Short rotation woody crops have gained global interest as an alternative energy source to fossil fuels. The availability of this resource is, however, dependent on successful research trials and the identification and quantification of the environmental controls on rapid growth. Knowledge of willow root dynamics is required to determine belowground and aboveground growth relationships, and to provide valuable inputs for the development of a willow carbon model. The objectives of this study were to 1) determine fine root turnover, biomass, and productivity of six willow clones over two growing seasons at four locations in Saskatchewan using the minirhizotron method; 2) determine fine root biomass and fine root carbon sequestration of six willow clones over one growing season at four locations in Saskatchewan using the soil coring method; and 3) determine lateral coarse root structure of six willow clones at two locations in Saskatchewan.<p>
Monthly fine root biomass and production was estimated for six willow clones in Saskatoon, Saskatchewan using repeated minirhizotron observations from May to September of 2008 and 2009. Fine root biomass increased from 0.78 Mg ha-1 in May 2008 to 25.75 Mg ha-1 in September 2009. Significant differences were seen between months throughout each growing season, but not between the clones. Mean monthly productivity reached its peak of 8.00 Mg ha-1 in July 2009. Mean turnover for all the clones was 0.96 yr-1 and mean longevity was 1.04 yr-1. The high fine root biomass estimates determined by the minirhizotron method in Saskatoon suggest that this method is not suitable for use in a Vertisolic soil. There was no significant effect of clone on fine root productivity, biomass, turnover or longevity (P < 0.05).<p>
Fine root biomass estimates from the soil cores were lower than those from the minirhizotron method. The mean fine root biomass value in Saskatoon for September 2008 was 0.298 Mg ha-1. Mean fine root biomass at each site from September 2007 to September 2008 ranged from 0.022 Mg ha-1 to 0.915 Mg ha-1. Mean root carbon content ranged from 0.010 to 0.426 Mg C ha-1. Fine root biomass and root carbon content were significantly different between each site, with the exception of Saskatoon and Estevan (P < 0.05). Differences in fine root estimates between the sites are suggested to be a function of the soil texture and moisture accessibility at each site. This research indicates that willow roots in Saskatchewan find initial establishment difficult in low moisture, fine textured soils. Also, approximately 44.6 % of fine root biomass is comprised of C, and decomposes to form soil organic matter. Therefore, fine roots have potential to store substantial amounts of carbon if growing conditions are suitable.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-07262010-122132 |
| Date | 09 August 2010 |
| Creators | Stadnyk, Christine Noelle |
| Contributors | Bedard-Haughn, Angela, Kort, John, Van Rees, Ken, Anderson, Darwin |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-07262010-122132/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto 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 University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, 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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