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

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