The subject of weeds continues to interest the farmers of the state, as much, perhaps, as any problem connected with the farm. An abundance of weeds in a crop seriously interferes with production, not only by shading and crowding the agricultural crop, but by removing useful and necessary constituents from the soil. We receive annually many inquiries from farmers who desire information about the character of weeds, and the best methods of dealing with them. The results of some experiments conducted by the Botanical Section to determine the value of several means of weed extermination are presented in this bulletin. W e are indebted to Professor J. B. Davidson for the chapter on spraying machinery. W e are also indebted to, Mr. Lyle Clapper, who had charge of the quack grass experiments on a farm near Ames and who assisted in the experiment of burying seeds in compost.