Carbon and Nitrogen Dynamics From Incubated Field Soils Receiving De-Inked and Composted Papermill Biosolids.

Papermill biosolids (PMB) form part of a large organic waste stream in North America which have potential as soil conditioners.  Large variability between different papermill biosolids related to treatment processes, species, and level of post-treatment can make the development of BMP's a difficult task. In this study, increasing rates of de-inked PMB, from a paper recycling facility in Toronto, Ontario, and a composted PMB, from a pulp and paper mill in Nova Scotia, were incubated in fields soils to model carbon and nitrogen mineralization rates over time.  In both studies, a nitrogen fertilizer amendment was added to establish the suitability of these materials as agricultural soil conditioners. Despite differences in composition of the PMBs, carbon mineralization was rapid during the initial two weeks with up to 60% of input carbon being released.  The composted PMB did not require additional nitrogen fertility while the de-inked PMB required some nitrogen fertilizer to offset immobilization.