The aim of this work was to evaluate the effects of herbicides and tillage systems used to control weeds, on corn, soybeans and sorghum crops, cultivated in sequence of irrigated rice. These crops were grown in no-till, minimum tillage and conventional systems in Hidromorfic Soil. The best results for these crops in that kinds of soil were achieved with the conventional system. The sorghum crop stood out that objective, when compared to the other two crops. The atrazine herbicide used in sorghum, attained 80% of grasses control, while s-metolachlor (soybean) and atrazine + s-metolachlor (corn) accomplished 70% and 50%, respectively. The maximum technical efficiency ratio for atrazine and smetolachlor herbicides was, respectively 3.85 and 3.26 l/ha (c.p.), no matter the tillage system used. There were interactions with ratios and tillage systems when atrazine + smetolachlor was used (corn). The maximum technical efficiency ratio to that herbicide on minimum tillage was 5.7 l/ha (c.p.), on no-till was 3.9 l/ha (c.p.) and on conventional system was 3.65 l/ha (c.p.).