Resumen:
The main objectives o f this paper were to study the effects o f tillage soil in the soybean yields to for two types o f soils .
The tillage treatments were:
1. plowing and two tanden disking; 2. two tanden disking; 3. one rotary tillage and 4. no-tillage system.
The sta tistic analysis did not show any affect o f the tillage treatment on the grain yields for the two types o f soils
studied.