EN 
PT_BR 
Since the 2015/2016 harvest, Embrapa Soja (PR) and the Paraná Rural Development Institute (IDR-Paraná) have been monitoring and validating the adoption of good practices for biological nitrogen fixation (FBN (Read more about this topic in the box below the article) among producers in the state, with a recorded average increase of 8,33% in productivity from seed co-inoculation. Co-inoculation consists of the joint application of two or more beneficial microorganisms, enhancing the action of BNF and combining profitability with economic and environmental sustainability.
The data obtained over the last decade are available in the publication "Coinoculation of soybeans with Bradyrhizobium and Azospirillum in the 2024/2025 crop season in Paraná," which presents the results from crops in Paraná, in Technological Reference Units (URTs). The authors of the publication are André Mateus Prando, Arnold Barbosa de Oliveira, Divania de Lima, Edison Ulisses Ramos Júnior, Edivan José Possamai, Eliana Aparecida Reis, Marco Antonio Nogueira, and Mariangela Hungria.
“Over these ten years, the URTs, which are conducted directly in commercial fields on rural properties, have allowed us to evaluate and validate the effectiveness of the technology in practice. The results obtained year after year have confirmed that the proper use of inoculation/co-inoculation has increased soybean productivity and relieved farmers of the costs of nitrogen fertilization in the crop, guaranteeing increased profitability and environmental benefits for the whole society,” state researcher André Prando, from Embrapa Soja, and Edivan Possamai, technical coordinator of the Grains project at IDR-Paraná.
The existence of a network of URTs (Regional Technology Units) throughout Paraná, structured by IDR-Paraná with the support of Embrapa, made it possible to include inoculation with Bradyrhizobium bacteria in the technology validation protocol for the 2015/2016 crop season. Co-inoculation began to be validated from the 2017/2018 crop season onwards, with the advancement of research and the findings that Azospirillum, a plant growth-promoting bacterium, was an ally of Bradyrhizobium in increasing soybean grain productivity.
According to Possamai, data was obtained from 22 URTs (Units of Reference Technology), installed in commercial farms in 17 municipalities across different regions of Paraná, during the 2024/2025 growing season. “These URTs, due to their geographical diversity, are important benchmarks for inoculation and co-inoculation technology. They offer an overview of what occurred during the growing season, since the locations present different soil types, climates, cropping systems, crop rotation (second-crop corn, wheat, oats, ryegrass, etc.), sowing times (early, normal, or late), and levels of technology employed by producers,” analyzes Possamai.
According to a survey by IDR-Paraná and Embrapa Soja, the average grain productivity in co-inoculated areas was 3,916 kilograms per hectare (kg/ha), while in non-inoculated areas it was 3,615 kg/ha. The average productivity in the URTs with co-inoculation in the 2024/2025 crop season was higher than the Paraná average of 3,663 kg/ha and the national average of 3,561 kg/ha, according to the National Supply Company (Conab).
On average, 641 of the Paraná producers surveyed stated that they used inoculant in soybean cultivation during the 2024/2025 crop season. The average use of co-inoculation with Bradyrhizobium and Azospirillum was 281 in the 2024/2025 crop season, according to the National Association for the Promotion and Innovation of the Biological Industry (ANPII Bio), in market research conducted by Kynetec in Paraná.
Benefits of technology
Research conducted by Embrapa Soja researchers Mariangela Hungria and Marco Antonio Nogueira reveals that annual inoculation of soybeans with the Bradyrhizobium bacteria, even in traditional cultivation areas that have previously received inoculants, guarantees maximum productivity without any application of nitrogen fertilizer.
In addition to annual inoculation with Bradyrhizobium, starting with the 2013/2014 crop season, Embrapa began recommending the combined use of a second bacterium for soybean inoculation in a process called co-inoculation, which uses two strains of the species Azospirillum brasilense (Ab-V5 and Ab-V6). "Soybean plants co-inoculated with Bradyrhizobium and Azospirillum exhibit more abundant and earlier nodulation, increasing the gains provided by annual inoculation with Bradyrhizobium alone," highlights Hungria.
