The assay

was conducted at the Fabio Baudrit Experiment Station of the

University of Costa Rica, located in the San Jose district, in

Alajuela, Costa Rica. The effect of drying the rice stubble

with glyfosate was measured, between June 2000 and

January 2001, in different periods before the direct planting

of the beans; on the control of weeds and the bean yield. The

application of glyfosate on the rice stubble and weeds, before

planting the beans or after planting, but before the

emergence, allowed an adequate ground cover by the stubbles

during the critical competence period of the bean, which

reduced the presence of weeds and achieved high bean yields

without applying other herbicides. When the holding period

was prolonged (30-45 days) after the glyfosate application,

the ground cover was poor due to the advanced decomposing

stage of the stubble. There was a larger presence of weeds

and negative effects on the bean production when the weed

control was not timely.