Jump to Main Content
Mineral nitrogen impairs the biological nitrogen fixation in soybean of determinate and indeterminate growth types
- Saturno, Diogo Fernando, Cerezini, Paula, Moreira da Silva, Pedro, Oliveira, Arnold Barbosa de, Oliveira, Maria Cristina Neves de, Hungria, Mariangela, Nogueira, Marco Antonio
- Journal of plant nutrition 2017 v.40 no.12 pp. 1690-1701
- Bradyrhizobium, Glycine max, field experimentation, genotype, grain yield, indeterminate growth, nitrogen, nitrogen fixation, nodulation, nutrient solutions, sowing, soybeans, Brazil
- Soybean (Glycine max Merrill) crop production in Brazil relies mainly on biological nitrogen fixation (BNF) for nitrogen (N) supply. Recent adoption of indeterminate growth-type genotypes has raised doubts on the need for supplemental mineral N that might negatively affect the BNF. We assessed the effects of mineral N on BNF attributes of soybean genotypes grown in central and southern Brazil. Genotypes were inoculated with Bradyrhizobium sp. and/or received mineral N in three sets of experiments. In the first set, two genotypes received increasing rates of mineral N in nutrient solution, which consistently reduced the BNF. In the second set, mineral N applied at sowing and/or topdressing reduced nodulation and ureides-N in determinate and indeterminate growth-type genotypes. In the third set, mineral N applied at R5.3 stage, foliar or as topdressing, did not increase grain yield in four field experiments. Mineral N impaired BNF irrespective of the growth type and had no effect on grain yield.