Topdressing sand on high-sand rootzones has no effect on microbial activity.

• A. True
• B. False
• C. Sometimes
• D. Never

Answer: (B)

Microbial activity in turf rootzones is driven by moisture, oxygen, temperature, and available organic carbon. Topdressing with sand changes the soil’s physical environment: it can reduce surface crust, improve water infiltration and drainage, and increase air-filled porosity in the rootzone. These changes typically boost oxygen availability and help maintain a more stable moisture level, both of which stimulate microbial processes. Even though the sand itself doesn’t provide nutrients, the improved structure and moisture dynamics often lead to greater microbial activity, especially in a high-sand rootzone prone to drying out or compacting. The exact effect depends on how much sand is applied, how well it’s incorporated, irrigation practices, and the organic matter present, but there is definitely an impact.