Can a Plant Fight Climate Change & Reduce Fertilizer Use?

The Azolla filiculoides fern— with leaves the size of gnats, is considered a wonder-plant that played a pivotal role in cooling our planet 50 million years ago. Among its many properties, the Azolla can capture CO2 and nitrogen from the air and has genes that provide insect resistance.

Some 50 million years ago, however, the planet was a much hotter place and Azolla grew as far north as the Arctic Ocean. Fossil records show that, fueled by abundant nitrogen and carbon dioxide, the fern formed thick mats across the entire ocean and crept onto the surrounding continents. Over the course of 1 million years, the plant pulled an estimated tens of trillions of tons of CO2 from the atmosphere, which scientists believe helped cool the planet to a climate more similar to what Earth has today.

Azolla filiculoides is a water fern and has been used as "green manure" in rice paddies in Asia for well over 1,000 years because of its symbiotic relationship with the cyanobacteria Nostoc azollae. The fern and the bacteria work together to capture nitrogen from the air and convert it into something the fern and other surrounded plants can use. This eliminates the need for nitrogen-added fertilizers.
Scientists are hopeful that they will be able to use genomes from the natural bio fertilizer of the plant to help lead to future sustainable agricultural practices.

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Fertilizers as Water Pollutants

Article Credit: wisconsinlakes.org

Fertilizers, leaves, grass clippings, eroded soil, and animal waste are all sources of nutrients, including phosphorus. Phosphorus is main nutrient that drives eutrophication (premature aging) in most lakes. Relatively small amounts of phosphorus can cause water quality declines. A concentration of 25 parts per billion of phosphorus in water can promote excessive algae growth in lakes.

Phosphorus—an essential nutrient for plant growth—is a common ingredient in many lawn and garden fertilizers. However, the same phosphorus that helps keep lawns green is also the primary nutrient that turns lakes green with algae. Algae blooms can turn lakes into a thick, smelly green soup that is undesirable for swimming and other recreation. Too much algae clouds water and blocks sunlight from reaching aquatic plants; it also lowers the oxygen levels in the water which can cause fish kills.

Soil can retain only so much phosphorus and plants cannot absorb more phosphorus than they can use. Spreading manure and other fertilizers on lake watershed soils already saturated with phosphorus contributes to chronic nutrient loading, as nutrients can run directly into the lake and/or leach into our lakes from groundwater for years.

Excess algae and aquatic plant growth caused by an over-abundance of nutrients can impact boating and other water recreation and increase lake management costs for lake groups.

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