Some Studies of the Herbicidal Control of Four Undesirable Grass Species

This study focuses on the effects of herbicides on varied species of weeds. The experiment used of four general methods of treatment with various concentrations of herbicidal materials, namely, pre-emergence (application of the herbicidal material either as a liquid spray or as a dry powder of dust on the soil surface of the infested area), post-emergence foliage sprays (application of a spray or dust to the vegetative parts of the undesired species), treatment of the seed in the field, and treatment of fully-headed plants. All plots were replicated and randomized wherever a sufficiently large area of infestation permitted. Where experimental areas were small, permitting only a single unreplicated treatment, these tests were considered as exploratory and used mainly as indicators for future experiments. Results of the various treatments were recorded in actual per cents of weeds killed where size of plots permitted accurate stand counts to be made. In the case of the larger experimental units, such as square red plots, the use of a weedy grass index was employed. Overall the results indicated that specific conditions and types of treatments worked best at the removal of the differing species of weeds. This experiment was carried out during the Summer and Fall of 1947. Advisor: Noel S. Hanson