Nitrogen (N) is the most limiting nutrient for corn production. Thereby, the goal of the paper was to evaluate inoculation methods of Azospirillum brasilense in order to partially supply N required by the crop. The experiment was carried out in Guarapuava, PR, Brasil, in 2011/2012

Seed treatment is a practice that helps the initial establishment of the crop without the effects caused by pests and diseases. The association of diazotrophic bacteria with grasses has been used in the supply of nitrogen to plants; however, these microorganisms produce growth-promoting substances, which promote benefits in the growth and development of the crops. Thus, the objective of this study was to evaluate the compatibility of Azospirillum brasilense associated with the fungicide difenoconazole and the insecticide thiamethoxam by observing the effects on the quality of seed emergence of three wheat cultivars (Triticum aestivum L.). Three wheat cultivars, arranged in a 4 x 2 factorial system with four replicates, were tested. The treatments were the control; difenoconazole (Spectro® at a dose of 150 mL per 100 kg of seed); thiamethoxam (Cruiser® FS 350 at a dose of 200 mL per 100 kg seed) and difenoconazole + thiamethoxam, applied on wheat cultivars TBIO Mestre, TBIO Itaipu and TBIO Sinuelo. Bacteria from the Azospirillum genus were used in the inoculation. The wheat seed retains its quality when it checks the germination, vigor and independent accelerated aging, whether or not fungicide, insecticide and A. brasilense were used. The insecticide thiamethoxam increased the length of shoots and roots and provided compatibility with A. brasilense, and fungicide inhibited the length of shoots and roots and was antagonistic to the bacterium A. brasilense.

Nitrogen is available in insufficient quantities in Brazilian soils, and is the nutrient that raises the most cost of production of maize. Nowadays there is a more interest in the use of alternative nitrogen sources, such as biological nitrogen fixation, to supply plant demand. Among the most used bacteria in association with grasses is Azospirillum brasilense. In this way this study aimed to establish a relationship between the genetic bases of corn and the forms of A. brasilense application and the effects on the plant morphological components, grain yield, and relative nitrogen contribution. Experiments were conducted during the 2013/14 and 2014/15 crop seasons. The experiments included two single hybrids, two double hybrids, and two triple hybrids inoculated with A. brasilense via seed treatment; foliar application during phenological stages V2, V2 + V4, and V4; and a control treatment without bacteria. The response varied with the hybrid and the year. In the 2013/14 crop, a significant difference was observed in the grain yield for the single hybrid AG9045 inoculated with A. brasilense via seed and foliar application in V2. In the 2014/15 crop, inoculation with A. brasilense via seed application resulted in significant increases in the grain yield for the triple hybrid BG7051. Foliar application of A. brasilense is an efficient alternative for the improvement of plant morphological traits, and inoculation via seed and with foliar application in V2 increases the relative contribution of N.

The practice of soybean seed inoculation cannot exceed the 24-hour prior to sowing. The objective of this study was to assess the effects of inoculation and co-inoculation of osmoprotectant soybean seeds, performed at different times of sowing. The experiments were conducted during two crop seasons at "sandy clay loam Acrisol" and "Cfa climate" in Santa Maria, RS, Brazil. The experimental design consisted of completely randomized blocks with four replications. Nine distinct treatments of seeds inoculation were carried out with bacteria of the genus Bradyrhizobium were inoculated alone (conventional inoculation) or combined with Azospirillum brasilense (co-inoculation), associated with the use of osmoprotectants. The components of nodulation, leaf chlorophyll, plant growth and grain yield were evaluated. The number of nodules and pods per plant are the variables most correlated with grain yield. Number of grains per pod, mass of thousand grains, and A, B and total chlorophyll content were not influenced by inoculation, co-inoculation and nitrogen fertilization. All treatments that used osmoprotectant had an increased 30% (in the first year) at average number of nodules in V5 compared to the treatments that did not use it. Co-inoculation provided an increase of 31% and 16% of yield, respectively, compared to the no-inoculation treatment, for the first and second experimental years. Inoculation and co-inoculation when carried out seven days before sowing and associated with the use of the osmoprotector, provides grain yield similar to the inoculation performed at the time of sowing.

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