What is Runoff?

For many of us that might not be aware of the meaning of Runoff, it would be defined as the movement of wanter and any contaminants across the soil surface. A Runoff occurs when irrigation, rain or snow melt adds water to a surface faster than it can enter the soil. Therefore, water running off the land towards canals,streams,rivers and lakes can also move chemicals, such as pesticides and fertilizers. It is a fact that pesticides may be move with the runoff water if dissolved in the water or adsorbed to eroding soil particles. However, how much a pesticide will move from the area where it was applied depends on a complex interactio of pesticide and soil properties with weather condititons and site characteristics.
The soil mosture content and soil texture are the characteristics which possbily affect the runoff. Other features would be the weather or irrigation,slope and vegetation which takes place. Other factors which play a significant role would be the pesticide characterisctics that affect Runoff. Such as solubility,adsorbency,pesticide persitence,pesticide formulation and pesticide application method.