Response of determinate and indeterminate soybean cultivars to basal and topdressing N fertilization compared to sole inoculation with Bradyrhizobium
Soybean (Glycine max (L.) Merrill) new cultivars have high N demands to sustain increasing grain yields. One may ask whether these cultivars would need basal and/or topdressing N application as perhaps symbiotic N2 fixation would not catch up with the increased N needs. In this study, three field ex...
| Autores principales: | , , , |
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| Formato: | info:ar-repo/semantics/artículo |
| Lenguaje: | Inglés |
| Publicado: |
Elsevier
2018
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| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12123/3681 https://www.sciencedirect.com/science/article/pii/S0378429016301630?via%3Dihub https://doi.org/10.1016/j.fcr.2016.05.010 |
| Sumario: | Soybean (Glycine max (L.) Merrill) new cultivars have high N demands to sustain increasing grain yields. One may ask whether these cultivars would need basal and/or topdressing N application as perhaps symbiotic N2 fixation would not catch up with the increased N needs. In this study, three field experiments were performed in three different ecoregions of Brazil to compare soybean with determinate (BRS-294-RR and BRS-295-RR) and indeterminate (Vmax-RR, BMX-Potência-RR and BRS 284) growth types. The experiments consisted of four treatments, all inoculated with efficient Bradyrhizobium strains, but with differences in N fertilizer (as urea) application: (T1) control without N fertilizer; (T2) basal application of 30 kg N ha−1 at sowing; (T3) topdressing of 50 kg N ha−1 at full flowering; (T4) 30 kg N ha−1 and 50 kg N ha−1 as basal and topdressing, respectively. None of the basal or topdressing treatments improved biomass production or grain yield. However, N fertilizer negatively affected nodule number and dry weight, pointing out a down-regulation in the symbiotic performance, without improving crop yields. Similar results were observed in cultivars of both growth types, indicating that biological nitrogen fixation can supply N needs of new soybean genotypes of both growth types. |
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