NITROGEN ACQUISITION BY WHEAT, CANOLA, AND SOYBEAN INOCULATED WITH THE N2-FIXING BACTERIUM GLUCONACETOBACTER DIAZOTROPHICUS
Date
2024-01-30
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0009-0001-6783-2392
Type
Thesis
Degree Level
Masters
Abstract
Demands for food and fiber continue to increase, as does the global population. As a consequence, the use of nitrogen (N) fertilizers also is increasing globally. However, as the use of N fertilizer increases, so do concerns about the impacts of N loss to the environment. Efforts to reduce reliance on synthetic N fertilizers involve multiple strategies, including the development of biofertilizers. Capitalizing on microorganisms that fix N is one potential avenue for reducing the need for fertilizer N. There exist in nature many species of soil microorganisms (collectively referred to as diazotrophs) that can fix atmospheric N. One group of diazotrophs, including the species Gluconacetobacter diazotrophicus, are endophytes that invade plant roots and either colonize the spaces between the cells (intercellular) or the cell matrix itself (intracellular). Azotic North America recently began marketing a G. diazotrophicus-based inoculant (Envita™) reported to have beneficial effects including N fixation and yield improvement in crops as diverse as rice, wheat, corn, and soybean. This research aimed to quantify N-fixation in crops important to Saskatchewan producers (e.g., wheat, canola, and soybean) that were inoculated with Envita™. Experiments relied on the use of 15N tracing to verify N-fixation and a new droplet digital polymerase chain reaction (ddPCR) method to verify the presence of G. diazotrophicus in plant tissues of the Envita™-inoculated crops. Different methods of introducing the inoculant to the plants also were evaluated. On average, soybean showed no significant difference between treatments, though a few plants did show evidence of N-fixation. Moreover, while some treatment differences in 15N content were found for wheat and canola when the inoculant was introduced using the root bath application (RBA) method, the inoculation status from the ddPCR was inconsistent and yielded conflicting results. The data suggest that Envita™ has the potential to provide some N through N fixation to wheat, canola, and soybean but that more research is needed to optimize inoculation approaches and to fully understand the conditions necessary for N fixation to take place.
Description
Keywords
GLUCONACETOBACTER DIAZOTROPHICUS, Wheat, Soybean, Canola, Biofertilizer, N fixing bacteria
Citation
Degree
Master of Science (M.Sc.)
Department
Soil Science
Program
Soil Science