Abstract Detail

Agronomy

Sanders, Don [1], Lawley, Yvonne [1], Gulden, Robert H. [2], Tenuta, Mario [3].

Moving beyond the wheat canola rotation: The effect of crop sequence on soybean grain yield, mycorrhizal colonization, and N fixation by bradyrhizobium. D. Sanders, Y. Lawley, R. Gulden, M. Tenuta.

Manitoba has seen a twenty-fold increase in soybean acres seeded since 2000, with over a million acres seeded in 2013. This change presents unique opportunities and challenges to improve crop rotations in Manitoba. This experiment studied the effect of four crop sequences on soybean yield, mycorrhizal colonization, and N fixation by bradyrhizobium bacteria. In the first year of this experiment wheat, canola, corn and soybeans were grown at three sites in Manitoba (Carman, Portage la Prairie and Kelburn). In the second year soybeans were grown on these same plots as a test crop. This two year sequence of crops was repeated twice in 2012-13 and 2013-14. To determine mycorrhizal colonization root samples were collected at the V3 stage and then analyzed microscopically for mycorrhizal infection. Nitrogen fixation was estimated using the natural abundance method using soybeans collected at the R5 and R6 stage and a canola reference crop. Results from the 2013 soybean test crop indicate that crop sequence had an impact on soybean yield with the soybean-soybean rotation having the highest yield. There were no significant differences in yield between the other three rotations in 2013. Yield results from 2014 indicate that a soybean-soybean rotation yielded significantly lower at one site, while there were no differences between rotations at two other sites. There were significant differences in levels of mycorrhizal colonization and biological nitrogen fixation between crop rotations. Results from 2013 indicate that a soybean-soybean rotation results in significantly higher mycorrhizal colonization and biological nitrogen fixation than other rotations. In summary, results from the first year of the study indicate that a soybean-soybean rotation results in higher mycorrhizal colonization and biological nitrogen fixation, however there may be a detrimental impact in yield compared to other rotations.

1 - University of Manitoba, Plant Science, 222 Agriculture Building, 66 Dafoe Road, Winnipeg, MB, R3T 2N2, Canada
2 - Univeristy of Manitoba, Plant Science, 222 Ag Building, 66 Dafoe Road, Winnipeg, MB, R3T 2N2, Canada
3 - University of Manitoba, Soil Science, 222 Agriculture Building, 66 Dafoe Road, Winnipeg, MB, R3T 2N2, Canada

Keywords:
crop rotation
yield
Soybean
arbuscular mycorrhizal fungi
N fixation
agronomy.

Presentation Type: Oral Paper:Papers for Topics
Session: 62
Location: Salon 8/The Shaw Conference Centre
Date: Wednesday, July 29th, 2015
Time: 8:45 AM
Number: 62003
Abstract ID:1115
Candidate for Awards:CSA Graduate Student Competition for Best Paper Presentation