You have probably noticed it covering the surface of a dam as you drive by. It’s often a pinkish colour, but can be green when shaded from direct sunlight. It can grow so thickly and cover the water so completely, that you might be tempted to walk upon it!
We are talking about an aquatic fern, Azolla filiculoides. It floats on the surface, with its roots hanging down into the water about 4-5 cm.
It is native to all countries around the Pacific rim, including Tasmania, with several different species of it flourishing, depending primarily on the climate and temperatures. Azolla has become prominent in rice-growing areas because it can help as a natural fertiliser.
At TEVA we are well aware of this plant’s benefits. It is able to “fix” nitrogen from the air, rather like legumes (peas and beans, for example), but Azolla is 3 times more efficient than the legumes in doing this. Azolla also takes up nitrogen from the water of the dam, at the same time as removing phosphates which are dissolved in the water. So, as well as producing an excellent slow-release fertiliser, the Azolla can help to prevent pollution and eutrification - damaging the ecosystem with excess nutrients.
Deb, Dave and Alan (who wrote this article) recently harvested Azolla from one of our dams at TEVA and placed it on garden beds, helping to rejuvenate our sandy soil.
For more information on Azolla, visit the website: www.azollafoundation.org
How long does azolla live before it dies off.