01977naa a2200313 a 450000100080000000500110000800800410001902400570006010000200011724500690013726000090020652010450021565000190126065000180127965000260129765000290132365000200135265300290137270000160140170000210141770000170143870000220145570000200147770000240149770000200152170000170154170000280155877300770158621187912020-06-16       2019    bl uuuu     u00u1 u    #d7 aDOI: http://dx.doi.org/10.5772/intechopen.902422DOI1 aSILVA, E. F. da  aOrganic nitrogen in agricultural systems.h[electronic resource]  c2019  aThis work summarizes information about organic nitrogen (N) in the agricultural system. The organic N forms in soils have been studied by identifying and quantifying the released organic compounds when soils are acid treated at high temperature, in which the following organic N fractions are obtained: hydrolyzable total N, subdivided into hydrolyzable NH4 +-N, amino sugars-N, amino acids-N, and unidentified-N and acid insoluble N, a fraction that remains associated with soil minerals after acid hydrolysis. Nitrogen mineralization and immobilization are biochemical processes in nature. This chapter summarizes how these processes occur in the agricultural system. Then, soluble organic nitrogen (SON), volatilization and denitrification processes, and biological nitrogen fixation (BNF) as a key component of the nitrogen cycle and how it makes N available to plants are also discussed. Finally, we discuss the use of organic fertilizers as N source to satisfy the worldwide demand for organic foods produced without synthetic inputs.  aMineralization  aOrganic foods  aSoil organic nitrogen  aFixação de Nitrogênio  aMineralização  aFertilização orgânica1 aMELO, M. F.1 aSOMBRA, K. E. S.1 aSILVA, T. S.1 aFRETIAS, D. F. de1 aCOSTA, M. E. da1 aSANTOS, E. P. da S.1 aSILVA, L. F. da1 aSERRA, A. P.1 aNEITZKE, P. R. de M. C.  tIn: RIGOBELO, E. (Ed.). Nitrogen Fixation. London, UK: IntechOpen, 2019.