02329naa a2200265 a 450000100080000000500110000800800410001902200140006002400350007410000210010924501230013026000090025352015550026265000190181765000220183665000120185865000290187065000160189965000170191565000180193265000090195070000160195970000210197577300670199615678462024-04-24       2004    bl uuuu     u00u1 u    #d  a0178-27627 a10.1007/s00374-004-0739-12DOI1 aMENDES, I. de C.  aEstablishment of Bradyrhizobium japonicum and B. elkanii strains in a Brazilian Cerrado oxisol.h[electronic resource]  c2004  aThe competition with established soil populations of Bradyrhizobium able to nodulate soybean has been one of the major constraints to the introduction of more efficient strains in Cerrado soils. The effects of nodulation establisment and persistence of four serologically distinct strains of Bradyrhizobium japonicum (CPAC 15 and CPAC 7, belonging to serogroups USDA 123 and CB 1,809) and B. elkanii (29 W and SEMIA 587, belonging to serogroups 29 W and 587) were examined. These strains were introduced in a dark-red oxisol, without indigenous populations of soybean bradyrhizobia, and were evaluated for 6 years. The experimental design was a completely randomized block with four replicates. In the first year, besides the inoculation treatments, there was also an uninoculated control. In the second year,, the main plots were split into three sub-plots and treatments consisted of an uninoculated control, CPAC 7 and CPAC 15. In the third year, the entire area was inoculated with CPAC 7. In the fourth and sixth years, the plots were planted with soybean without inoculation, and in the fifth year the plots were left fallow. The strains introduced in the first year influenced nodule occupancy by strain CPAC 7 until the third sucessive growing season. By the forth sixth years, as a consequence of dispersal of strains serologically related to serocluster 123 in the entire experimental area, this serogroup dominated the nodulation, occurring, on average, in more than 50% of the nodules of the treatments where it had never been inoculated.  aBradyrhizobium  aNitrogen fixation  aCerrado  aFixação de Nitrogênio  aGlycine Max  aInoculação  aMicrobiologia  aSoja1 aHUNGRIA, M.1 aVARGAS, M. A. T.  tBiology and Fertility of Soils, Berlingv. 40, p. 28-35, 2004.