Loss of phosphorus (P) from soil may degrade water quality. The problem exists
where soil has been heavily fertilized with P, including use of poultry litter as fertilizer for
pastures on the Coastal Plain. This research proposed that amending a P-enriched soil
with a material that has a relatively high capacity to sorb P would decrease such loss in
runoff or subsurface drainage. The P sorption behavior of two adsorbent materials,
naturally occurring soil ironstone and bauxite refining residue (red mud), was examined
in laboratory studies, with results guiding the design of a greenhouse experiment using
these materials mixed with P-enriched Ruston soil (fine-loamy, siliceous, semiactive,
thermic Typic Paleudults) used to grow common bermudagrass (Cynodon dactylon).
The Langmuir P sorption maxima of ironstone and red mud were about five-times
greater than that of Ruston but sorption was affected by kinetics. Miscible displacement
studies confirmed reduced P mobility in these materials compared to Ruston, and
reduced mobility of P in Ruston when mixed at a 9 to 1 ratio, with red mud being more
effective than ironstone. The greenhouse experiment compared Ruston mixed with the
P adsorbents at 0, 5, 10 and 20% with 4 replicates in a completely randomized design.
Bermudagrass yield was greatest in the red mud treatments but variability among
replicates led to no significant treatment effect in mass of P leached. Decreased
infiltration with red mud led to ponding lasting longer than one day, which therefore
represented potential loss of desorbed soil P in runoff. However, under simulated
rainfall later in the experiment losses of P were numerically least from the red mud
treatments, suggesting that the shorter-term results reflected transient behavior and that
red mud may have potential as a soil amendment to reduce P losses.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-07102017-141359 |
| Date | 26 July 2017 |
| Creators | Smith, Samantha Karyn |
| Contributors | Gaston, Lewis, Wang, Jim Jian, Beasley, Jeffrey |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-07102017-141359/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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