Degree Type
Dissertation
Date of Award
1986
Degree Name
Doctor of Philosophy
Department
Agronomy
Abstract
Field and greenhouse studies investigated microbiological interactions in Iowa soybean (Glycine max) rhizospheres. The effects of P fertilization on mycorrhizal development and rhizobial nodule occupancy were evaluated in a 2-year field study, and follow-up greenhouse experiments evaluated rhizobial strain competition. As expected, P fertilization significantly decreased mycorrhizal infection. Unexpectedly, there was also a significant decrease in nodule occupancy of Bradyrhizobium japonicum 123;Rhizosphere microbial populations were measured in field-grown soybeans six times over the season. Rhizobia-stimulating isolates were evaluated for effect on B. japonicum 123 nodule occupancy. Two organisms statistically enhanced nodulation, but the results could not be reproduced in nonsterile soil;A preliminary study investigated fluorescent pseudomonad populations and B. japonicum serogroup 135 dominance in a calcareous and noncalcareous soil. Sterilization of the calcareous soil increased recovery of B. japonicum 123 when equal numbers of 123 and 135 were added.
DOI
https://doi.org/10.31274/rtd-180813-6890
Publisher
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Copyright Owner
Patrick M. Hicks
Copyright Date
1986
Language
en
Proquest ID
AAI8703711
File Format
application/pdf
File Size
89 pages
Recommended Citation
Hicks, Patrick M., "Ecology of Bradyrhizobium japonicum in Iowa soybean rhizosphere soil " (1986). Retrospective Theses and Dissertations. 8252.
https://lib.dr.iastate.edu/rtd/8252
