This research was carried out in Santa Maria/RS during the 2004/2005 crop season to evaluate the influence of salts and water pH on different sources of spray suppliers (mineral water, dam water and artesian well water) on imazethapyr (75 g L-1) + imazapic (25 g L-1) efficiency in red rice control. Thus, water under original condition and acidified water with citric acid to pH 4,5 have been used to prepare the herbicide solutions. It has been verified that the treated plots with water at pH 4,5 showed better action of imazethapyr (75 g L-1) + imazapic (25 g L-1) in the red rice control than alkaline water with pH 9,4 and 8,7. All the treatments with herbicide presented intoxication in the rice. Nevertheless, the treatments with alkaline water showed a fast recuperation in rice plants (IRGA 422CL).
red rice; control; water hardness; Oryza sativa
