Location: Soil Management ResearchTitle: Soil inoculations with Anabaena cylindrica improve aggregate stability and nutrient dynamics in an arable soil and exhibit potential for erosion control
|ALVAREZ, ADRIANA - University Of Minnesota|
|GARDNER, ROBERT - University Of Minnesota|
Submitted to: Journal of Applied Phycology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/31/2021
Publication Date: 7/30/2021
Citation: Alvarez, A.L., Weyers, S.L., Johnson, J.M., Gardner, R.D. 2021. Soil inoculations with Anabaena cylindrica improve aggregate stability and nutrient dynamics in an arable soil and exhibit potential for erosion control. Journal of Applied Phycology. 33:3041-3057. https://doi.org/10.1007/s10811-021-02526-9.
Interpretive Summary: Microalgae, such as cyanobacteria, have potential to serve as both biofertilizers and soil structure enhancers, but further understanding of use and impacts are needed. Researchers in Morris, MN, from the University of Minnesota and USDA-ARS determined how soil inoculations with Anabaena cylindrica, a nitrogen-fixing cyanobacteria, influenced soil aggregate stability, erosion resistance, and nutrient delivery. Following soil inoculation with the algae, water stable soil aggregates increased, which reduced soil loss in surface runoff and potential nutrient loss through runoff or drainage. Plant available N and P was also provided through mineralization of algal biomass. These findings suggest agriculture might benefit from microalgae-based biofertilizers and can be used by other researchers and policy makers to further develop and promote microalgae as a biofertilizer.
Technical Abstract: Microalgal biofertilizers are promising for enhancing soil structure and fertility, but further understanding and development are needed. This study evaluated the effects of inoculating an arable soil with the dinitrogen (N2)-fixing cyanobacteria Anabaena cylindrica. In two experiments fresh cyanobacterial biomass was applied to surface soil in pots and incubated under controlled conditions. Experiment 1 showed inoculation increased water stability of macroaggregates (3-5 and 5-9 mm) after 6-weeks, while in Experiment 2, simulated rainfall provided evidence inoculation reduced soil erosion. Soil nutrient content was enhanced in both experiments. Experiment 3 measured mineralization of cyanobacterial biomass into plant available forms of nitrogen (N) and phosphorus (P). These experiments confirm that inoculating soil with cyanobacterial biomass can increase aggregate stability, enhance resilience to water erosion and provide plant nutrients. The study supports the advancement of microalgae-based biofertilizers to promote sustainable and resilient agriculture.