In the Fabio Baudrit Experiment Station, Alajuela, Costa Rica from September of 1998 to February of 1999, the effects of stubbles from Ixophorus unisetus, Digitaria spp., Cynodon dactylon and Rottboellia cochinchinensis were evaluated to judge the efficacy of the herbicide pendimetalin, alachlor and imazetapir, Rhizobium nodulation and the growth of bean. It was found that the presence of stubbles on the surface of the soil (4.5 t dry matter/ha) was not effective in reducing the growth of weeds in bean crop under no tillage management. The efficacy of the herbicides pendimetalin, imazetapir and alachlor was not affected by the presence of stubbles on the surface of the soil. The stubbles of Ixophorus unisetus negatively affected the growth and production of bean. Stubbles of Digitaria spp.and Cynodon dactylon had a positive effect on the crop.