Plant Species Effect on Soil Micronutrients and Aluminum in Secondary Forests at Masako Forest Reserve, Kisangani, Democratic Republic of Congo

Plant species in secondary forests can significantly influence soil nutrients. We assessed how soil micronutrients (B, Fe, Cu, Zn, Mn) and Al were affected by plant species in secondary forests at Masako Forest Reserve. Soil samples were collected in June 2022 and 2023 at three depths: 0–10 cm, 10-20 and 20-30 cm along five plant species. A com-pletely randomized design was used with 3 soil depths (SD) x 5 plant species (PS) replicated 4 times. Soil samples were air-dried, sieved 2 mm and sent to Brookside Laboratories (OH, USA) for analyses. Results showed that in 2022, Mn (p=0.0014) and Al (p=0.0216) were significantly affected by SD. Mn (18.30 mg/kg) concentrations were higher in 0-10 cm while Al (443.80 mg/kg) was concentrated in 20-30 cm depth. Boron, Fe, Mn, Zn and Al were all significantly affected by PS (p< 0.01). The soil under Musanga cercopoides had the highest concentrations of Mn, Cu (in magnitude), Zn and lowest in Al. Boron (0.50 mg/kg) and Fe (215.67 mg/kg) were highest in soils under Tricula Africana. As in 2022, Mn (p=0.0166) was also significantly affected by SD in 2023 with its highest concentration (5.45 mg/kg) in 0-10 cm. As for 2022, the soil under Tricula Africana had significantly higher concentrations of Fe (192.67 mg/kg) and Zinc (27.76 mg/kg). The 0-10 cm layer seems to significantly hold more nutrients as compared to deeper soil layers. Triculia africana seems to play a significant role in micronutrients cycling at Masaka Forest Reserve.