Luis Longeri S.1 y AMonso Herrera O.2

The effect of seed inoculation on yield of the soybean, var. Amsoy, was studied in a field experimento Yield of inoculated plants was compared to that of non-inoculated controls, and to non-inoculated plants grown under two different levels of nitrogen fertilization. Grain yield as well as grain protein and oil content were determined.
Nodulation was never observed among non-inoculated plants. Lack of nodulation indicated the absence of indigenous soybean rhizobia in the soil where the experiment was conducted.
Among the inoculated plants, grain yield, protein and oil production content increased in 225.7-204.6 and 164,9%, respectively, when compared to control plants.
No increase in yield was obtained under a fertilization of 38.1 unit of nitrogen per hectare. At a level of 76.2 units, grain production was increased in 12.4%. Fertilization with sodium nitrate or urea gave similar result. It was calculated that 167.2 kilograms per hectare of atmospheric nitrogen were fixed as a consecuence of the symbiotic process.
A highly significant negative correlation was found between protein and oil contents of soybean grains.

1Ing. Agr., Profesor Titular del Departamento de Microbiología, Instituto de Ciencias Médico-Biológicas, Universidad de Concepción. Casilla 272, Concepción, Chile.
2Ing. Agr., Instructor del Departamento de Fitotecnia, Escuela de Agronomía, Universidad de Concepción. Casilla 537, Chíllán, Chile.