01855naa a2200241 a 450000100080000000500110000800800410001910000130006024501500007326000090022352011380023265000160137065000230138665000230140965000230143265000100145570000140146570000220147970000150150170000190151670000190153577300590155411341272023-12-15       2023    bl uuuu     u00u1 u    #d1 aHAHN, L.  aNitrogen doses and sources applied as top-dressing in onion crops grown under no-tillage and conventional tillage systems.h[electronic resource]  c2023  aNitrogen (N) fertilization effectiveness in onion depends on N source, as well as on soil type and management system. The aim of the study is to investigate the effect of N sources and doses applied as top-dressing on bulb yield, leaf N contents and on the postharvest conservation of onion bulbs grown under no-tillage (NTS) and conventional tillage (CTS) systems. Three experiments were carried out: two in Lebon R??gis County-SC, under NTS; and one in Ca??ador County-SC, under CTS. The herein tested N sources comprised urea, ammonium nitrate, calcium nitrate and ammonium sulfate, in combination to N doses applied as top-dressing (70, 140, 210, 280 and 350 kg N ha-1) in addition to the control, without N. The N sources did not affect yield parameters, leaf N content and post-harvest onion losses. The maximum technical efficiency in bulb yield was observed at N doses of 195.8 and 258.4 kg ha-1 in the no-tillage system (NTS) and at 270.7 kg N ha-1 in the CTS. The NTS enabled maximum yield at N dose 47% lower than the officially recommended one. Maximum relative commercial yield was associated with 31.1 g kg-1 of leaf N.  aAllium cepa  anitrato de am??nio  anitrato de c??lcio  asulfato de am??nio  aureia1 aKURTZ, C.1 aGRAZZIOTIN, A. F.1 aBEE, A. M.1 aFELTRIM, A. L.1 aMACHADO, R. G.  tRevista Ceres, Vi??osa, MGgv. 70, n. 6, p. 1-8, 2023.