Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

Monitoring wild lowbush blueberry (WLB) leaf tissue during the sprout year provides adequate guidelines for fertilizer recommendations. Conventional mineral (MIN) fertilizers and dried poultry manure (organic (ORG)) are environmentally and financially costly to acquire. Pulp and paper mill sludge (PPMS) and synthetic anhydrite (SA) are two industrial by-products that could be used from an industrial ecology perspective to substitute conventional fertilizers due to their local availability and positive agronomic effects. Our study assessed the impacts of conventional MIN, ORG, PPMS, and SA applications on the nutrient leaf status of WLB in the Saguenay-Lac-Saint-Jean region (Québec, Canada). An experimental study was carried out in 2021 on 10-m2 plots that included seven fertilization treatments (MIN, ORG, PPMS, 1SA, 2SA, PPMS+1SA, PPMS+2SA) and control without fertilization. A nitrogen (N) input of 50 kg N ha‑1 was used for N-containing fertilizers. A calcium (Ca) input of 1,558 kg Ca ha‑1 was used for 1SA. Nutrients were monitored in leaf tissue analyses (N, phosphorus (P), potassium (K), Ca, magnesium (Mg), manganese (Mn), sulfur (S), carbon (C), and hydrogen (H)). Compared to the control, 1SA application (no N input) significantly increased N, P, K, and S leaf contents by 17, 40, 68, and 263%, respectively. The PPMS applied on its own had similar effects as ORG fertilization. However, N, P, K, Mn, and S leaf contents increased significantly when PPMS was combined with SA. Compared to SA fertilization on its own, Mn leaf content was lower with PPMS and ORG than other fertilization treatments. Fertilization had no detectable effects on Ca and Mg leaf contents. A combination of different by-products as fertilizers could be a promising alternative to conventional fertilizers, as their use ensures optimal leaf nutrient contents, which could be translated into WLB productivity and improved local circular economy among industries.