Grain yield, efficiency and the allocation of foliar N applied to soybean canopies

• Autor(a) principal: Oliveira, Silas Maciel de
• Data de Publicação: 2019
• Outros Autores: Pierozan Junior, Clovis, Lago, Bruno Cocco, Almeida, Rodrigo Estevam Munhoz de, Trivelin, Paulo Cesar Ocheuze, Favarin, José Laércio
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Scientia Agrícola (Online)
• Texto Completo: https://www.revistas.usp.br/sa/article/view/157013
• topic: Glycine max (L.) Merr; foliar N fertilization; 15N tracer; foliar application; nitrogen recovery efficiency

Soybean [Glycine max (L.) Merr.] grain yield is closely associated with the level of optimal nitrogen (N) supply, especially during the reproductive stages. Foliar fertilization with low rates of N have been considered as a strategy for furnishing additional N and enhancing grain yields. Field studies using 15N tracer were conducted over two growing seasons to investigate the impact of foliar N fertilization on grain yield, plant N content, the amount of N derived from fertilizer (NDFF) and N recovery efficiency (NRE). Four foliar N rates (0, 1300, 2600 and 3900 g ha–1) were supplied by two equal split applications at the R1 and R3 stages. Foliar N fertilization of soybean canopies did not affect grain yield, grain N content, shoot N content nor plant N content. Total NDFF was increased from 0.7 to 2.0 kg ha–1 across the N rates. Nonetheless, NRE was unaffected by foliar N fertilization, which averaged 53 %. Soybean plants allocated the same amount of N fertilizer to both grains and shoots. No significant effects of low rate foliar N fertilization were registered on soybean grain yield nor plant N content, despite considerable N fertilizer recovery by plant organs.