Pseudomonas fluorescens increases the productivity of second-crop corn

Efficient use of phosphorus remains one of the main challenges in second-crop corn cultivation, especially in tropical soils under no-till systems. Even with proper soil correction and fertilization practices, some of the applied phosphorus may remain unavailable to plants, reducing nutrient uptake and impacting productivity.

In this scenario, the use of beneficial microorganisms emerges as a complementary alternative in the nutritional management of crops. The bacterium Pseudomonas fluorescens has stood out for its action in the rhizosphere, favoring the solubilization of phosphorus and stimulating root development, which can result in better productive performance.

The objective of this study was to evaluate the effect of applying Pseudomonas fluorescens, alone or in combination with Azospirillum brasilense, on the productivity of second-crop corn under real field conditions.

Regarding the area under analysis

The experiment was conducted in a commercial area in the municipality of Bauru (SP), in soil classified as eutrophic red latosol, under a no-till system. The area had a history of adequate fertility management, with soil correction and fertilization carried out according to the technical practices of the property.

Methodology used

The early-cycle corn hybrid P3889R was used, sown in the second crop season, with an approximate population of 65 plants per hectare and a spacing of 0,50 meters between rows. Nutritional management included base fertilization with NPK fertilizer and nitrogen topdressing.

The treatments evaluated consisted of applying different management techniques with biological inoculants directly into the planting furrow: area without inoculant application; application of Azospirillum brasilense; application of Pseudomonas fluorescens; combined application of both bacteria at the commercial dose; and combined application at half the dose. Applications were carried out at planting time, using a directed spray in the furrow.

Throughout the crop cycle, the overall development of the plants was monitored. At the end, the production components and grain yield were evaluated. Harvesting was carried out manually, at the appropriate moisture level, aiming to preserve grain quality and reduce losses.

Productivity was expressed in sacks per hectare, allowing for direct comparison between the different management practices evaluated. The data obtained were subjected to statistical analysis to assess the productive performance of the treatments.

Results obtained

Statistical analysis of the data indicated that there was no statistically significant difference between the treatments evaluated, considering the probability level adopted. The production components and final productivity showed similar behavior between the management practices, demonstrating the productive stability of the corn under the experimental conditions.

Despite the absence of a statistically significant difference, relevant numerical differences were observed between the treatments.

The management system using only Pseudomonas fluorescens resulted in the highest average productivity, reaching approximately 187 sacks per hectare, equivalent to 11.220 kg per hectare.

Treatments involving the application of Azospirillum brasilense, alone or in combination with Pseudomonas fluorescens, showed yields ranging from 168 to 184 sacks per hectare, while the area without inoculant application showed the lowest average yield.

These results indicate that the use of growth-promoting microorganisms can contribute to consistent productivity gains, even when the differences are not statistically significant.

From a practical standpoint, numerical differences of this magnitude can represent a significant economic impact for the producer, especially when considered on a commercial scale.

Graphical analysis of the results

The graphical analysis of the data facilitates the visualization of the productive behavior of the different management practices evaluated. The graphs of productivity, average ear weight, and number of ears show the trend of higher performance in the treatment with Pseudomonas fluorescens, in addition to the overlap of average values ​​between treatments, which is consistent with the results of the statistical analysis.

The data distribution shows a relatively uniform pattern, reinforcing the observed productive stability. Even so, the treatment with Pseudomonas fluorescens shows the highest average productivity values, indicating a positive response under real field conditions.

The histogram represents the frequency distribution of the data of interest, such as the application of bacteria in response to P remineralization in corn production; the density curve smooths and presents the distribution of the histogram, providing a continuous view of the relative probabilities. It helps to better understand the central tendency, dispersion, and the presence of possible asymmetries or peaks.

Observing the density of the graphs presented in Figure 1, the responses to the bacterial applications showed symmetrical patterns and converged to a response that centered the data around the mean and standard deviation. Reinforcing this response, Bashan et al. (2014) highlighted that the variability in the response to inoculation may be a result of factors such as the compatibility between the bacteria and the plant, the availability of nutrients, and environmental conditions.

The closing thought

Results obtained under real field conditions indicate that the application of Pseudomonas fluorescens in second-crop corn has the potential to increase productivity and improve phosphorus use efficiency. Application in the planting furrow proved to be simple, operationally feasible, and compatible with the routine of commercial crops.

The use of biological inoculants does not replace conventional fertilization, but it can act as a complementary tool in the nutritional management of the crop. Further evaluations in different environments and growing seasons can contribute to consolidating the use of this technology in the second-crop corn production system.

* By Leonardo Monteiro Rocha, Emmanuel Zullo Godinho and Caetano Dartiere Zulian Fermino (Unisagrado)

Article published in issue 320 of Cultivar Grandes Culturas Magazine