Master of Science (MS)
Plant, Environmental Management and Soil Sciences
Container-grown woody ornamentals require high volumes of water and sufficient nutrients to develop into healthy, high quality plants. The increased awareness of possible contamination of ground and surface water resources from nursery runoff has forced growers to implement higher water use efficiency techniques to maximize fertilizer efficiency and reduce nutrient and irrigation runoff. Components of a large container production system that could affect irrigation volume, substrate nutrition levels and runoff include fertilizer placement, irrigation frequency and irrigation method. Irrigation and fertilization components were evaluated in two experiments to determine which would maximize growth, minimize effluent and reduce the amount of nutrient loss from container substrate. Treatments tested included fertilizer placement (incorporated and topdressed), irrigation frequency [once daily (1x) and three times daily (3x)] and irrigation method (drip rings and spray stakes). In the first experiment, Ulmus parvifolia Jacq. (Chinese elm) trees were grown for a year and new trees were planted the second year. In the second experiment, Lagerstroemia indica x fauriei 'Acoma' ('Acoma' crape myrtle) trees were grown for two consecutive years. Incorporated fertilizer produced higher growth indices and maintained higher substrate nutrient content (N, P and K) in chinese elms compared to topdressed fertilizer. Similar results where found in crape myrtle with the exception of P substrate content, where no significant differences occurred. In the chinese elm experiment, the 3x irrigation treatments resulted in higher growth indices and less effluent compared to 1x irrigation. Conversely, 3x irrigation resulted in higher growth indices but no differences in effluent in the crape myrtle experiment. Spray stake treatments resulted in less effluent in the elm study. Drip ring treatments produced larger growth indices in the crape myrtle study. These results suggest a grower could maximize growth and greatly reduce runoff by incorporating fertilizer, practicing cyclic irrigation methods and using drip rings in a large container production system. These results could be used to improve the nursery best management practices in a container nursery production setting.
Document Availability at the Time of Submission
Release the entire work immediately for access worldwide.
Witcher, Anthony Lynn, "Evaluation of fertilizer and irrigation production systems for large nursery containers" (2003). LSU Master's Theses. 1974.
Edward W. Bush