Nutrient pollution can occur even without applying manure or fertilizer during winter. Nutrients from earlier applications often remain near the surface if they weren’t fully absorbed before the ground froze.
When snow melts or rain falls on frozen or saturated soil, the resulting runoff can pick up these leftover nutrients and carry them into nearby waterways. Manure storage structures, uncovered piles, and compacted areas around livestock facilities can also release nutrients if they leak or wash off during thaw events. Even natural soil nutrients can be mobilized when freeze–thaw cycles disturb the surface.
