Sewage Sludge could make great Sustainable Fertilizer
As technological improvements increased the phosphorus content of sewage sludge, it now is a readily available alternative to commercial fertilizers in agriculture. To assess its effectiveness, Andry Andriamananjara from the University of Antananarivo (Madagascar) and his colleagues used a phosphorus radiotracer technique to measure the availability of phosphorus for plants in thermally conditioned sewage sludge.
They grew ryegrass in pots filled with soil that underwent isotopic P-labelling, and added either no fertilizer, thermally conditioned sewage sludge as fertilizer, or commercial triple superphosphate fertilizer. Shoot and roots were harvested at fixed intervals, and their radioactivity was analyzed to measure phosphorus uptake.
As expected, fertilizer application increased shoot biomass significantly over the harvest time, while only a trend towards an increase in root biomass was found. The addition of fertilizer increased phosphorus uptake by the plants. This wasn't only because the fertilizer offered an additional phosphorus source, but also because the plants increased their soil exploitation. https://adalidda.net/posts/aLBvN6cacH2aMq8Tf/sewage-sludge-could-make-great-sustainable-fertilizer