Disponibilidade de micronutrientes em solos submetidos a diferentes manejos no semiárido

Abstract

Soil micronutrient availability is a key factor for plant productivity, particularly in semi-arid regions where soils often exhibit chemical limitations due to degradation and intensive land use. Land use for reforestation may favor the availability of micronutrients, bringing it closer to that observed in native forest areas, depending on management practices and time. This study evaluated the contents of copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), and boron (B) in soils under different land uses (eucalyptus plantation, native forest, and degraded area), within two soil classes: Argissolo Vermelho-Amarelo and Neossolo Quartzarênico, in Acaraú, Ceará, Brazil. A 3 × 5 factorial design was adopted (three land uses × five depths: 0–5, 5–10, 10–30, 30–50, and 50–70 cm), with four replicates. Evaluations were carried out in 2022 and 2023. Micronutrient analyses were performed by atomic absorption spectrometry after Mehlich-1 extraction, except for boron, which was extracted with KCl. Data were subjected to tests for normality and homogeneity, followed by mathematical transformations and ANOVA. Results showed that eucalyptus cultivation promoted greater availability of Cu, Mn, and B compared to the degraded area, while Zn contents were higher in the native forest. Micronutrient availability was greater in surface layers, especially for Zn and Mn, with a decreasing trend between the evaluated years. It is concluded that eucalyptus land use contributes to the partial recovery of soil fertility in degraded environments, approaching the condition of native vegetation for some micronutrients.