02191naa a2200289 a 450000100080000000500110000800800410001902200140006002400460007410000210012024501290014126000090027050001560027952011600043565000120159565000150160765000130162265300330163565300400166870000200170870000210172870000170174970000210176670000200178770000240180777300700183121142992019-11-26       2019    bl uuuu     u00u1 u    #d  a1678-39217 a10.1590/S1678-3921.pab2019.v54.007212DOI1 aARAUJO, E. da S.  aComparison of 15N isotope methods to determine the recovery efficiency of nitrogen from green manure.h[electronic resource]  c2019  aTítulo em Português: Comparação de métodos isotópicos de 15N na determinação da eficiência de recuperação do nitrogênio da adubação verde  aThe objective of this work was to compare three methods of 15N isotope application to the soil in order to determine the recovery efficiency of nitrogen derived from green manure by corn (Zea mays). The used experimental design was a randomized complete block with six replicates. The treatments consisted of three 15N isotope methods: indirect method I, isotope dilution with 15N-labelled synthetic fertilizer applied through a small hole next to each corn plant; indirect method II, isotope dilution with 15N-labelled synthetic fertilizer spread in the furrow next to the corn planting row; and direct method, application of a legume straw as green manure, treated with 2.23% excess 15N. The green manure used was jack bean (Canavalia ensiformis). Applying synthetic 15N to the soil (indirect methods I and II) did not interfere in the estimation of the recovery efficiency of N derived from green manure. The recovery efficiency of N from green manure was 17% for the indirect methods, overestimated when compared with that of 7% for the direct method. The direct method is the most adequate to determine the recovery efficiency of N from green manure.  aLegumes  aLeguminosa  aZea Mays  aBiological nitrogen fixation  aFixação biológica de nitrogênio1 aSILVA, B. F. da1 aDALLA CHIEZA, E.1 aURQUIAGA, S.1 aGUERRA, J. G. M.1 aROUWS, J. R. C.1 aESPINDOLA, J. A. A.  tPesquisa Agropecuária Brasileira, Brasíliagv. 54, e00721, 2019