See more from this Session: Microbe, Plant , and Soil Interactions (Includes Graduate Student Poster Competition)
Monday, October 17, 2011
Henry Gonzalez Convention Center, Hall C, Street Level
Canola within a crop rotation is a non-host for mycorrhizal fungi and has been shown to reduce development of arbuscular mycorrhiza in a subsequent mycorrhizal crop. Flax is reported in Manitoba to be strongly associated with mycorrhiza. Significant reduction in mycorrhizal colonization of flax after canola, relative to a previous crop of wheat, has been reported. Reduced growth and reduced early season nutrition for P have also been noted for flax after canola. Presented here are results to determine the amount of additional P fertilizer needed to offset this detrimental effect of canola on flax. For each of three sites in their first year, one plot for each of six replicate blocks was sown to wheat or canola. Samples taken in 2009 and 2010 confirmed the wheat was colonized by mycorrhizal fungi. These sites were sown to flax in 2010 and 2011, respectively. P fertilizer was applied as a side band to flax of 0-45-0 as the split-plot factor at four rates: 0, 10, 25 and 50 kg P ha-1. For the split-split plot factor, mycorrhizal inoculum was applied to flax at two rates: recommended or not applied. A third site was sown to wheat and canola in 2011, with flax planned for 2012. If demonstration is made that P fertilizer can support adequate growth of flax after canola, this would confirm that the mechanism at work in the suppression is P related. Inclusion of a mycorrhizal inoculation treatment in the experimental design provides a test of whether suppression of mycorrhiza for flax by the previous canola crop is the mechanism by which P limitation limits flax growth after canola. Results for the first two years of the three years of flax growth are presented in terms of mycorrhizal colonization, yield, and P nutrition.