Root system architecture (RSA) plays a central role in determining how plant species acquire resources, tolerate stress, and interact with neighboring plants. Variation in soil matrices-ranging from texture, structure, compaction, and organic matter content to nutrient and moisture availability-strongly influences RSA development and plasticity. These soil-driven alterations in root architecture directly impact how plants engage in intra and interspecific interactions. For instance, nutrient-rich patches may encourage dense root proliferation, intensifying competition among neighboring species, whereas heterogeneous or low-nutrient soils often promote niche differentiation as species adopt contrasting root placement strategies to minimize overlap. Likewise, soils with high organic matter can enhance microbial associations, which may facilitate positive interactions such as nutrient sharing or stress mitigation between coexisting species. Conversely, compacted or poorly aerated soils may restrict root growth, increase competitive pressure and alter plant community dynamics. This study highlights the current understanding of how diverse soil environments regulate root growth patterns, including branching density, rooting depth, lateral spread, and root hair proliferation, and how these architectural traits modulate belowground interactions between coexisting species. Understanding these dynamic relationships is essential for improving crop performance in multi-species systems, optimizing soil health, and designing resilient agro ecosystems. This synthesis underscores the need for integrated approaches combining soil physics, root phenotyping, and ecological modeling to unravel the complex interplay between RSA and interspecific interactions across varied soil matrices.