Date of this Version
Thesis (M.S.)--University of Nebraska--Lincoln, 1956. Department of Agronomy.
Nebraska has approximately 750,000 acres infested with perennial weeds. The development of a chemical control measure to help prevent the spread of and eliminate these perennial weeds would be of inestimable value to the farmers of this state. The results reported in this study were obtained from an experiment designed to determine under field conditions the rapidity of breakdown of high rates of 2,4-D, with and without boron additions, applied to the soil at four intervals before planting a crop.
The rapidity of breakdown of three herbicides applied to the soil at four intervals before planting a crop was studied. The activity of the herbicides in the soil was determined by the effect on stand, degree of stunting, height, and yield of corn. Studies to determine the necessary time lapse between the time of chemical application and safe planting date were conducted. Soil temperatures at three depths were recorded in an attempt to establish a relationship between breakdown of herbicides, soil temperatures, and biological activity. The herbicides varied greatly in their rate of inactivation. 2,4-D sodium salt at 40 1b/A plus boron trioxide at 340 1b/a was the most persistent, followed by 2,4-D amine salt at 40 lb/A plus boron trioxide at 48 1b/A and 2,4-D amine salt at 40 1b/A.
Advisor: Neal E. Shafer.