Understanding Bacteria in Soil to Develop Intelligent NanoFertilizers
Funded through the Biological Greenhouse Gas (GHG) Management Program in 2014, this project used genomics to determine the dynamics of the soil bacterial populations in the rhizospheres of wheat and canola. The rhizosphere is the portion of soil found adjacent to the roots of living plants and is subject to the influence of chemicals excreted by the roots of living plants and the microbial community. These microbes control the soil nitrogen cycling processes and crops‘ nitrogen uptake, which ultimately impacts the efficiency and usage of fertilizers. The project was completed in 2016, and the information gathered will help develop Intelligent NanoFertilizers (INF) designed to increase nitrogen use efficiency by crops.
Around 25 to 50 per cent of the fertilizer-nitrogen applied to crops is lost before plants take it up and is released as nitrous oxide emissions, which is a greenhouse gas. An ideal approach to prevent nitrogen losses and nitrous oxide emissions in crop production is to develop INFs, in which the fertilizer release is synchronized with the demand by the plant, dependent upon its stage and rate of growth. However, plant growth is a very complex process, and there are several scientific and technological challenges to producing and using adequate INFs. These challenges include understanding the interactions between chemical signals, crop nitrogen uptake, and the dynamics of soil nitrogen cycling controlled by rhizosphere soil microorganisms. Given that, the main goal of the project was to understand the temporal dynamics of rhizosphere soil bacterial populations during the growing season of canola and wheat. This understanding helps to identify the bacterial populations associated with soil nitrogen cycling processes, informing the design of targeted INF that would improve fertilizer uptake for these crops. The successful development, commercialization and adoption of novel INF, at the farm level, has the potential to increase nitrogen use efficiency by crops by at least another 30 to 50 per cent, thereby reducing GHG emissions and lowering fertilizer costs for farmers.
Specific Bacteria Affect Nitrogen Uptake
The researchers found the dynamics of nitrogen uptake by canola were closely associated with the presence and abundance of specific soil bacterial growth during the crop’s growing season; namely, three specific bacteria – Sphingomonas jaspi, Lysobacter arseniciresistens ZS79 and Luteimonas vadosa – showed a strong correlation with the rate of nitrogen uptake in canola. Conversely, for wheat, there was no clear temporal association between the rate of nitrogen uptake and the number of soil bacterial accessions in the rhizosphere during its growing season. These findings provide insights into the composition and varied dynamics of soil microbial communities in the rhizosphere of canola and wheat, as well as their interactions with nitrogen cycling processes and crop nitrogen uptake. The results contribute to a better understanding of the role of soil bacteria in nutrient dynamics and can potentially inform strategies for optimizing nutrient management and reducing greenhouse gas emissions in agricultural systems.
What’s next?
Uptake of nano fertilizers is low in Alberta primarily due to the cost. The product has good potential with high value crops including malt barley or sugar beets, however more piloting is needed in these areas. The non-confidential scientific findings of this research were published in peer-reviewed scientific literature. The bacterial genomics knowledge provided a credible basis for the successful long-term commercialization of a new generation of highly efficient INF for delivering macro- and micronutrients in agriculture. Carleton University researchers continue to utilize these findings while developing their Smart Fertilizer prototype, which has been tested in the lab and greenhouses with positive results. Patent applications for this technology have been filed in Canada, the United States and Australia, and the researchers intend to test it in real-life conditions.