Nitrogen cycling in root associated soils at bolting, flowering and seed pod filling across eight diverse Brassica napus (canola) genotypes

Non-Peer ReviewedNitrogen (N) mineralization and nitrification can be used predict the amount of N that is available to crops. Brassica napus L. (canola) production is N intensive; therefore, to improve and sustain yields, a better understanding of N cycling patterns for fertilization application is needed. The objective of this study is to examine N cycling after urea fertilization at the three major canola growth stages: bolting, flowering and seed pod filling; and how N cycling may differ between diverse canola lines grown in different soil types. Eight diverse B. napus lines were grown on Dark Brown Chernozemic soil and Black Chernozemic soil in Saskatchewan, Canada. Root-associated soils were collected from each line at bolting, flowering and seed pod filling, and this soil was analyzed for potential nitrification and mineralization, as well as soil nitrate and ammonium content. We predict that potential nitrification will be higher during the bolting and flowering stages of canola growth because the urea fertilizer that was applied to the field would have been converted to nitrate-N, which is plant available. We predict that potential mineralization will be higher during flowering and seed pod filling, because the demand for N to make protein-rich seeds is high enough to deplete much of the inorganic fertilizer N. We also predict that both nitrate-N and ammonium-N will decrease over the growing season, with significant differences between the canola lines and the soil environments. Mixed effect analyses and ANOVA will be used to analyze N cycling in the soil in relation to soil type differences, canola line differences, and growth stage differences. By characterizing soil N processes, this research will advance efforts to understand and improve N uptake for B. napus lines

Dynamics of root-associated fungal community of canola genotypes in Saskatchewan soils

Non-Peer Reviewe

The potential of prairie grasses to clean-up hazardous waste sites

Non-Peer Reviewe

Development of plant-bacterial systems for the in situ remediation of halogenated aromatics

Non-Peer Reviewe

Microbial diversity in the rhizosphere of field grown herbicide-tolerant transgenic canola

Non-Peer ReviewedIn Saskatchewan it is becoming a common agricultural practice to include herbicide tolerant transgenic canola (Brassica spp.) varieties in crop rotation. These varieties provide an economic and agronomic benefit to farmers because of their ability to provide superior weed control with the use of a minimal number of herbicides. However, concerns regarding the effects of transgenic plants on soil and rhizosphere microbial communities have been raised. As part of an ongoing three-year field study we assessed the effects of field-grown transgenic canola on soil microbial diversity. Four transgenic and four non-transgenic commercial canola varieties were grown at six field locations across Saskatchewan. The rhizosphere and endophytic microbial communities were characterized through community level physiological profiles (CLPP), fatty acid methyl ester analysis (FAME) and DNA analysis. Results from the first year of our field study indicated that in some cases transgenic canola varieties supported different microbial communities than their non-transgenic counterparts, but in some cases field and soil type significantly influenced these differences. In addition, there were differences among non-transgenic varieties, which implies that microbial communities vary from plant to plant and site to site. Differences between the microbial communities of transgenic and non-transgenic plants may not be due to genetic engineering, but to soil variance