New insights into soybean biological nitrogen fixation

• Autores: Ciampitti, Ignacio A.; Salvagiotti, Fernando
• Año de publicación: 2018
• Idioma: inglés
• Tipo de recurso: artículo
• Fuente: Agronomy Journal 110 (4) : 1185-1196 (2018)
• Materia: Soja; Nitrógeno; Fijación Biológica del Nitrógeno; Rendimiento; Soybeans; Nitrogen; Biological Nitrogen Fixation; Yields
• Institución: Instituto Nacional de Tecnología Agropecuaria

Soybean biological N2 fixation (BNF) relationships with fertilizer N and yield response have been comprehensively reviewed in the scientific literature. However, the study of the N-gap between N uptake and N supplied by N2 fixation, and the partial N balance (fixed N in aboveground biomass – N seeds) needs further investigation. Therefore, the goals of this synthesis–analysis were to (i) quantify seed production per unit of fixed N under different amounts of N derived from the atmosphere (NDFA, %), (ii) study the N-gap and explore limitations of N2 fixation (kg ha–1) for satisfying plant N demand, and (iii) calculate a partial N balance for soybean and determine its relationship with the N2 fixation process. Data was gathered from 1955 through 2016 using studies reporting BNF, seed yield, and plant N uptake (n = 733 data points). The main outcomes of this review were (i) as NDFA increased, seed production per N2 fixation decreased (from 0.033 to 0.017 Mg yield kg–1 N from low, 28%, to high, 80%, NDFA); (ii) N-gap increased faster when NDFA values were above 80% and after plant N content was above 370 kg N ha–1 suggesting that the crop needs additional N for coping yield potential; and (iii) when excluding roots, the partial N balance calculation revealed negative values across all NDFA levels. Future studies should consider a holistic approach to quantify the contribution of BNF in overall N cycling, including N contribution from roots, and to better understand the soil × plant × rhizobia interactions.
EEA Oliveros
Fil: Ciampitti, Ignacio A. Kansas State University. Department of Agronomy; Estados Unidos
Fil: Salvagiotti, Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Oliveros. Departamento de Agronomía; Argentina