Eutrophication mitigation from runoff is best addressed by which practice?

• A. Buffer strips and riparian zones.
• B. Erosion control and conservation practices.
• C. Integrated pest management and proper pesticide handling.
• D. Drip irrigation adoption.

Answer: (A)

Mitigating eutrophication from runoff relies on stopping nutrient-rich water from reaching streams. Vegetated buffer strips and riparian zones along waterways act as natural filters: the plants, soils, and microbes trap and take up nitrogen and phosphorus carried by runoff, while the dense vegetation slows and redirects flow, promoting infiltration rather than direct discharge into the water. This combination reduces the amount of nutrients entering streams, helping prevent algal blooms and the ensuing oxygen problems that characteristically follow eutrophication.

Other practices help with water quality in related ways, but they’re not as directly focused on nutrient removal from runoff. Erosion control and conservation methods reduce soil loss, which indirectly lowers nutrient losses tied to sediment, but buffers provide a more immediate nutrient-capturing effect along the runoff path. Integrated pest management and proper pesticide handling target chemical contaminants from pesticides rather than nutrients. Drip irrigation can cut water use and leaching, but its primary impact on eutrophication is indirect unless paired with buffers to intercept any remaining nutrient runoff.