| dc.description.abstract | This study investigates the repurposing of pulp and paper mill residuals as soil amendments for agriculture around Thunder Bay, Ontario, Canada. Two pulp and paper mill residuals, wood ash (WA) and pulp and paper mill mixed biosolids (PPMS), were applied to agricultural soils as a liming agent and organic amendment, respectively, to improve soils and plant productivity. To determine the suitability of soils in the area to receive these materials under Ontario’s Nutrient Management Act and O.Reg. 267/03, soils from 17 farms in the Thunder Bay area were collected and analyzed to establish heavy metal and fertility ranges. Soils were then collected from three farms in the area for a greenhouse pot experiment. The pot experiment was designed to compare the effects of adding PPMS and WA separately and in combination with and without the addition of supplementary mineral fertilizers in accordance to O.Reg 267/03, the legislation regulating the land application of these materials in Ontario. The addition of PPMS at recommended rates significantly increased grass yield, soil organic matter (SOM) concentrations, nutrient availability, pH, and soil health scores, demonstrating the benefits that land application of PPMS can offer to area growers. In soils that require a pH adjustment and could benefit from additional organic matter, the results showed applying WA and PPMS together is more beneficial when either are applied alone. Results indicate that the application of WA and PPMS in the ratio of 1:3 (by mass) had the greatest benefit. The benefits observed were immediate but may not be realized in the year of application in the field due to weather constraints that may constrain the solubility of inorganics and the decomposition and solubility of organic materials. | en_US |
