00916naa a2200325 a 450000100080000000500110000800800410001910000180006024500810007826000090015930000150016865000110018365000210019465000250021565000160024065000120025665000100026865000220027865000150030065000230031565000260033865300220036465300110038665300230039765300150042065300220043565300190045765300210047677300930049715447641999-03-04       1998    bl uuuu     u00u1 u    #d1 aSPEHAR, C. R.  aProduction systems in the savannas of Brazilbkey factors to sustainability.  c1998  ap.301-320.  aBrazil  acropping systems  aenvironmental impact  agrain crops  aCerrado  aGrão  aImpacto Ambiental  aProdução  aSistema de Cultivo  aSistema de Produção  aAspecto economico  aBrasil  aEconomic situation  aProduction  aProduction system  aSustainability  aSustentabilidade  tIn: LAL, R., ed. Soil quality and agricultural sustainability. Chelsea: Ann Arbor, 1998.