Research studies soybean cultivation in the North and Northwest of Rio de Janeiro

Soybean cultivation has been identified as one of the alternatives to occupy areas that were previously used by sugar cane in the North and Northwest of Rio de Janeiro. However, there are no associated climate risk studies, and any recommendation of cultivars for this region is entirely empirical. Embrapa hopes to contribute with research to fill this gap, with some projects that complement each other. Last year, the project Adaptation of soybean cultivation for grains and human consumption in the edaphoclimatic conditions of the North and Northwest of Rio de Janeiro, led by Embrapa Agrobiologia (Seropédica, RJ) researcher Cláudia Pozzi, was approved by the Rio de Janeiro Research Support Foundation (Faperj). The proposal is directly related to another project already conducted in the region by Embrapa, led by researcher Jerri Zilli.

The common intention of these projects is to introduce soybean cultivars into the region that are more adapted to the local climate and soil, with technological bases, increasing the State's economy and, simultaneously, contributing to the recovery of degraded areas and the reduction of the negative impact that observed with the decline of sugarcane cultivation, which began to decline mainly from the 1990s onwards. “These areas, previously occupied with sugarcane or in the renovation of sugarcane fields, could be used for the sustainable production of soybeans, making it possible to make the region is a regional hub for cultural production”, argues Pozzi.

The expectation, according to the researcher, is to identify 20 soybean genotypes that adapt to the location and have high production potential. Initially, 20 cultivars available on the market were selected for the experiments, all recommended by Embrapa Soja (Londrina, PR). “It is expected, for example, to identify early and later materials that can be sown at different times within the rainy season and that enable high grain yields from the crop”, she says. 

For the tests, the genotypes will be grown at two different sowing times, in locations whose soil is representative of the region and has been occupied in the past by sugarcane crops. At least three rural properties located in the Rio de Janeiro municipalities of Campos dos Goytacazes and Macaé will be selected, considering the 2019-2020, 2020-2021 and 2021-2022 harvests.

Productivity, cost and viability

Several factors will be analyzed over the planned three years of the project so that recommendations can be made for soybean cultivars that adapt to the region's conditions. Firstly, the cultivation value and use of the selected genotypes will be analyzed, following the criteria established by the Ministry of Agriculture, Livestock and Supply (Mapa). Other technical criteria include plant cycle, final stand, insertion height of the first pod, plant height, seed weight per 100 grams, lodging, productivity and protein and oil content. 

Based on the studies, the researchers involved hope to contribute to the specification of a soybean crop management system, subsidizing the work of rural extension technicians, farmers, development agencies, among other actors involved in production. Furthermore, the team will quantify the contribution of biological nitrogen fixation of soybean genotypes, through the assessment of aboveground biomass production and determination of total nitrogen content and natural abundance of 15N. Finally, production costs and crop profitability for the region will be estimated. 

The technical information generated on the agronomic performance of soybeans will provide support for the preparation of the Agricultural Climate Risk Zoning (ZARC) and the definition of the Edaphoclimatic Region for Culture (REC). “ZARC and REC, as a rule, are initially structured based on climate and soil information available for a given region, but local data from experimentation with the crop are essential for measuring local adjustments”, explains Pozzi.

Previous soybean studies in the Rio de Janeiro regions

Research on soy in the Northwest region of Rio de Janeiro is nothing new. In the 1980s and 1990s, Pesagro-Rio and the Universidade Estadual do Norte Fluminense (UENF) carried out tests with different cultivars of the grain from the Central-West and Southeast regions. “The results at the time demonstrated that some varieties had grain yields close to 4 thousand kilos per hectare, a rate well above the current national average”, explains the researcher. 

The difficulty in distributing production, among other factors, ended up preventing the development of culture in the area. “Currently, in addition to the domestic market, the inauguration of the Açu Port Complex, a sea port located just 40 kilometers from the potential producing region, with a structure for transporting grain production, could be a strategic factor”, he adds.

However, more than 13 years have passed without research related to the indication of soybean varieties for the region and, in this period of time, in addition to new varieties having emerged, many of the previously tested cultivars are no longer commercialized. “Considering the current situation of agriculture in the north and northwest of Rio de Janeiro, and also knowing the potential for soybean production there, this is a bottleneck to be resolved by research”, argues Pozzi.

The Federal Rural University of Rio de Janeiro, UENF and Pesagro-Rio also participate in the project.