliloti mutants affected in the survival during the maturation of peat-based inoculant formulations. Through this approach, we were able to identify a set of mutants whose behavior suggests that persistence in peat inoculants involves a complex phenotype that is connected to diverse cellular activities, mainly related to satisfying the requirements of bacterial nutrition (e.g., carbon sources, ions) and to coping with specific stresses (e.g., oxidative, mutational). These results also provide a base knowledge that could be used to more completely understand the survival mechanisms used by rhizobia during the maturation of peat-based inoculants, as well as for the design and implementation of practical strategies to improve inoculant formulations.

Agroeconomic response of inoculated common bean as affected by nitrogen application along the growth cycle

Biological nitrogen fixation (BNF) is an alternative for the supply of N, aiming at reducing production costs and environmental impacts of common bean crops. This work aimed to evaluate the agroeconomic performance of the inoculated common bean subjected to N-fertilizer application at different phenological phases. N-fertilizer, in a total of 90 kg ha-1 as urea, was applied at 3 phases: planting (P), phenological phase V4 (V4), and phenological phase R5 (R5) of the common bean, in two field experiments. The used treatments were: P0V40R50, P0V445R545, P0V490R50, P0V40R590, P30V430R530, P30V460R50, P30V40R560, P60V430R50, P60V40R530, and P90V40R50. All treatments were inoculated with peat inoculum containing the commercial strain SEMIA 4077 (Rhizobium tropici). The number of nodules (NN), nodule dry mass (NDM), leaf area index (LAI), root dry mass (RDM), shoot dry mass (SDM), grain yield (GY), production cost (PC), gross revenue (GR), net revenue (NR), and benefit-cost ratio (BCR) were determined. Inoculated treatment (P0V40R50) showed higher NN and NDM. Although inoculated treatment (P0V40R50) showed lower values of LAI, RDM, SDM, and GY, inoculation can result in GR, NR, and BCR equal to N-fertilized treatments, depending on the prices achieved for grains sale.

Efficacy of Peat and Liquid Inoculant Formulations of Bradyrhizobium japonicum Strain WB74 on Growth, Yield and Nitrogen Concentration of Soybean (Glycine max L.)

South African soils generally lack native Bradyrhizobium strains that nodulate and fix atmospheric nitrogen (N2) in soybeans (Glycine max L.). It is therefore very important to inoculate soybeans with products that contain effective Bradyrhizobium strains as active ingredients. In this study, a field experiment was conducted on two bioclimatic zones in South Africa during the 2019/2020 season to assess the effect of Bradyrhizobium japonicum strain WB74 inoculant formulation on nitrogen fixation, growth and yield improvement in soybeans. The first bioclimatic zone was characterized by a sandy clay loam soil, whereas the second bioclimatic zone has a sandy loam soil. The results showed that inoculation of soybeans with both peat and liquid formulations of Bradyrhizobium japonicum WB74 increased nitrogen uptake, which resulted in yield increase. The amount of N fixed was measured as 15N isotopes and increased with all treatments compared to the uninoculated control in both liquid and peat inoculant formulations. In bioclimatic zone A, slightly better results were obtained using the liquid formulation (1.79 t ha−1 for liquid compared to 1.75 t ha−1 for peat treatments), while peat formulations performed better in bioclimatic zone B (1.75 t ha−1 for peat compared to 1.71 t ha−1 for liquid treatments). In both areas higher yields were obtained with the formulations used in this study compared to the registered standards (treatment T3). The findings in this study provide vital information in the development and application of formulated microbial inoculants for sustainable agriculture in South Africa.

Productivity and gas exchanges of the common bean subjected to inoculation and nitrogen fertilization

Beans are one of the main foods consumed in Brazil. It is considered an essential ingredient in the basic diet of Brazilians. As a management practice, aiming to supply N and increase crop productivity, producers have used the association of seed inoculation with nitrogen fertilization. Thus, the objective of this study is to evaluate the effects of split nitrogen fertilization and seed inoculation on common bean productivity. The experiment was carried out in completely randomized blocks and a 2x2x3 factorial design with four replications. The first factor was seed inoculation (presence or absence) with peat inoculant containing the strains SEMIA 4077 and SEMIA 4080 from R. tropici and the strain SEMIA 4088 from R. freirei. The second factor was the parceling of nitrogen cover fertilization (80+40 and 60+60 kg ha-1 of N at 20 and 40 days after emergence (DAE)). The third factor was time of assessment (50, 65 and 80 DAE). The inoculated bean showed a 5% higher leaf N content than non-inoculated ones. Transpiration and liquid photosynthesis rates were higher in inoculated plants and in those with 60+60 kg ha-1 of N. However, productivity was 13% higher in uninoculated beans regardless of nitrogen fertilization.

Use of Spent Mushroom Substrate as an Inoculant Carrier and an Organic Fertilizer and Their Impacts on Roselle Growth (Hibiscus sabdariffa L.) and Soil Quality

The potential of using spent mushroom substrate (SMS) as inoculant carrier and organic amendment on the growth of Hibiscus sabdariffa was evaluated. SMS, peat and vermiculite were mixed with plant growth promoting bacteria (PGPB) isolate Bacillus amyloliquefaciens. Different treatments were applied in the cultivation of H. sabdariffa. We found that application of NPK fertilizer, SMS based inoculant, and peat based inoculant significantly promoted plant growth and chlorophyll content compared to other treatments. SMS based inoculant was the best treatment for increasing biomass and chlorophyll content, followed by NPK fertilizer. In addition, application of SMS inoculant or only SMS as soil amendment showed a significant improvement in soil properties including soil NPK, organic matter, soil PGPB and soil enzyme (i.e. soil fluorescein diacetate and dehydrogenase) as well as peat inoculant application. Our results suggested that SMS could be considered as an alternative low-cost, potential carrier in biofertilizer production or soil amendment for providing soil nutrients and recovering soil fertility in farming.

Use of inoculants and nitrogen fertilization related to yield and quality of soybean grains

Nitrogen (N) is the essential nutrient for soybean crop, which can be supplied to the crop through bacteria of the genus Bradyrhizobium, present in inoculants. Globally, soybeans are the main product for the production of oils and animal feed, thus the quality of the grains produced is extremely important. Thus, the objective of this study was to determine: yield and physical and physiological properties of grains, depending on the use of different types of inoculants and nitrogen fertilization, in transgenic and conventional soybean. We used a randomized block design with two cultivars, four replications and four treatments: peat inoculant, liquid inoculant, N fertilization and no inoculant, and nitrogenous fertilizer. The results show that the inoculation of soybean with liquid and peaty inoculants resulted in an increase in grain yield. In productivity, the conventional cultivar surpassed the transgenic cultivar. For conventional soybean, the peat inoculant proved to be efficient, since a larger mass of 1,000 grains and greater real specific mass were observed. The liquid inoculant showed high values when evaluated in the transgenic soybean, because it obtained higher values for apparent and real specific masses, number of grains germinated in the germination test and in the accelerated aging test.

Productivity and Economics of Inoculated Common Bean as Affected by Nitrogen Application at Different Phenological Phases

Nitrogen fertilizers are widely used on the cultivation of common bean in Brazil, affecting the production cost and the environment. Biological nitrogen fixation (BNF) can reduce the negative impacts related to N supply. This work aimed to evaluate the agroeconomic response of the inoculated common to N-fertilizer topdressing at different phenological phases of the common bean. N-fertilizer in a total of 90 kg ha−1 was applied in the form of urea at 3 phases: planting (P), phenological phase V4 (V4), and phenological phase R5 (R5) of the common bean, in two field experiments. The used treatments were P0V40R50, P0V445R545, P0V490R50, P0V40R590, P30V430R530, P30V460R50, P30V40R560, P60V430R50, P60V40R530, and P90V40R50. All treatments were inoculated with peat inoculum containing the commercial strain SEMIA 4077 (Rhizobium tropici). The number of nodules (NN), nodule dry mass (NDM), leaf area index (LAI), root dry mass (RDM), shoot dry mass (SDM), grain yield (GY), production cost (PC), gross revenue (GR), net revenue (NR), and benefit-cost ratio (BCR) were determined. N-fertilizer splitting at any dose and phenological phase decreased NN and NDM. N-fertilizer treatments provided higher LAI and SDM compared with the inoculated treatment (P0V40R50). Inoculated treatment presented higher GY and lower PC, resulting in greater NR and BCR. Inoculation with Rhizobium tropici provided high nodulation to the common bean and increased its GY in 10.2% as compared with N-fertilization, which allowed a 15.8% and 7.8% higher NR and BCR, respectively, than the N-fertilized treatment.

Nitrogen released from soybean crop in the performance of off season maize

The objective of this study was to evaluate the effect of Nitrogen (N), released from the soybean straw, on the variables of vegetative growth and grain yield of off season maize. The maize hybrid 2B688 PW ® was sowed on 02/26/2014, on the straw of a previous soybean experiment, seeded in October 2013, at the experimental area of the UFMT, campus Sinop-MT. The experimental design was randomized block with four replicates and a 2x8 factorial scheme. The first factor was the soybean cultivars (TMG 133 RR and TMG 1188 RR) and the second factor was the management of the soybean crop with different forms and doses of inoculant, plus a control and a treatment with the application of 200 kg of mineral N. The vegetative growth variables and grain yield were assessed. The variables of vegetative growth were not altered by the management of inoculation/fertilization with mineral N or the soybean cultivar used as the previous crop. The grain yield was affected by the soybean cultivar and the interaction of cultivar and treatments carried out on the soybean previous cultivated. The grain yield was higher with the use of the TMG 1188 RR cultivar and inoculation in the seed by peat inoculant.

English

Pre-inoculation of soybean seeds with Bradyrhizobium spp. associated with polymers could be an alternative to the conventional inoculation performed at the day of sowing. The objectives of this study were i) to determine whether the HiCoat® technology (peat inoculant + liquid inoculant + polymer) allows the survival of B. elkanii after storage of the inoculated seeds, and ii) to evaluate whether the pre-inoculation and seed treatment reduces the physiological quality of seed and soybean yield. Soybean seeds were treated with different fungicides and insecticides associated with pre-inoculation using HiCoat® and the seeds were stored at room temperature. The survival of B. elkanii was reduced over time with standard inoculation, however there was above 2 x 106 colony-forming units of B. elkanii per seed at 60 days after inoculation with HiCoat®. Seed germination, number of nodules per plant, mass of nodules, yield, number of grains per plant and number of pods per plants were not significantly affected by the pre-inoculation and seed treatments. Our findings indicated that the fungicide and insecticide associated with HiCoat® can be used to treat and to pre-inoculate seeds that can be stored for up to 71 days without compromising the nodulation of plants and soybean yield. Key words: Industrial seed treatment, biological nitrogen fixation, storage period, fungicide, insecticide, polymer, HiCoat, Glycine max.

Analysis of soybean cultivars in response to different forms of inoculation

Biological Nitrogen Fixation (BNF) is essential for soybeans in Brazil, eliminating the use of mineral nitrogen and reducing the cost of production. This study aimed to analyse the soybean cultivars in response to different ways of seed inoculation. The experiment was conducted at the Federal University of Mato Grosso in the municipality of Sinop-MT, implemented in the 2014/15 crop. A randomized block design with four replicates was used and four treatments were tested: 1) peat inoculant; 2) liquid inoculant; 3) control (without inoculation and without nitrogen fertilizer); 4) fertilization with mineral N (240 kg ha -1 N), and 120 kg ha -1 of N were applied at sowing and the same rate 35 days after emergence. All seeds were treated with Fipronil insecticide + Pyraclostrobin and Methyl Thiophanate fungicides. The parameters evaluated were plant height, leaf chlorophyll and at the end of soybean cycle, the number of pods per plant, grain yield, weight of 1000 seeds, and productivity. Overall, no significant differences were found between treatments, this may have occurred due to the fact that the soil already has an established population of rhizobia, which are capable of forming a symbiosis with soybeans.

Maize Inoculation with Azospirillum brasilense Ab-V5 Cells Enriched with Exopolysaccharides and Polyhydroxybutyrate Results in High Productivity under Low N Fertilizer Input.

Although Azospirillum strains used in commercial inoculant formulations presents diazotrophic activity, it has been reported that their ability to produce phytohormones plays a pivotal role in plant growth-promotion, leading to a general recommendation of its use in association with regular N-fertilizer doses. In addition, a high variability in the effectiveness of Azospirillum inoculants is still reported under field conditions, contributing to the adoption of the inoculation technology as an additional management practice rather than its use as an alternative practice to the use of chemical inputs in agriculture. To investigate whether the content of stress-resistance biopolymers would improve the viability and performance of Azospirillum inoculants when used as substitute of N-fertilizers, biomass of A. brasilense strain Ab-V5 enriched in exopolysaccharides (EPS) and polyhydroxybutirate (PHB) was produced using a new culture medium developed by factorial mixture design, and the effectiveness of resulting inoculants was evaluated under field conditions. The culture medium formulation extended the log phase of A. brasilense cultures, which presented higher cell counts and increased EPS and PHB contents than observed in the cultures grown in the OAB medium used as control. An inoculation trial with maize conducted under greenhouse conditions and using the biopolymers-enriched Ab-V5 cells demonstrated the importance of EPS and PHB to the long term bacterial viability in soil and to the effectiveness of inoculation. The effectiveness of liquid and peat inoculants prepared with Ab-V5 cells enriched with EPS and PHB was also evaluated under field conditions, using maize as target crop along different seasons, with the inoculants applied directly over seeds or at topdressing under limiting levels of N-fertilization. No additive effect on yield resulted from inoculation under high N fertilizer input, while inoculated plants grown under 80% reduction in N fertilizer showed yields at levels compared to fully fertilized plants, regardless the inoculation method. The presented data highlights the feasibility to partially substitute the N-fertilizer demand in non-legume crops using high-quality inoculant formulations, prepared with diazotrophic bacteria enriched with stress-resistance biopolymers that confer increased viability an effectiveness to the bacterial cells.

Legume inoculant application methods: effects on nodulation patterns, nitrogen fixation, crop growth and yield in narrow-leaf lupin and faba bean

Liquid and granular rhizobial inoculants have some practical advantages for delivering rhizobial inoculants to legume crops in terms of ease-of-use and in separating rhizobia from potentially harmful seed-applied pesticides. The aim of this research was to determine whether inoculant application methodologies altered the patterns of nodulation on roots, inputs of symbiotic nitrogen (N2) fixation, the accumulation of legume shoot dry matter (DM), grain yield, and grain nitrogen (N). Eight field experiments were established at four different locations in south-eastern Australia to quantify the response of lupin (Lupinus angustifolius L.) and faba bean (Vicia faba L.) to three inoculant application methods (on-seed application as a peat slurry, in-furrow peat inoculant delivered as a liquid suspension at seeding, in-furrow peat granules delivered at seeding) compared with uninoculated treatments. N2 fixation was assessed using the 15N natural abundance method and canola was included as a non-legume reference. Inoculation significantly improved crown nodulation, from 0.05 to 13 nodules plant−1 in lupin at two sites and from 0.17 to 21.3 nodules plant−1 in faba bean at three sites. Nodulation responses were decreased for faba bean treatments at sites with low pH, and for both lupin and faba bean at sites where soils contained large populations of naturally-occurring rhizobia. Inoculation increased grain yield from 0.48 to 1.94 t ha−1 in faba bean relative to uninoculated treatments at two sites; N2 fixation increased by 175 kg N ha−1 in lupin at one site and by 46 to 280 kg N ha−1 in faba bean at two sites. The different inoculant application methods led to minor differences in crown and lateral root nodulation patterns but only impacted N2 fixation and grain yield at one site with faba bean, where peat slurry treatments had 186 to 195 kg N ha−1 more N2 fixation than other treatments and peat slurry and granules provided 0.8 to 1.0 t ha−1 more grain yield than liquid inoculants. On-seed application of peat slurry always provided the best nodulation, grain yield and N2 fixation. Small changes in nodulation patterns using in-furrow inoculants only resulted in reduced N2 fixation in faba bean at one site. At that site faba bean grain yield was reduced by 1.0 t ha−1 in liquid inoculant treatments, compared with on-seed peat slurry treatments.

Contribution of a mixed inoculant containing strains of Burkholderia spp. and Herbaspirillum ssp. to the growth of three sorghum genotypes under increased nitrogen fertilization levels

Sorghum bicolor is a C4 plant that is normally associated with diazotrophs. Inoculation with selected bacteria can improve plant growth, biological nitrogen fixation (BNF) and nutrient uptake. Therefore, the objective of the current study was to evaluate the ability of twenty-two diazotroph strains to improve sorghum growth in a greenhouse. Then, a mixture of the best performing strains was applied in the field under different levels of N-fertilizer applied to three sorghum genotypes to evaluate crop productivity, N content, BNF contribution and the efficiency of the N fertilizer used under field conditions. Two Herbaspirillum and two Burkholderia species were selected under greenhouse conditions using a sterile substrate of three sorghum genotypes: grain sorghum lineage 9920044, grass BRS655 and sweet sorghum BR501. Four diazotrophs were selected for the field trial. Burkholderia kururiensis (16 and 109), B. tropica (PPe6) and Herbaspirillum seropedicae (ZMS176) were cultivated and mixed at planting in a Typic Hapladult soil using peat inoculant. Crop yield, N-content and BNF quantification were determined using the natural abundance of 15N, and the use efficiency of the applied N was assessed using urea labelled with 15N. The grain yield showed a 24% enhancement in the inoculated grain sorghum compared with the control without nitrogen. In addition, the aerial biomass was 13% higher in the grass genotype compared with the control. The sweet sorghum did not respond to any treatment. BNF quantification reached 31.4% in the grain, 22.7% in the grass and 19.4% in the sweet sorghum genotypes. Grain sorghum inoculation increased BNF by 4% (9.5kgha−1N fixed). Inoculation increased fertilizer efficiency recovery by 28.9%. Inoculation using a mixture containing the four diazotrophs improved the sorghum productivity by enhancing the dry mass, N-content, N from BNF and N use efficiency in the grain and grass genotypes. Under zero nitrogen fertilizer application, 22% of the N that accumulated in the biomass was derived from the air. New inoculants using a mixture of different bacterial species/strains can improve the knowledge and contribution of BNF in agricultural systems.

Co-inoculação e Modos de Aplicação de Bradyrhizobium japonicum e Azospirillum brasilense e Adubação Nitrogenada na Nodulação das Plantas e Rendimento da Cultura da Soja

As new cultivation techniques arise, crops require the development of new technologies and management practices that aim higher yields with lower production cost. Thus, the objective of this study was to evaluate the efficiency of co-inoculation and different ways of application of Bradyrhizobium japonicum and Azospirillum brasilense and nitrogen fertilization on nodulation and yield of soybean. The experiment was established in November 2013 in an area located in the Iguatemi Experimental Farm, of State University of Maringa (UEM). The design was a randomized block with four replications. The treatments consisted of a control, fertilization with nitrogen (200 kg N ha -1 ), standard inoculation in seeds (liquid and peat inoculant), co-inoculation on seed and co-inoculation at sowing, using different doses of inoculant B. japonicum and A. brasilense. The following determinations were carried out in the field and in the laboratory: number of nodes at flowering, mass of nodules at flowering, the shoot dry mass, nitrogen content in the shoot, grain nitrogen content, number of pods/plant, thousand grain mass and yield. The results showed that inoculation through seed treatment with liquid inoculant presents an adequate option to farmers, in the conditions of this experiment. Nitrogen fertilization did not increase yield and yield components, being unnecessary.

Contrasting Rhizobium inoculation requirements of zero-tannin faba bean and narrow-leafed lupin in western Canada

Lopetinsky, K. J., Lupwayi, N. Z., Olson, M. A., Akter, Z. and Clayton, G. W. 2014. Contrasting Rhizobium inoculation requirements of zero-tannin faba bean and narrow-leafed lupin in western Canada. Can. J. Plant Sci. 94: 1117–1123. Zero-tannin faba bean (Vicia faba minor) and narrow-leafed lupin (Lupinus angustifolius L.) have shown potential as new pulse crops in Alberta cropping systems, but their inoculation requirements to maximize biological N2 fixation (BNF) are unknown. We conducted a 6 site-year study to compare the effects of several commercial rhizobial inoculant products (eight for faba bean and three for lupin) in different formulations (granular, peat and liquid) on nodulation, N accumulation, grain yield and grain protein of the two crops. The liquid and peat formulations were applied to the seed, while the granular inoculant was applied to the soil. Inoculation had no significant effects on nodulation, grain yield and seed weight of faba bean in all site-years. Un-inoculated and inoculated plants nodulated equally well, suggesting the presence of adequate populations of effective indigenous Rhizobium leguminosarum bv. viciae for nodulation of untreated plants. The indingenous rhizobia could have originated from previous field pea (Pisum sativum L.) crops or leguminous native plants/weeds. By contrast, narrow-leafed lupin responded to inoculation in all site-years, and poor nodulation of un-inoculated plants indicated inadequate populations of indigenous R. lupini for nodulation in the soils. The seed-applied peat inoculant Nitragin Lupin and the soil-applied granular inoculant Soil Implant Lupin were equally effective in increasing nodulation relative to the un-inoculated control in 3 of 5 site-years (nodulation was not assessed in 1 site-year). However, relative to the un-inoculated control, Nitragin Lupin increased grain yields in 4 of 6 site-years compared with 1 of 5 for Soil Implant Lupin (and 2 of 6 for seed-applied TagTeam Lupin). These results show that faba bean probably does not require inoculation in these soils, although periodic checking is required to ensure that its high BNF potential is always realized, but narrow-leafed lupin needs to be inoculated with suitable inoculant products to increase BNF.

Contrasting Rhizobium inoculation requirements of zero-tannin faba bean and narrow-leafed lupin in western Canada

Lopetinsky, K. J., Lupwayi, N. Z., Olson, M. A., Akter, Z. and Clayton, G. W. 2014. Contrasting Rhizobium inoculation requirements of zero-tannin faba bean and narrow-leafed lupin in western Canada. Can. J. Plant Sci. 94: 1117-1123. Zero-tannin faba bean (Vicia faba minor) and narrow-leafed lupin (Lupinus angustifolius L.) have shown potential as new pulse crops in Alberta cropping systems, but their inoculation requirements to maximize biological N2 fixation (BNF) are unknown. We conducted a 6 site-year study to compare the effects of several commercial rhizobial inoculant products (eight for faba bean and three for lupin) in different formulations (granular, peat and liquid) on nodulation, N accumulation, grain yield and grain protein of the two crops. The liquid and peat formulations were applied to the seed, while the granular inoculant was applied to the soil. Inoculation had no significant effects on nodulation, grain yield and seed weight of faba bean in all site-years. Un-inoculated and inoculated plants nodulated equally well, suggesting the presence of adequate populations of effective indigenous Rhizobium leguminosarum bv. viciae for nodulation of untreated plants. The indingenous rhizobia could have originated from previous field pea (Pisum sativum L.) crops or leguminous native plants/weeds. By contrast, narrow-leafed lupin responded to inoculation in all site-years, and poor nodulation of un-inoculated plants indicated inadequate populations of indigenous R. lupini for nodulation in the soils. The seed-applied peat inoculant Nitragin Lupin and the soil-applied granular inoculant Soil Implant Lupin were equally effective in increasing nodulation relative to the un-inoculated control in 3 of 5 site-years (nodulation was not assessed in 1 site-year). However, relative to the un-inoculated control, Nitragin Lupin increased grain yields in 4 of 6 site-years compared with 1 of 5 for Soil Implant Lupin (and 2 of 6 for seed-applied TagTeam Lupin). These results show that faba bean probably does not require inoculation in these soils, although periodic checking is required to ensure that its high BNF potential is always realized, but narrow-leafed lupin needs to be inoculated with suitable inoculant products to increase BNF.

Rhizobial counts in peat inoculants vary amongst legume inoculant groups at manufacture and with storage: implications for quality standards

Inoculation of legumes at sowing with rhizobia has arguably been one of the most cost-effective practices in modern agriculture. Critical aspects of inoculant quality are rhizobial counts at manufacture/registration and shelf (product) life. In order to re-evaluate the Australian standards for peat-based inoculants, we assessed numbers of rhizobia (rhizobial counts) and presence of contaminants in 1,234 individual packets of peat–based inoculants from 13 different inoculant groups that were either freshly manufactured or had been stored at 4 °C for up to 38 months to determine (a) rates of decline of rhizobial populations, and (b) effects of presence of contaminants on rhizobial populations. We also assessed effects of inoculant age on survival of the rhizobia during and immediately after inoculation of polyethylene beads. Rhizobial populations in the peat inoculants at manufacture and decline rates varied substantially amongst the 13 inoculant groups. The most stable were Sinorhizobium, Bradyrhizobium and Mesorhizobium with Rhizobium, particularly R. leguminosarum bv. trifolii the least stable. The presence of contaminants at the 10−6 level of dilution, i.e. >log 6.7 g−1 peat, reduced rhizobial numbers in the stored inoculants by an average of 37 %. Survival on beads following inoculation improved 2–3 fold with increasing age of inoculant. We concluded that the Australian standards for peat-based rhizobial inoculants should be reassessed to account for the large differences amongst the groups in counts at manufacture and survival rates during storage. Key recommendations are to increase expiry counts from log 8.0 to log 8.7 rhizobia g−1 peat and to have four levels of inoculant shelf life ranging from 12 months to 3 years.