Restoring Soil Health Through Plant Diversity: Interplanting Schefflera octophylla Enhances Soil Function and Microbial Diversity in Mango Orchards

Mango monoculture cultivation, reliant on chemical fertilizers and pesticides, has led to significant soil degradation and water contamination. As a sustainable alternative, mixed plantations involving diverse plant species have been suggested to improve soil health and mitigate the environmental impacts of monoculture. In this study, we interplanted a native medicinal plant “Schefflera octophylla” in a mango orchard to evaluate its impacts on soil properties, enzyme activities, and microbial communities. After 7 years of interplanting, soil samples were collected from five treatments: CK (sole mango), CKM (median of the control treatment), M (Mango + Schefflera), SOV (Schefflera octophylla rhizosphere) and TM (Median of the mix plantation). Results showed that interplanting with Schefflera octophylla significantly enhanced soil properties, increasing soil moisture, available potassium, organic carbon, ammonium nitrogen, and nitrate nitrogen by 52%, 14%, 51%, 20%, and 90%, respectively, compared to sole mango cultivation (CK). Furthermore, interplanting with Schefflera octophylla significantly improved the activities of soil enzymes, including catalase (30%–50%), acid phosphatase (8%–12%), sucrase (7%–28%) and urease activity (6%–22%) compared to the baseline values in the mango monoculture system (p < 0.05). The mixed plantation enhanced both the species richness and abundance (p < 0.05) based on the Shannon and Chao indices of microbiome. Furthermore, the principle component analysis (PCA) showed significant microbial community shifts among the treatments, further validated by hierarchical clustering and network analysis. Spearman correlation analysis revealed significant relationships between microbial composition and soil properties at both the bacterial and fungal levels. Redundancy analysis (RDA) showed a positive relationship between soil chemical and biochemical properties and the bacterial and fungal communities at the species level. These findings demonstrate that interplanting Schefflera octophylla in mango orchards can significantly enhance soil health and microbial communities, offering a promising and sustainable approach to address the ecological challenges associated with mango monoculture. Future studies are recommended to explore its applicability across various soil types and climatic conditions to support its broader adaptation.