Runoff in agricultural water management is

• A. Airborne dust
• B. Evaporation from manure
• C. Soil erosion
• D. Water carrying waste into the environment

Answer: (D)

Runoff is the movement of water that flows over the land surface and carries with it waste and other pollutants into the environment. This is exactly what the option describes—water that picks up manure, fertilizers, and other contaminants from agricultural fields and transports them into rivers, lakes, or streams. It happens when rainfall or irrigation volumes exceed the soil’s ability to infiltrate, so surface water runs off rather than soaking in. In livestock settings, this means manure and nutrients can be washed from paddocks or manure-handling areas into water bodies, harming water quality and potentially causing eutrophication or pathogen issues. While evaporation and soil erosion relate to water and soil processes, the defining feature of runoff is the transport of waste-laden water into the environment. Reducing runoff involves practices like buffer strips, cover crops, proper manure management, contour farming, and retention basins.