This study aimed to evaluate the performance of an innovative pulp mill sludge-based organomineral fertilizer (OrgM) in comparison with a conventional mineral fertilizer (Min). We also assessed its combination with a controlled-release fertilizer (CRF) and potassium sulfate (K). A greenhouse trial was conducted in 50 L pots, utilizing three fertilization treatments (Min, OrgM, and OrgM+CRF+K), to evaluate their effects on the early growth of Eucalyptus globulus and nutrients leaching.
The highest plant growth was obtained with OrgM, compared to mineral fertilization (Min). After five months, total plant biomass was 662.5 g/plant and 439.6 g/plant in the "OrgM" and "Min" treatments, respectively. This trend was consistent across the other growth parameters measured. During the same period, the "Min" treatment caused the greatest loss of nutrients through leaching (5 g N, 2.2 g P, and 3.3 g K/pot), which was significantly higher than that observed in the "OrgM" treatment (0.61 g N, 0.10 g P, and 0.54 g K/pot). The combination of OrgM with CRF and K had no relevant effect. Results show that the nutrients in the pulp mill sludge-based organomineral fertilizers were used more efficiently, resulting in greater growth of Eucalyptus globulus.