Date of Award
12-2025
Degree Type
Dissertation
Degree Name
Doctor of Philosophy - Forestry
Department
Forestry
First Advisor
Dr. Brian Oswald
Second Advisor
Dr. Kenneth Farrish
Third Advisor
Dr. Daniel Unger
Fourth Advisor
Dr. Brent Burt
Abstract
There is anecdotal evidence that old-fields with high available soil phosphorus (P) are difficult for the successful establishment of loblolly pine (Pinus taeda L.) plantations, with high mortality of seedlings and atypical tree form. These fields often acquired high P soil concentrations as a result of decades of poultry litter applications. While excessive P has been recognized in horticulture and agronomy research to adversely affect micronutrient uptake in plants causing reduced growth or even mortality, its effects in forestry applications have not been documented, aside from a companion pot study completed by Hannah Bays (2022) in conjunction with this study. This field study evaluated the influence of high soil P on loblolly pine survival, growth, physiological performance, and foliar nutrition. Six P fertilizer treatments (0, 250, 500, 750, 1000, and 1250 mg kg-1 P) were applied in five replicated plots to simulate legacy poultry litter inputs. Seedling survival, height, ground level diameter, chlorophyll fluorescence, chlorophyll content, morphological traits, and foliar nutrient concentrations were measured, and UAV imagery was used to derive NDVI, GNDVI, NDRE, and RECI indices. Seedling mortality increased with higher P application rates, and chlorophyll concentrations declined under conditions of elevated P. Of the spectral indices, NDVI explained the greatest proportion of variation in chlorophyll content, while GNDVI showed the strongest correlation with the measured chlorophyll values because of a more linear relationship between the two. Due to the low explanatory power of each of the iii tested indices, they were poor predictors of chlorophyll concentrations in the loblolly pine seedlings. Potential antagonisms were identified between P and foliar Al, Cu, and Zn based on the foliar analyses. Based on this study, it may be more difficult to successfully establish loblolly pine on old fields with high legacy soil P concentrations.
Repository Citation
Oliver, Brianna, "Effects of Excessive Soil Phosphorus on Pinus taeda L. Nutrient Uptake, Survival, and Growth" (2025). Electronic Theses and Dissertations. 621.
https://scholarworks.sfasu.edu/etds/621
Creative Commons License
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