Dredged lake sediment could nourish new crops

Every year, farmers fertilize their crops with nitrogen and phosphorus to ensure a good harvest. And every year some of that fertilizer inevitably makes its way into ponds and lakes, where it can trigger ecosystem-wrecking algal blooms. According to a new study published last month in Science of the Total Environment , though, there may be a relatively simple way to close the loop on this leaky system: using the nutrient-rich lake sediments as fertilizer . “We’d be wise as a society to recycle these nutrients,” says University of Illinois Urbana-Champaign soil scientist Andrew Margenot, who was not involved in the research. “There’s no silver bullet, but there’s lots of tiny little solutions. And this is one of them.” When excess nutrients from agricultural runoff build up in waterways, it can cause algal growth to explode in a process called eutrophication. After the algae die and decompose, carbon dioxide emissions soar and oxygen is sucked up, killing fish and other marine life. For decades, environmental managers have worked to restore lakes and improve water quality by dredging up the decaying organic matter in the sediments and often dumping it nearby or in landfills. Priit Tammeorg and Olga Tammeorg, researchers at the University of Helsinki who specialize in fertilizer recycling and phosphorus dynamics, decided to try something different with a small shallow lake called Mustijärv in Estonia. In 2017, they recruited ...
Source: ScienceNOW - Category: Science Source Type: news