00629naa a2200181 a 450000100080000000500110000800800410001910000180006024501160007826000090019465000130020365000230021665000090023965300080024865300080025665300230026477301600028716154931995-06-27       1990    bl ---       0--  u    #d1 aWAGNER, G. H.  aUsing natural abundance of 13C and 15N to examine soil organic matter accumulated during 100 years of cropping.  c1990  aHistoria  aMatéria Orgânica  aSolo  a13C  a15N  aABUNDANCIA NATURAL  tIn: International Symposium on the use of Stable Isotopes in Plant Nutrition, Soil Fertility and Environmental Studies. Vienna, Austria.gv., p.1-10, 1990.