Surface-applied poultry litter generated using a phytase-amended diet may release less phosphorus (P) to runoff water than does litter from a conventional diet. The release of soluble reactive (SRP) and total dissolved P (TDP) from litter generated under conventional and phytase-amended diets was examined in three studies: 1) batch desorption, 2) flow-through cell, and 3) field micro-plot. In Study 1, samples of litter (10 from conventional, C, and 20 from phytase-amended, A, diets) were extracted with water at litter: water ratios from 1:5 to 1:200. Phosphorus in A litter was significantly less at the 1:10 extraction ratio; however, there was no difference at wider ratios. When desorbed P was plotted against solution concentration, all isotherms were sigmoidal. In Study 2, water was passed uniformly through samples of litter (~ 4 g in 4 cm diameter by 1 cm deep cell) at a flux of 7.5 cm h<sup>-1</sup> for 1.5 h and litter effluent collected in fractions for analysis. Less P was lost from the A than from the C litter, however, less P was recovered than in Study 1. Study 3 compared losses of P from litters A and C in field runoff from 324 cm<sup>2</sup> plots during a series of simulated rainfalls (7.5 cm h<sup>-1</sup> for 1 h each). Although significantly less P was initially lost from the A litter, P losses from the A and C litters tended to converge over the course of Study 3. Thus, whereas there was less TDP in the A than in the C litter, differences in SRP and TDP are small.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-1111103-174600 |
| Date | 14 November 2003 |
| Creators | Foster, Anserd Julius |
| Contributors | Jun Xu, Lee Southern, Lewis Gaston |
| 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-1111103-174600/ |
| Rights | unrestricted, I hereby grant to LSU or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation. |
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