Growth and foliar nutrition of a hybrid poplar clone following the application of a mixture of papermill biosolids and lime mud

Abstract

Fertilization of hybrid poplar (HP) plantations with papermill by-products is a promising solution to improve soil fertility and nutrient availability, increase plantation productivity, and provide added value to these materials that would otherwise be incinerated or sent to the landfill. We assessed the growth and foliar nutrition of a HP clone (Populus x. canadensis × P. maximowiczii) at six plantation sites aged three to five years in southern Quebec, Canada. Sites received a fertilization treatment consisting of a mixture of papermill biosolids (120 to 140 t ha-1, depending on site) and lime mud (10 to 15 t ha-1) before being planted, or no fertilization (control). Tree growth was significantly improved by fertilization, with fertilized trees showing a mean annual height increment of 1.3 m (all-site mean; SD = 0.2), compared with 0.5 m (SD = 0.4) for unfertilized trees. Foliar Ca and Mg increased following fertilization and levels met optimal thresholds at all sites, whereas N, P, and K concentrations also increased but nutritional deficiencies remained for these elements at several sites. Our results confirm the benefits of fertilizing hybrid poplars with papermill by-products, but indicate that adjustments in application rates or type of by-products could be made in order to fully satisfy nutritional requirements and thus optimize tree growth.

Opportunities and challenges to improve carbon and greenhouse gas budgets of the forest industry through better management of pulp and paper by-products

“…In forestry, the use of PBs can be particularly significant for carbon sequestration. It has the potential to stimulate tree growth by improving foliar nutrition and, consequently, accelerating carbon capture through photosynthesis (Lteif et al, 2007;Rodriguez et al, 2018;Bilodeau-Gauthier et al, 2022). However, further work is necessary to assess how fertilization with PBs can influence carbon sequestration of forest plantations under different climates, site conditions (e.g., soils), site (mechanical) preparation and weed management.…”

“…With the aim of developing a circular economy and mitigating climate change more efficiently, the pulp and paper industry has been looking at alternatives to landfilling and incineration of PBs. Notably, the industry has been using its biosolids as a soil amendment for silvicultural, agricultural and ecological restoration purposes, as well as for biorefinery products such as wood adhesives and fillers, thermoplastic composites, and sorbent materials (Pervaiz and Sain, 2015;Bilodeau-Gauthier et al, 2022;Chen et al, 2023;Grimond et al, 2023). Recycling of PBs in silviculture could increase carbon sequestration by maximizing tree growth (Bilodeau-Gauthier et al, 2022) and promoting a stable form of carbon in soils (Khlifa et al, 2023), as well as reducing GHG emissions compared to synthetic fertilizers (Chen et al, 2023).…”

“…Notably, the industry has been using its biosolids as a soil amendment for silvicultural, agricultural and ecological restoration purposes, as well as for biorefinery products such as wood adhesives and fillers, thermoplastic composites, and sorbent materials (Pervaiz and Sain, 2015;Bilodeau-Gauthier et al, 2022;Chen et al, 2023;Grimond et al, 2023). Recycling of PBs in silviculture could increase carbon sequestration by maximizing tree growth (Bilodeau-Gauthier et al, 2022) and promoting a stable form of carbon in soils (Khlifa et al, 2023), as well as reducing GHG emissions compared to synthetic fertilizers (Chen et al, 2023). Additionally, it could avoid a significant CO 2 -equivalent flux to the atmosphere associated with the landfilling or incineration of PBs.…”