LEED AP with Operations and Maintenance (O+M ) Practice Exam

What primarily reduces soil's ability to support plant life and maintain biodiversity?

1. Loss of organic material

2. Excessive pesticide use

3. Loss of topsoil

4. Improper irrigation

The correct answer is: Loss of topsoil

The reduction of soil's ability to support plant life and maintain biodiversity is significantly impacted by the loss of topsoil. Topsoil is the uppermost layer of soil, rich in organic matter and nutrients, which is crucial for plant growth. It serves as the primary medium for root development and provides essential minerals and nutrients to support a wide variety of plant species. When topsoil is lost due to erosion, compaction, or improper land management practices, it depletes the soil's fertility and alters its structure, making it less hospitable to plants. Without this vital layer, the soil is less capable of retaining water and nutrients, directly impacting plant health and reducing biodiversity. Plants that are essential for supporting various ecosystems, including insects and microorganisms, struggle to thrive without an adequate supply of nutrient-rich topsoil. While loss of organic material, excessive pesticide use, and improper irrigation can also affect soil health and plant life, these factors often have more localized or specific impacts. For instance, loss of organic material primarily affects soil structure, while excessive pesticide use can harm specific populations of beneficial organisms. Improper irrigation may lead to issues such as salinization or waterlogging, but topsoil loss represents a more foundational degradation that severely compromises the overall ecosystem's capacity