Question

How does agriculture pollute water?

Answer 1

Agriculture pollutes the water mostly by runoff, but also by drainage and leaching..

Explanation:

Polluting material reaches the ground water by leaching or by mixing with surface water of rivers, lakes and ponds by runoff and drainage.

Agriculture pollutes water by runoff from these agriculture areas:

• barnyards
• feedlots
• cropland

Runoff rinses these polluting elements into the water:

• manure
• fertilizers (nitrogen, potassium, and phosphorous)
• ammonia
• pesticides
• livestock waste
• oil and toxins from farm equipment
• soil and sediment (This runoff also erodes the land)

Here's a video about water pollution you might like to watch:
http://protectingwater.com/agriculture.html

The runoff of excess agricultural fertilizers may cause `"eutrophication"` of ponds and lakes.

Here's a Khan Academy presentation of eutrophication that you might like to see:
https://www.khanacademy.org/science/biology/ecology/biogeochemical-cycles/v/eutrophication-and-dead-zones