Comparative Study between Silvopastoral and Agroforest Systems on Soil Quality in a Disturbed Native Forest of South-Central Chile

Agroforestry systems (AFSs) have gained recognition as a land use strategy to address food security and climate change. They involve intentionally cultivating trees alongside crops and/or animals. AFSs cover approximately 5% of the global forest area and promote sustainable soil conservation, including soil organic carbon (C) sequestration (C_SEQ). In some areas of Chile, AFSs are used to preserve the ecological value of native forests. This study evaluates the effects of two AFSs, namely, an agroforest for fodder production (A_GROF_RST) and Silvopastoral (SPS), within a degraded native forest (<i>Nothofagus obliqua</i> sp.). The evaluation focuses on their impact on C_SEQ capacity and soil quality (SQ), using soil quality indexes (SQIs) derived from 30 soil quality indicators (SI_NDs) related to physical, chemical, and microbiological properties at two depths (0–5 and 5–20 cm). The results for the total depth analyzed (0–20 cm) indicate an average C_SEQ of 6.88 and 4.83 Mg C yr⁻¹ and a global SQI of 37.8% and 31.0% for A_GROF_RST and SPS, respectively. Among the thirteen SI_NDs that demonstrated significant differences (<i>p</i> < 0.05), five were associated with the considered depths (P⁺, Ca²⁺, S, ECEC, and Al_SAT), three differed between A_GROF_RST and SPS (BD, NH₄⁺, NO₃⁻), while SOC, K⁺, and Mg²⁺ varied across all conditions (e.g., combinations of systems and depths), and β-_GLU and N_MIN differed in a single condition. However, almost all 30 SI_NDs analyzed showed higher values at the 0–5 cm depth, indicating the positive effects of soil organic matter (SOM)/SOC additions. Significant interactions (Pearson’s correlation) revealed that SOC correlated with most SI_NDs (e.g., N, NH₄⁺, P⁺, K⁺, Ca²⁺, Mg²⁺, S, ECEC, N_MIN). These findings suggest that both A_GROF_RST and SPS systems have similar capabilities in restoring the ecological value of native <i>Nothofagus</i> forests while providing conditions for productive and complementary use. This sustainable option offers opportunities for cattle production alongside ecological restoration efforts and provides a possible strategy to generate public policies related to the ecosystem services of agroforestry systems.