caa a22 4500 606220186 CHVBK 20210128101122.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s11104-015-2468-7 doi (NATIONALLICENCE)springer-10.1007/s11104-015-2468-7 Uptake and allocation of nitrogen applied at low rates to soybean leaves [Elektronische Daten] [Clovis Pierozan Jr., José Favarin, Rodrigo de Almeida, Silas Maciel de Oliveira, Bruno Lago, Paulo Trivelin] Background and aims: Foliar nitrogen (N) fertilization of soybean crops is a practice that is being adopted in Brazil because soybean crops require N during the reproductive stages and certain soils have low N availability and reduced biological N fixation (BNF). Thus, low rates of leaf N are being used without scientific evidence for supporting the practice. The aim of this study was to analyze the uptake efficiency and allocation of N provided by foliar applications of low rates of urea-N during the soybean reproductive stage. Methods: The study was conducted in Taquarituba, Sao Paulo State (SP), Brazil during the 2012/13 and 2013/14 crop seasons. Rates of 0, 650, 1300 and 1950gNha−1 applied at the R1 or R3 growth stage were analyzed. Grain yield, N extraction by the grains, shoots (including leaves + stems + pod husks), total plants (grains + shoots), N derived from fertilizer (NDFF), 15N accumulation in grains or shoots, and fertilizer N-use efficiency by plant (NUE) were measured using 15N. Results: Foliar application of 1950gha−1 of N increased the N content in the shoots by up to 22kgha−1. Regardless of the year, the application during R3 yielded the highest NDFF values in the grains that were, on average, 20% higher than in R1. However, the highest mean values of NDFF and NUE were obtained from the R3 or R1 applications when there was less rainfall. Despite the high NUE (64%), foliar applications of low rates of N on soybean crops did not increase the seed yield. Conclusions: Most of the fertilizer N was allocated to the grains, especially when applied at the R3 growth stage. The NUE of the soybean crop ranged from 51 to 72%, and it was dependent on the phenological stage of the crop and climate conditions during crop growth in addition to the timing of fertilizer application. Foliar application of low rates of N on soybean crops did not increase seed yield. Springer International Publishing Switzerland, 2015 Glycine max nationallicence N-use efficiency nationallicence 15N nationallicence Fate of N nationallicence N derived from fertilizer nationallicence Foliar N nationallicence Pierozan Jr. Clovis Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), 11, Av. Pádua Dias, 13418-900, Piracicaba, SP, Brazil aut Favarin José Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), 11, Av. Pádua Dias, 13418-900, Piracicaba, SP, Brazil aut de Almeida Rodrigo Fishery and Aquiculture, Brazilian Corporation of Agricultural Research (EMBRAPA), 77020-020, Palmas, TO, Brazil aut Maciel de Oliveira Silas Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), 11, Av. Pádua Dias, 13418-900, Piracicaba, SP, Brazil aut Lago Bruno Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), 11, Av. Pádua Dias, 13418-900, Piracicaba, SP, Brazil aut Trivelin Paulo Center of Nuclear Energy in Agriculture (CENA), University of São Paulo (USP), 13400-970, Piracicaba, SP, Brazil aut Plant and Soil Springer International Publishing 393/1-2(2015-08-01), 83-94 0032-079X 393:1-2<83 2015 393 11104 https://doi.org/10.1007/s11104-015-2468-7 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s11104-015-2468-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Pierozan Jr Clovis Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), 11, Av. Pádua Dias, 13418-900, Piracicaba, SP, Brazil aut NATIONALLICENCE 700 1- Favarin José Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), 11, Av. Pádua Dias, 13418-900, Piracicaba, SP, Brazil aut NATIONALLICENCE 700 1- de Almeida Rodrigo Fishery and Aquiculture, Brazilian Corporation of Agricultural Research (EMBRAPA), 77020-020, Palmas, TO, Brazil aut NATIONALLICENCE 700 1- Maciel de Oliveira Silas Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), 11, Av. Pádua Dias, 13418-900, Piracicaba, SP, Brazil aut NATIONALLICENCE 700 1- Lago Bruno Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), 11, Av. Pádua Dias, 13418-900, Piracicaba, SP, Brazil aut NATIONALLICENCE 700 1- Trivelin Paulo Center of Nuclear Energy in Agriculture (CENA), University of São Paulo (USP), 13400-970, Piracicaba, SP, Brazil aut NATIONALLICENCE 773 0- Plant and Soil Springer International Publishing 393/1-2(2015-08-01), 83-94 0032-079X 393:1-2<83 2015 393 11104