02363naa a2200313 a 450000100080000000500110000800800410001910000200006024501250008026000090020530000100021452014030022465000200162765000200164765000150166765000190168265000230170165300470172465300180177165300480178965300260183770000200186370000230188370000250190670000230193170000180195470000200197277300570199220611402017-01-18       2016    bl uuuu     u00u1 u    #d1 aVERAS, M. de S.  aCover crops and nitrogen fertilization effects on nitrogen soil fractions under corn cultivation in a no-tillage system.  c2016  a12 p.  aABSTRACT: The use of cover crops has recently increased and represents an essential practice for the sustainability of no-tillage systems in the Cerrado region. However, there is little information on the effects of nitrogen fertilization and cover crop use on nitrogen soil fractions. This study assessed changes in the N forms in soil cropped to cover crops prior to corn growing. The experiment consisted of a randomized complete block design arranged in split-plots with three replications. Cover crops were tested in the plots, and the N topdressing fertilization was assessed in the subplots. The following cover species were planted in succession to corn for eight years: Urochloa ruziziensis, Canavalia brasiliensis M. ex Benth, Cajanus cajan (L.) Millsp, and Sorghum bicolor (L.) Moench. After corn harvesting, the soil was sampled at depths of 0.00-0.10 and 0.10-0.20 m. The cover crops showed different effects at different soil depths. The soil cultivated with U. ruziziensis showed higher contents of total-N and particulate-N than the soil cultivated with C. cajan. Particulate-N was the most sensitive to changes in the soil management among the fractions of N assessed. The soil under N topdressing showed a lower content of available-N in the 0.10-0.20 m layer, which may be caused by the season in which the sampling was conducted or the greater uptake of the available-N by corn.  aplant nutrition  asoil management  aAdubação  aManejo do solo  aNutrição vegetal  aAdubação e nutrição de culturas anuais  aCultura anual  aFertilization and nutrition of annual crops  aNutrição de plantas1 aRAMOS, M. L. G.1 aOLIVEIRA, D. N. S.1 aFIGUEIREDO, C. C. de1 aCARVALHO, A. M. de1 aPULROLNIK, K.1 aSOUZA, K. W. de  tRevista Brasileira de Ciência do Sologv. 40, 2016.