Algal Biofertilizer to Improve Soil Health

Problem: To meet the growing global food demands, agriculture needs to increase productivity. However, growth of traditional farming practices degrade overall soil fertility, which leads to over application of fertilizers and the subsequent leaching and runoff of excess nutrients into groundwater and surface water bodies. With the predominant use of synthetic fertilizers, researchers observe elevated levels of nitrogen (N), phosphorus (P), and carbon dioxide (CO2) in agricultural runoff. This is a direct contributor to poor water quality, and often causes eutrophication of surface water bodies across Minnesota. Eutrophication removes oxygen from the water which promotes the growth of unwanted and often toxic algal growth. These algae are detrimental to the surrounding ecosystem and potentially harmful to humans.

Solution: Sustainable agricultural practices have emerged as a set of tools for farmers, to help them better manage aspects like soil fertility, erosion control, water quality, and nutrient cycling. The Gardner lab has early results indicating that the use of microalgae (single-cellular) as a component in natural bio-based fertilizer improves soil fertility, while also replacing the need for synthetic fertilizers. This lab-based study reports that traditional synthetic urea fertilizer harms soil microorganisms while algal biofertilizer enhances soil health in multiple ways. Unlike synthetic fertilizers, algae supply organic matter and favor soil microbial dynamics. Algae stabilize soil particles and structure, thereby reducing erosion rates, and they release organic nutrients at a slower rate than synthetic fertilizers. This results in longer nutrient availability for crops and less nutrient loss to runoff. And lastly, the remaining live algae capture atmospheric N2 and CO2 in the soil surface, offering a natural nitrogen input and carbon capture potential.

Impact: Many aspects of this proactive approach for improving soil health offer beneficial outcomes for arable MN soils compared to traditional farming techniques. The use of algal biofertilizer as a replacement of synthetic urea fertilizer can contribute to long-term soil fertility and lower carbon emissions from crop production by reducing synthetic fertilizer demand. Stabilizing soil particles is also critical for reducing erosion and nutrient runoff rates, which should result in lower nutrient levels in waterways that receive agricultural runoff.
** MnDRIVE regrets to report that Dr. Gardner passed away in October 2019.