Date of Award:
Master of Science (MS)
Plants, Soils, and Climate
John O. Evans
Some of the factors influencing the performance of bromoxynil, 4(2,4-DB), or a companion crop for weed control in seedling alfalfa were studied in the greenhouse and at field locations in Farmington and Logan , Utah. The effect of application rate , stage of growth, temperature, and soil moisture on the phytotoxicity of bromoxynil and 4(2,4-DB) to alfalfa and weeds were studied.
Alfalfa yields were increased by 4(2,4-DB) at all rates and stages of application. All rates and stages of bromoxynil treatment except the one-fourth pound per acre three to four trifoliate application resulted in alfalfa yields below that of the control.
The use of a companion crop was not conducive to the growth and development of alfalfa although it did control the weeds . Bromoxynil at all rates and at both stages of application resulted in effective mustard control. Mustard control in the 4(2,4- DB) plots was excellent at the early stage of application but required three- fourths pound per acre for control at the later stage of weed growth . Pigweed control was rather ineffective in bromoxynil plots at Logan where moisture was optimum, but effective in plots at farmington where moisture was limited for 18-20 days following application. The density of the pigweed stand in bromoxynil treatments at Logan was attributed to an influx of weed growth following initial control of weeds . Control of pigweed by 4(2 , 4- DB) was in excess of 90 percent at the four to five leaf stage of weed growth.
Leavitt, Ferrin D., "Factors Influencing the Performance of Bromoxynil 4(2,4-DB), or a Companion Crop for Weed Control in Seedling Alfalfa" (1970). All Graduate Theses and Dissertations. 2928.
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