In 2005 only did statistical analysis indicate a significant cotton density effect with respect to soybean yield. Means separation analysis indicated a lower soybean yield for only the highest cotton density of 5.25 plants /row m-1 when compared to other cotton densities. In 2004 and 2005, statistical analysis indicated no significant cotton interference interval effect on soybean height nor yield in 2004. A significant linear relationship between cotton interference period and soybean yield was observed in 2005. Based on best fit regression equation, a soybean yield reduction for an interference interval of 8 wk would equate to a minimal yield decrease of only 3.3% when calculated from the intercept value.
With respect to cotton height, a linear relationship with soybean density was observed both years in Louisiana but not in North Carolina. Based on results at St. Joseph in 2004, height reductions of 6, 3, 1.2, and 0.6% can be expected following season-long competition with soybean densities of 3.3 plants/row m-1, 1.6 plants/row m-1, 0.7 plants/row m-1, and 0.3 plants/row m-1, respectively. Based on 2005 St. Joseph results, expected height reduction was 0, 10.6, 11.3, and 7% for these respective densities. At North Carolina, there was not a significant height effect was not observed. Based on results at St. Joseph in 2004, seed cotton yield reduction of 30, 15, 6, and 3% can be expected at the respective densities. Based on 2005 Louisiana and North Carolina results, expected yield reduction for these densities were similar at 37, 19, 7, and 4% and 21, 11, 4, and 2% respectively. At St. Joseph in 2004, a significant linear relationship between interference period and cotton height was observed. Soybean interference for 4 and 8 wk would result in an expected cotton height reduction of 3 and 5%, respectively. Based on 2004 results in Louisiana and North Carolina, a seed cotton yield reduction greater than 4% can be expected beginning with 4 wk soybean interference, however, in 2005 in Louisiana a similar yield reduction can be expected beginning at 2 wk.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-04102008-101701 |
| Date | 16 April 2008 |
| Creators | Lee, Donna R |
| Contributors | Donnie K. Miller, James L. Griffin, Alexander M. Stewart, Billy J. Williams |
| 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-04102008-101701/ |
| Rights | unrestricted, 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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