Texas FFA Nursery Landscape Practice Exam

Why is soil around the foundation of a house often more alkaline?

1. Chemicals applied to prevent termites

2. Leaching from the home's paint

3. Leaching from masonry mortar and debris

4. Decaying wood scraps buried during construction

The correct answer is: Leaching from masonry mortar and debris

The reason soil around the foundation of a house is often more alkaline is due to leaching from masonry mortar and debris. When structures are built, various materials are used, including mortar, which is commonly made from cement, lime, and sand. Over time, the substances in the mortar can leach into the surrounding soil. The lime content in the mortar is particularly significant since it is alkaline. This leaching process can raise the pH of the soil near the foundation, making it more alkaline. While other options may have effects on the environment surrounding a house, they do not contribute as directly to the alkalinity of the soil as leaching from masonry materials does. For instance, chemicals applied to prevent termites might not notably alter the pH of the soil unless they have a specific alkaline component. Similarly, leaching from the home’s paint typically involves more organic compounds, which wouldn’t significantly influence soil pH. Decaying wood scraps buried during construction may lead to more acidic conditions due to the breakdown of organic matter rather than contributing to alkalinity. Thus, the influence of masonry materials on soil chemistry is the most relevant factor here.